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Feasibility of TAMDAR: an aircraft-based weather data collection system
ARTICLE IN PRESS
Journal of Air Transport Management 10 (2004) 207–215
Feasibility of TAMDAR: an aircraft-based weather data collection system Paul Kauffmanna,*, Erol Ozana, Yesim Sirelib b
a East Carolina University, 201 Science and Technology Building, Greenville, NC 27858, USA University of North Carolina at Charlotte, 9201 University City Blvd., Charlotte, NC 28223-0001, USA
Abstract The tropospheric airborne meteorological data and reporting (TAMDAR) system is a new meteorological data collection system carried aloft by participating aircraft to gather weather data and relay this information to ground-based receiving stations for distribution into the national system for weather data dissemination. These improved forecasts provide a wide range of societal benefits including enhanced air safety and improved operational efficiency in national air space. This paper presents the results of a TAMDAR system feasibility study that evaluated implementation alternatives, defined the conceptual framework of the business case, estimated related costs and benefits, and combined the results into a comprehensive road map for future system development and implementation. r 2003 Elsevier Ltd. All rights reserved. Keywords: Meteorological data acquisition systems; Value of weather data; Business case; Aviation efficiency and safety
1. Introduction Tropospheric airborne meteorological data and reporting (TAMDAR) is a conceptual weather datagathering system consisting of an instrument sensor suite with a data conversion unit, an air to ground data link with GPS (geographical positioning system) capability, and a ground-based receiving and processing system. Participating aircraft will carry the technology to gather weather data, and relay this information to ground-based receiving stations for distribution into the national weather data dissemination system (Fig. 1). The US Federal Aviation Administration (FAA) and the National Aeronautics and Space Administration (NASA) have concluded that TAMDAR has the potential to improve the accuracy and completeness of weather data and the resulting weather forecasts (Kauffmann and Ozan, 2001). In turn, these improved forecasts enhance aviation safety, improve operation of the National Airspace System (NAS) and provide additional economic benefits.
*Corresponding author. Tel.: +1-252-328-9645; fax: +1-252-3281618. E-mail addresses: [email protected] (P. Kauffmann), [email protected] (E. Ozan), [email protected] (Y. Sireli). 0969-6997/$ - see front matter r 2003 Elsevier Ltd. All rights reserved. doi:10.1016/j.jairtraman.2003.11.001
There are many questions related to the feasibility of a conceptual technology such as TAMDAR. For example, it may operate as a completely government operated system, a public/private partnership, or a for-profit enterprise. From the viewpoint of the funding entity, TAMDAR must provide benefits that exceed its costs. Relative to cost–benefit, it is not clear that TAMDAR can compete in the market place and establish its usefulness in comparison to currently operating weather data-gathering and reporting systems.
2. ACARS overview This section describes operating features of the Aeronautical Radio, Inc. (ARINC) based system that gathers weather data, with the voluntary participation of six transport carriers. This is done because TAMDAR is viewed as an operational extension of this program. In addition, the growth and evolution of this system provides lessons and guidance for TAMDAR development. ARINC is a $450 million corporation that is owned by a number of United States and international airlines and aircraft operators. Its focus is development and operation of communications and information
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Fig. 1. Basic structure of TAMDAR system.
processing systems and services that support the efficiency, operation, and performance of the aviation and travel industries (Aeronautical Radio Inc, 2001). ARINC’s aircraft communication addressing and reporting system (ACARS) is a data link system, primarily transmitted via VHF radio that allows communication with aircraft during various phases of flight operation (Forecast System Laboratory, 2000). Using the ACARS system, six cooperating transport carriers gather weather data during flight and, route this information to ARINC’s ground system where it is decoded and sent to the Forecast Systems Laboratory (FSL) of the National Weather Service (NWS). Consequently the FSL uses the designation ACARS to describe these automated weather reports from commercial aircraft. Currently, ACARS averages about 80,000 observations/day (90% over the continental US) from more than 500 aircraft (Forecast System Laboratory, 2000). This system has several significant limitations. As a result of the limited number of participants and their flight patterns, there are deficiencies in the temporal and spatial coverage of the ACARS data set (Moninger et al., 2002; Jamison and Moninger, 2001). These gaps are compounded since participants gather the weather data required for their operations and do not coordinate these data-gathering decisions. Consequently, hubs that are frequented by several participants may have excessive data and other geographic areas may be deficient. In addition, data from ACARS is incomplete in its capability to fully support forecast needs. Information on relative humidity, in particular in the troposphere, has great potential to improve forecast accuracy. Unfortunately very few ACARS aircraft are equipped with humidity sensors and this is not likely to change in the future due to the cost of instruments for transport
aircraft. Furthermore, these transport aircraft typically cruise at less desirable higher elevations and are often scheduled for major airports where data is plentiful. Even without humidity data and with the limitations of high cruise elevations, the positive impact of ACARS data on short-term forecasts is well documented. For example, Mamrosh et al. (2001) studied the use of ACARS data at twenty weather service forecast offices and found a number of aviation related improvements such as terminal aerodrome forecasts (TAF), ceiling height, fog dissipation, and low level wind shear. Nonaviation related uses included providing data for avalanche rescue on Mount Rainier, forecasts for helicopter flights to oil rigs in the Gulf of Mexico, waterspout forecasts in Miami, lake effect snows in Chicago, and jet stream locations. From a funding viewpoint, ACARS operates based on the good-will of participants. As the system evolved current participants did not have to address significant system start-up costs because the data link and weather sensors were already installed on the participating transport aircraft. As a result, the hurdle of funding nonrecurring costs was avoided and this is a primary reason that ACARS exists today. Current recurring, incremental cost for the participants is primarily related to transmission of the data to the weather service and this is estimated at over $300,000/year.
3. Package and regional carriers: a promising platform for TAMDAR A fundamental TAMDAR feasibility question involves identification of the preferred participants and their motivations to become involved in the system. There are several possible target aviation segments including general aviation (GA), business, package carriers, and regional/commuter airlines. The key issue in prioritizing these choices is demonstrating that the possible investment in sensors and data link equipment produces a stream of data with forecast value that justifies these costs. A number of operational characteristics are strongly correlated with TAMDAR system success and can be used to prioritize the possible participant segments: *
*
Predictable routes: Forecast models and forecasters must be able to rely on consistent data availability to realize forecast improvement. Consequently, the TAMDAR system should provide a reliable stream of weather data and aviation segments that represent predictable routes and schedules should be preferred over those that have more random data-gathering patterns. Flight time density: Desirable participant segments should provide the spatial and temporal coverage,
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*
*
*
along with a high level of daily flight hours (including night operations), required to augment the current ACARS data and achieve forecast improvement. Segments with low levels of monthly flight time gather less weather data for a given equipment investment. Cruise elevation: Weather data below 18,000 ft are of primary interest in the TAMDAR program and segments that frequently cruise at or below this elevation are more desirable. Professional maintenance: An effective quality control and failure feedback system is essential to assure a flow of credible data. Once the investment is made in equipment to obtain TAMDAR data, the system must perform reliably and produce quality data. Aviation segments that facilitate professional, scheduled maintenance of a reliable system that produces high quality data are more desirable. Low nonrecurring cost: Advantageous segments should present the opportunity to outfit participating aircraft with reduced nonrecurring costs. For example, segments that are already, or soon will be, equipped with ACARS-like data link systems will minimize start up costs. Conversely, segments with a small installed base of data link equipment are less desirable.
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indicated that the regional and package carriers are cost sensitive in that both groups expect compensation for their incremental data transmission and sensor installation costs. The package carriers also ranked reimbursement for operating and maintenance (O&M) costs highly. The survey also examined whether providing TAMDAR information directly to the participant aircraft would be attractive to these segments as a motivation to participate. Responses indicated that the emergency aircraft tracking feature of TAMDAR and receipt of free weather data were significant motivators for these aviation segments. However, on balance, participants’ interest in cost free sharing of these TAMDAR features did not outweigh the importance of compensation for incremental recurring and nonrecurring costs. Consequently, the system requires a significant level of government financial support.
4. Integrated business case for the TAMDAR system Eq. (1) describes the general business case model that this study employs to value TAMDAR: TAMDAR system value ¼ Nonrecurring investment Recurring costs
These characteristics are weighted and used to rate desirability of the aviation segments based on representing the most value for TAMDAR success. Table 1 indicates that regional carriers offer the best operational potential for TAMDAR success followed by the package carriers. The aviation segments were scored using a 9-3-1 scale with nine being high impact for the success characteristic, three moderate impact, and one marginal impact. The total value score for each segment was calculated by summing the product of the success characteristic weight and the aviation segment score. Due to the favorable operational characteristics of the package and regional segments, they are used as the target participants for the business model examined later. To identify the motivations for these important segments a survey was conducted to prioritize factors that motivate or inhibit their decision. Responses
þWeather service savings þForecast improvement value;
ð1Þ where: *
*
*
Table 1 Evaluation of aviation segments for TAMDAR participation Success characteristics
Weight GA Business Package Regional
Predictable routes Flight density Cruise elevation Professional maintenance/ data quality Low nonrecurring cost Total value score
0.2 0.2 0.1 0.3
*
1 1 9 1
1 3 3 9
9 9 9 3
9 9 3 9 *
0.2 1.0
1 1.8
3 4.4
1 5.6
3 7.2
TAMDAR system value: represents the present value of the estimated benefits and costs using methods stipulated in Office of Management and Budget (1992) Circular A-94 and the Federal Aviation Administration directive on cost–benefit analysis (Federal Aviation Administration, 1999a). Nonrecurring investment: includes the cost of equipping a target number of aircraft with the TAMDAR sensor and communication suite, certification costs, and one-time infrastructure and software costs needed to expand ACARS. Recurring costs: values the annual cost to maintain the TAMDAR system components on the aircraft, data downlink costs, and the ground-based data processing. Weather service savings: represent reductions in other weather data-gathering costs that may be achieved by implementing TAMDAR such as reduction in radiosonde (weather balloon) launches. Forecast improvement value: this values the annual financial impact of TAMDAR on forecast improvement. Although improved forecasts have significant economic benefit that has been well documented over
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the last forty years, the feasibility study focused on the aviation industry including improvements in National Airspace System (NAS) operations that enhance efficiency and reduce passenger delay. 4.1. Nonrecurring investment required by TAMDAR Data was gathered from the package and regional/ commuter carriers on the current equipage status and technology migration plans related to the data link equipment required by TAMDAR. In general, the package carrier segment is not currently equipped with data link technology to enable transmission of TAMDAR weather information and does not see a business oriented reason to equip in the future. Since this group indicated that compensation for nonrecurring expenses is a requirement for participation in TAMDAR, these costs must be included in the business case. $10,000 ($5000 for the sensor and $5000 for the data link) is a benchmark estimate for a basic sensor–communication package based on data provided by sensor and communication link producers and this cost will be incurred for every package carrier aircraft that participates in TAMDAR. On the other hand, regional/commuter airlines are experiencing a significant market change that includes a shift to regional jets, consolidation of carriers, and the need for improved communication/interface with the NAS and air traffic control. These trends will reduce the nonrecurring investment costs in this segment for communication equipment related to the TAMDAR data link. Several of the largest commuter carriers already have fleets that are ACARS equipped, with others planning to make this transition a part of the acquisition of regional jets. Overall there is a movement in the regional airline segment to flight information
Table 2 Data point estimate for package and regional domestic flight Sounding (ascent–descent) Elevation Package Elevation Regional
0–5k 16 0–5k 16
5–13k 6 5–25k 12
systems that include the necessary communication data link for TAMDAR. In spite of the move to regional jets, there will be a number of regional/commuter turboprops during the next 10 years that will require data link equipment for TAMDAR. For example, the number of jets in the regional airline fleet is 580 of 2271 (Regional Airline Association, 2001). As TAMDAR is implemented over the next several years and the proportion of regional jets grows, Kauffmann and Ozan (2001) identified 25% as a conservative estimate of the proportion of regional aircraft that participate in TAMDAR and need to be equipped for data link at TAMDAR’s expense. Considering these trends, the base business case uses a sensor cost of $5000/aircraft (jet or turboprop) and $1250 (25% of $5000) for the communication link for a total average cost of $6250 to equip a regional/commuter aircraft. To develop nonrecurring costs from these estimates, the number of aircraft in the projected TAMDAR fleet must be identified. Estimating the number of TAMDAR aircraft involves analysis of the temporal and spatial coverage that optimizes the balance of operating cost compared to the benefits of improved forecasts. The World Meteorological Organization (WMO) has developed a standard for the temporal and spatial coverage of airborne data sampling (AMDAR, 2001). Since there is no US standard, the TAMDAR data-gathering plan conforms as closely as possible to the WMO benchmark. *
*
*
Cruise
Total
10
54
10
66
Horizontal resolution: a sampling goal for the cruise flight segment was established as every 60 miles and every 100 miles for soundings (ascent). Vertical resolution: the WMO specifies taking a data sample every 300 ft. from takeoff up to 5000 ft and every 1500 ft from 5000 ft to cruise elevation. This standard was adopted using an average cruise elevation of 25,000 ft for regional carriers and 13,000 ft for package carriers. Temporal resolution: an average temporal resolution target was established as 1 sample/h for cruise and every 1.5 h for soundings.
Table 2 summarizes the number of data points that a typical domestic flight for the package and regional carriers would gather using these standards. Figs. 2 and 3 demonstrate use of the TAMDAR sample guidelines
60x60 mile grid
1,500 miles Cruise Sampling Goal: One point per grid every hour 1250grids*24hours =30,000 daily cruise points
3,000 miles Fig. 2. Example of national coverage grid—cruise elevation sampling.
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100x100 mile grid
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1,500 miles Sounding Sampling Goal: One sounding per grid every 1-3 hours (30*15 grids)*25 points/ sounding*18 / day =210,000 daily points
3,000 miles Fig. 3. Example of national coverage grid—sounding sampling.
along with Table 2 to estimate the total number of data points that TAMDAR requires in both a cruise and sounding sampling plan. Fig. 2 examines cruise sampling and shows a graphic representing the continental US as a 1500 3000 mile rectangle. Using a 60-mile horizontal coverage grid, the continental US contains 1250 grid segments and, if each grid is sampled once per hour by cruising aircraft, 30,000 points will be gathered daily. Fig. 3 employs a 100 100 mile grid for soundings and a rationale similar to that used for Fig. 2. With an average of 25 points/sounding and 18 soundings/day at a 1.5 h interval, the TAMDAR system will gather 210,000 sounding points/day. The estimate of 240,000 daily data points developed in Figs. 2 and 3 demonstrates an integrated system and indicates TAMDAR would add 160,000 points to the current 80,000 gathered by ACARS. Using this data gathering plan, the size of the regional/package fleet needed to sample an additional 160,000 points per day can be estimated. Table 3 develops an estimate of the required fleet by allocating 80% of the needed points to the regional carriers and 20% to the package carriers. This allocation is based on two conflicting factors: nonrecurring cost reduction and night/location coverage. Using regional carrier aircraft in lieu of package carriers reduces nonrecurring equipment cost as described previously ($10,000 to equip a package aircraft and only $6250 for a regional aircraft). However, the package segment presents the opportunity to obtain night flight coverage when commuter carriers are not flying. The business model estimated this balance should result in selection of package carriers for 80% of the data points required for TAMDAR. Using the number of points per flight segment from Tables 2 and 3 estimates that 1939 regional flights and 533 package flights are required per day. Employing data obtained from the regional airlines and package carriers on the average number of flight legs per aircraft per day, 277 regional aircraft and 178 package aircraft are required if they are 100% utilized on routes that are desirable for TAMDAR. This number was further adjusted based on two considerations: only 50% of the equipped aircraft flights are desirable (based on temporal and spatial coverage goals) and that the equipped aircraft are available 75% of the time. Based on these adjustments, the resulting target TAMDAR fleet is 739
Table 3 Estimate of required TAMDAR aircraft fleet Target TAMDAR points
Percent of total point allocation Target points Points per flight (Table 2) Flights required Flight legs per day Aircraft required based on 100% utilization Adjustment: 50% desirable legs Adjustment: 75% available aircraft Round up based on fleet wide negotiations
160,000 Day (regional)
Night (package)
80% 128,000 66 1939 7 277 554 739 1000
20% 32,000 54 533 3 178 356 474 500
for the regional segment and 474 for the package segment. As a final consideration, this fleet estimate may increase slightly due to the manner in which TAMDAR is implemented in the carrier fleets. From a practical viewpoint, TAMDAR will enlist a number of regional and package carriers to participate and this requires the negotiation of operating agreements. In these cases, the entire fleet of the target firm should be equipped for TAMDAR participation so that scheduling problems are minimized and carrier aircraft are available for desirable routes and locations. For example, to obtain desired national coverage, the top 10 regional airlines may be the target TAMDAR participants for the regional fleet. The combined fleet of this group is slightly over 1000 aircraft and as a result, TAMDAR would have to support equipping this entire group. To include this possibility and conservatively recognize the anticipated impact of the fleet—wide procurement/ negotiation process, the business case is based on equipping 1000 regional aircraft and 500 package carriers as noted in Table 3. In addition to sensors and data link equipment, there are two other significant nonrecurring costs: certification of the TAMDAR sensor for aircraft installation and the cost of one-time infrastructure improvements. Certification costs were benchmarked at $1million for each of the target segments using recent data from similar equipment. Infrastructure costs relate to the addition of a variety of aircraft to the ACARS system and required data interface software. Previous experience indicated a cost of $1000/aircraft was a reasonable estimate for
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Table 4 Nonrecurring cost estimate summary Sensor Regional aircraft Package aircraft Certification Infrastructure
Data link
$5000/A/C $1250/A/C $5000/A/C $5000/A/C $1,000,000 $1,000,000 $1,500,000 for interface software and server systems Total estimated nonrecurring cost
these startup issues. Since 1500 aircraft are forecast to be added by the TAMDAR system, this cost is identified at $1.5 million. Table 4 summarizes the nonrecurring cost estimates and indicates that the nonrecurring start up costs for TAMDAR are about $14.75 million. 4.2. Base case analysis—recurring cost The recurring costs for TAMDAR can be summarized in three categories: data down link/processing, maintenance of aircraft based systems, and infrastructure at FSL/NWS to operate and manage the expanded ACARS/TAMDAR system. *
*
*
Data link and transmission cost calculations employ the current ACARS system estimate of $0.024/data point and an incremental volume of 160,000 additional points per day. Annual equipment maintenance cost estimate are based on 10% of the installed aircraft system costs for the package carriers and 7% for the regional carriers. A reduced level is appropriate for the regional carriers since maintenance of flight information systems and data link equipment for many of these aircraft is the responsibility of the aircraft owner since these systems will be installed prior to TAMDAR. To assure that the TAMDAR/ACARS system is managed effectively and the full potential to improve forecast performance is achieved, incremental recurring costs include a full-time, professional staff with these responsibilities. Primary duties of this group include development of training programs for forecasters, identification of best practices so that the forecast improvements are realized, and management of data gathering and quality control.
Table 5 summarizes these recurring costs for TAMDAR at $2.939 million/year. 4.3. TAMDAR benefit analysis Table 6 develops an annualized cost of TAMDAR by combining the recurring and nonrecurring cost estimates from the previous sections. This annual cost equivalent serves as a benchmark to compare the annual savings
Number of aircraft
Total
1000 500
$6,250,000 $5,000,000 $2,000,000 $1,500,000 $14,750,000
Table 5 Recurring cost estimate summary Recurring cost
Package
Regional
Total
Daily data points Yearly data points Transmission cost/point Processing cost/point Annual data point cost Equipment maintenance FSL/NWS infrastructure Total
32,000 11,680,000 $0.010 $0.014 $280,320 $500,000 $300,000 $1,080,320
128,000 46,720,000 $0.010 $0.014 $1,121,280 $437,500 $300,000 $1,858,780
160,000 58,400,000 NA NA $1,401,600 $937,500 $600,000 $2,939,100
Table 6 Annual worth of TAMDAR cost elements Year
Year 0 (Nonrecurring)
Nonrecurring cost Annual data point cost Maintenance Infrastructure Savings Cost summary Present value of cost Equivalent annual cost
$14,750,000
Year 1–10 (Recurring) $1,401,600 $ 937,500 $600,000
$14,750,000 $35,393,009 $5,039,168
$2,939,100
that are necessary to justify the TAMDAR program. Using a 7% rate and a 10-year life, Table 6 indicates that TAMDAR must demonstrate an annual benefit (savings) of slightly over $5 million to be worthwhile. The basic equation for the business case (Eq. (1)) contained several saving related terms: annual savings from the weather service based on elimination of redundant data-gathering systems (primarily weather balloons) and annual savings for operational improvement of the national airspace system. The next paragraphs examine these areas and develop an estimate of the total savings from TAMDAR. North American Observing System (2000) examines the use of ACARS to replace radiosonde weather data gathered at 14 launch sites that were co-located with airports. It found that removal of the radiosonde data from three forecast models and use of only ACARS data had little meaningful effect on the forecast output of these models and saved $1.8 million/year. The study concluded that it might be possible to eliminate these
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radiosonde launches if ACARS included moisture data. Since TAMDAR has the capability to add that feature to ACARS, it is reasonable to estimate that $1.8 million in radiosonde launch costs related to these fourteen sites can be credited to TAMDAR as an annual cost reduction. Considering the coverage expansion that TAMDAR promises, it may be possible to assume that 14 additional sites can be identified with similar radiosonde replacement potential and the radiosonde program savings could be as much as $3.6 million. Elimination of 28 of the 121 radiosonde sites represents only a 23% reduction in the total program. To establish a conservative cost reduction target, the base business case assumes that the $1.8 million projected in the NAOS report will be achieved and that only seven additional sites will be reduced resulting in a $2.7 million total reduction in radiosonde costs credited to TAMDAR. TAMDAR weather data has the potential to improve forecast accuracy and better forecasts reduce NAS system delay and improve operations. In 1999, the FAA documented 89 million minutes of delay, comprised of 21 million minutes in scheduled delay with the remainder classified as unscheduled (Office of Inspector General, 2000). This report defines unscheduled delay as delay that in fact occurs but is masked because the carriers have extended published schedule times to compensate for anticipated system delays. Weather plays a significant role both in delay and the growth of delay. The Federal Aviation Administration (1999b) indicates the 25% increase in aviation delays that occurred from 1997 to 1998 was primarily a result of a 36% increase in weather delays. Weather delays as a percent of all delays increased from 68% to 74% in this period. In addition, The Office of Inspector General (OIG) study found that weather was the cause of about 43% of the delay increase between 1998 and 1999 and the FAA indicated that weather was the cause of 68% of delays in 1999. The OIG valued the direct operating cost of the 89 million delay min at over $3.2 billion using a value of $36.50/min, a composite figure developed from data furnished by 45 airlines to reflect their view of the cost of delays. This report also indicated that 154,311 cancellations occurred in 1999 as a result of these delays and valued these at a conservative $5092 each for a total annual cancellation cost of $786 million. Combining these two costs (operating cost and cancellations), OIG found the annual cost of delays for the air carriers at over $4 billion. The Air Transport Association (ATA) performed a similar study and, using only the schedule delay (not unscheduled), found the direct cost of delay to the ten major carriers was $2 billion. When ATA included the cost of passenger delay and other indirect costs, its estimate of the cost of delay was over $5 billion for 1999.
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To provide an independent validation of these numbers, the feasibility study developed a comprehensive estimate of delay cost that included direct airline operations, passenger costs, and cancellations together. Table 7 provides the starting point for this calculation by allocating the 89 million min of delay to three aviation sectors (carriers, air taxi, and GA) based on the proportion of delayed operations identified in the FAA Consolidated Operations and Analysis System (2001) database. The Federal Aviation Administration (1998) provides guidance on valuing the direct cost of an aircraft-operating minute and a passenger delay minute for these three segments and that data is described in Table 8. For example, the average cost of a minute of carrier aircraft time is $51.55 (fixed and variable costs included), there are an average of 114.75 passengers on a carrier aircraft that experience delay, and passenger time is valued at $0.45/min. Table 9 uses the information in Tables 7 and 8 to estimate the total cost of delay for 1999 in the NAS as $8.4 billion including direct aircraft cost, passenger delay cost, and cancellation cost. This estimate represents a comprehensive delay cost and is consistent with the estimates reviewed above from the OIG ($4 billion without passenger delay) and ATA ($2 billion for scheduled delay only and $5 billion including passenger delay but omitting unscheduled delay). Although Office of Inspector General (2000) found that weather causes approximately 70% of delay, it did not indicate what percentage is related to specific weather phenomena for which TAMDAR can improve forecasts. To provide a conservative value for the potential weather related savings, Table 9 identifies 50% of the total cost as a reasonable proportion of the delay costs that TAMDAR may influence.
Table 7 Allocation of delay minutes Delayed operations Total Carriers Air taxi GA
450,289 360,669 70,747 18,539
Delayed minutes Scheduled
Unscheduled
Total
22,609,046 18,109,219 3,552,212 930,845
67,368,277 53,960,121 10,584,543 2,773,642
89,977,323 72,069,340 14,136,756 3,704,487
Table 8 Aircraft and passenger cost data
Carrier Air taxi GA
Aircraft operating cost per minute
Average number of passengers per flight
Passenger delay cost per minute
$51.55 $13.00 $9.42
114.75 2.90 2.75
$0.45 $0.45 $0.52
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Table 9 Estimated weather related delay cost
Carrier Air taxi GA Total
Carrier cost
Passenger
$3,715,174,485 $183,777,826 $34,883,916 $3,933,836,227
$3,680,005,692 $18,268,647 $5,280,437 $3,703,554,776
A number of studies substantiate the 0.1% savings benchmark as conservative. For example, Allen and Gaddy (2000) studied delay issues at the Newark airport and found a number of cases in which improvements in basic weather information, such as TAMDAR is designed to provide, would have yielded delay savings as high as $1million for a single event. Similarly, Evans et al. (1999) found that improved prediction of wind shifts would reduce delay by 3000 h at Los Angeles International Airport alone.
5. TAMDAR business case summary Table 10 employs the NAS operational savings from TAMDAR at a reduction of 0.1% in delay and combines this with the other cost and savings factors discussed in the previous sections. In this analysis, TAMDAR has a positive present value over $13 million and an internal rate of return (IRR) of 24%. Sensitivity analysis of the calculations in Table 10 shows a robust business case since the nonrecurring cost estimates would need to nearly double for the business case to drive the $13 million present value into a negative value. Table 11 illustrates this point by providing the value to which the costs of equipping aircraft or the number of aircraft would have to increase to change the business case outcome. For example, considering the changes one factor at a time, the cost of equipping a package aircraft would have to increase from the base case estimate of $10,000 to $25,477. Similarly, the number of package aircraft would have to increase from 500 to 1230 to turn the base case negative. The base case was also examined for sensitivity of changes in savings for the projected radiosonde reductions and the impact of this change on the percent delay savings required for a positive business case. Table 12 summarizes the results using three scenarios: base radiosonde case (eliminate 21 sites), optimistic radiosonde savings (eliminate 28 sites), and no radiosonde savings. In the base case, the delay savings can be reduced by nearly half from 0.1% to 0.056% before the business case becomes negative. If the radiosonde savings become optimistic and increase by 25% from $2.7 million to $3.6 million, the delay savings required for a positive business case are only 0.034%. Finally, if
Cancellations
Total
$785,000,000 50% weather related
$8,422,391,003 $4,211,195,502
Table 10 TAMDAR base business case summary Cash flow summary Year
0
Cost summary Initial nonrecurring Annual data cost Maintenance Infrastructure Annual equivalent cost
1–10
$14,750,000 $1,401,600 $937,500 $600,000 $5,039,168
Savings summary Radiosonde savings (21 sites) Delay savings (% 0.1 reduction) Annual equivalent savings TAMDAR present value TAMDAR IRR=
$2,700,000 $4,211,196 $6,911,196 $13,148,337 24%
Table 11 Decision reversal levels for nonrecurring investment
Investment per aircraft Fleet size
Base package
Package reversal
Base regional
Regional reversal
$10,000
$25,477
$6,250
$15,065
500
1230
1000
2273
the radiosonde savings are eliminated, a positive TAMDAR business case requires a delay saving increase from 0.1% to only 0.12%. The bottom line of Table 12 lists the sensitivity of the business case IRR to each of the scenarios with a constant percentage delay reduction. For example, using a 0.2% delay savings results in an IRR of 55% for the base case, 61% for the optimistic radiosonde case, and 35% for the pessimistic radiosonde case.
6. Conclusion TAMDAR is complimentary to the current ACARS system and has the potential to improve short-term weather forecasts and yield significant societal benefits. This study identified a strong business case based on evaluating only the positive impact of this new system on the aviation sector. Even without valuing the varied
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Table 12 Sensitivity summary for radiosonde variation
Annualized cost of TAMDAR Savings Radiosonde savings Required delay savings for positive business case Percent weather related delay required for positive business case IRR if weather related delay saving is 0.2%
societal impact of improved short-term forecasts, the business case was insensitive to changes in the cost factors and saving benefits. TAMDAR success requires participation by the regional and package carriers. In the case of regional airlines, the transition to regional jets and other market shifts reduce the nonrecurring costs of implementing TAMDAR based on increasing adoption and wider implementation of the necessary data link equipment. On the other hand, package carriers are not planning to install the needed data link technology since it is not a necessity for their continued operational success. Consequently, installations in this segment are more expensive. Participation motivation on the part of both segments is cost sensitive and requires compensation for related costs including recurring and nonrecurring items. This expectation for reimbursement necessitates government involvement to defray these system costs. However, the potential to increase the safety and system efficiency of the National Airspace System justifies this commitment.
Acknowledgements We wish to thank the NASA Aviation Weather Information (AWIN) program that funded this research. The project report is contained in Old Dominion University Research Foundation Project Report (Contract L-11623). In addition, thanks are due to the many participants, including airlines, regulatory agencies, avionics manufacturers, and aviation experts, who gave their time to provide information for this study.
References Allen, S.S., Gaddy, S.G., 2000. Delay reduction at Newark International Airport using terminal weather information systems. Ninth Conference on Aviation, Range and Aerospace Meteorology, American Meteorological Society, Orlando. AMDAR, 2001. The Atmospheric Meteorological Data and Reporting Programme. UK Meteorology Office, Retrieved from the World Wide Web, April 6. http://www.metoffice.com/research/interproj/ amdar/index.html.
Base Radiosonde
Optimistic radiosonde
No radiosonde
$5,039,168
$5,039,168
$5,039,168
$2,700,000 $2,339,168 0.056% 55%
$3,600,000 $1,439,168 0.034% 61%
$0 $5,039,168 0.120% 35%
Aeronautical Radio Inc., 2001. Corporate Overview. Annapolis, Aeronautical Radio Inc., Retrieved from World Wide Web, January 30, http://www.arinc.com/About/corpov.html Consolidated Operations, and Analysis System, 2001. Retrieved from the World Wide Web May 20, 2000: http://www.apo.data.faa.gov/ Evans, J.E., Dasey, T.J., Cole, R.E., Rhoda, D.A., 1999. Weather sensing and data fusion to improve safety and reduce delays at major west coast airports. Project Report ATC-290. Massachusetts Institute of Technology, Lincoln Laboratory, MA. Federal Aviation Administration, 1998. Economic Values for Evaluation of Federal Aviation Investment and Regulatory Decisions. US Department of Transportation, Washington, DC. Federal Aviation Administration, 1999a. Federal Aviation Administration Airport Benefit-Cost Analysis Guidance. Office of Aviation Policy and Plans, Washington, DC. Federal Aviation Administration, 1999b. Aviation Capacity Enhancement Plan. Office of System Capacity, Washington. DC. Forecast System Laboratory, 2000. Aircraft communication addressing and reporting system information. Retrieved from the World Wide Web October 30: http://acweb.fsl.noaa.gov/FAQ.html. Jamison, B.D., Moninger, W., 2001. Aircraft communication addressing and reporting system coverage-May 2001. A study in support of the Tropospheric Airborne Meteorological Data and Reporting project. Retrieved from the World Wide Web, October 29: Forecast Systems Laboratory. http://acweb.fsl.noaa.gov/may 01 coverage/ Kauffmann, P., Ozan, E., 2001. Feasibility study of tropospheric airborne meteorological data and reporting. Project Report Contract L-11623, Old Dominion University Research Foundation. Mamrosh, R.D., Decker, R., Weiss, C., 2001. Field forecaster evaluation of aircraft communication addressing and reporting system data-results of the North American observing system aircraft communication addressing and reporting system assessment. Fifth Symposium on Integrated Observing Systems. American Meteorological Society, Albuquerque. Moninger, W., Mamrosh, R., Pauley, P., 2002. Automated weather reports from commercial aircraft. In the Bulletin of the American Meteorological Society. Retrieved from the World Wide Web October 29: to be published . http://acweb.fsl.noaa.gov/bams/ North American Observing System, 2000. Radiosonde/meteorological data collection and reporting system (MDCRS) evaluation findings and recommendations. North American Observing System Report. Authorized by the North American Observing System Council. Office of Inspector General, 2000. Audit report—air carrier flight delays and cancellations. Report No. CR-2000-112. Federal Aviation Administration, Bureau of Transportation Statistics. Office of Management and Budget, 1992. Circular A-94. Revised. Office of Management and Budget, Washington, DC. Regional Airline Association, 2001. Summary of Regional Aircraft in Regional Airline use—2000. Retrieved from the World Wide Web May 20: http://www.raa.org/aircraft/airandeq.htm.
Journal of Air Transport Management 10 (2004) 207–215
Feasibility of TAMDAR: an aircraft-based weather data collection system Paul Kauffmanna,*, Erol Ozana, Yesim Sirelib b
a East Carolina University, 201 Science and Technology Building, Greenville, NC 27858, USA University of North Carolina at Charlotte, 9201 University City Blvd., Charlotte, NC 28223-0001, USA
Abstract The tropospheric airborne meteorological data and reporting (TAMDAR) system is a new meteorological data collection system carried aloft by participating aircraft to gather weather data and relay this information to ground-based receiving stations for distribution into the national system for weather data dissemination. These improved forecasts provide a wide range of societal benefits including enhanced air safety and improved operational efficiency in national air space. This paper presents the results of a TAMDAR system feasibility study that evaluated implementation alternatives, defined the conceptual framework of the business case, estimated related costs and benefits, and combined the results into a comprehensive road map for future system development and implementation. r 2003 Elsevier Ltd. All rights reserved. Keywords: Meteorological data acquisition systems; Value of weather data; Business case; Aviation efficiency and safety
1. Introduction Tropospheric airborne meteorological data and reporting (TAMDAR) is a conceptual weather datagathering system consisting of an instrument sensor suite with a data conversion unit, an air to ground data link with GPS (geographical positioning system) capability, and a ground-based receiving and processing system. Participating aircraft will carry the technology to gather weather data, and relay this information to ground-based receiving stations for distribution into the national weather data dissemination system (Fig. 1). The US Federal Aviation Administration (FAA) and the National Aeronautics and Space Administration (NASA) have concluded that TAMDAR has the potential to improve the accuracy and completeness of weather data and the resulting weather forecasts (Kauffmann and Ozan, 2001). In turn, these improved forecasts enhance aviation safety, improve operation of the National Airspace System (NAS) and provide additional economic benefits.
*Corresponding author. Tel.: +1-252-328-9645; fax: +1-252-3281618. E-mail addresses: [email protected] (P. Kauffmann), [email protected] (E. Ozan), [email protected] (Y. Sireli). 0969-6997/$ - see front matter r 2003 Elsevier Ltd. All rights reserved. doi:10.1016/j.jairtraman.2003.11.001
There are many questions related to the feasibility of a conceptual technology such as TAMDAR. For example, it may operate as a completely government operated system, a public/private partnership, or a for-profit enterprise. From the viewpoint of the funding entity, TAMDAR must provide benefits that exceed its costs. Relative to cost–benefit, it is not clear that TAMDAR can compete in the market place and establish its usefulness in comparison to currently operating weather data-gathering and reporting systems.
2. ACARS overview This section describes operating features of the Aeronautical Radio, Inc. (ARINC) based system that gathers weather data, with the voluntary participation of six transport carriers. This is done because TAMDAR is viewed as an operational extension of this program. In addition, the growth and evolution of this system provides lessons and guidance for TAMDAR development. ARINC is a $450 million corporation that is owned by a number of United States and international airlines and aircraft operators. Its focus is development and operation of communications and information
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Fig. 1. Basic structure of TAMDAR system.
processing systems and services that support the efficiency, operation, and performance of the aviation and travel industries (Aeronautical Radio Inc, 2001). ARINC’s aircraft communication addressing and reporting system (ACARS) is a data link system, primarily transmitted via VHF radio that allows communication with aircraft during various phases of flight operation (Forecast System Laboratory, 2000). Using the ACARS system, six cooperating transport carriers gather weather data during flight and, route this information to ARINC’s ground system where it is decoded and sent to the Forecast Systems Laboratory (FSL) of the National Weather Service (NWS). Consequently the FSL uses the designation ACARS to describe these automated weather reports from commercial aircraft. Currently, ACARS averages about 80,000 observations/day (90% over the continental US) from more than 500 aircraft (Forecast System Laboratory, 2000). This system has several significant limitations. As a result of the limited number of participants and their flight patterns, there are deficiencies in the temporal and spatial coverage of the ACARS data set (Moninger et al., 2002; Jamison and Moninger, 2001). These gaps are compounded since participants gather the weather data required for their operations and do not coordinate these data-gathering decisions. Consequently, hubs that are frequented by several participants may have excessive data and other geographic areas may be deficient. In addition, data from ACARS is incomplete in its capability to fully support forecast needs. Information on relative humidity, in particular in the troposphere, has great potential to improve forecast accuracy. Unfortunately very few ACARS aircraft are equipped with humidity sensors and this is not likely to change in the future due to the cost of instruments for transport
aircraft. Furthermore, these transport aircraft typically cruise at less desirable higher elevations and are often scheduled for major airports where data is plentiful. Even without humidity data and with the limitations of high cruise elevations, the positive impact of ACARS data on short-term forecasts is well documented. For example, Mamrosh et al. (2001) studied the use of ACARS data at twenty weather service forecast offices and found a number of aviation related improvements such as terminal aerodrome forecasts (TAF), ceiling height, fog dissipation, and low level wind shear. Nonaviation related uses included providing data for avalanche rescue on Mount Rainier, forecasts for helicopter flights to oil rigs in the Gulf of Mexico, waterspout forecasts in Miami, lake effect snows in Chicago, and jet stream locations. From a funding viewpoint, ACARS operates based on the good-will of participants. As the system evolved current participants did not have to address significant system start-up costs because the data link and weather sensors were already installed on the participating transport aircraft. As a result, the hurdle of funding nonrecurring costs was avoided and this is a primary reason that ACARS exists today. Current recurring, incremental cost for the participants is primarily related to transmission of the data to the weather service and this is estimated at over $300,000/year.
3. Package and regional carriers: a promising platform for TAMDAR A fundamental TAMDAR feasibility question involves identification of the preferred participants and their motivations to become involved in the system. There are several possible target aviation segments including general aviation (GA), business, package carriers, and regional/commuter airlines. The key issue in prioritizing these choices is demonstrating that the possible investment in sensors and data link equipment produces a stream of data with forecast value that justifies these costs. A number of operational characteristics are strongly correlated with TAMDAR system success and can be used to prioritize the possible participant segments: *
*
Predictable routes: Forecast models and forecasters must be able to rely on consistent data availability to realize forecast improvement. Consequently, the TAMDAR system should provide a reliable stream of weather data and aviation segments that represent predictable routes and schedules should be preferred over those that have more random data-gathering patterns. Flight time density: Desirable participant segments should provide the spatial and temporal coverage,
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*
*
*
along with a high level of daily flight hours (including night operations), required to augment the current ACARS data and achieve forecast improvement. Segments with low levels of monthly flight time gather less weather data for a given equipment investment. Cruise elevation: Weather data below 18,000 ft are of primary interest in the TAMDAR program and segments that frequently cruise at or below this elevation are more desirable. Professional maintenance: An effective quality control and failure feedback system is essential to assure a flow of credible data. Once the investment is made in equipment to obtain TAMDAR data, the system must perform reliably and produce quality data. Aviation segments that facilitate professional, scheduled maintenance of a reliable system that produces high quality data are more desirable. Low nonrecurring cost: Advantageous segments should present the opportunity to outfit participating aircraft with reduced nonrecurring costs. For example, segments that are already, or soon will be, equipped with ACARS-like data link systems will minimize start up costs. Conversely, segments with a small installed base of data link equipment are less desirable.
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indicated that the regional and package carriers are cost sensitive in that both groups expect compensation for their incremental data transmission and sensor installation costs. The package carriers also ranked reimbursement for operating and maintenance (O&M) costs highly. The survey also examined whether providing TAMDAR information directly to the participant aircraft would be attractive to these segments as a motivation to participate. Responses indicated that the emergency aircraft tracking feature of TAMDAR and receipt of free weather data were significant motivators for these aviation segments. However, on balance, participants’ interest in cost free sharing of these TAMDAR features did not outweigh the importance of compensation for incremental recurring and nonrecurring costs. Consequently, the system requires a significant level of government financial support.
4. Integrated business case for the TAMDAR system Eq. (1) describes the general business case model that this study employs to value TAMDAR: TAMDAR system value ¼ Nonrecurring investment Recurring costs
These characteristics are weighted and used to rate desirability of the aviation segments based on representing the most value for TAMDAR success. Table 1 indicates that regional carriers offer the best operational potential for TAMDAR success followed by the package carriers. The aviation segments were scored using a 9-3-1 scale with nine being high impact for the success characteristic, three moderate impact, and one marginal impact. The total value score for each segment was calculated by summing the product of the success characteristic weight and the aviation segment score. Due to the favorable operational characteristics of the package and regional segments, they are used as the target participants for the business model examined later. To identify the motivations for these important segments a survey was conducted to prioritize factors that motivate or inhibit their decision. Responses
þWeather service savings þForecast improvement value;
ð1Þ where: *
*
*
Table 1 Evaluation of aviation segments for TAMDAR participation Success characteristics
Weight GA Business Package Regional
Predictable routes Flight density Cruise elevation Professional maintenance/ data quality Low nonrecurring cost Total value score
0.2 0.2 0.1 0.3
*
1 1 9 1
1 3 3 9
9 9 9 3
9 9 3 9 *
0.2 1.0
1 1.8
3 4.4
1 5.6
3 7.2
TAMDAR system value: represents the present value of the estimated benefits and costs using methods stipulated in Office of Management and Budget (1992) Circular A-94 and the Federal Aviation Administration directive on cost–benefit analysis (Federal Aviation Administration, 1999a). Nonrecurring investment: includes the cost of equipping a target number of aircraft with the TAMDAR sensor and communication suite, certification costs, and one-time infrastructure and software costs needed to expand ACARS. Recurring costs: values the annual cost to maintain the TAMDAR system components on the aircraft, data downlink costs, and the ground-based data processing. Weather service savings: represent reductions in other weather data-gathering costs that may be achieved by implementing TAMDAR such as reduction in radiosonde (weather balloon) launches. Forecast improvement value: this values the annual financial impact of TAMDAR on forecast improvement. Although improved forecasts have significant economic benefit that has been well documented over
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the last forty years, the feasibility study focused on the aviation industry including improvements in National Airspace System (NAS) operations that enhance efficiency and reduce passenger delay. 4.1. Nonrecurring investment required by TAMDAR Data was gathered from the package and regional/ commuter carriers on the current equipage status and technology migration plans related to the data link equipment required by TAMDAR. In general, the package carrier segment is not currently equipped with data link technology to enable transmission of TAMDAR weather information and does not see a business oriented reason to equip in the future. Since this group indicated that compensation for nonrecurring expenses is a requirement for participation in TAMDAR, these costs must be included in the business case. $10,000 ($5000 for the sensor and $5000 for the data link) is a benchmark estimate for a basic sensor–communication package based on data provided by sensor and communication link producers and this cost will be incurred for every package carrier aircraft that participates in TAMDAR. On the other hand, regional/commuter airlines are experiencing a significant market change that includes a shift to regional jets, consolidation of carriers, and the need for improved communication/interface with the NAS and air traffic control. These trends will reduce the nonrecurring investment costs in this segment for communication equipment related to the TAMDAR data link. Several of the largest commuter carriers already have fleets that are ACARS equipped, with others planning to make this transition a part of the acquisition of regional jets. Overall there is a movement in the regional airline segment to flight information
Table 2 Data point estimate for package and regional domestic flight Sounding (ascent–descent) Elevation Package Elevation Regional
0–5k 16 0–5k 16
5–13k 6 5–25k 12
systems that include the necessary communication data link for TAMDAR. In spite of the move to regional jets, there will be a number of regional/commuter turboprops during the next 10 years that will require data link equipment for TAMDAR. For example, the number of jets in the regional airline fleet is 580 of 2271 (Regional Airline Association, 2001). As TAMDAR is implemented over the next several years and the proportion of regional jets grows, Kauffmann and Ozan (2001) identified 25% as a conservative estimate of the proportion of regional aircraft that participate in TAMDAR and need to be equipped for data link at TAMDAR’s expense. Considering these trends, the base business case uses a sensor cost of $5000/aircraft (jet or turboprop) and $1250 (25% of $5000) for the communication link for a total average cost of $6250 to equip a regional/commuter aircraft. To develop nonrecurring costs from these estimates, the number of aircraft in the projected TAMDAR fleet must be identified. Estimating the number of TAMDAR aircraft involves analysis of the temporal and spatial coverage that optimizes the balance of operating cost compared to the benefits of improved forecasts. The World Meteorological Organization (WMO) has developed a standard for the temporal and spatial coverage of airborne data sampling (AMDAR, 2001). Since there is no US standard, the TAMDAR data-gathering plan conforms as closely as possible to the WMO benchmark. *
*
*
Cruise
Total
10
54
10
66
Horizontal resolution: a sampling goal for the cruise flight segment was established as every 60 miles and every 100 miles for soundings (ascent). Vertical resolution: the WMO specifies taking a data sample every 300 ft. from takeoff up to 5000 ft and every 1500 ft from 5000 ft to cruise elevation. This standard was adopted using an average cruise elevation of 25,000 ft for regional carriers and 13,000 ft for package carriers. Temporal resolution: an average temporal resolution target was established as 1 sample/h for cruise and every 1.5 h for soundings.
Table 2 summarizes the number of data points that a typical domestic flight for the package and regional carriers would gather using these standards. Figs. 2 and 3 demonstrate use of the TAMDAR sample guidelines
60x60 mile grid
1,500 miles Cruise Sampling Goal: One point per grid every hour 1250grids*24hours =30,000 daily cruise points
3,000 miles Fig. 2. Example of national coverage grid—cruise elevation sampling.
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100x100 mile grid
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1,500 miles Sounding Sampling Goal: One sounding per grid every 1-3 hours (30*15 grids)*25 points/ sounding*18 / day =210,000 daily points
3,000 miles Fig. 3. Example of national coverage grid—sounding sampling.
along with Table 2 to estimate the total number of data points that TAMDAR requires in both a cruise and sounding sampling plan. Fig. 2 examines cruise sampling and shows a graphic representing the continental US as a 1500 3000 mile rectangle. Using a 60-mile horizontal coverage grid, the continental US contains 1250 grid segments and, if each grid is sampled once per hour by cruising aircraft, 30,000 points will be gathered daily. Fig. 3 employs a 100 100 mile grid for soundings and a rationale similar to that used for Fig. 2. With an average of 25 points/sounding and 18 soundings/day at a 1.5 h interval, the TAMDAR system will gather 210,000 sounding points/day. The estimate of 240,000 daily data points developed in Figs. 2 and 3 demonstrates an integrated system and indicates TAMDAR would add 160,000 points to the current 80,000 gathered by ACARS. Using this data gathering plan, the size of the regional/package fleet needed to sample an additional 160,000 points per day can be estimated. Table 3 develops an estimate of the required fleet by allocating 80% of the needed points to the regional carriers and 20% to the package carriers. This allocation is based on two conflicting factors: nonrecurring cost reduction and night/location coverage. Using regional carrier aircraft in lieu of package carriers reduces nonrecurring equipment cost as described previously ($10,000 to equip a package aircraft and only $6250 for a regional aircraft). However, the package segment presents the opportunity to obtain night flight coverage when commuter carriers are not flying. The business model estimated this balance should result in selection of package carriers for 80% of the data points required for TAMDAR. Using the number of points per flight segment from Tables 2 and 3 estimates that 1939 regional flights and 533 package flights are required per day. Employing data obtained from the regional airlines and package carriers on the average number of flight legs per aircraft per day, 277 regional aircraft and 178 package aircraft are required if they are 100% utilized on routes that are desirable for TAMDAR. This number was further adjusted based on two considerations: only 50% of the equipped aircraft flights are desirable (based on temporal and spatial coverage goals) and that the equipped aircraft are available 75% of the time. Based on these adjustments, the resulting target TAMDAR fleet is 739
Table 3 Estimate of required TAMDAR aircraft fleet Target TAMDAR points
Percent of total point allocation Target points Points per flight (Table 2) Flights required Flight legs per day Aircraft required based on 100% utilization Adjustment: 50% desirable legs Adjustment: 75% available aircraft Round up based on fleet wide negotiations
160,000 Day (regional)
Night (package)
80% 128,000 66 1939 7 277 554 739 1000
20% 32,000 54 533 3 178 356 474 500
for the regional segment and 474 for the package segment. As a final consideration, this fleet estimate may increase slightly due to the manner in which TAMDAR is implemented in the carrier fleets. From a practical viewpoint, TAMDAR will enlist a number of regional and package carriers to participate and this requires the negotiation of operating agreements. In these cases, the entire fleet of the target firm should be equipped for TAMDAR participation so that scheduling problems are minimized and carrier aircraft are available for desirable routes and locations. For example, to obtain desired national coverage, the top 10 regional airlines may be the target TAMDAR participants for the regional fleet. The combined fleet of this group is slightly over 1000 aircraft and as a result, TAMDAR would have to support equipping this entire group. To include this possibility and conservatively recognize the anticipated impact of the fleet—wide procurement/ negotiation process, the business case is based on equipping 1000 regional aircraft and 500 package carriers as noted in Table 3. In addition to sensors and data link equipment, there are two other significant nonrecurring costs: certification of the TAMDAR sensor for aircraft installation and the cost of one-time infrastructure improvements. Certification costs were benchmarked at $1million for each of the target segments using recent data from similar equipment. Infrastructure costs relate to the addition of a variety of aircraft to the ACARS system and required data interface software. Previous experience indicated a cost of $1000/aircraft was a reasonable estimate for
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Table 4 Nonrecurring cost estimate summary Sensor Regional aircraft Package aircraft Certification Infrastructure
Data link
$5000/A/C $1250/A/C $5000/A/C $5000/A/C $1,000,000 $1,000,000 $1,500,000 for interface software and server systems Total estimated nonrecurring cost
these startup issues. Since 1500 aircraft are forecast to be added by the TAMDAR system, this cost is identified at $1.5 million. Table 4 summarizes the nonrecurring cost estimates and indicates that the nonrecurring start up costs for TAMDAR are about $14.75 million. 4.2. Base case analysis—recurring cost The recurring costs for TAMDAR can be summarized in three categories: data down link/processing, maintenance of aircraft based systems, and infrastructure at FSL/NWS to operate and manage the expanded ACARS/TAMDAR system. *
*
*
Data link and transmission cost calculations employ the current ACARS system estimate of $0.024/data point and an incremental volume of 160,000 additional points per day. Annual equipment maintenance cost estimate are based on 10% of the installed aircraft system costs for the package carriers and 7% for the regional carriers. A reduced level is appropriate for the regional carriers since maintenance of flight information systems and data link equipment for many of these aircraft is the responsibility of the aircraft owner since these systems will be installed prior to TAMDAR. To assure that the TAMDAR/ACARS system is managed effectively and the full potential to improve forecast performance is achieved, incremental recurring costs include a full-time, professional staff with these responsibilities. Primary duties of this group include development of training programs for forecasters, identification of best practices so that the forecast improvements are realized, and management of data gathering and quality control.
Table 5 summarizes these recurring costs for TAMDAR at $2.939 million/year. 4.3. TAMDAR benefit analysis Table 6 develops an annualized cost of TAMDAR by combining the recurring and nonrecurring cost estimates from the previous sections. This annual cost equivalent serves as a benchmark to compare the annual savings
Number of aircraft
Total
1000 500
$6,250,000 $5,000,000 $2,000,000 $1,500,000 $14,750,000
Table 5 Recurring cost estimate summary Recurring cost
Package
Regional
Total
Daily data points Yearly data points Transmission cost/point Processing cost/point Annual data point cost Equipment maintenance FSL/NWS infrastructure Total
32,000 11,680,000 $0.010 $0.014 $280,320 $500,000 $300,000 $1,080,320
128,000 46,720,000 $0.010 $0.014 $1,121,280 $437,500 $300,000 $1,858,780
160,000 58,400,000 NA NA $1,401,600 $937,500 $600,000 $2,939,100
Table 6 Annual worth of TAMDAR cost elements Year
Year 0 (Nonrecurring)
Nonrecurring cost Annual data point cost Maintenance Infrastructure Savings Cost summary Present value of cost Equivalent annual cost
$14,750,000
Year 1–10 (Recurring) $1,401,600 $ 937,500 $600,000
$14,750,000 $35,393,009 $5,039,168
$2,939,100
that are necessary to justify the TAMDAR program. Using a 7% rate and a 10-year life, Table 6 indicates that TAMDAR must demonstrate an annual benefit (savings) of slightly over $5 million to be worthwhile. The basic equation for the business case (Eq. (1)) contained several saving related terms: annual savings from the weather service based on elimination of redundant data-gathering systems (primarily weather balloons) and annual savings for operational improvement of the national airspace system. The next paragraphs examine these areas and develop an estimate of the total savings from TAMDAR. North American Observing System (2000) examines the use of ACARS to replace radiosonde weather data gathered at 14 launch sites that were co-located with airports. It found that removal of the radiosonde data from three forecast models and use of only ACARS data had little meaningful effect on the forecast output of these models and saved $1.8 million/year. The study concluded that it might be possible to eliminate these
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radiosonde launches if ACARS included moisture data. Since TAMDAR has the capability to add that feature to ACARS, it is reasonable to estimate that $1.8 million in radiosonde launch costs related to these fourteen sites can be credited to TAMDAR as an annual cost reduction. Considering the coverage expansion that TAMDAR promises, it may be possible to assume that 14 additional sites can be identified with similar radiosonde replacement potential and the radiosonde program savings could be as much as $3.6 million. Elimination of 28 of the 121 radiosonde sites represents only a 23% reduction in the total program. To establish a conservative cost reduction target, the base business case assumes that the $1.8 million projected in the NAOS report will be achieved and that only seven additional sites will be reduced resulting in a $2.7 million total reduction in radiosonde costs credited to TAMDAR. TAMDAR weather data has the potential to improve forecast accuracy and better forecasts reduce NAS system delay and improve operations. In 1999, the FAA documented 89 million minutes of delay, comprised of 21 million minutes in scheduled delay with the remainder classified as unscheduled (Office of Inspector General, 2000). This report defines unscheduled delay as delay that in fact occurs but is masked because the carriers have extended published schedule times to compensate for anticipated system delays. Weather plays a significant role both in delay and the growth of delay. The Federal Aviation Administration (1999b) indicates the 25% increase in aviation delays that occurred from 1997 to 1998 was primarily a result of a 36% increase in weather delays. Weather delays as a percent of all delays increased from 68% to 74% in this period. In addition, The Office of Inspector General (OIG) study found that weather was the cause of about 43% of the delay increase between 1998 and 1999 and the FAA indicated that weather was the cause of 68% of delays in 1999. The OIG valued the direct operating cost of the 89 million delay min at over $3.2 billion using a value of $36.50/min, a composite figure developed from data furnished by 45 airlines to reflect their view of the cost of delays. This report also indicated that 154,311 cancellations occurred in 1999 as a result of these delays and valued these at a conservative $5092 each for a total annual cancellation cost of $786 million. Combining these two costs (operating cost and cancellations), OIG found the annual cost of delays for the air carriers at over $4 billion. The Air Transport Association (ATA) performed a similar study and, using only the schedule delay (not unscheduled), found the direct cost of delay to the ten major carriers was $2 billion. When ATA included the cost of passenger delay and other indirect costs, its estimate of the cost of delay was over $5 billion for 1999.
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To provide an independent validation of these numbers, the feasibility study developed a comprehensive estimate of delay cost that included direct airline operations, passenger costs, and cancellations together. Table 7 provides the starting point for this calculation by allocating the 89 million min of delay to three aviation sectors (carriers, air taxi, and GA) based on the proportion of delayed operations identified in the FAA Consolidated Operations and Analysis System (2001) database. The Federal Aviation Administration (1998) provides guidance on valuing the direct cost of an aircraft-operating minute and a passenger delay minute for these three segments and that data is described in Table 8. For example, the average cost of a minute of carrier aircraft time is $51.55 (fixed and variable costs included), there are an average of 114.75 passengers on a carrier aircraft that experience delay, and passenger time is valued at $0.45/min. Table 9 uses the information in Tables 7 and 8 to estimate the total cost of delay for 1999 in the NAS as $8.4 billion including direct aircraft cost, passenger delay cost, and cancellation cost. This estimate represents a comprehensive delay cost and is consistent with the estimates reviewed above from the OIG ($4 billion without passenger delay) and ATA ($2 billion for scheduled delay only and $5 billion including passenger delay but omitting unscheduled delay). Although Office of Inspector General (2000) found that weather causes approximately 70% of delay, it did not indicate what percentage is related to specific weather phenomena for which TAMDAR can improve forecasts. To provide a conservative value for the potential weather related savings, Table 9 identifies 50% of the total cost as a reasonable proportion of the delay costs that TAMDAR may influence.
Table 7 Allocation of delay minutes Delayed operations Total Carriers Air taxi GA
450,289 360,669 70,747 18,539
Delayed minutes Scheduled
Unscheduled
Total
22,609,046 18,109,219 3,552,212 930,845
67,368,277 53,960,121 10,584,543 2,773,642
89,977,323 72,069,340 14,136,756 3,704,487
Table 8 Aircraft and passenger cost data
Carrier Air taxi GA
Aircraft operating cost per minute
Average number of passengers per flight
Passenger delay cost per minute
$51.55 $13.00 $9.42
114.75 2.90 2.75
$0.45 $0.45 $0.52
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Table 9 Estimated weather related delay cost
Carrier Air taxi GA Total
Carrier cost
Passenger
$3,715,174,485 $183,777,826 $34,883,916 $3,933,836,227
$3,680,005,692 $18,268,647 $5,280,437 $3,703,554,776
A number of studies substantiate the 0.1% savings benchmark as conservative. For example, Allen and Gaddy (2000) studied delay issues at the Newark airport and found a number of cases in which improvements in basic weather information, such as TAMDAR is designed to provide, would have yielded delay savings as high as $1million for a single event. Similarly, Evans et al. (1999) found that improved prediction of wind shifts would reduce delay by 3000 h at Los Angeles International Airport alone.
5. TAMDAR business case summary Table 10 employs the NAS operational savings from TAMDAR at a reduction of 0.1% in delay and combines this with the other cost and savings factors discussed in the previous sections. In this analysis, TAMDAR has a positive present value over $13 million and an internal rate of return (IRR) of 24%. Sensitivity analysis of the calculations in Table 10 shows a robust business case since the nonrecurring cost estimates would need to nearly double for the business case to drive the $13 million present value into a negative value. Table 11 illustrates this point by providing the value to which the costs of equipping aircraft or the number of aircraft would have to increase to change the business case outcome. For example, considering the changes one factor at a time, the cost of equipping a package aircraft would have to increase from the base case estimate of $10,000 to $25,477. Similarly, the number of package aircraft would have to increase from 500 to 1230 to turn the base case negative. The base case was also examined for sensitivity of changes in savings for the projected radiosonde reductions and the impact of this change on the percent delay savings required for a positive business case. Table 12 summarizes the results using three scenarios: base radiosonde case (eliminate 21 sites), optimistic radiosonde savings (eliminate 28 sites), and no radiosonde savings. In the base case, the delay savings can be reduced by nearly half from 0.1% to 0.056% before the business case becomes negative. If the radiosonde savings become optimistic and increase by 25% from $2.7 million to $3.6 million, the delay savings required for a positive business case are only 0.034%. Finally, if
Cancellations
Total
$785,000,000 50% weather related
$8,422,391,003 $4,211,195,502
Table 10 TAMDAR base business case summary Cash flow summary Year
0
Cost summary Initial nonrecurring Annual data cost Maintenance Infrastructure Annual equivalent cost
1–10
$14,750,000 $1,401,600 $937,500 $600,000 $5,039,168
Savings summary Radiosonde savings (21 sites) Delay savings (% 0.1 reduction) Annual equivalent savings TAMDAR present value TAMDAR IRR=
$2,700,000 $4,211,196 $6,911,196 $13,148,337 24%
Table 11 Decision reversal levels for nonrecurring investment
Investment per aircraft Fleet size
Base package
Package reversal
Base regional
Regional reversal
$10,000
$25,477
$6,250
$15,065
500
1230
1000
2273
the radiosonde savings are eliminated, a positive TAMDAR business case requires a delay saving increase from 0.1% to only 0.12%. The bottom line of Table 12 lists the sensitivity of the business case IRR to each of the scenarios with a constant percentage delay reduction. For example, using a 0.2% delay savings results in an IRR of 55% for the base case, 61% for the optimistic radiosonde case, and 35% for the pessimistic radiosonde case.
6. Conclusion TAMDAR is complimentary to the current ACARS system and has the potential to improve short-term weather forecasts and yield significant societal benefits. This study identified a strong business case based on evaluating only the positive impact of this new system on the aviation sector. Even without valuing the varied
ARTICLE IN PRESS P. Kauffmann et al. / Journal of Air Transport Management 10 (2004) 207–215
215
Table 12 Sensitivity summary for radiosonde variation
Annualized cost of TAMDAR Savings Radiosonde savings Required delay savings for positive business case Percent weather related delay required for positive business case IRR if weather related delay saving is 0.2%
societal impact of improved short-term forecasts, the business case was insensitive to changes in the cost factors and saving benefits. TAMDAR success requires participation by the regional and package carriers. In the case of regional airlines, the transition to regional jets and other market shifts reduce the nonrecurring costs of implementing TAMDAR based on increasing adoption and wider implementation of the necessary data link equipment. On the other hand, package carriers are not planning to install the needed data link technology since it is not a necessity for their continued operational success. Consequently, installations in this segment are more expensive. Participation motivation on the part of both segments is cost sensitive and requires compensation for related costs including recurring and nonrecurring items. This expectation for reimbursement necessitates government involvement to defray these system costs. However, the potential to increase the safety and system efficiency of the National Airspace System justifies this commitment.
Acknowledgements We wish to thank the NASA Aviation Weather Information (AWIN) program that funded this research. The project report is contained in Old Dominion University Research Foundation Project Report (Contract L-11623). In addition, thanks are due to the many participants, including airlines, regulatory agencies, avionics manufacturers, and aviation experts, who gave their time to provide information for this study.
References Allen, S.S., Gaddy, S.G., 2000. Delay reduction at Newark International Airport using terminal weather information systems. Ninth Conference on Aviation, Range and Aerospace Meteorology, American Meteorological Society, Orlando. AMDAR, 2001. The Atmospheric Meteorological Data and Reporting Programme. UK Meteorology Office, Retrieved from the World Wide Web, April 6. http://www.metoffice.com/research/interproj/ amdar/index.html.
Base Radiosonde
Optimistic radiosonde
No radiosonde
$5,039,168
$5,039,168
$5,039,168
$2,700,000 $2,339,168 0.056% 55%
$3,600,000 $1,439,168 0.034% 61%
$0 $5,039,168 0.120% 35%
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