- Email: [email protected]
Flight safety, aircraft vortex wake and airport operation capacity
Air Transport
Flight Safety, Aircraft Vortex Wake and Airport Operation Capacity Victor V. VYSHINSKY
One of the major problems that challenge today's aeronautics is the problem of improving flight safety, A zone of increased hazard is the aerospace in the vicinity of an airport. Here, one of aircraft accidents" causes is wake turbulence generated by aircraft. The encountering of an aircraft on take-off or landing with the vortex wake of a preceding aircraft can lead to an accident especially dangerous near the ground. ccording to ICAO's forecasts, the required average armual growth rate of the world's air traffic over the next ten )'ears is ,,.~ ..,, for cargo and 5% for passenger transportation, which reflects the growth of the Earth's population and the deepening division of labour. The failure to realize the required cargo/passenger air traffic leads to significant economic losses (now losses of the USA aviation companies exceed US$3.5 billion a year [1]); restrictions on air traffic growth cost Western European countries' economies US$10 billion in the year 2000). By the estimate of the European Strategic Research Institute, !3 European airports will be capacity constrained by the vear 2010 even with substantial potential improvements and will not be able to meet the growing requirements for air transportation. A still more severe crisis is expected for airports of the AsiaPacific region (in the case of the normal development of their economies), where the annual air traffic growth is twice as
high. Japan plans to spend about US$4147 billion on the new airport creations. The construction of a new runway about 4 kilometres in length takes more than 10 years from the beginning of funding. The costs of a rnodern singlerunway airport total about US$5 billion (USA Denver). An airport on an artificial island (Cansa}5 Japan) will cost three times as much. As can be seen, extensive ways to solve the airport problems have exhausted themselves. At present growth rates it will be impossible for the aviation industry to meet the demand for the air travel by the year 2006 with the present aircraft, air traffic control and airport infrastructure. A way out of today's airport crisis is possible only by using new technologies aimed at decreasing safe-separation distances between aircraft both due to enhancements of aircraft's survivability in a vortex-wake environment and improvements in air traffic control and the creation of systems for timely detection of vortex wakes. Measures directed to artificial aging of wakes and a search
for aircraft configurations fa\'ourable from the viewpoint nf decreasing saDseparation distances [2] also should not be discarded. It is also necessary to answer the questions about optimum sizes of ultra-high capacity aircraft ~;)~r under study and development. Now 90% of annual air traffic growth is due to the increasing the number of flight,,, [3]. To the question "More often or more seats" AI answers by creating the A-3S0 super heavy aircraft. The main problem here is the possibility to utilize the standam safe separation matrix for it,
exploitation 141.
The ISTC projects Investigations into the trailing wakes ol aircraft have been performed at TsA(;I over manv years. ISTC l'roject #201-c>~ ("lnvestigati~m of Vortex Wake F\ olution and Fligilt Safety I~roblems '') has con tributed to the accderated dexelopment of these activities on a large scale. Ihc investigations were carried out in the fig lowing five directions: enhancing the aerodynamic model of the vortex ~akc',
Table I. Vortex wake issues in TsAGI in 1994-2000. Main teams, Projects' duration and cost. Aerohydromechanics
Physics of the atmosphere
Strength and aeroelasticity
Applied aeromechanics
Flight dynamics and control
ISTC Project #201-95 VORSAF
WAVENC # BE97-4112
ISTC Project #1018-98
INTAS Projects #632, #1815, #1816, #1817
ISTC Project #2086-p
01.04.95 - 30.09.97 US$330,000
1.12.97- 29.02.00 65,000 ECU
1.05.98 - 30.04.00 US$250,000
Two-year projects
One-year project U8576,000
Contact with Airbus Industrie 01,08,98 - 30,06,99
W
Air T r a n s p o r t
. . . . . . . . . . . . . . . . . . . . . . . . . .
studying the encountering aircraft from the standpoint of aerodynamic loads, ~tructural strength and flight dynamics. Issues concerning wake visualization ~cere studied separately (see table I). (~ollaborators of the Project were instit,ltes and organizations of USA (Boeing, NASA, University of California, "4cDonnell-Douglas), Europe (Airbus l ndustrie AI, Aerospatiale, British , ~erospace Airbus, Daimler-Benz ,~erospace Airbus DASA, German ,~erospace Research Est. DLR, ONERA, National Aerospace Laboratory NLR), J.tpan (Japan Aircraft Development Corporation, National Aerospace I,aboratory). ~he results obtained [5] have allowed ~,ne to pose the question about searching for concrete technical solutions to ~.afely increase airports' capacity. ISTC l'roject #1018-98 ("Flight Safety, Aircraft Vortex Wake and Airport Operation Capacity") was dedicated to this problem (table I). Collaborators of the Project were European institutes and organizations: A1, ONERA, CERFACS, NLR, 1)ASA, DLR. The following concrete measures were considered [6]: • The issues of alleviation of the trailing wake behind a heavy aircraft. The following possible means were investigated: redistributing the wing circulation over span and decreasing the maximum tangential velocity; multiple vortex system creation and diminishing the vortices span; small-scale turbulence effects on the vortices aging (the sources of it are engines, additional control surfaces, landing gear); • Means for wake visualization and self-visualization, when additional equipment can be installed on a heavy aircraft for illumination of its own vortex wake. Both active and passive methods for onboard and groundbased equipment were studied; • Creation of an early vortex wake encounter warning system with displaying an optimum avoidance maneuver (aircraft deviation by 15-20 m from a vortex core is enough for safely executing the landing or take-off operation). This research direction is first off all intended for general-aviation aircraft becattse their owners are ready to pay extra many for extra safety and extra comfort;
1%
SAFETy
6% mpaymeris to Participants • Equipment DMaterials mOther Direct Costs mTravel mBank fees mOvetlqead
2' 6%
Figure I. Financial structure of the ISTC Project #7078.
• Use of additional aerodynamic surfaces (for example, spoilers) for automatically compensating the trailing wake effect; • Creation of trailing wake turbulence flight simulators to be used for research (investigating the control and stabili~ of the encounter aircraft, evaluation of possible technical decisions, determining the safe-separation criteria) and training purposes (elaborating the pilot's skill to cope with hazardous situations). Financial structure of Project #1018 is represented in fiwre 1. Approximately the same structure was in Project #201.
Practical application of the results obtained Tile successful implementation of these studies was favoured bv the participation of TsAGI's scientists in the WAVENC Project Programme of Brite/EuRam (European Commission, contract number BRPR-CT97-0593) "WAke Vortex evolution and wake vortex ENCounter" [7] (table I). By using the experimental data obtained in the European research centers (catapult
setup of ONERA, wind tunnels of DNW) one has managed extra to validate the TsAGl-developed mathematical models. Very interesting practical application of the mathematical model developed during Projects implementation and TsAGI's experimental facility was the comparative investigation of B-747 and A-3XX wakes evolution and decay in the framework of the Contract with AI (table i). Practical realization of the techniques, in particular, the stochastic vortex wake model, will be the subject of the investigations in the framework of ISTC partnet's Project #2086-p of TsAGI and DFS (Deutsche Flugsicherung GmbH) "Wake Turbulence Problem in Frankfurt am Main Airport Final Approach Area" (table l). Concrete issues to be handled in this Project are aimed at safely tightening the air traffic in Frankfurt am Main's airport.
The INTAS projects The issues remaining unsolved are to be further considered in the four INTAS Projects (see table ll), intended for refining the effects of small-scale turbulence (#632) and engine jets (#1816) on the
Table II. Names of the INTAS Projects and proposed budget including teams from INTAS members. #632 "External flow turbulence scale and level effect on aircraft wake characteristics at low speeds" #1815 "Development of vortex wake visualization/detection methods via radiation and scattering fields sensing" #1816 "Theoretical investigations of the influence of the aircraft engine jet on the wake vortex formation" #1817 "Experimental and theoretical investigation of ion/molecular clusters in the subsonic turbulent flow"
I 1,~0114
£ 106,000 £ 105,000
£ 80,000 £ 150,000
AIR & SPACE EUROPE • VOL. 3 • No 3/4
2001
FLIGHTSAFETY Table III. Russian participants (* with taking into account participation of scientists, teams and organizations in several Projects). TsAGI
MIPT
MATU
STC FRI
GPI
All Projects
All Projects
#632, 1816
#632
#1817
IPC
CC
TASTC
lAP
N IIAO
#1817
#1817
#1816
#1815
#1815
Project no,
Number of Participants
Number of teams
Number of Organizations
632 1815 1816 1817
18 14 15 21
4 4 4 6
4 4 4 5
Total
62*
17*
1O* [3) Butterworth-Hayes Ph., The benefits of thinking small, Aerospace America 07 (1997) 4 5.
Table IV. European participants. AI 1
EADS Airbus 3
A M Airbus 4
AirbusUK 5
All Projects
All Projects
All Projects
All Projects
Total 13
(4) Jurgen T,, The Airbus A380 Programme the big task of Europe's Aerospace Industry, Book of Abstracts Fourth Community Aeronautical Days. 29 31 Jan, 2001, Hamburg, Germany.
vortex wake structure and the associated issues regarding the wake visualization (#1815, #1817). Together with TsAGI, participating on the Russian side are nine widely known research centers: Moscow Institute of Physics and Technology (MIPT); Military Aviation Technical University (MATU); Scientific Technical Center, Flight Research Institute (STC FP,I); General Physics Institute, Russian Acad. Sci. (GPI); Karpo\ institute of Physical Chemistry (IPC); Computing (~enter, Russian Mad. Sci. (CC); Taganrog Aviation Scientific Technical Complex (TASTC); Institute of Atmospheric Physics, Russian Acad. Sci. (lAP); Institute of Aviation Equipment (NIIAO) (see table III). European participants are presented in tabh' IV.
decisions can be suggested for improving flight safety in the wake turbulence environment ~md airport operational capacity. Wake vortex investigation is the exampie of the fruitful international cooperation. A unique experience gained over the last six years of continuous researches requires that it be practically embodied in the technical decisions usable for
Conclusions
References
Atmospheric vortices are very stable
administration, Aerospace America. 01
VictorV.Vyshinskyis Deputy Head of
(2001) 3.
Aerodynamics Division, Central Aerohydrodynamics Institute, TsAGI,in Moscow, [email protected]
formations featuring a slow mass, momentum and energy exchange with surrounding atmosphere, they are rather difficult for understanding. Concrete measures, concrete technical
world comn~unitv.
•
(5) Vyshinsky V.V., Soudakov G G , Investigation of the vortex wake evoM tion and flight safety, ICAS-96-1.11 3 (1996) 2590-2600 [6) Vyshinsky ~Z~4,Aircraft vortex wake flight safety and crisis of airports, ICAS 98-6.5.1 (1998) (7) De Bruin A., WAke Vortex Evolution and ENCounter (WAVENC), Air & Space Europe 2, No. 5, (2000) 84 87
Acknowledgements The work described in this paper was supported by funding from the
International Science and Technology Center (1STC) and the European Union. The attthor wishes to gratefully ackno;x ledge them for financial support and all participants of the Projects for fruitful collaboration. (1) Grey J., A mandate for the new
(2] Rossow V.J., Lift-generated vortex wakes of subsonic transport aircraft, Progress in Aerospace Sciences. 35, No 6 (1999) 507 660.
W
About the author:
Flight Safety, Aircraft Vortex Wake and Airport Operation Capacity Victor V. VYSHINSKY
One of the major problems that challenge today's aeronautics is the problem of improving flight safety, A zone of increased hazard is the aerospace in the vicinity of an airport. Here, one of aircraft accidents" causes is wake turbulence generated by aircraft. The encountering of an aircraft on take-off or landing with the vortex wake of a preceding aircraft can lead to an accident especially dangerous near the ground. ccording to ICAO's forecasts, the required average armual growth rate of the world's air traffic over the next ten )'ears is ,,.~ ..,, for cargo and 5% for passenger transportation, which reflects the growth of the Earth's population and the deepening division of labour. The failure to realize the required cargo/passenger air traffic leads to significant economic losses (now losses of the USA aviation companies exceed US$3.5 billion a year [1]); restrictions on air traffic growth cost Western European countries' economies US$10 billion in the year 2000). By the estimate of the European Strategic Research Institute, !3 European airports will be capacity constrained by the vear 2010 even with substantial potential improvements and will not be able to meet the growing requirements for air transportation. A still more severe crisis is expected for airports of the AsiaPacific region (in the case of the normal development of their economies), where the annual air traffic growth is twice as
high. Japan plans to spend about US$4147 billion on the new airport creations. The construction of a new runway about 4 kilometres in length takes more than 10 years from the beginning of funding. The costs of a rnodern singlerunway airport total about US$5 billion (USA Denver). An airport on an artificial island (Cansa}5 Japan) will cost three times as much. As can be seen, extensive ways to solve the airport problems have exhausted themselves. At present growth rates it will be impossible for the aviation industry to meet the demand for the air travel by the year 2006 with the present aircraft, air traffic control and airport infrastructure. A way out of today's airport crisis is possible only by using new technologies aimed at decreasing safe-separation distances between aircraft both due to enhancements of aircraft's survivability in a vortex-wake environment and improvements in air traffic control and the creation of systems for timely detection of vortex wakes. Measures directed to artificial aging of wakes and a search
for aircraft configurations fa\'ourable from the viewpoint nf decreasing saDseparation distances [2] also should not be discarded. It is also necessary to answer the questions about optimum sizes of ultra-high capacity aircraft ~;)~r under study and development. Now 90% of annual air traffic growth is due to the increasing the number of flight,,, [3]. To the question "More often or more seats" AI answers by creating the A-3S0 super heavy aircraft. The main problem here is the possibility to utilize the standam safe separation matrix for it,
exploitation 141.
The ISTC projects Investigations into the trailing wakes ol aircraft have been performed at TsA(;I over manv years. ISTC l'roject #201-c>~ ("lnvestigati~m of Vortex Wake F\ olution and Fligilt Safety I~roblems '') has con tributed to the accderated dexelopment of these activities on a large scale. Ihc investigations were carried out in the fig lowing five directions: enhancing the aerodynamic model of the vortex ~akc',
Table I. Vortex wake issues in TsAGI in 1994-2000. Main teams, Projects' duration and cost. Aerohydromechanics
Physics of the atmosphere
Strength and aeroelasticity
Applied aeromechanics
Flight dynamics and control
ISTC Project #201-95 VORSAF
WAVENC # BE97-4112
ISTC Project #1018-98
INTAS Projects #632, #1815, #1816, #1817
ISTC Project #2086-p
01.04.95 - 30.09.97 US$330,000
1.12.97- 29.02.00 65,000 ECU
1.05.98 - 30.04.00 US$250,000
Two-year projects
One-year project U8576,000
Contact with Airbus Industrie 01,08,98 - 30,06,99
W
Air T r a n s p o r t
. . . . . . . . . . . . . . . . . . . . . . . . . .
studying the encountering aircraft from the standpoint of aerodynamic loads, ~tructural strength and flight dynamics. Issues concerning wake visualization ~cere studied separately (see table I). (~ollaborators of the Project were instit,ltes and organizations of USA (Boeing, NASA, University of California, "4cDonnell-Douglas), Europe (Airbus l ndustrie AI, Aerospatiale, British , ~erospace Airbus, Daimler-Benz ,~erospace Airbus DASA, German ,~erospace Research Est. DLR, ONERA, National Aerospace Laboratory NLR), J.tpan (Japan Aircraft Development Corporation, National Aerospace I,aboratory). ~he results obtained [5] have allowed ~,ne to pose the question about searching for concrete technical solutions to ~.afely increase airports' capacity. ISTC l'roject #1018-98 ("Flight Safety, Aircraft Vortex Wake and Airport Operation Capacity") was dedicated to this problem (table I). Collaborators of the Project were European institutes and organizations: A1, ONERA, CERFACS, NLR, 1)ASA, DLR. The following concrete measures were considered [6]: • The issues of alleviation of the trailing wake behind a heavy aircraft. The following possible means were investigated: redistributing the wing circulation over span and decreasing the maximum tangential velocity; multiple vortex system creation and diminishing the vortices span; small-scale turbulence effects on the vortices aging (the sources of it are engines, additional control surfaces, landing gear); • Means for wake visualization and self-visualization, when additional equipment can be installed on a heavy aircraft for illumination of its own vortex wake. Both active and passive methods for onboard and groundbased equipment were studied; • Creation of an early vortex wake encounter warning system with displaying an optimum avoidance maneuver (aircraft deviation by 15-20 m from a vortex core is enough for safely executing the landing or take-off operation). This research direction is first off all intended for general-aviation aircraft becattse their owners are ready to pay extra many for extra safety and extra comfort;
1%
SAFETy
6% mpaymeris to Participants • Equipment DMaterials mOther Direct Costs mTravel mBank fees mOvetlqead
2' 6%
Figure I. Financial structure of the ISTC Project #7078.
• Use of additional aerodynamic surfaces (for example, spoilers) for automatically compensating the trailing wake effect; • Creation of trailing wake turbulence flight simulators to be used for research (investigating the control and stabili~ of the encounter aircraft, evaluation of possible technical decisions, determining the safe-separation criteria) and training purposes (elaborating the pilot's skill to cope with hazardous situations). Financial structure of Project #1018 is represented in fiwre 1. Approximately the same structure was in Project #201.
Practical application of the results obtained Tile successful implementation of these studies was favoured bv the participation of TsAGI's scientists in the WAVENC Project Programme of Brite/EuRam (European Commission, contract number BRPR-CT97-0593) "WAke Vortex evolution and wake vortex ENCounter" [7] (table I). By using the experimental data obtained in the European research centers (catapult
setup of ONERA, wind tunnels of DNW) one has managed extra to validate the TsAGl-developed mathematical models. Very interesting practical application of the mathematical model developed during Projects implementation and TsAGI's experimental facility was the comparative investigation of B-747 and A-3XX wakes evolution and decay in the framework of the Contract with AI (table i). Practical realization of the techniques, in particular, the stochastic vortex wake model, will be the subject of the investigations in the framework of ISTC partnet's Project #2086-p of TsAGI and DFS (Deutsche Flugsicherung GmbH) "Wake Turbulence Problem in Frankfurt am Main Airport Final Approach Area" (table l). Concrete issues to be handled in this Project are aimed at safely tightening the air traffic in Frankfurt am Main's airport.
The INTAS projects The issues remaining unsolved are to be further considered in the four INTAS Projects (see table ll), intended for refining the effects of small-scale turbulence (#632) and engine jets (#1816) on the
Table II. Names of the INTAS Projects and proposed budget including teams from INTAS members. #632 "External flow turbulence scale and level effect on aircraft wake characteristics at low speeds" #1815 "Development of vortex wake visualization/detection methods via radiation and scattering fields sensing" #1816 "Theoretical investigations of the influence of the aircraft engine jet on the wake vortex formation" #1817 "Experimental and theoretical investigation of ion/molecular clusters in the subsonic turbulent flow"
I 1,~0114
£ 106,000 £ 105,000
£ 80,000 £ 150,000
AIR & SPACE EUROPE • VOL. 3 • No 3/4
2001
FLIGHTSAFETY Table III. Russian participants (* with taking into account participation of scientists, teams and organizations in several Projects). TsAGI
MIPT
MATU
STC FRI
GPI
All Projects
All Projects
#632, 1816
#632
#1817
IPC
CC
TASTC
lAP
N IIAO
#1817
#1817
#1816
#1815
#1815
Project no,
Number of Participants
Number of teams
Number of Organizations
632 1815 1816 1817
18 14 15 21
4 4 4 6
4 4 4 5
Total
62*
17*
1O* [3) Butterworth-Hayes Ph., The benefits of thinking small, Aerospace America 07 (1997) 4 5.
Table IV. European participants. AI 1
EADS Airbus 3
A M Airbus 4
AirbusUK 5
All Projects
All Projects
All Projects
All Projects
Total 13
(4) Jurgen T,, The Airbus A380 Programme the big task of Europe's Aerospace Industry, Book of Abstracts Fourth Community Aeronautical Days. 29 31 Jan, 2001, Hamburg, Germany.
vortex wake structure and the associated issues regarding the wake visualization (#1815, #1817). Together with TsAGI, participating on the Russian side are nine widely known research centers: Moscow Institute of Physics and Technology (MIPT); Military Aviation Technical University (MATU); Scientific Technical Center, Flight Research Institute (STC FP,I); General Physics Institute, Russian Acad. Sci. (GPI); Karpo\ institute of Physical Chemistry (IPC); Computing (~enter, Russian Mad. Sci. (CC); Taganrog Aviation Scientific Technical Complex (TASTC); Institute of Atmospheric Physics, Russian Acad. Sci. (lAP); Institute of Aviation Equipment (NIIAO) (see table III). European participants are presented in tabh' IV.
decisions can be suggested for improving flight safety in the wake turbulence environment ~md airport operational capacity. Wake vortex investigation is the exampie of the fruitful international cooperation. A unique experience gained over the last six years of continuous researches requires that it be practically embodied in the technical decisions usable for
Conclusions
References
Atmospheric vortices are very stable
administration, Aerospace America. 01
VictorV.Vyshinskyis Deputy Head of
(2001) 3.
Aerodynamics Division, Central Aerohydrodynamics Institute, TsAGI,in Moscow, [email protected]
formations featuring a slow mass, momentum and energy exchange with surrounding atmosphere, they are rather difficult for understanding. Concrete measures, concrete technical
world comn~unitv.
•
(5) Vyshinsky V.V., Soudakov G G , Investigation of the vortex wake evoM tion and flight safety, ICAS-96-1.11 3 (1996) 2590-2600 [6) Vyshinsky ~Z~4,Aircraft vortex wake flight safety and crisis of airports, ICAS 98-6.5.1 (1998) (7) De Bruin A., WAke Vortex Evolution and ENCounter (WAVENC), Air & Space Europe 2, No. 5, (2000) 84 87
Acknowledgements The work described in this paper was supported by funding from the
International Science and Technology Center (1STC) and the European Union. The attthor wishes to gratefully ackno;x ledge them for financial support and all participants of the Projects for fruitful collaboration. (1) Grey J., A mandate for the new
(2] Rossow V.J., Lift-generated vortex wakes of subsonic transport aircraft, Progress in Aerospace Sciences. 35, No 6 (1999) 507 660.
W
About the author: