Analysis on variation of wake separation standard at home and abroad

Transcription

1 Analysis on variation of wak sparation standard at hom and abroad Abstract Zhiqiang Tian Civil Aviation Flight Univrsity of China, Guanghan, , China Aircraft wak is on of th important factors affcting airport capacity and flight safty. Rducing th minimum wak safty sparation and incrasing th numbr of aircraft tak-off and landing will hlp to allviat th flow control of larg airports and improv th airport opration fficincy. Our country has furthr rducd th wak saf sparation on th basis of th original waks safty sparation standard, which is in lin with th currnt ICAO waks saf sparation standard, which is hlpful for our country to carry on th rlatd xchang with othr countris in civil aviation wak. Th Unitd Stats FAA and Europan Control hav bn prfcting th proposd wak standards and thn (RECAT), gradually introducd a nw policy to rfin th wak safty sparation btwn aircraft. In this papr, th main aircraft in our country ar dividd and analyzd by RECAT for rfrnc of th forign rsarch rsults, and th vortx strngth of ach aircraft is compard, th latst study on th waks policy of forign countris is prsntd, which provids a rfrnc for th formulation of th waks policy in our country. Kywords Flight safty, Standard for saf sparation of wak turbulnc, Vortx strngth, Wak policy. 1. Forword With th incras of th numbr of flights, th air traffic managmnt is facing svr challngs in th nw situation. Th program is dsignd around th problms of rducing th landing and landing sparations of aircraft and nsuring th saf and fficint opration of th aircraft. Navigation facilitis and rgulation managmnt ar constantly updatd, among which, rducing th minimum wak sparation btwn aircraft is also an important part of furthr improving fficincy, and domstic and forign ar also activly xploring and updating. As arly as th 36th sssion of th Gnral Assmbly of th Intrnational Civil Aviation Organization, th Russian Fdration submittd th urgnt issu of th safty of civil aviation wak turbulnc. Among thm, th typical wak rlatd aircraft accidnts and accidnt symptoms ar pointd out. Europ and th Unitd Stats hav stablishd th Wak turbulnc Coordination Council and activly carrid out rlvant rsarch. Th wak r-classification is th bst proof, but for our country, Whthr considring th trnd of civil aviation dvlopmnt, or from th point of viw of safty or conomic bnfit analysis, th study of wak flow and th promotion of policy ar ncssary. In ordr to nsur th flight safty of th aircraft, China has introducd a sris of rgulations on wak spacing. Th minimum standard for wak sparation is stipulatd in th Air Traffic Managmnt ruls of China Civil Aviation in Th rgulations on th running of paralll Runway and instrumnt in 2004 stipulat th running of paralll Runway undr th minimum Wak spacing Standard. Th minimum Wak spacing Standard for A380 Supr larg aircraft in 2008 is stipulatd in th rgulations on Wak Typ and Wak spacing of Airbus A380 modls in In th advisory notic of Wak and paralll Runway Opration in 2015, th harm and avoidanc mthods of wak ar pointd out. As arly as 2000, A.Hinton and so on combind with wathr and wak charactristics, dsignd and updatd th aircraft wak sparation systm to incras th airport throughput, and providd guidanc and guarant for th minimum wak spacing safty btwn aircraft. In 2002, Hu Jun dmonstratd th minimum wak spacing standard undr radar control conditions in dtail [1], and mad a 53

2 comparativ analysis and study on svral kinds of wak spacing standards implmntd in th arly stag. Stvn Lang t al. [2] analyzd th chang of minimum wak safty sparation of aircraft undr ICAO wak turbulnc rclassification, and usd wak inducd roll torqu factor to judg th wak of th aircraft. Th usability of th saf sparation matrix for wak rclassification is provd. In 2011, Liu Fang [3] pointd out th importanc of wak spacing, and discussd th application and rduction of wak spacing. In 2014, Fay Wong t al. [4] analyzd th structur composition and application of wak spacing rduction tchnology at hom and abroad, and pointd out th futur dvlopmnt trnd of wak spacing distanc standard to wak sparation tim standard. In 2015, Li Yaowi [5]. Ni run Rabbit t al [6] mad a comparison and safty assssmnt of th currnt wak classification standard (RECAT), which is tstd and popularizd by FAA. Wi Zhiqiang t al. [7] compard with FAA RECAT1,RECAT1.5 and RECAT-EU, analyzd th opration ffct of wstrn countris, and prdictd th implmntation of RECAT in China. Th continuous study of wak provids a rfrnc for th improvmnt of waks policy in China. 2. Advanc of Wak spacing Standard in China In ordr No. 30 of 2017, China rvisd th wak sparations btwn aircraft. From th contnts of th rvisions, w can s that th classification of aircraft wak is still dividd into thr catgoris according to th maximum allowabl tak-off full wight of th aircraft. Howvr, th wak spacing btwn aircraft is basically in lin with th currnt ICAO wak sparation standard, and th wak sparation btwn most aircraft is rducd, and th influnc of wak on traffic flow is furthr rducd. Th main civil aircraft in China ar classifid according to th currnt wak sparation standard. As shown in figur 1, ach aircraft is classifid into thr catgoris: havy, mdium and light. Fig. 1 Wak classification of major civil aircraft in China Compard with th civil aviation rgulations bfor rvision, th radar wak sparation standards for diffrnt typs of aircraft running as shown in Tabl 1 ar obviously rducd, and ar basically th sam as th currnt ICAO wak sparation standards. B737 and A320 ar th most widly usd modls in our country. It can b sn from th tabl that thy blong to mdium-sizd aircraft. Th wak sparation btwn this typ of aircraft and havy aircraft is 9.3 km, which is 0.7 km lss than bfor. In trms of th numbr of tak-offs and landings of th aircraft pr day, Th capacity problm can b gratly allviatd. Tabl 1 currnt radar wak spacing standards in China Aircraft typ ladr followr Radar wak sparation (km) Havy 11.1 A380 Mdium 13.0 Light 14.8 Havy 7.4 Havy Mdium 9.3 Light 11.1 Mdium Light

3 Taking B and A320 as xampls, according to th nw standard of wak spacing in th Civil Aviation Air Traffic Managmnt Cod, th maximum tak-off amount of B as shown in figur 2 is kg, and th maximum tak-off wight of th havy aircraft A320 is 73500kg, which is a mdium aircraft. During dpartur, th minimum wak intrval btwn th B aircraft and th A320 aircraft was rducd from th original 10km to 9.3 km, and all wr saf. This can ffctivly incras th numbr of tak-offs and landings of th aircraft for busy airports. Improv airport flow control capability. Fig. 2 Wak spacing standard btwn havy and mdium machins 3. Discussion on rclassification of wak Both FAA and Europan control ar activly dvloping th Rcatgorization of wak, that is, furthr dividing th typs of aircraft wak and furthr rducing th standard of wak spacing btwn aircraft on th basis of safty. From th uniform wak spacing of th aircraft typ to th on-to-on partition btwn th aircraft typs, th wak spacing standard is mor rfind and accurat. In addition, with th incras of th short-rang paralll runway, th coordinatd tak-off and landing of th shortrang paralll runway is also th focus of domstic and forign rsarch. Sinc 2006, th (CSPR) has bn studying th saf wak mitigation program for th short-rang paralll runway. In 2008, D. Williams t al. [8] volvd an approach wak turbulnc to mitigat (WTMA), cross-wind conditions and rduc th wak spacing standard. In 2013, A. Tittsworth J t al. [9] pointd out th FAA rul, which consists of an off-sit wak turbulnc mitigation (WTMD), WTMA and RECAT as a complt st of wak mitigation schms to support th ralization of th nxt gnration air traffic systm (NxtGn) goals. According to Kutta-Joukowski thorm of lift loop, th intnsity of wak producd by aircraft is mainly rlatd to th wight, wingspan, and spd of th aircraft, so FAA RECAT1.5 classifis th aircraft according to its maximum tak-off wight and wingspan. Th aircraft wak class as shown in Tabl 2. Tabl 2 FAA RECAT1.5 typ wak classification Typ MTOW/klb WS/ft A B C >= >= >=WS>= >=WS>=125 D 125>=WS>=65 300>MTOW>41 E 90>=WS>=65 F =<41 =<125 For th main civil aircraft in our country, according to th classification of aircraft typ wak according to FAA RECAT1.5, At th sam tim, as shown in figur 2, th main civil aircraft in our country ar classifid into catgoris A, B and C,D,E and F. Hr, w can s that th larg aircraft A380 is classifid sparatly into catgory A, th havy aircraft is dividd into catgoris B and C, and th mdium-sizd aircraft is dividd into catgoris D and E. Light aircraft as Class

4 Fig. 3 Classification of main civil aircraft basd on FAA RECAT1.5 wak in China At th sam tim, th RECAT1.5 also mad a dtaild minimum wak safty intrval basd on th ability of th aircraft itslf to rsist th wak induction, still taking B and A320 as xampls, as shown in figur 3, th wak intrval btwn Class B and Class D aircraft. Compard with th currnt standards of wak sparation in China, th wak safty intrval btwn diffrnt typs of aircraft is mor dtaild, from th typ of aircraft typ to th typ of aircraft modl and th rlativ ordr of ach modl furthr dvlopmnt dirction. Fig. 4 standard for FAA RECAT1.5 wak spacing btwn catgory B and catgory D aircraft Th influnc of wak on th rar aircraft is affctd by th intnsity of th front wak and th ability of rsisting th wak inducd by th wak itslf. As shown in figur 4, th initial annular volum of th typical civil aircraft in China is much largr than that of th class D aircraft. According to th spac-tim circulation volution quation (1) of th dcay potntial vortx at givn viscosity, th variation of wak intnsity attnuation as shown in figur 5 can b obtaind. Th wak flow will drop rapidly aftr a fw sconds, but vn if it falls quickly, th intnsity of th wak flow will b strong nough for smallr aircraft to sriously affct th normal opration of th aircraft in a short priod of tim. Γ(r, t) = Γ 0 (1 xp ( r 2 /4νt)) (1) Fig. 5 initial wak intnsity of typical modls 56

5 Fig. 6 Wak intnsity attnuation In addition, Han Hongrong t al. [10] stablish a calculation modl of disturbd paramtrs, and dtrmin th aircraft safty intrval according to th maximum accptabl slop angl of th aircraft. In th rsarch, th aircraft safty intrval is usually dtrmind according to th roll angl and th wak vortx induction momnt factor. 4. Nw Dvlopmnt of Wak flow Rsarch FAA kps pushing forward in th rsarch of wak flow, and constantly rfins th saf intrval of aircraft wak. In th command JO , th aircraft Intgratd Wak Radar intrval Standard (CWT),) is continud to dscrib th pair-wis spacing matrix of th most common typ of aircraft idntifid by ICAO, th dvlopmnt of which dpnds on th wak data. Instad of wight-basd data. On th basis of th classification systm stablishd by th command JO on th radar wak turbulnc intrval, th aircraft grouping is furthr improvd. Dividd into catgory A-A388, catgory B-Pair-wis Uppr Havy Aircraft, catgory C- Pair-wis Lowr Havy Aircraft, catgory D- non-pair-wis havy aircraft, catgory E-B757, aircraft, catgory F-Uppr Larg Aircraft xcluding B757 aircraft, catgory G-lowr larg aircraft, catgory H-Uppr Small Aircraft with a maximum takoff wight of mor than 6985 kg up to kg, catgory I-Small Aircraft with a maximum takoff wight of 6985 kg or lss. At prsnt, small aircraft ar dfind as aircraft wighing mor than to kilograms, a valu changd to 6985 kilograms at th lowr boundary of a high and small aircraft, which would b consistnt with th boundaris of ICAO light and mdium aircraft; in addition, You know, thr ar som small plans in Class I. Th aircraft wak spacing critria, as shown in Tabl 3, may b usd in th following cass: (1) whn th aircraft in front of th aircraft is flying within 762m from th ground and 305m blow th fairway. (2) whn th aircraft in front of th aircraft is flying within 762m from th ground and 152m blow th fairway. (3) clos paralll runways which do not involv th dpartur of Class 2 aircraft bfor Class E aircraft. Issu wak turbulnc warning rcommndations and instructions and stablish horizontal intrvals in accordanc with Articl 2. No instructions shall b issud to prmit th passag of Class I aircraft on Class E aircraft. Tabl 3 Wak Turbulnc Sparation for Dirctly Bhind Followrs(km) A B C D E F G H I L a d A B C D E

6 r s F G H I Not: th minimum wak safty intrval of th aircraft bfor and aftr mpty spac is 4.63 km. In th approach procss, in addition to th abov rquirmnts, in front of th aircraft byond th landing ntranc to nsur th safty of wak as shown in Tabl 4. Tabl 4 Wak Turbulnc Sparation for On Approach Followrs (km) A B C D E F G H I L a d r s A B C D E 7.41 F 7.41 G H I Not: th minimum wak safty sparations of th aircraft bfor and aftr mpty spac is 4.63 km. Both FAA and Eurocontrol hav stablishd thir own standards for aircraft wak safty intrvals according to thir national conditions or gographical charactristics, and ar gradually updating thir wak standard policis. Thy ar moving from static wak sparations standards to dynamic wak sparations standards by continuously rfining th typs of aircraft, whil th wak intrvals btwn catgoris ar bcoming clarr. Espcially in th approach and dpartur squnc of aircraft in th clos paralll runway, a sris of masurs to mitigat th inlt and outlt wak ar implmntd, and th aircraft intrval is ffctivly rducd. 5. Conclusion This papr first introducs th nwly modifid aircraft wak sparation standards in China, classifis th main aircraft running in civil aviation in China, and compars th changs of aircraft wak intrvals undr th nw and old standards. Thn w try to classify th main aircraft of our country by FAA RECAT1.5, and dtrmin th safty intrval of wak flow according to th ordr of th aircraft bfor and aftr, so as to rduc th dpartur intrval btwn th aircraft and incras th throughput of th airport. In addition, th formulation of forign aircraft intgratd wak radar intrval standard is also discussd, which is basd on th masurd wak data. FAA and Eurocontrol mak th standard of wak intrval according to th local conditions. Undr th nw situation of th grat dvlopmnt of civil aviation, China should adjust th typ and quantity of aircraft in opration stp by stp, study th charactristics of wak, and constantly updat th rlvant policis and rgulations. Acknowldgmnts Natural Scinc Foundation Rfrncs [1] Hu Jun. Study on wak safty intrval in air traffic [D]. Nanjing Univrsity of Aronautics & Astronautics,

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