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Tu-204 has two engines PS-90A. Those engines are equipped with mechanical system that should prevent increasing of rpm if TR is not fully deployed. It is not clear if this system was bad adjusted (on both engines??) or if it doesn't work perfectly. MAK did some tests with RA-64050 to find the answer. I don't know details.
Anyway I suppose that it is not the cause of the accident but it was surely contributing factor. |
PJ2
Well, in my experience, reverser systems, including indications, were extremely reliable just the the stuff going on in Lauda etal is enough to suggest that todays reverser system suffer from multiple false interlocks and warnings requiring the crew to manually retard the throttles before something goes tits up when they expected forward thrust only. we finally had to add even a third manual lock (not at the engine level) to accomodate all these clap-track sensor foul-ups If we were to have tied all these interlocks into a FADEC I'm afraid we would have lost even more aircraft during the critical V1-V2 takeoff phase. Sorry but we do depend on the pilots even today :ok: |
Karel_x, Lomapaseo, thanks for your responses.
I certainly agree we still need pilots! I'm just stuck a bit on how these guys could have known that their reversers weren't fully deployed so that they didn't apply thrust the second time. I had read here somewhere that a relay that was supposed to prevent deployment was "stuck due to the cold" - that seems a bit implausible to me - I'll wait for the report and see what they have to say. From what I have heard MAK does good work. |
Originally Posted by PJ2
(Post 7711381)
I'll wait for the report and see what they have to say. From what I have heard MAK does good work.
Maybe KulverStukas can start some translating for us. But it is a big job to actually do a proper translation of an entire report. |
At least the conclusions are usually reproduced on avherald
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JammedStab, I don't think that full MAK report will be inside my skill and level of stamina of translation :) But if you interested in technical part of reverse malfunction, this is already covered by aviaforums and investigation. It affects only limited count of a/c equipped with Perm's engines, which are installed on 204-100B planes and which - because of bad practice of engagement and lousy maintenance - can be set to direct thrust by moving reverse levers in one move and with force about 20 kg. And this malfunction can be prevented by ajustment of prevention lock on engine. Amendments to maintenance manuals has been already issued.
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IMHO, the list of causes and factors could look like this:
1. Uncooperative atmosphere in cockpit 2. High speed landing with late touchdown 3. Bad manipulation with levers of TR 4. Lack of SOP action: - FE: reports IDLE REVERSAL ON - FE: checks Spoilers Auto Function, if it doesn't work, deploys them manually by lever - FE: reports SPOILERS, AIR BRAKES DEPLOYED 5. Repeating useless attempt to TR 6. No attempt for Go Around 7. Engine mechanical interlocks - lack of maintenance or design fault 8. Lack of crew training Without spoilers, the breaking action of gears is very, very low, breaking force of spoiler is missing too and with light a/c in a crosswind, the WoW switches may not be activated. Without WoW, hydraulic of TR are electrically blocked... With good mechanical interlocks on engines, they cannot stop too, only their speed was lower. Force for TR levers are about 3 kg, mechanical stop (TR idle) needs twice a more of force to overcome it. As supposed in our case, with unadjusted mechanical interlock on both engines, the force could be about 20 kg (Kulverstukas) to overcome it regardless of blocking. |
"On Jun 18th 2013 Rosaviatsia announced, that the air operators certificate has been renewed and permits Red Wings to again carry out passenger scheduled and charter flights as well as cargo flights."
In Avherald. :rolleyes: |
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Final report published today.
Tu-204 RA-64047 29.12.2012 Investigations PS: Karel X, your summary was right and almost in exact words of report. |
Final report published today... |
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Here is Avherald's approximate translation w slight revs
Misalignment of mechanism and locks of thrust reversers on both engines as well as inappropriate actions (not in accordance with the flight crew operating manual) by the crew during the landing run that resulted in lack of effective braking overrunning the runway and colliding with obstacles at high speed (about 190 kph/102 knots), the destruction of the aircraft and loss of life. Contributing factors were: - lack of documentation in what sequence the adjustments and checks of the engine control system should be performed upon replacing the engine control system as well as lack of documentation on the rigidity of the controls and thrust reverser locks. This factor only becomes relevant in a handling of the thrust reversers in violation of the flight crew operating manual. - inconsistencies and contradictions in the maintenance manuals of the aircraft and engines. - lack of a formal procedure for maintenance organisations engaged in replacing engine management systems (including control mechanism and thrust reverser locks) to provide feedback to the aircraft and engine manufacturer in a timely manner to eliminate defects. - unstable approach and significant speed exceedance (45 kph/24 knots), that resulted in a prolonged flare, significantly increased landing distance (by about 950 meters), soft touchdown (+1.12G) preventing simultaneous activation of left and right gear compressed signals and thus preventing automatic extension of spoilers and air brakes. - lack of checks by the crew for extension of spoilers and air brakes - lack of extending the spoilers manually - violation of the flight crew operating manual by the crew with respect to the use of reverse thrust, evidenced by the application of maximum reverse thrust in one motion without pause at low reverse thrust and without checking whether the thrust reversers had deployed, which resulted in an increase of (forward) engine thrust. - absence of a (combined) gear compressed signal (more than 5.5 tons of weight on each main landing gear) throughout the entire landing roll and the crew's failure to extend the spoilers manually resulted in the thrust reversers remaining stowed. - poor cockpit resource management by the commander throughout the entire flight, which in the approach phase led to lack of monitoring of flight remaining within stabilized approach criteria and the runway overrun - unsatisfactory organisation of flight operations and non-functional safety management system at the operator, unsatisfactory formal verification of qualification of flight instructors to conduct pilot proficiency verifications, lack of proper monitoring of qualifications and flight operations [using FDR readouts] by the operator made it impossible to identify and eliminate systemic weaknesses in pilot techniques including speed control on landing and use of thrust reversers. - absence of periodic training of flight crew in reacting to scenarios involving the malfunction of landing gear switches requiring the manual extension of spoilers and speed brakes. The techhnical possibilities at the simulators do not permit to work such scenarios. |
Thank you, vovachan !
'Never thought to have a peek there. (still chuckling over the irony that "nonsense" would have posted a link to gobbly-gook ! ) |
PS: in the Soviet days all FDRs were decoded after every flight so Big Brother was always watching you. Not any more
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Considering data processing capabilities in the Soviet times were somewhat lacking, I have some doubts as to that last statement.
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2 flyboy:
Yak42, Tu134, Tu154, IL62, IL86 - EVERY flight had being decoded |
in the Soviet days all FDRs were decoded after every flight so Big Brother was always watching you |
end to top it off ......no Emas!
Why don't airports with their huge profits, install these on EVERY COMMERCIAL RUNWAY! MANDATORY!! Oh:ugh:, I know, forgot :} ... aviation is ALLLL about profit! Just look at that #%$@ little adi that I have to work with when the plumming hits the fan... |
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