Aircraft Crash in Moscow

[PJ2]

Eugr, thank you very much.

[Kulverstukas]

The state air transport agency Rosaviation said it was suspending Red Wings operations.

"Red Wings is experiencing a deficit of financial resources to ensure the current operations," Rosaviation said following a probe into the airline after the December 29 crash.

... the probe had exposed "numerous significant violations in the organisation of flights, technical maintenance of aircraft, training of pilots and other shortcomings."

The flights will be suspended from Monday, Feb 4, said the statement, encouraging those who were set to fly with the company in the near future to return the tickets.

Owner said that company will not operate again even if suspension will be lifted. He again begin his old song about "Putin's hairy hand".

Lebedev whose company operates a fleet of modern Tu-204 jets said the state watchdog was suspending the company's operations without a reason.

"Russian officials decided that the Tu-204 is dangerous and because we are the only company to fly Tu-204 planes (lie! ) they decided to suspend us and not the plane type ," he told AFP.

PS: As we can see, it is airline that is grounded, not aircraft.

UPD: Lebedev refuted the statement that necessarily closes airline. "I did not say that. I said that this is a possible option. I will decide based on the situation. I will talk to all members of the government, I do only with the Minister of Transport said, and then we will make sensible and informed decision."

[Karel_x]

He again begin his old song about "Putin's hairy hand"

In cases like this the Rosaviatsia suspend or take away AOC very often. In last year for example Yak Service afer Yaroslavl accident, or RusAir after Petrozavodsk accident.

Who is Lebedev, company owner, oligarch, multibillioner and user of brute force?

Russian billionaire Lebedev charged with hooliganism, faces prison - Rough Cuts - YouTube

[Kulverstukas]

Hmm... If anybody are interested in this video, then I can comment that guy who got this blow is famous with saying "who do not have a billion goes to arse" and since begining of the Year is kept in jail at Camodgia.

PS: Lebedev already dumped one airline.

[Sunamer]

Although I have to admit that Lebedev (who had problems with political elite before since he started to support some of russian political activists) gave (though not by his own actions) the formal reason for the "elite" to deal with him.


I think it is pointless to bring along political part here since it is not the matter of the thread and neither Putin nor Lebedev were sitting in the cockpit of the AC in question.

[Kulverstukas]

UAC (Tupolev) conducted 3 test flights to confirm that there was possibility to avoid accident. In short, even with landing on one gear AND switching direct thrust on instead of reverse, reaching 230 km/h at the middle of rvy, crew still have chance to stop plane before the treshold by using manual spoilers, no matter with or without reverse.

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[Speed of Sound]

So basically saying that the initially poor landing was recoverable?

[Kulverstukas]

Yes. It seeems that Point Of No Return was second reverse engagement.

[PJ2]

Kulverstukas;

Thank you for this information.

These "tests" miss the point.

Under no operational and technical circumstances should above-idle engine thrust be available / selectable to cockpit crew when the reverse selection has been made and the reversers are not in the fully deployed position.

What have I missed in the intent of these tests? For me, this smells of finding ways to blame the crew for the overrun. I don't know the actual operation of how reverse is selected in this aircraft, but is there any news regarding fixing the system that permitted above-idle thrust with reversers stowed while reverse was being called for by the pilot?

[Sunamer]

I think the point is that even with nominal forward thrust instead of the reverse one, AC can stop safely.

[PJ2]

Originally Posted by GobonaStick

You can't design out every possible combination of mishap. . . . Sometimes you just have to rely on people thinking before acting.

Agree. The A320 squat-switch problem in the overrun accident at Warsaw is another example. However people must act on known data or best guesses. Selecting reverse on landing is a normal procedure, the mechanical aspect of which is rarely prone to failure. The pilots could not have known that the reversers were not deployed and, having selected reverse, operated the thrust levers in accordance with that understanding. We could argue that the second application of thrust was "the cause" of the overrun but the source of the original problem was a reverse system design that permitted higher-than-idle thrust without deployed reversers while the thrust levers were in the familiar, reverse-thrust position. How does one apply "think before acting" in such a circumstance and still keep the airplane within the confines of the runway?

Originally Posted by Sunamer

I think the point is that even with nominal forward thrust instead of the reverse one, AC can stop safely.

Not sure what "nominal" means but if it means idle or close to idle forward thrust there is again nothing to be proven because that is a certification standard - ie., reverse thrust is not counted in stopping distance calculations.

And if it has been proven that the airplane can be stopped within the confines of the runway at thrust levels greater than idle, what has been proven except that? Do we then blame the crew for not, "thinking before acting"? How does this advance understanding for others such that another accident is prevented? If you'll recall, this was the second event of this type on this type of aircraft, the first one having occurred a week or so prior to this accident.

[lomapaseo]

These "tests" miss the point.

Under no operational and technical circumstances should above-idle engine thrust be available / selectable to cockpit crew when the reverse selection has been made and the reversers are not in the fully deployed position.

What have I missed in the intent of these tests? For me, this smells of finding ways to blame the crew for the overrun. I don't know the actual operation of how reverse is selected in this aircraft, but is there any news regarding fixing the system that permitted above-idle thrust with reversers stowed while reverse was being called for by the pilot?

Lots of what ifs have to be considered when designing systems. Redundancy is the key to descision making. One of the major tenants is to err on the side of full takeoff thrust available should the pilot elect that action. If this is not what is wanted the pilot always has the ability to pull the cock on the engines and use the brakes. Even in a confused state this should be an inherent feature available.

OTOH as a logical state it's preferrable that full forward thrust to reject a landing can be quickly obtained.(spool up times start the clock)

Given the possibilities for short times for decision making it seem the pilot has more time to make a stop decision than to make a go decsiion.

IMO This crew just didn't sort this decision out in a reasonable time.

I wouldn't want to redesign the system to furthur reduce the time to make a "Go" decsion by putting in yet another interlock.

[BOAC]

Originally Posted by PJ

The pilots could not have known that the reversers were not deployed

- was there not mention of some 'SOP' call required from the 'flight engineer' to confirm reverser deployment? 'Reverser green' or similar?

[Sunamer]

2 P2J
Not sure what "nominal" means

I apologize for this term, what I meant was 'normal'. So, normal full reverse thrust setting but only in direct regime (N1 ~80-84%)

from www_flightglobal_com
The pilots also simulated the incorrect engagement of the thrust-reversers which resulted in the Red Wings aircraft's accelerating along the runway.

As the Tu-204SM reached a speed of 124kt (230km/h) the test crew manually deployed the spoilers and activated the brakes.

"The landing distance achieved confirmed it was possible to complete the landing on the runway even after the emergency situation and improper actions of the crew during the initial touchdown phase," says United Aircraft .

So, I guess even with another test that's should shed some light on how actually reverse thrust level mechanism works, in the case it will show abnormality in logic of its work, UAC already have something to cover their butts with.

2 BOAC
was there not mention of some 'SOP' call required from the 'flight engineer' to confirm reverser deployment? 'Reverser green' or similar?

FE should confirm that reverse is available according to FCOM and the problem with RT was mentioned here in posts 455, 459.

http://www.pprune.org/rumours-news/5...ml#post7653562

[Kulverstukas]

BOAC - was there not mention of some 'SOP' call required from the 'flight engineer' to confirm reverser deployment? 'Reverser green' or similar?

Yes, there is - right in FCOM. Moreover, there was FE report "reverse NOT engaged".

[BOAC]

See post #513? I'm not sure what is 'not true'? I was answering PJ2 in post #509..

[Karel_x]

Tu-204 SOP

CAP at touchdown:

- В момент касания:"МАЛЫЙ РЕВЕРС"

At touchdown: IDLE REVERSAL!

F/O consequently:

- Переводит РУР в положение ПРОМЕЖУТОЧНЫЙ УПОР

Moves levers to a position Intermediate Stop

FE after nose gear down:

- "МАЛЫЙ РЕВЕРС ВКЛЮЧЕН"
- Контролирует автоматический выпуск интерценторов и воздушных тормозов (в случае невыпуска выпускает рукояткой ИНТЕРЦЕПТОРЫ)
- "ИНТЕРЦЕПТОРЫ, ВОЗДУШНЫЕ ТОРМОЗА ВЫПУЩЕНЫ"

- Reports IDLE REVERSAL ON
- Checks Spoilers auto function, if not works, deploys them manually by lever
- Reports SPOILERS, AIR BRAKES DEPLOYED

CAP:

- Убедившись в правильном положении самолета относительно оси ВПП:"МАКСИМАЛЬНЫЙ РЕВЕРС"

After verification alignment with the RWY axis REVERSAL FULL!

...and so on

http://aviadocs.net/RLE/Tu-214/CD1/R...4_RLYE_kn1.pdf

[uitauoesnth]

I have worked on FADEC software for Large Civil Aircraft:

In the software that I have worked with, when thrust reversers have been commanded, engine thrust cannot be increased until the software is absolutely sure that the mechanism is locked in place --- exactly to prevent this sort of accident.

FADEC has been around for 30 years, and these sorts of common-sense protections are a big part of the reasons that reason that it exists. If you can be confident that you know the position of the TR mechanism, then it's a very simple task to limit engine power to some idle while the mechanism is in transition -- I am somewhat surprised that a extremely modern engine does not have this functionality: I can vouch for the fact that engines had it 20 years ago.

I also find it hard to fault the pilots for the crash given that the TRs operated so counter-intuitively: Thrust Reversers are designed to slow a plane down. Instead, they made the plane speed up. That means they worked the exact opposite of how they should have done.... I'm not sure if there is a way they could possibly have behaved worse in that situation.

[lomapaseo]

it's a very simple task to limit engine power to some idle while the mechanism is in transition

the problem is the reliable determination that the reverser is in transition.

One little bobble on take off would be very very awkward.

Software is easy and the reliability of FADECs are adequate to do the job. It's the reliability of the command and motion structure of the reverser that precludes idle until you are absolutely sure that the idea is to stop and not to go.

[PJ2]

Hi lomapaseo;

the problem is the reliable determination that the reverser is in transition.

Well, in my experience, reverser systems, including indications, were extremely reliable. Once in a while we saw a "sticky" reverse cascade on a DC8-53 (PW, not RR) aircraft but the system was not prone to anomalies or failure. FADECs, as has been pointed out, have contributed enormously to reverser reliability in more complex (sensor/software) systems. There was just never a time in the aircraft I flew when one could get more than idle reverse thrust until the reversers were solidly in position. So a system in which this can happen is a significant anomaly in the industry and isn't primarily a "pilot problem". No matter what the pilot does, it should never be possible to obtain more than idle thrust until all reversers are deployed, and that has been my experience in all types flown. The systems are extremely reliable in both the takeoff and landing cases described.

BOAC;

Sorry for the late reply.

Yes, I do recall something in the thread regarding the monitoring and calling of "reverse green" or whatever the verbal affirmation was/is, and I see Karel_x has provided information on the SOP - which seems pretty straightforward and in line with what other familiar procedures for use of reverse on landing are.

This isn't a DC8-era airplane, it is a relatively modern, computerized airplane. It is entirely within industry design experience that if there is no indication that reverse is fully engaged then in system design that should preclude the application of more than idle thrust, period.

Until now I've never even heard of a system that would permit otherwise. Even if just the cockpit indication fails then only idle reverse should be available and with FADEC that is what happens, at least on Airbus aircraft.