Stuck thrust lever B733 sim scenario

[W.SHIRRA]

Hi all!
I was given the following scenario in the sim: before the approach one thrust lever got stuck at 77% N1.
I elected to shut the engine down and fly a single engine approach.
Boss said NO! you have to fly it like that, managing drag with gear and flaps, and shutting it down, MAYBE, at a later stage (on the runway).

Keeping the engine running would seem a good safe idea, but I think there are statistically more chances for the crew to screw up with an engine running at low power when it should be at high and at high when it shoul be at idle.
I had to order my copilot to shut it down after touch down, but what would have happened if he shut the wrong engine down in the hurry?

Flying the whole approach single engine at least the pilots know exactly what to do - and are used to it.

[Notso Fantastic]

Gotta agree wid da Boss! Why subject yourself to the risks of going SE when you can get yourself into a high drag situation and use thrust on the other to keep going?

[Phoenix_X]

I don't know -- there seem so be significant risks involved with operating one engine on a relatively high thrust setting. It's something you're not trained for and can make life quite difficult. You're already on the approach, IMHO SE risks may not be as high as flying with one engine stuck at high thrust.

[18-Wheeler]

Agree with the boss in the sim - In the real world do as you think best, based on your training, SOP's, situation, and experience at the time.

[Geardownandlocked]

I'm not familiar with 737 procedures etc, but I would definitely shut the engine down if the other wasn't showing any signs of problems. It's so easy to screw up the approach if you have one engine running at 77 % if you have never done that!!!

In my opinion, your instructor just loves this scenario and knows an easy way to handle such an approach, but what if you have never done it before???

If you feel more comfortable shutting it down, for christs sake, shut it down.

GDAL

[Hudson]

Don't you just hate idiot instructors who play silly bug***ers in the simulator? I do not recall ever seeing this scenario in the Boeing published type rating syllabus - and nor should it be.
Ask him to do a demonstration for you - that usually fixes the fools.

[lomapaseo]

Too much thrust on one engine in real life has a much higher bad outcome than the other way arround.

It ain't a big deal when you can trim for it, but when you are doing hand and feet stuff and then have something else go a teensy bit wrong it screws with your brain trying to adjust assymetry.

I've seen several experiments run on pilots where they got too much thrust and those that didn't shut down the offending machine often couldn't handle deteriorating situations.

[411A]

Had a thrust lever (#1 engine) 'stick' at cruise setting on a Lockheed TriStar enroute VIE some years ago. First Officer was flying.
He looks at me and says...."ah, you want to do the landing?"

My reply was..."certainly not, you're a good stick and rudder guy."

He suggested that the engine should be shutdown, as handling would be more predictable. And he was absolutely right. IMO.

By the way, his total flying time (behind the pole) was 700 hours.
Proper training pays off, every time.

[Agaricus bisporus]

<<Too much thrust on one engine in real life has a much higher bad outcome than the other way around.>> (I can only assume you don't mean this is more hazardous than too little thrust on just one engine, which is what you appear to have written...)

How do you achieve more thrust on one side than in the SE go around case, one of the more hazardous of the "non standard" maneuvres?

No! Surely the point is the instructor was making (and I'm hypothesysing here) was that a running engine is a useful engine. It makes hydraulic pressure, electrics and thrust too. The harder scenario is surely one where all thrust (100% of it) is on one side, plus short of Hyd and a Gen (APU notwithstanding). This stuck thust scenario provides you with:

1) less asymmetric thrust than a single engine (if you were to shut it down) which must be safer and easier to handle.

2) Hyd and Elec that you would otherwise lose if you shut it down, making systems management easier.

3) much closer to full power for a go around if needed, again better than the SE case.

After landing it will give you useful reverse cancellable via the start lever.

Apart from which its a good chance that the stuck lever was caused by a frozen teleflex that will thaw at lower levels and restore full use of engine. Even so, it's Boeing built, so use all your strength to try to free it. You won't break anything (except your hand, or the ice blockage...)

Just an idea!

[Capt Pit Bull]

I'v had stuck thrust levers on 3 different occaisions, on 2 different types (ATR and Avro RJ).

So its by no means a 'silly ******' scenario, Hudson!

Shut it down or not?

Lots of different factors to go into the melting pot.... I won't insult everyone by listing them, but here is one that is well worth considering:

Its highly likely to be caused by moisture ingress to the control run. This was the cause of all 3 jams, we kept the engine running, and regained thrust lever / throttle movement eventually during the descent.

The RJ actually has a procedure for it; basically engine / airframe anti ice on for the affected wing / pylon, to get as much hot air moving around as possible and try and thaw things out. It does eventually lead you down the path of shutting the engine down if movement is not regained... however, thats a 4 engined aircraft.

Incidentally, though its not part of the original question, can I offer up the following generalised point for everyones consideration?

Do not make the mistake of thinking that shutting down the engine will just give you a simple assymetric approach and landing.

It MAY do... but the odds are, depending on the type of aircraft and what position the lever is stuck in, that there will be some system interlock complications.

For example, will you be able to select reverse? Will ground spoilers auto deploy? Will you be able to use the airbrake to manage your descent? Will autobrakes work? If not, they are all manageable issues, but I would think everyone would agree that forewarned about them would be a great help.

For example, sitting in the cruise over France, as we worked through the depths of the flight manual to find the procedure a plan was already forming in my head... 'its probably frozen, it'll probably thaw, we'll just start descent a bit earlier than usual and use handfuls of airbrake if we need it'. Excellent basic plan, with 1 minor drawback... it was rubbish! With number 1 or 4 Thrust lever forward of ((some number I forget now)) Throttle quadrant angle, airbrake is inhibited on the RJ. Since engine 1 throttle was jammed, airbrake just wasn't going to happen.

So I guess what I'm saying is nothing is simple! When it comes down to it, how well do you really know your type?

Anyhow, lets be careful up there....

CPB

[LEM]

If boss was able to insert that problem in the sim, that means the scenario is possible.
I wouldn't shut the engine down in cruise, but before the approach, definitely yes .
There are risks associated with both philosofies: if you shut it down the only risk is having an eng failure on the other one.
But if you keep it running the risks are higher: first of all you are not trained to do that; second you have no clear pattern ( for a go around, for example) with an engine which is producing a thrust which is no meat nor fish; third, when the time comes to shut it down -after touchdown at latest- better you don't make mistakes: you'll be on the grass before you realise it, and not with idle as it usually happens, but with 77% thrust on one side!

Flying a single eng approach is a piece of cake, people fly 3 hours on one engine in the middle of the ocean, but how many accidents/incidents have happened with asymmetrical high thrust?

Did boss give you such an analysis of all the risks associated in the debriefing, or just he told you "NO, do it this way!"

[Anthony Carn]

There is a breed of simulator instructor which takes the view that if you don't deal with scenarios exactly as they would deal with them, then you are incorrect. I think that this is a bit poor, but I've encountered it and had it described to me by colleagues many times.

What's incorrect is the attitude that there's only one way to skin a cat !

I can't resist giving my solution --- My personal preference would be to keep the engine going for as long as it did'nt cause difficulties eg cruise, descent, in fact, possibly all but the intermediate and final approach. It would require some familiarisation with the situation to determine the range of possibilities, hence my proposal is vague in terms of when to shutdown, or even if it would be necessary. My overall philosophy would be to keep te engine going for a long as sensible, but see below.

The Captain should decide who is to be the handling pilot. (the Capt. in my view should be handling in this case).

I would use any time available, or make time, fuel permitting (eg by holding) to :

(a) Try to resolve the jammed throttle problem.

(b) If (a) unsuccesful, very thoroughly review the potential shutdown procedure with my colleague, revising the need for confirmation by BOTH crew members of correct throttle/fuel lever/whatever etc BEFORE anyone moved anything to off/closed/shut. Some items of the procedure could be completed in anticipation eg ignition settings, de-icing system implications etc etc.

(c) Inform ATC and arrange a "calm" approach. Consider diversion to longer runway/better aids/better emergency cover/ better maintenance.

(d) Ensure that any shutdown would not be coincident with high workload phases of flight, especially the final approach. Basically decide to either shutdown or not to shutdown in very good time.

(e) Review the need and procedure for shutdown after successful landing. (won't stop too well with 77% N1 I'm guessing and reverse is locked out due to no idle throttle position).

(f) Try to decide how much degradation in landing distance might be incurred -- is the runway going to be long enough ?

(g) Review the procedure for relight of the affected engine, to avoid delay should relight be necessary, for whatever reason.

(h) Brief the cabin crew

(i) Inform the passengers, if considered necessary.

(j) Inform Company, time and workload permitting.

The above would need to be amended according to timescale and proiorities. I always remind myself throughout -- "Aviate, Navigate, Communicate" in that order of priority.



My main point, however, is that if X pilots contribute here, then there could easily be X proposed solutions to the situation and many of them would be just as valid as any of the others. No simulator instructor should dictate that their solution is the only one. To hear his suggested method, without obligation, would definitely be worthwhile, though. Maybe their solution would be better, in which case something gained !

Always willing to learn. Never seem to stop !

All of the above is just IMHO.

[lomapaseo]

There are multiple ways to get too much thrust (and too much is anything more than expected or commanded).

Stuck cockpit levers can be quite nasty if unrecognized and autothrottle is connected. However far worse are stuck fuel controls on engines. There are some failure modes where cockpit levers will no longer command the engine and instead the engine fails-safe to the last power setting or worse it simply runs up on its own to its max limit. All have happened.

[LEM]

Right, typically on big airplanes where the fuel is controlled electrically only.
Typically on Boeings that have all the E&E bay located in the worst possible place....
See the accident of F-GITA at Tahiti, where the crew couldn't shut n°1 down because the E&E bay was in the water after the overrun...

[Maximum]

Trouble with your instructor's scenario (if he's saying his way is the only way) is that it's so specific - what if the thrust was stuck at 90% or 40% for example?

Two points to ponder - if you leave it running, do you plan for a flap 15 landing and use the QRH checklist for this - GPWS warnings with thrust lever asymmetry on the approach spring to mind. And what go-around flap setting will you use with thrust available less than normal two engined go-around?

And the big one - landing. If you leave it running, the flare's gonna be mighty interesting as you cruise along in ground effect with 77% N1 on one side, and large, changing rudder inputs being suddenly needed so close to the ground. And if you decide that the co-pilot will shut it down in the flare, all the normal cross-checking has gone out the window - it'll be very interesting in this rushed situation if he/she shuts down the wrong one.

Then, once on the ground, if you've decided to leave it running until the landing roll, things will get very interesting again as you're stuck between running out of runway or falling below Vmcg before it's shut down. And as Anthony Carn has already said, thrust reverser won't work.

Being devil's advocate to some extent, as unusual situations like this must be evaluated on the day, but I definitely prefer the relative predictability of a shutdown. The shutdown has you working within the SOP's - the other way, you're out there on your own.

[HotDog]

LEM, most all modern jets that I can think of have their E&E bays in the lower 41 section, it's not just a Boeing design. Air France couldn't shut down NO1 because they lost the battery bus once they hit the water. With a power failure, the fuel shutoff valve fails safe in the open position. They should have executed a go around and shut that engine down, they would not have finished in the water. I believe the aircraft was recovered and put back into service. I also seem to recall that the cause of the accident was ultimately put down to pilot error apart from the FCU malfunction. Lucky nobody was hurt.

[LEM]

There was no FCU malfunction, the overrun occured because the crew didn't know that at the end of the VNAV descent, which coincided roghly with the MAP, the autothrottle would have commanded go around thrust (incredibly, during the investigation, they found out all other AF 744 pilots didn't know as well this behaviour).
The copilot, when he felt the thrust levers advancing, instead of disconnecting pulled them back and hold them back (!), yes, all except N°1 (small hand maybe...).
At touchdown of course there was no spoiler nor autobrake, nor the captain was aware of what was going on.
Despite heavy braking, eng 1 was still producing full thrust when they skid to the right in the lagoon...
Firefighters eventually shut the engine down with water...

F-GITA was returned to service, and the NTSB recommended the E&E bay shouldn't be positioned there in the next millennium...:rolleyes:

[skinteastwood]

This thread is by far one of the most interesting that I have read here in some time, free (as yet) of the back-biting and bitching which usually occurs when people express a difference of opinion on PPRune!

My question, as a non pilot, would be this; what would your procedure be if BOTH thrust-levers became stuck on (for argument's sake) 77%?

Thanks and regards,

Skint.

[fritzi]

Im not a certified pilot but I do have flying hours in a C 185, so my answer will be to the best of my knowledge.

In the case you mentioned, shutting off both of the engines, would not be a very good idea. I would deploy the airbrakes until the drag produced by them cancels out the thrust produced by the engines. Then you would be able to control the speed by extending/retracting the airbrakes.



Once again, this reply is not from a proffesional, only an aviation fanatic and a future ATP.

[LEM]

My question, as a non pilot, would be this; what would your procedure be if BOTH thrust-levers became stuck on (for argument's sake) 77%?
77% is too much even with flaps 40 and speed brakes extended, so I'm afraid the only option would be to shut one engine down and to manage drag in the approach with all means available...

[HotDog]

Thank you LEM for supplying the details that were not available to me. However, I still can't see what the lower 41 E&E bay design had to do with this accident. Can you please explain and also tell me where you would place all the electronic equipment in your design of a large airplane?

[LEM]

The E&E bay had no direct relation with the accident itself, but as the NTSB pointed out, everytime the nose goes into the water after an overrun, all the electronic equipment suffer the most... in that case, the crew was unable to shut eng 1 down, and it was still at full power during the evacuation (which took place after a considerable dalay...).

Where would I place it? somewhere else, in the roof maybe! :ouch:

[HotDog]

So next time AF or some other crew have an over run into the water, let's hope they don't submerge enough to flood the E&E bay (upper 41 section) on the roof. I really think you should submit this idea to Boeing and Airbus.:ok:

[LEM]

HD, jokes apart, there would be SO MANY things to be suggested to aircraft manufacturers.
The industry wants us to believe that we are on the best possible track, as demonstrated by Airbus with the 380.
Bull****!
They are scared of losing money in case something should happen that the public opinion (ignorance, I might say) would attribute to different designs.
So we'll continue to have airworthy, but not crashworthy, airplanes.
We'll continue to have landing gears and engines attached to fuel tanks.
We'll continue to try to avoid disasters, not to make them survivable.
If you think moving the E&E bay would be a great deal, go to the Burnelli site - with an open mind, I hope....
For those who think we live in the best possible world!
http://www.aircrash.org/burnelli/
LEM

[HotDog]

Sorry LEM, I think Burnelli is on magic mushrooms. Modern aircraft and systems are as safe as present day technology can devise them. Unfortunately us, human beings have to operate them and that is the weak link.:(

Let me quote an excerpt from Rudyard Kipling's poem,

The Secret of the Machines

Modern Machinery.

We can pull and haul and push and lift and drive,
We can print and plough and weave and heat and light,
We can run and race and swim and fly and dive,
We can see and hear and count and read and write!

But remember, please, the Law by which we live,
We are not built to comprehend a lie,
We can neither love nor pity nor forgive.
If you make a slip in handling us you die!
We are greater than the Peoples or the Kings-
Be humble, as you crawl beneath our rods!--
Our touch can alter all created things,
We are everything on earth--except The Gods!

[LEM]

The Wright brothers were probably on magic mushrooms too.

Your point of view will lead to complete automation, mechanization, and the death of Man.

[HotDog]

I agree LEM, that's more likely to eventuate before the E&E compartment is moved to the roof!

[LEM]

Yes, HD.
Now, can we have your opinion on the original question (the sim scenario)?
Merci beaucoup! :zzz:

[HotDog]

That should have been evident in one of my previous posts. I think the Instructor was not correct but I have never operated two engine aircraft as all my experience is on three and four engine jets, I am certain in my mind that the engine should have been shut down prior to landing. Hope this answers your question LEM. I really don't know how we strayed off topic onto airplane re-design, do you? :rolleyes:
De rien.

[sycamore]

I`ve not flown a-733, so what I suggest may leave me open to be shot-down, but maybe it might give you a few thoughts.
Personally , I would get away into free airspace, to experiment, as a starter. Use airbrakes, flap, gear,steep-turns, and climbs to get the speed down, as it will.Fly the a/c without all the electronics/Fms/ autopilot/; then you can start to sort out how much control you actually have! and simulate an approach and go around at a safe height.
The Flight Manual will give you a list of most common emergencies, but it won`t cover all, so that is why you are highly paid - first of all to consider all the options, then to think of all the possibilities...

Where better to look at a bit of lateral -thinking than in the sim. doing a "what- if" scenario , as opposed to normal tick-in-the box t/o, cruise, etc,,
You might also like to consider jammed stick/ rudder/ ailerons/spoilers. Remember the Sioux City DC-10 crash, the crew in that a/c never gave up flying until they hit the ground, and a lot of people alive today owe it to their efforts ..
If you fly light a/c , you can of course practice them at a safe height, using trimmers,flaps, secondary effects of control to see how much you can do, and I think you would be surprised.
Now, do I hear" incoming"???
:ok: :ok:

[Maximum]

Going back to the original question.

I've now tried the scenario in the sim and to keep the engine running on the approach seems to me to be the more risky option. I'm not saying it can't physically be done, but it's definitely more "seat-of-the-pants", and results in a much less stable approach than with one engine shut down.

Sure, keep it running if you've still a long transit to make, but in my opinion it should be shut down in preparation for the approach.

Why?

1.) Because even with flap 40 and the other engine at idle, the speed still wants to run away. This should not be overlooked as a minor inconvenience. It presents a fairly major handling problem. It may be necessary to exceed flap limiting speeds and use speedbrake with flaps at very low level to control the speed.

2.) Now we're making a flap 40 approach, yet we don't have full thrust available for the go-around.

3.) Rudder pedal inputs need considerable attention as they are not what we are used to single engine.

4.) It's not easy to get the aircraft on to the ground in the flare with 77% still pushing away and some excess speed as well. Runway then gets eaten up as the engine (will it be the correct one) is shut down.

5.) All the above requires the aircraft to be operated in a totally non standard manner.

The idea of "experimenting" in free airspace is fine if we have a truly serious control problem. However, all we actually need to do is shut the engine down when ready for the approach, and we can then fly the aircraft within the SOP's as we are trained to do, hopefully in a calm and stable manner to an uneventful landing. I know which one I'd go for.

[411A]

One poster here mentioned going off route to 'experiment' with varoius configurations etc, to enable the offending engine to remain running.

Experimentation can be carried just a bit too far.
Recall Alaska Airlines and their ill-fated MD-80 just offshore in California with tailplane trim problems.
Had these folks diverted when this problem was first noticed, they might well be alive today, together with all their passengers.

Leave the test flying to the test pilot pros, and use your standard simulator practiced abnornal procedures for unusual situations.

Don't end up dead trying to be a hero.

[GlueBall]

Had one stuck Power Lever (Throttle) at 90% N1 at Top Of Descent. The lever couldn't be moved, neither by the F/O nor by the F/E. Our plan was to shut the engine down when established on final approach, but the Power Lever became unstuck when passing a lower Flight Level. I wouldn't want to touch down with an engine stuck in a high power setting, unless it's a single engine landing.

[W.SHIRRA]

Thanks a lot for your input, Gentlemen.

[timzsta]

ATPL student here.

Anyone considered what the wind is on the runway? Lets say the No1 (left) hairdryer is stuck at 77%. The aeroplane is going to want to go right all the time. Lets say we have a lot of crosswind from the right. We need lots of right aileron and left rudder to compensate. But we are already using lots of left rudder to counteract the asymmetric thrust. Does that make any sense?

With regard to the hydraulics etc - we have standby system/PTU etc so that we can keep everything moving in the event of loss of a system/engine. So shutting down an engine - is it really that dangerous from a loss of hydraulics point of view?

Only a humble student here, but IMHO I would keep the engine running until just before final approach, then shut down so as electrics/hyd/air con and press still available etc. But it surely much safer to do a single engine approach and landing because that is one of the most trained for emergencies, rather than try and do something that you have probably never done before.

[LEM]

Some people have expressed different opinions, but shutting the engine down before final approach is definitely much safer than trying to proove your test pilot skills.
LEM

[mutt]

IMHO use the engine in cruise and descent, if the throttle doesn’t unfreeze during the descent, shut the engine down when established on the approach. Perform a normal single engine approach.

Don’t go experimenting......

Mutt.

[Maximum]

Hey, W.Shirra, if you're around, would be very interesting to know why your instructor thought it was such a great idea not to shut it down. Seems very odd to me.

[arba]

I want to ask W.SHIRRA, in the 'coolbox' was it the Boz telling you that the THR LVR stucked or the Sim can produce the problem?..he..he..just curious

I go with 18-WHEELER, when it's giving me the hard time, I'll go SE, but not instantly.

[LEM]

I want to ask W.SHIRRA, in the 'coolbox' was it the Boz telling you that the THR LVR stucked or the Sim can produce the problem?..he..he..just curious

I was given the same anomaly a few days ago.
Yes the sim can reproduce that.

We shut the engine down before approach.

Not doing so would have meant a bust!

Power was stuck at 60% ( a perfect setting for the approach), but nevertheless our chief pilot confirmed it's unthinkable to land like that.

SHUT IT DOWN! :ok:

[TR4A]

NTSB Inspector Wannabe 411A Said:Experimentation can be carried just a bit too far.
Recall Alaska Airlines and their ill-fated MD-80 just offshore in California with tailplane trim problems.
Had these folks diverted when this problem was first noticed, they might well be alive today, together with all their passengers.
I think they would still be dead and a lot of people on the ground too.

[john_tullamarine]

Is it possible that we have missed the point that the AFM and SOPs address many of the problems which fall out of the FMECA processes but certainly not all eventualities ? I contend that it is neither possible, nor commercially feasible, to train for all events.

There have been more than a few situations arise where the crew was stuck with a problem with no easy solution and certainly no guidance in the flight bag.

Clearly, if the wing or tail comes unstuck, then the end is nigh ... and even then there was the instance of an highly skilled aerobatic pilot with a (presumably) lower cap or pin spar failure who rolled inverted and recovered to a half roll crash landing and survived .....

But, as has been shown by crew recoveries of very difficult situations with no-one there to hold their individual hands, a lot of situations, while extremely hazardous and having a high probability of an unsuccessful outcome, need not necessarily be a fatal in waiting.

I, for one, see considerable value in using spare simulator time for crews to get some exposure to out of the ordinary situations in a non-checking, non-training, "have a look at this" type environment.

Clearly, it has to be understood that a simulator is a bunch of computers arguing with each other and the fidelity of the simulation in a particular situation which has not been optimised by the simulator's operator may be imprecise or significantly at variance with the aircraft. As such, the value of simulator time in non-optimised situations may not have as much transfer value as some would presume - but should that negate the flight discipline and management benefits which might be gained by such exposure ?

The opportunity to test the crew's planning and management skills provides crewmembers with feedback into the strengths and weaknesses of the individual crewmembers. This, in an ideal world, might then provide the crewmembers with some food for thought over a wine that evening.

The realistic aim is not to train for some improbable situation where such training cannot reasonably be justified in a commercial environment. Rather, the value is in the underlying development of the crewmember as a manager of hazardous situations.

Is this such a bad thing ?

As to the Monday morning quarterbacking arguments after the accident, one can hypothesize all day long and this, too, will have some value in a disciplined environment. Having a look at the problem in a simulated environment, while not a perfect answer, possibly is coincidentally useful to crewmembers.