Stuck thrust lever B733 sim scenario
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Stuck thrust lever B733 sim scenario
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.
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.
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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.
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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
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
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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.
Ask him to do a demonstration for you - that usually fixes the fools.
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.
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.
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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.
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.
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<<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!
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!
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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
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
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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!"
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!"
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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.
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.
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.
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.
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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...
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...
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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.
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.
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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.
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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...
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...
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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.
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.
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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.
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.
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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%?