Thrust lever stuck on B737, what do you do.

[elpilote]

hi guys, got a question ,

what do you do if you got a thrust lever stuck a high % and that the other engine has experience a failure before,???

[BigHitDH]

Eject?

This seems like an extremely remote possibility, and actions would depend on which (Classic, NJ) 737 you're on about.

[411A]

what do you do if you got a thrust lever stuck a high % and that the other engine has experience a failure before,???
Wish you were senior (or fortunate) enough to be in a three or four engine airplane.
Next?;)

Or..if the above is not the case and you are stuck with a 'lesser' airplane, add drag as necessary until landing is assured...then, fuel off, on the one remaining operative engine....and hope the weather is suitable.
IE; trade speed for glide distance.

[BigHitDH]

I think elpilote is asking us to assume one engine failed, with the other stuck wide open.

and that the other engine has experience a failure before,???

so

on the one remaining operative engine

is not an option? (assuming I've understood his hypothetical question correctly?)

[HundredPercentPlease]

Use the stuck open one to climb as high as possible.

Turn it off.

Glide to the most suitable airfield.

[Lime Rock]

Autorotate safely to the ground?

[Kempus]

Autorotate safely to the ground?


Hahahahahaha! I like that!

The thrust levers arent attatched by wire to spring loaded butterfly like on piston engines so unsure how the situation would exist. If it was stuck "open" it must mean that the EEC has lost control of the engine or it is somehow stuck inbetween the soft/hard altn mode. However the HMU servos are driven by the EEC so if the servo failed??

Anyone else any ideas on how it could happen?

What to do, eh, move all pax/wieght where poss to the side with the high running engine, boot full of rudder and aileron trim, get the gear down and find a huge runway close to a hospital and school and grease it in!

[sycamore]

As you have spoilers/airbrakes,use them to reduce speed,combined with a bit of climb,and/or steep turn, then get the gear down,then flaps until you can descend; then it`s up to sorting a long approach,adjusting the flaps/a/brakes,to fly an approach,and then turn it off,retrim yaw and land.... failing that,if you can`t get the speed back,join overhead ,abot 4-5000, about 220 kts,kill the engine,keep it clean, circle to d/w about 3000 ,gear,bit of flap,abot 180kts,aim 1/3 up the r/wy,adjust turn and flaps as rqd to bring
touchdown towards threshold.... Try it in the sim first...

[MarkerInbound]

There's a letter (SB?) from Pratt about runaway JT8Ds as found on -200s. There is a shaft from the N2 section supplying feedback to the FCU. If the shaft fails, the FCU goes to a preset setting which IIRC on twin engine planes is 100%. There had been 30 some cases of the failure mode in the mid 90s when the letter came out.

As to the OP's question, I'd land the airplane.:)

[glad rag]

I think the op is asking if you would rely on the donkey going at 100%+ OR the donkey that has failed but is running for now......:cool:

[captjns]

Lean out the mixture and feature the prop?

[boltz]

The B737 Classics have cables running from the thrust lever to the fuel control unit on the engine, so it could happen, but is very unlikely.

[lomapaseo]

There's a letter (SB?) from Pratt about runaway JT8Ds as found on -200s. There is a shaft from the N2 section supplying feedback to the FCU. If the shaft fails, the FCU goes to a preset setting which IIRC on twin engine planes is 100%. There had been 30 some cases of the failure mode in the mid 90s when the letter came out.


I recall that the concern in cases like this was the flight condition when this could happen. If during takeoff roll the pilot's natural action would be a sensed engine out and attempt to correct accordingly. Unfortuately this could rapdidly take the plane off the runway before they would realize that they had to chop the throttle on the bad engine. I believe that a fatal crash was attributed to this in Saudi.

The other bad news condition would be landing.

This kind of problem can not be eliminated, although minimized and can occur on all engines that I am familar with albeit for different reasons.

[elpilote]

HEY? tanks to all of you for your differents answer.

the situation is the following:

1 engine out & on the remaining engine , the thrust lever is stuck at hight rpm.


What i will do if it happen,


i will continue the climb and accelerate to clean A/C, then just prior reaching 270 KTS ( max speed to extend gear) i will drop the gear and use the speedbrake to maintain the speed.

When on final and clear to land on this huge rwy, and that i m sure to make the rwy ( for example at 50ft) i will shut down the remaining engine to be able to decelerate.

DO you agree????

[Busserday]

Hey, if it works I would agree completely, if it doesn't then of course ...
Just kidding, as with all hypothetical situations, they make good training exercises and bring to the forefront some excellent discussion. Precisely why these questions should be posted on these forums, far better than waiting to read an incident report about the accident.
Of course in this kind of scenario, gear speeds are not limiting but if can, should be observed. Flaps and LEDs may have to take a hit but probably not if the stars and moon aligns for you and of course the weather will be at minimums with no close in alternate.
Its going to be a handful and depending on available (excess) thrust you should have a chance.

[BOAC]

I don't think gear/flaps and speedbarke will contain your speed unless it is very hot or high, and I reckon you will need to do some steep turns (up to 60 deg AoB) to hold it back. Whoever fed you this one needs to be reminded that we do not GENERALLY plan for double emergencies in aviation, but certainly worth thinking about. It certainly would not be
1) Your day
2) Very likely

[Agaricus bisporus]

As this is a case of double jeopardy it is not a realistic scenario, so why bother asking?

[framer]

Heh heh, , good fun question.
I would find the longest runway, position myself overhead the field at 5000ft, gear down, F15, APU on the busses, speed ??? cut the remaining engine and eyeball it round with the aim point starting maybe 3000ft in and adjusting as neccessary. Maybe make a point at a 2nm from touchdown in the fmc and have that as a gate aiming for 1200ft 180kts. After that point I'd just aim it at the threshold.
Anyone got access to a sim to see if that would work?:ooh:

[john_tullamarine]

We've done lots of training famil deadsticks in the 737 Classic sim.

Your average fighter jock eyeballs it first time up just fine. The rest of us tend to need one or two practice goes to get the revised descent gradient picture in the mind.

Providing one has had a looksee in the box, it should be a very straightforward exercise ...

Now, in worse than Cat II conditions, there might be justification for a little sweat ... :}

[RAT 5]

I wonder if, even with gear down & speed brake, you could reduce speed to anywhere near F5 limiting speed. Indeed I'm curious if lowering the gear at 270kts, with 1 donk at 100% will slow it down. I expect that overhead at a good height and dead stick it would be a safer bet. At least you know what is going to happen when you dangle all the bits that will help. The last thing you want is bits flying off and causing unexpected severe handling problems low down.

[lomapaseo]

Don't forget the rudder and it's limitations.

Too much speed is not your problem until you get on the ground, too little is your problem in the air.

The piper must be paid either way.

[p51guy]

Make it a glider at a comfortable altitude and proximity to the airport. Maybe stay a dot high and wait for final configuration until close final. We did this in a jet landing at SNA with a 500 ft ceiling after curfew one night and landed at idle from 3 miles out. Yes, we got by with it and made the first turn off. 35 years ago. I don't do that crap now.

[muduckace]

Do not kow of this happening in any twin jet. I would suspect the use of drag in any form but would not worry about flap or gear overspeed limitations. Chop the overspeed engine at a low altitude, using aerodynamic breaking, better to steer off or run off the runway than landing short due to crytical miscalculation of glide expectations in an emergency.

RWY's like at JFK with over run retardent materal are great for scenarios like this.

[TheOptimist]

I think some of you are underestimating the difficulty of the situation. Having only one engine on a twin engine plane is difficult enough, let alone the opposing engine being stuck on maximum thrust.

[fullyspooled]

Selective on/off of the fire handles/low pressure/high pressure fuel cocks (depending on a/c type) with ignitors on continuosly, would permit thrust to be modulated until closer to finals. This would enable a/c to be configured for a final glide. If too low at this point, simply go round and try again!

[Old Smokey]

Selective on/off of the fire handles/low pressure/high pressure fuel cocks (depending on a/c type) with ignitors on continuosly, would permit thrust to be modulated until closer to finals - Aha!, we've gone full circle in aviation, the Sopwith Camel Technique!!!:ok:

Seriously though, the approach is going to be your only real challenge. Aircraft of the B737-200 and DC9 era (and most others which followed) use/used reduced Flap settings for OEI Approach. Personal observations of engine failure with Full Landing Flap, and the Flap being retracted to the OEI setting ALMOST compensated for the engine loss, with about 7% N1 increase required on the live engine. So....... throw the SOP out the window (allowed when you're having a 'bad hair day') and approach with FULL Landing Flap. Speed may still be a bit high on final (not as much as you may think), and use the NORMAL Landing performance data, which provides a 1.67 times multiplier on actual landing distance. For a 130 Kt Vref, that allows for about 169 kt at touch-down. Cut the fuel as the wheels touch down.

Worth thinking about:ok:

Regards,

Old Smokey

[singpilot]

I'd bet that Old Smokey and I have shared a bar for lunch up on the hill by Seletar in Singapore!

This was a very usual sim exercise in the DC9 and Gulfstream types. 'Frozen' throttle just prior to TOC.

Energy mangement on descent, take your time, and when ready stop cock the bad one, and by the book the rest of the way in.

What the sim instructor would watch for was if the PF was having too much 'fun'. Then he'd start failing 'stuff' driven by the 'good' engine, or 'stuff' you'd like to have (but not need) for the approach, knowing you were goona shut the bad one and lose all of it's systems.

These types of sim instructors were abused as children.

Another fav was to 'freeze' BOTH throttles at idle at bottom of descent.

Pulled the T/R deploy C/B's, and flew the rest of the flight using the piggybacks for throttles.

Heard the sim instructor's head hit his desk as I proposed, and then did that one.