PPRuNe Forums

PPRuNe Forums (https://www.pprune.org/)
-   Tech Log (https://www.pprune.org/tech-log-15/)
-   -   Thrust lever stuck on B737, what do you do. (https://www.pprune.org/tech-log/388255-thrust-lever-stuck-b737-what-do-you-do.html)

elpilote 9th Sep 2009 13:18

Thrust lever stuck on B737, what do you do.
 
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 9th Sep 2009 15:30

Eject?

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

411A 9th Sep 2009 15:37


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 9th Sep 2009 15:44

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 9th Sep 2009 19:03

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

Turn it off.

Glide to the most suitable airfield.

Lime Rock 9th Sep 2009 19:14

Autorotate safely to the ground?

Kempus 9th Sep 2009 19:53


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 9th Sep 2009 20:05

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 9th Sep 2009 20:53

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 9th Sep 2009 20:53

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 9th Sep 2009 22:07

Lean out the mixture and feature the prop?

boltz 9th Sep 2009 22:20

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 10th Sep 2009 02:33


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 10th Sep 2009 10:51

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 10th Sep 2009 12:14

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 10th Sep 2009 13:18

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 10th Sep 2009 13:58

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

framer 11th Sep 2009 04:17

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 11th Sep 2009 05:45

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 11th Sep 2009 17:03

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.


All times are GMT. The time now is 18:57.


Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.