View Full Version : B737 CL Thrust levers large split
EnergyIsSafety
30th Apr 2013, 14:04
Hello fellow pilots and technical engineers,
Could someone explain what could lead to a large asymmetry in thrust during approach ?
Conditions: A/P on, A/T on, localizer intercepted, flaps 30 speed decreasing on schedule.
Fault: reaching the MCP speed, the A/T advanced only the engine 2 lever, the engine 1 lever remaining in idle.
Trying to keep the speed, the #2 N1 reached approx 85% (#1 N1 approx 30%).
At that time the A/T and A/P were disengaged and the #2 thrust lever manually advanced to re-establish aircraft control.
Thank you.
---------------
"Keep the hand on the thrust lever when flying at low altitude"
B737900er
30th Apr 2013, 19:20
Clutch motor failure (if thats the correct wording). Usually TRE's give it in the sim to see how you react.
I was given it during a turn, but, being below MSA my hands cover the controls and levers so a simple disconnect solved the issue.
EnergyIsSafety
1st May 2013, 02:10
And it is was happened ... left turn to intercept the loc, and left engine remained at idle... I was on the J/S ... hopefully.
It could be a PMC fault perhaps ;)
737 Elpiloto
2nd May 2013, 06:31
I agree, perhaps PMC failure...
But normally you only get a +-7% difference with the PMC OFF but you never know....
Centaurus
2nd May 2013, 12:12
but, being below MSA my hands cover the controls and levers
Not trying to be clever, but what is the significance of flight below the MSA to do with where your hands are?
....no doubt it is an 'SOP:somewhere and therefore 'a good idea':confused:
Not trying to be clever, but what is the significance of flight below the MSA to do with where your hands are?
These a/c can fly a long time and it is very tiring keeping your hands covering the automatics all the way. Holding the newspaper with your teeth and turning the pages with your nose is not cover in TQ courses. There is a tongue, somewhere, lodged in my cheek, if only I could find it.
Holding the newspaper with your teeth and turning the pages with your nose is not cover in TQ courses. - isn't that why there are 2 crew?
If the Eng1 thrust lever did not advance, surely it's an auto-throttle problem?:confused:
B737900er
2nd May 2013, 19:22
I think we all agree that once the autopilot is in, we have a tendency to remove our hands. Whilst we should always cover the controls most, if all the time, people still rely on the automatics, and flying at low altitude or below MSA this is when you need to be more vigilant than ever.
MSA has nothing to do with, if or when the controls need to be covered.
BOAC - My company does have an SOP regarding making sure the controls are 'Covered' below MSA at all times.
Flying Wild
2nd May 2013, 21:36
I think we all agree that once the autopilot is in, we have a tendency to remove our hands. Whilst we should always cover the controls most, if all the time, people still rely on the automatics, and flying at low altitude or below MSA this is when you need to be more vigilant than ever.
MSA has nothing to do with, if or when the controls need to be covered.
BOAC - My company does have an SOP regarding making sure the controls are 'Covered' below MSA at all times.
As does my present and also previous company. Arguably if the PF of the Turkish NG at AMS had done this they would have recognised the problem sooner and it could have been a non-event.
If we really want this forum to "Be the very best in practical discussion on the web" then the OP needs to get his act together. Posting contradictory statements such as " Fault: reaching the MCP speed, the A/T advanced only the engine 2 lever, the engine 1 lever remaining in idle. " and " At that time the A/T and A/P were disengaged and the #2 thrust lever manually advanced to re-establish aircraft control." won't give your ground crew much to go on!:hmm:
BOAC - My company does have an SOP regarding making sure the controls are 'Covered' below MSA at all times.
:)Make me feel strange!
B737900Er I think we don't need that to be written in SOP, it's common sense to be vigilant following and scanning all the authomatism of the aircraft and have your hands closely to the A/T during our final descent(STARS, APPROACH..etc):rolleyes: isn't it?
B737900er
3rd May 2013, 09:56
Yotty- You also have to take into account English is not everyones first language, or people have difficulties with spelling and grammar.
Seeing as he is from most bureaucratic country ever :E the guy can speak English French and Dutch.
B737900er
3rd May 2013, 10:01
JQKA - Yes it would be common sense and we should be doing it, but jump seat any flight and I guarantee a lot of flight deck dont do it.
Making it an SOP makes sure you actually do it. Thats the idea anyway.
I dont get into SOP politics I just follow it, of course if I feel it cant be done due to the situation, or its an unsafe SOP for example then I wont follow it.
B737900er, well I just hope he/she knows his/her Links from Rechts! :)
911slf
4th May 2013, 09:35
Will an Airbus person tell us if the throttles are back driven (I heard they were not). If not, what benefit would be gained from having hands on throttle?
Speed of reaction? Avoiding both pilots trying to grab the levers?
cosmo kramer
4th May 2013, 16:36
"Guarding the controls below MSA" that a poorly written SOP in my opinion.
Sometimes MSA is 14000 feet sometimes it's 1800. If it's 1800, why shouldn't you guard the controls at 2000 feet. (Don't answer because the SOP says so). :)
Our SOP say with flaps extended, which makes sense because a) you started to configure which makes it easier to take over in case of flap asymmetry, and b) it provides a fairly equal height above terrain where the controls are covered.
Personally I guard the controls when ever I am getting ready to "fly" the aircraft. Which means about 10000 feet AFE.
B737900er
4th May 2013, 21:33
"Personally I guard the controls when ever I am getting ready to "fly" the aircraft."
I would hope you do so, because who will be flying the plane when the AP gets disconnected :E
cosmo kramer
5th May 2013, 15:27
Yes, but then " " meant even if the autopilot remains connected until 400'. I still "fly" the aircraft (and guard the controls) during the final part of the arrival and approach.
And no, I don't "fly" the aircraft during cruise. The autopilot flies, I monitor (and drink coffee).