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View Full Version : LOSS OF THRUST PROCEDURE ON B-737


bob3
2nd Nov 2000, 21:57
I was wondering, if it is required to recycle Start Levers, if we dont have a lightup in 30 sec on B737,in case of loss of thrust on both engines.

[This message has been edited by bob3 (edited 02 November 2000).]

Captain Tobias Wilcox
2nd Nov 2000, 22:34
You need to read your QRH, carefully (it is a Boeing product, and thus, a long way far from perfect).

Ours tells us to position the START LEVERS to CUTOFF, wait for the EGT to decrease, and then position them to IDLE DETENT.

If EGT reaches 930 degrees, the steps must be repeated.

If neither start is successful, and N2 is below 15%, there is a further procedure to follow. No advice is given as to what to do if N2 is above this value (perhaps it never could be... I shall check in the simulator when I am next there). This procedure uses APU bleed air to do a starter-driven start in the air.

It appears that if neither restart is successful, then the QRH assumes that another windmilling start attempt will not yield fruit.

The THRUST LEVER position is not of consequence.

[This message has been edited by Captain Tobias Wilcox (edited 02 November 2000).]

Cough
3rd Nov 2000, 03:09
I believe the point of putting the start levers to cut-off then idle detent is to put the engines into the start mode (i.e The gentle increase in fuel flow that occurs on the CFM's (but not the -200...so satisfying that thud when you get light up!) and once they are in the start mode, recycling them shouldn't make too much difference (and why you don't need to move them on a -200). This in no way says I wouldn't try it if it were getting into the altitude above me syndrome!

bob3
4th Nov 2000, 01:08
Yes that is what actually is missing in the CKL, what if the N2 is above 15 %. Cause the CKL wants you to start the engines on APU only when neither start is succesful and N2 is below 15 % .The light up time in air is 30 sec, so should we go for another attemp of recycling the start levers, if 30 sec is up and N2 is still ( by any chance ) above 15 % .(specially if you dont have APU)