Compressor Stall

[Chryse]

Just a simple question..

A scenario:
After encountering a compressor stall on takeoff in a B737, the checklist items of reducing the thrust lever to idle etc are conducted. Now if the engine continues to operates normally, the thrust lever can be advanced to an intermediate position so as to keep the engine from stalling again. With the thrust lever now in an intermediate position my question is what flaps should be selected for landing back? Full Normal Landing Flaps or Single Engine Non Normal Flaps 15?

Thanks

[AVIATOR757]

There is nothing against using landing flaps after a commitment to land(Short finals).Thrust required will never be more that 65% N1, if you are heavy.Would also depend on Field length available permitting a 15 landing.The only issue here would be a Flap 15 or A fLAP 1 go-around with one Thrust lever in mid position.Try opening all bleed valves and advancing the thrust.May be that will almost definately slve the problem.
Cheers:O

[Flight Detent]

Hi all,
Anytime you experience a compressor stall, first thing I always do is select engine anti-ice on that engine, which instantly decreases your chance of having another one.
Then go ahead and reduce power etc, but further use of the engine would probably be quite OK, albiet with very slow movement of the p/l, and leave the TAI ON for the rest of the flight, that also increases the normal flight idle speed to the approach flight idle speed in a B737, for both engines, if I'm not mistaken!
It works for me!
Cheers:ok:

[Chryse]

Ok thanks so far.

Why select engine Anti Ice on? Is this an approved procedure and whats the logic for its selection? By selecting EAI do you reduce some of the bleed thats directly affects or is causing the stall?

Thanks

[lomapaseo]

The idea behind the anti-ice on is to drop the pressure behind the stalled stage thus giving it a better chance to recover. Any bleed opening behind the stalled staged would do the same thing and of course if you lower the RPM it has the same effect.

The opening of bleeds however decreases the total airflow to the turbine so do expect EGT and Fuel flow to go up for the same EPR.

Some newer engines do this for you automatically.

However, it won't work in all cases, although reducing RPM is more effective (even that doesn't work in all cases so be prepared to shut one down some day.)

Most engine mechanical failures result in stall symptoms. Unfortunately some perfect mechanicaly working engine may stall and need to be recovered under some conditions.