B737NG Flaps Stuck on ILS APP between 15 and 30.

[B737NG_Pilot]

Scenario 1: On an ILS Approach, Flaps are stuck between 15 and 30. What's the best course of action and why?

Scenario 2: After Departure, unable to retract flaps, using Flap Lever. Everything else is normal. Departure Aerodrome is now closed, and we do not have take off alternate, only destination alternate. What is the best course of action?

Just trying to get the view of everyone.

[Jwscud]

Scenario 1 - Go Around (carefully - flaps aren't moving so watch the limit speeds). QRH. Landing distance. Decide where you want to go. Do it. On a very nice sunny day you may want to keep a very close eye on fuel burn and fuel flow as you may be into your reserves fairly quickly if you are stuck at high flap settings. Do not trust FMC fuel predictions - use fuel flow and do it the old fashioned way.

Scenario 2 - Surely if your departure field is unavailable after departure, you should have a takeoff alternate already? Level off, QRH. Pick an alternate. With flaps stuck at a takeoff setting (you could be only Flap 1), you may need a nice long runway. As above, remember fuel predictions from the FMC are rubbish, so check your fuel flow at your cruise level. Also remember you are limited to FL200 with flaps extended.

[ImbracableCrunk]

If fuel was very short, I'd go over 20,000 if it would help. That's a limitation only because Boeing didn't test it higher for certification and has no data.

[Kefuddle]

Based on observation of selecting flap at 19,000, above 20,000 with flaps 1 at flaps 1 speed, I reckon you will probably be at or in or very close to the lower amber band. Not the end of the world, but clearly not in normal territory.

Interesting how the limitation is actually worded as "max flap extension altitude" (i.e. selecting flap), inferring that climbing past 20,000 with the flaps already extended is not included in the limitation. Bad wording or deliberate?

Surely if your departure field is unavailable after departure, you should have a takeoff alternate already?
For a short sector, your destination maybe your takeoff alternate. With the flaps not retracting you may or may not have range to make a suitable field. Makes for a good scenario for assessing how well the crew balance the relative risks. Arguably makes for negative training if the best solution is to bust limitations and minima.

[latetonite]

1. If early, land, Vref 15.

2. Try to retract flaps using alt flaps electrically.

[Kefuddle]

2. Try to retract flaps using alt flaps electrically.
He said that everything else is normal. So without a hyd problem, retracting the flaps electrically could be disastrous!

[latetonite]

The chance for an assymmetry is existing, but remote. One can still retract in steps.

[B737NG_Pilot]

Hey everyone, thanks for your inputs.

Now let's assume we loose NO. 2 engine on take off. While retracting the flaps, we observe that the flaps are stuck. Is it right, to retract them electrically and then place the alternate flap extension switch back, the OFF (guarded position).

There after carry out the appropriate non normal checklist?

[Tom!]

Interesting how the limitation is actually worded as "max flap extension altitude" (i.e. selecting flap), inferring that climbing past 20,000 with the flaps already extended is not included in the limitation. Bad wording or deliberate?


bad wording I think:
This is taken from the Boeing Airliner magazine:
"Several operators have asked Boeing why the Airplane Flight Manual has a limitation restricting the use of flaps above 20,000 feet. The reason for the limitation is simple; Boeing does not demonstrate or test (and therefore does not certify) airplanes for operations with flaps extended above 20,000 feet.

There is no Boeing procedure that requires the use of flaps above 20,000 feet. Since flaps are intended to be used during the takeoff and approach/land phases of flight, and since Boeing is not aware of any airports where operation would require the use of flaps above 20,000 feet, there is no need to certify the airplane in this configuration."
(my bold)

[BOAC]

we observe that the flaps are stuck. - why are they? Are you talking about two separate failures?

Why retract them anyway? Where are you going engine out?

[de facto]

. Is it right, to retract them electrically and then place the alternate flap extension switch back, the OFF (guarded position).
No.

Why retract them anyway? Where are you going engine out?
Hope somewhere far away:E

[BOAC]

Indeed - not near me!