B737NG Flaps 25 take-off

[oceancrosser]

I have only flown the B737Classic (max take-off flap 15), I can see from Boeing software and 737 FCTM that Flaps 25 is a certified take-off flap setting. Now I am wondering for a short runway in a -800 or -900, how is the Obstacle Clearance at flaps 25? Dismal?

My thought is that this flap setting will only work on a short runway with little or no obstacles, and probably not at all in a mountainous area?

Anyone with experience care to comment?

[ClimbSequence]

I think the -200 series also allowed for F25 TO.
Denti might give us better information about it

[Jwscud]

I have only seen this done for real out of Bristol when fat for southern Spain or the Canaries. If you aren't familiar it's a hilltop airfield with terrain falling away and a very short runway. I have done SE flap 25 in the sim and the climb gradient isn't great at all, but we dont operate out of short runways in mountainous terrain so can't comment I'm afraid.

Our aircraft don't have the SFP mod either which may make some difference but I haven't got any experience there either.

[chimbu warrior]

Flap 25 takeoff is permitted in the -700, but not -800.

[RTO]

Flap 25 takeoff is permitted in the -700, but not -800.

Bollox, F25 takeoffs are normal operation in both the older and the SWP 800's

From the -800 FCOM:

Enter takeoff flaps setting. Manual entry of 1, 5, 10, 15, or 25 allowed

[flyingchanges]

The SFP does 25 with the LE partially extended.

[737aviator]

Flap 25 takeoff is permitted in the -700, but not -800.

I've done several Flap 25 takeoffs in the -800. From memory I remember at one airport in calm wind, one end with distant terrain, the other without significant terrain, the Flap 25 RTOW was significantly less on the end with terrain than the Flap 5 RTOW (with the 25 being obstacle limit and the 5 rtow being field length limited), but on the end without terrain Flap 25 was around 500kg more than Flap 5.

[chimbu warrior]

I stand corrected............manual I had was an old one and stated as quoted.