Qantas Captain
Topic Author
Posts: 13
Joined: Sat Sep 16, 2000 7:32 pm

Flap Retraction

Fri Jun 15, 2001 9:18 am

At what Altitude does a jet retract flaps after takeoff?
Thanks Michael


RE: Flap Retraction

Fri Jun 15, 2001 9:25 am

Without any obstacles around, the minimum that we are allowed is 400 feet. A requirement to clear obstacles would drive this height higher.
Posts: 1066
Joined: Fri Mar 16, 2007 1:29 pm

RE: Flap Retraction

Fri Jun 15, 2001 11:15 am

On our normal North American departures, the flap retraction cycle starts in the third segment climb, usually at 1,000' AAL (above airport level) depending on climb segment obstacle clearance limits. In Europe and under some other noise abatement restrictions, flap retraction is delayed until above 3,000' AAL.

Flap retraction delays may also occur if a minimum radius turn is required in the DP (departure procedure, formerly known as SID [standard instrument departure]). Lower speed means tighter turn.

You might want to check out the Tech Forum if you have other questions like this!

Best Regards,


RE: Flap Retraction

Fri Jun 15, 2001 11:34 am

I love it, you get one answer from a pessimist and one from an optimist.

I believe that the engine will fail, hence the low clean up altitude. Buff believes that the engine won't fail and therefore gives the normal clean up heights.

Buffs answer is more likely in everyday operations.
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Joined: Thu Jan 13, 2000 3:58 pm

RE: Flap Retraction

Sat Jun 16, 2001 1:24 am

Typically speaking, clean up begins at around 1500 ft AGL (sometimes lower at 1000ft AGL), so you're looking at starting flap retraction sometime around then.

Flap retraction is airspeed dependent, not altitude dependent, however as you reduce your angle of climb at a certain altitude to increase speed, you retract flaps.