Flap retraction

[smails]

I fly with someone who believes that you cannot retract the flaps until you are 400ft AGL. For a normal all engine takeoff I cannot find any reference to this. Flap retraction is based on speed not altitude.(again normal ops, jet aircraft) Any opinions/facts.

Thanks

 

[say again]

Our SOP's state flap retraction at or above 400' and speed above Vfto. Thats the only place Ive seen this.

 

[BEfly]

It is based on speed. This guy must have flown the Beechjet too, just a part of the profile for that airplane. I like to see what he say's about a Flaps 0 T/O.

 

[MauleSkinner]

Do you fly with me?

To me, it boils down to knowing, as a crew, that I'm not going to mess things up by surprising the other crewmember. I also think that standard phraseology during the takeoff and the immediate aftermath is important to minimize confusion if something DOES go wrong...the things you normally hear are OK...anything else requires your immediate attention.

For a normal takeoff, it's "positive rate"--"gear up"; "400 feet"--"flaps up, climb check", at which time turns are made, switches are flipped, and ATC can be talked to.

Much like V1, I think that there need to be boundaries at critical times of flight between "as standard as possible" and "we can make adjustments on a whim", and 400 feet to me is one of them. It's a rather arbitrary point for flaps, but it has other significance that makes it important, and I'd rather have one boundary than several.

Heck, one guy I fly with can't decide whether it's "mine" or "yours" at 80 knots after landing. Heaven help us if he wants to actually transfer the aircraft to me rather than just the yoke, because there's gonna be confusion then.

I've also been the recipient of "gear up, your airplane" due to the captain's attitude gyro rolling over as we entered the clouds. Some things are confusing enough when they're clearly stated.

Fly safe!

David

 

[PURPLEHAZE21]

I thought "400 feet" was in reference to climb segements based on altitudes to ensure single engine climb perforemance. (1, 2, 3, and final segements). Also, not all aircraft have a 400 foot flap retract altitude. You have to see how the aircraft was certified for single engine ops after takeoff. Cessna citations in fact have different altitudes for flap retraction on the same segment...example the CJ1 versus CJ2 single engine profile...

look at your aircrafts certification pages in A/C manual.

 

[ackattacker]

What purplehaze said... you have to look at how the climb performance was certified.

If it was a Transport Category aircraft (which I realize the BeechJet is not) then takeoff flaps are NOT retracted until 3rd segment, which always at *least* 400 feet.

 

[ksu_aviator]

As with everything in aviation, the answer to your question/comment is "depends."

In general, I agree with everything above, but I would add one more thing; both airspeed and altitude play into flap retraction....in most airplanes. I think the posts above implied that airspeed and altitude are both important, I just thought I'd say it. How else am I going to get that post total up

Like everyone else, I suggest that you refer to the aircraft's performance criteria and the Pilot's Operating Manual for your best answer.

Edit:
PS....in the aircraft I have flown, 400 feet is a flatland number. If you have a departure procedure with an above standard climb rate to an altitude higher than 400 feet, you should not retract the flaps until reaching the higher altitude. The idea being that the angle of climb is greater with the flaps extended to the take off position than retracted.

 

[JAFI]

Edit:
PS....in the aircraft I have flown, 400 feet is a flatland number. If you have a departure procedure with an above standard climb rate to an altitude higher than 400 feet, you should not retract the flaps until reaching the higher altitude. The idea being that the angle of climb is greater with the flaps extended to the take off position than retracted.

That is a good point. I flew out of a "flatland" airport that had a smokestack just off the airport where we had to go up to 800 feet to clear the stack. Changing configuration below 400 feet or (obstacle clearance) is not a good practice.

 

[Rez O. Lewshun]

I like donuts

 

[PURPLEHAZE21]

Smails...not to beat a dead horse...but...Flap retraction is based on altitude at a "given speed" which should be V2 or V2 plus additive for some aircraft. To add insult to injury...look at high altitude takeoffs with flaps versus no flap takeoff. There can be a big difference in performance, yet you still have the same Airspeed for climbout...