CRJ, flap retract speeds
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CRJ, flap retract speeds
Hello all,
I fly the CRJ 900 and recently ended up in a discussion regarding the flap retract speeds and bank angle protection.
Our SOP states that as long you have V2+12 and positive speed trend, you can start retracting flap to 8 (assuming flap 20 take off)
And then V2+20 to retract to 1, and Vfto -15 to flap up.
The discussion we had is that the other pilot was claiming that you cannot retract flap from 20 to 8 unless speed is ABOVE FLAP 8 Manouvering speed.
His logic for this is that when on Approach, you are not allowed to fly below lets say FLAP 20 Manouvering speed (VAppr 20+ 10kt) with a bank higher than 15 degrees.
I see his logic in this, but I argue that during the flap retraction speed we ASSUME (and also a precondition) that Speed is INCREASING.
We will hence not stop acceleration at V2+12 and fly at flap 8, because then we are clearly not allowed to make more than 15 degree turn.
Whats you take on this?
Thanks!
I fly the CRJ 900 and recently ended up in a discussion regarding the flap retract speeds and bank angle protection.
Our SOP states that as long you have V2+12 and positive speed trend, you can start retracting flap to 8 (assuming flap 20 take off)
And then V2+20 to retract to 1, and Vfto -15 to flap up.
The discussion we had is that the other pilot was claiming that you cannot retract flap from 20 to 8 unless speed is ABOVE FLAP 8 Manouvering speed.
His logic for this is that when on Approach, you are not allowed to fly below lets say FLAP 20 Manouvering speed (VAppr 20+ 10kt) with a bank higher than 15 degrees.
I see his logic in this, but I argue that during the flap retraction speed we ASSUME (and also a precondition) that Speed is INCREASING.
We will hence not stop acceleration at V2+12 and fly at flap 8, because then we are clearly not allowed to make more than 15 degree turn.
Whats you take on this?
Thanks!
Last edited by dcoded; 7th Jun 2017 at 08:32. Reason: Clarification
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Think about what your "minimum speed" was in the takeoff configuration BEFORE you started retracting the flaps. You got airborne shortly after VR, and didn't achieve V2+10-15 until you were well airborne. So you were flying - but accelerating - well below the initial takeoff flap manoeuvring speed as well.
No-one questions whether it is "safe" to fly in the early stages of a takeoff below the "manoeuvring speed" and for the same reason, flap retraction as you have described it is perfectly logical and consistent.
No-one questions whether it is "safe" to fly in the early stages of a takeoff below the "manoeuvring speed" and for the same reason, flap retraction as you have described it is perfectly logical and consistent.
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It's pretty much the same on other a/c. On the Airbus after t/o you can retract flaps when passing F speed and slats at S speed. For approach S and F speeds become maneuvering speeds and you normally does go below them unless you're in the next config.
Never flown a Boeing, but I think it's the same
Never flown a Boeing, but I think it's the same
