Originally Posted by
Haroon
What is the reason of delaying the slats extension so much. Isn't earlier the better? Is it to avoid its pitch up side effect or something else? Thanks.
I don’t see a reason to delay the slat extension while recovering from a clean stall. Please have a look at the VLS before slat extension and after slat extension. You will see the VLS dropping by at least 30 knots or more after the slats extend. Now, you may recall that VLS is a factor of VS(1.28 VS in clean configuration and 1.23VS after retraction of one step of flaps indicating it’s relationship with the stall speed). However, on extension of slats, there is a tendency for the airplane to pitch up that could lead to a secondary stall. If prompt action is taken to prevent this pitch up tendency, I don’t see why you can’t extend the slats and make use of the additional safety margin it provides from stall speed