Thank You

Thank you

tomw5907, thank you for your comment. I have heard this concern before and it usually stems from the misconception of the source of lift generation at various flap settings. During flight most aircraft are more efficient at producing lift at the takeoff flap setting because high flap angle produce a lot of drag. When flaps are reduced to takeoff settings the reduction of drag allows the aircraft to accelerate and the increased airspeed creates a net gain of lift production. However, this gain of lift is not immediate as it required the aircraft to accelerate to produce the lift, and it only occurs when the aircraft has engine power or altitude to use for acceleration. Neither of these criteria are met during the landing roll. During the landing roll the loss of drag from flap retraction (both landing and takeoff settings) is not ideal as more drag would assist in lift destruction. However, this penalty is offset by the immediate loss of lift from the lower AOA and subsequent enhanced braking capabilities. I have tested this method on 35 different airframes over 5,000 landings and found that retracting the flaps at touchdown will reduce your landing roll distance on average by approximately 10 percent. Have you had the opportunity to test this method to see if these finding hold true for your aircraft or do you have any additional data that you have based you statement on? I would love to widen my understanding. One really easy and safe way to test the effect of flap settings is to get the aircraft stabilized at a safe altitude with full flaps. Then simply retract the flaps to the takeoff setting and see what the aircraft does. If the aircraft enters into an immediate climb then your concern may be valid for your aircraft. However, my experience is that most aircraft will immediately lose altitude, accelerate, and then gradually start into a climb. Please let me know what you find out, and fly safe my friend.