Use of Flaps

IFR Pilot wrote an entry a few weeks ago about an accident involving a Cessna 172 that stalled on short final at 50 feet AGL. The pilot was seriously injured and the passenger was fatally injured. What’s interesting about this entry is that IFR Pilot questions the pilot’s use of full flaps on the approach since the wind was right down the runway at less than 10 knots and the runway was 6100 feet long.

The exception, of course, to the use of flaps is crosswind landings, wind shear or turbulence in the circuit. But those situations aside, I was taught that flaps are used to lower the stall speed, which will allow the aircraft to have a lower speed at the point of touchdown. The end result of a lower touchdown speed is a shorter rollout on landing, less overall wear and tear on the aircraft (ie. less braking required) and most importantly, safer. If anything is going to happen on touchdown, in any situation I can think of, it would be better to have it happen at a lower speed, whether it’s a tire blowout or nose gear landing (heaven forbid). And to me, it doesn’t seem any less safe flying an approach with full flaps. In both cases (full flaps or no flaps) you will be flying the aircraft at a speed slightly above V_s (either V_s0 or V_s1). So whether you are flying at 10 knots above V_s0 or V_s1, you are still flying at a speed 10 knots above the airspeed at which the aircraft will stall. If you lose that 10 knots of speed for some reason, you will stall in both cases.

Am I simply too old school? I realize that any landing that you can taxi the aircraft off the runway and walk away from is a ‘good landing’, but why wouldn’t you want to use most of your flap (if not all) available if it’s safe to do so?

1 comment »

1. By IFR Pilot 10 days later:

   
   
   What I was questioning was why the accident pilot would opt for 40 degrees of flaps (available on that model of 172), instead of the 30 degrees that is now the maximum amount available. In our 172, which also has 40 degrees of flaps, we almost never go beyond the thirty degree setting. With 40 degrees in, we felt that while there was a substantial amount of increased drag, there was also a loss of lift associated with it. So, since the first few landings where we experimented with 40 degrees, we've avoided them altogether.