Introduction
The flapless approach, also known as a clean approach or flat approach is a method of landing an aircraft without the use of flaps. This manoeuvre is typically only used in military and light aircraft as the physical demands on the airframe and pilot are usually deemed too risky for commercial operations.
The Theory
The flaps on an aircraft wing increase the curvature of said wing. This creates increased lift when the flaps are deployed and thusly reduces the speed at which enough lift is provided for the plane to remain airborne, commonly known as the stall speed.
In a flapless approach the pilot must maintain a good speed, typically 80 knots in a light aircraft by applying power and altering the angle of attack. By pointing the nose down and increasing the power, the pilot maintains speed but sacrifices height. As a direct result of this, the flapless approach is a lot more shallow than a standard approach (flown with varying degrees of flap).
A secondary consequence of using a clean approach is that once near the ground and entering the flare, the plane will be travelling considerably faster than on a flapped approach. This means the flare and hold off will be a lot longer than a standard landing.
Flying the flapless approach
When flying a flapless approach the pilot must extend the downwind leg of the circuit to give a longer final approach. This will allow for speed to be removed by altering the angle of attack (lifting the nose) and reducing the power. The pilot must pay particular attention to the airspeed to prevent a stall.
When calling short final, the pilot must remove
carburettor heat early to allow for rapid throttle inputs and flare relatively early. Through the flare the power should be removed very calmly as the aircraft will still be losing height and speed. The
hold off will be pronounced but the pilot must be sure that they do not bring about an
incipient stall unless they are less than a foot away from the ground. Ideally the main wheels should touch down first with the nose following shortly. The
roll out will be extended as the plane will be travelling at a higher speed than in a flapped landing.
Why bother with a flapless approach?
Generally pilots will use flaps to slow the descent and void unnecessary workloads. However, many military planes have no flaps, or flaps which have little effect, and so these must utilise flapless approaches.
A civil pilot may use a flapless approach if there are strong winds. This is because a strong headwind increases the airflow over the wings. With flaps, this can cause increased lift and prevent the aircraft landing with stability.
Of course, flap systems can also fail.