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What is a Stabilized Approach?

August 27, 2017

This is an often asked question by students and flight instructors alike. The truth is it is a lot easier to describe a stabilized approach than it is to do one. For example the FAA describes a stabilized approach as a constant attitude, constant airspeed, constant rate, constant angle approach from the turn to final to the flare to touchdown, which of course is true. But it begs the question the question is how do you do that? 

 

 
Well let's start with constant attitude. The problem is we cannot pitch to our altitude or our airspeed and maintain a constant pitch attitude. So we must pitch to the runway and maintain that attitude and sight picture all the way to the runway. But to do that, we must first understand there is only one flight path that will get us to the runway, and that flight path is determined by pitch attitude of the airplane. But we also know the pitch attitude required is affected by wind and the airplane's airspeed. So we must understand these variables and make adjustment for them to fly a constant attitude approach to the runway.

 

So first the pilot must choose the right final approach speed. Now keep in mind the manufacturer's recommended airspeed is not a constant one size fits all airspeed. It is simply the lowest airspeed you can maintain a constant attitude, constant angle of descent to the runway in a no wind condition. Therefore if we increase the power to slow the rate of descent at a constant airspeed we will need to increase the pitch attitude, which destabilizes the approach. In the same way if we increase the pitch attitude to slow the rate of descent we will slow the airspeed, which will also destabilize the approach. So it should be evident the only logical way to fly a constant attitude, constant rate approach in a head wind is to maintain a constant ground speed by increasing the final approach speed in proportion to the headwind component.

 

So we take the manufacturer's recommended approach airspeed in the full flap landing configuration, the add the headwind component. So if the recommended no-wind approach speed is 70 KIAS, and there is a steady 10 knot headwind down the runway, then we would plan to use an 80 KIAS final approach speed which will enable us to maintain a constant attitude 70 knot ground speed. It is not necessary, nor a good idea, to fly the final approach in a nose high attitude to maintain the glide path at the manufacturer's recommended approach speed. This is dangerous technique in a strong wind and can lead to a stall during the flare.

 

So to fly a stabilized approach in all wind conditions, let's make the approach attitude and descent rate the constant. Then adjust the approach speed for the headwind component and wait on full flaps. On short final when the runway is made add full flaps if required and at approximately 100 feet above the ground close the throttle and continue the descent attitude to the flare altitude of approximately 30 feet AGL. So by the time we reach the flare height the excess airspeed will have bled off and we can continue with a normal flare to touchdown. It's that simple!

 

The only problem I've found in teaching pilots to fly a constant attitude approach at a higher airspeed is the pilot's fear of not being able to slow down after reaching the runway. The truth is it's easy to slow an airplane's airspeed in a headwind. But it's very difficult to increase airspeed when low and slow, which usually ends up in a bad landing or a last minute go-around. So my advice, don't do it! Turn final at the same altitude and distance from the runway and simply carry more airspeed on final, stabilize your approach, land normal...and fly like the pros.

 

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