Pilot’s audio released: ‘Engine flameout’

http://www.usatoday.com/story/news/world/2015/02/04/transasia-airways-taipei-plane-crash/22842757/

I’m sorry to have another tragic crash to comment on.

The recent video showing the crash and today’s release of the voice cock-pit recorder shows how horrible plane crashes can be. I want to take a few moments and explain the aerodynamics and pilot reactions in situations like this.

First off, all two-engine airplanes are designed to fly with one engine out. Four engine airplanes are designed to fly with two engines out. Any news broadcasts which says losing an engine will cash the crash is wrong.

When a engine goes out, particularly on departure, the first thing a pilot has to do is lower the nose. Maintaining airspeed is critical. The airspeed is what gives the pilot the other controls they need to control the airplane. As the airplane loses power the lost thrust on one side causes the plane to turn towards the lost engine (yaw). As that occurs the airspeed over that wing is slower and will cause it to stall first. That video clearly showed that.

With an engine out situation, the most important flight control is the rudder. That surface is the vertical surface on the tail. The pilot has to use more rudder to keep the airplane going straight so the wing drop doesn’t occur. An inexperienced pilot will tend to keep the nose up, aggravating the loss of airspeed.

The pilot has to keep the nose down and use the rudder to keep the airplane flying straight until it gets to a safe airspeed. Turning is very difficult. Sharp turns will decrease the airspeed, so only very gradual course changes can be made.

If the failure occurs on departure in an urban area the pilot has few choices. They may be able to fly, but only if they can lower the nose and fly straight while they accelerate. If the failure occurs in a city and they can’t do that, they will crash.

On CNN this morning, they showed the results of another similar crash in which the failed engine’s propeller didn’t respond correctly. When a propeller airplane loses an engine, the propeller automatically goes to a feather position. Feather is when the blade of the propeller turns so it aligns with the flight path. That position produces the least drag. If that fails to happen then the airplane is flying with a barn door on one side. If that failure occurs, recovery is almost impossible. There are procedures for the pilot to manually, feather the propeller, but the procedures take time and or altitude.

There is an old pilot saying which is, “The pilot keeps flying, until they run out of altitude, airspeed and ideas.”

 

Ray Jay Perreault

Science Fiction