Feathered propellers in focus in Nepal aircraft crash investigation; How they work

A preliminary investigation into the Yeti Airlines aircraft crash in Nepal final month, which killed all 71 folks on board, prompt that one of many pilots might have inadvertently pushed levers that “feathered” the engines earlier than touchdown, inflicting the engines to lose thrust and the aircraft to crash. (ALSO READ: Nepal aircraft crash: Human issue cannot be ‘disregarded’, says prelim report)

Before we are able to perceive feathering, we should first perceive the basics of flight. When an aeroplane is flying by way of the sky, 4 forces act on it on the identical time. The sum of those forces determines the flight path.

The 4 forces on plane

1) Thrust power is the power that propels an plane within the path of movement. It’s powered by an airplane’s engine.

2) Drag is a power that acts in the wrong way of movement. It has the impact of slowing down an object. Drag is brought on by friction and air stress variations.

3) Weight is the gravitational power.

4) Lift is the power that retains an airplane up into the air. The wings generate nearly all of the carry, a Nasa report says.

What would occur if the engine failed and was unable to generate sufficient thrust to beat air drag, stopping the aircraft from shifting ahead?

This is the place gliding is available in

Aircraft are designed to glide as a consequence of their fashionable wings and streamlined our bodies, so even when all engines fail (a uncommon occasion), the planes can nonetheless be guided to a secure touchdown spot. By gliding by way of the air, the pilot can find the closest airport or any secure touchdown spot. (ALSO READ: Nepal noticed 11 lethal aircraft crashes since 2010: Why is flying so dangerous there?)

How far can an plane fly?

If the aircraft’s engines aren’t producing the thrust for which they had been designed, it should inevitably lose altitude. But how far can a aircraft fly earlier than falling to the bottom?

The glide distance depends upon a variety of components, however on common, in response to retired US airline pilot John Cox’s article in USA Today, an plane can glide as much as 100 miles relying on the wind if the engines fail at 30,000 toes.

What half does feathering play in all of this, then?

The feathering position is now launched. The wind hitting the plane’s powerless propellers causes windmilling, which creates important gliding resistance thus decreasing the plane’s attain.

The drag could be lowered by holding the angle of the propeller blades virtually parallel to the incoming airflow, the method often called feathering of propellers within the aviation business. SKYbrary, a digital repository of information associated to aviation security defines feathering as “increasing the blade pitch to the point that the chord line of the blade is approximately parallel to the on-coming airflow.”

This considerably reduces drag, giving the plane worthwhile additional touchdown distance.

Yet, solely plane with variable-pitch propellers—which permit the pilot to regulate the propeller blade angle in mid-air—can accomplish this.

Now, feathering a windmilling plane can acquire a ways for it, feathering a powered and spinning propeller will cut back thrust. The preliminary report exhibits that the engines did not have sufficient thrust on the final leg of descent.

Source web site: www.hindustantimes.com

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