'Engines running' in crash plane

Soldato
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Both engines of the British Airways jet that crash-landed at Heathrow Airport were still running when it came down, investigators have said.
But the engines did not respond sufficiently to a thrust request as it came into land, the Air Accident Investigation Branch (AAIB) said.

US investigators have noted six previous engine failures in the same type of aircraft, it also emerged.

http://news.bbc.co.uk/1/hi/england/london/7206596.stm

Interesting.

Googles definition for those who don't know the meaning of Thrust in Aviation terms read this:

The force produced by the engines, thrust works opposite of and counteracts drag. Thrust is the forward movement that is necessary to sustain flight. It is one of the four basic principles of flight.

Thrust is the force upon a system (such as a rocket or jet engine) generated when that system expels or accelerates mass. The resultant thrust force is equal to and in the opposite direction of the expelled mass.

So, when you hear the engines getting louded upon landing it means they are getting faster?

Why are the US investigating? Its a British owned, British run jet.

So how does the system work, why didnt it respond to a thrust? What process as such does it go through?

Discuss. :D

James.
 
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Isn't Boeing an American company?

Possibly the yanks have better air investigators? Or so there's no bias in the investigation? I dunno.
 
Why are the US investigating? Its a British owned, British run jet.

It doesn't say they are, it just says that they have noted engine failures in the same type of aircraft before.

Possibly a software fault with the autothrottle. It is fly-by-wire isn't it?
 
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Gremlins

GremlinsBigPic.jpg
 
Yes the engines do have to power higher for landing... if you are able to see the rear of the engines on your next flight you will see a lot of interesting things happening to them on landing. The thrust is there to keep the plane moving forward as the "landing" is in effect a controled crash!... the wings are deformed though the use of flaps and other moving parts to heavily reduce the lift produced.

The wing is effectively near stalling ( the point at which the lift produced in no longer able to support the weight of the aircraft ). Under normal flight conditions if this happens the plane would usually nosedive amongst other things. However during landing the extra thrust of the engines provides more forward force to stop this happening.
A small light aircraft can glide into land with little or no engine power but the larger the plane the harder it gets as you must be able to keep enough lift to prevent a nosedive and crash.

When the plane actually lands the engines will power even higher and a very complicated arrangements of ducts and flaps on the back of the engine channel a large proportion of the thrust in a (near ) forward direction which in effect slows the plane down ( usually very quickly ). Often you hear of planes overshooting the runway on landing, this usually is because this thrust reversing did not happen for whatever reason.

As this plane came into land the pilot would have slowed the plane down and used the flaps and such to try and reduce the lift over the wings as he approached the runway. He would have asked the engines for more power as he began to rotate the nose upwards in preparation for touchdown. This apparently didnt happen so he had to quickly use what momentum he had to get the plane into a resonable angle and direction to make the best level and non nose first landing he could. He thankfully managed to do this and tbh he deserves a bloody medal for it! :eek:
 
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Yes the engines do have to power higher for landing... if you are able to see the rear of the engines on your next flight you will see a lot of interesting things happening to them on landing. The thrust is there to keep the plane moving forward as the "landing" is in effect a controled crash!... the wings are deformed though the use of flaps and other moving parts to heavily reduce the lift produced.

The wing is effectively near stalling ( the point at which the lift produced in no longer able to support the weight of the aircraft ). Under normal flight conditions if this happens the plane would usually nosedive amongst other things. However during landing the extra thrust of the engines provides more forward force to stop this happening.
A small light aircraft can glide into land with little or no engine power but the larger the plane the harder it gets as you must be able to keep enough lift to prevent a nosedive and crash.

When the plane actually lands the engines will power even higher and a very complicated arrangements of ducts and flaps on the back of the engine channel a large proportion of the thrust in a (near ) forward direction which in effect slows the plane down ( usually very quickly ). Often you hear of planes overshooting the runway on landing, this usually is because this thrust reversing did not happen for whatever reason.

As this plane came into land the pilot would have slowed the plane down and used the flaps and such to try and reduce the lift over the wings as he approached the runway. He would have asked the engines for more power as he began to rotate the nose upwards in preparation for touchdown. This apparently didnt happen so he had to quickly use what momentum he had to get the plane into a resonable angle and direction to make the best level and non nose first landing he could. He thankfully managed to do this and tbh he deserves a bloody medal for it! :eek:

Sorry to be pedantic Atreus but a lot of that just isn't true! The trailing edge flaps on the wing increase both the camber and the wing area, the leading edge devices also increase the camber but they also have a slot in them which allows higher pressure airflow from under the wing to re-energize the boundary layer on the top surface. Both the trailing and leading devices really increase the lift produced by the wing.

Just to explain how a wing works quickly, it is basically due to differential pressure from the top and the lower surfaces. When the wing is put into an airflow the lift is determine by the lift coffecient (which is dependant on the actual desgin of the wing), the speed of the airflow (which is actually a pressure) and the angle which the wing is to the airflow. During normal flight an airliner has a angle of attack(the angle the wing is to the airflow) of around 4 degrees. This is the most efficent angle and allows for minimal drag. Airliners have swept wings which give them good high-speed characteristics. The problem with swept wings is that they have very poor low speed characteristics. The wing has to have a lot of devices (as I explained above) to increase the lift it produces at low speed.

The reason that the engines are generally at a relatively high power setting during landing (however this depends on a number of factors) is that with an increase in lift this also produces a large increase in drag, which the engines need to conteract to keep the forces balanced. Also the gear also obviously produces a lot of drag!!

Sorry for waffling, hope that vaguely explains things to those who don't fly!
 
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Yeah sorry Atreus have to agree with Blinkz, but you may need a bit more of a memory jolt :P , a lot of that isnt correct.

The wing is effectively near stalling ( the point at which the lift produced in no longer able to support the weight of the aircraft ).
- The wing is no more near stalling as you come into land as it is in normal flight. That'd be bloody dangerous, as a gust of wind would stall the aircraft and when you're close to the ground = crash.

Also gliding the larger aircraft is no different to the smaller aircraft. You wont descent any quicker; all it takes is a faster speed and it'll glide just as well.

He would have asked the engines for more power as he began to rotate the nose upwards in preparation for touchdown.
- As you rotate you wont have any power on at all, and even put the thrust levers to idle before you rotate to land.
 
Yes the engines do have to power higher for landing... if you are able to see the rear of the engines on your next flight you will see a lot of interesting things happening to them on landing. The thrust is there to keep the plane moving forward as the "landing" is in effect a controled crash!... the wings are deformed though the use of flaps and other moving parts to heavily reduce the lift produced.

The wing is effectively near stalling ( the point at which the lift produced in no longer able to support the weight of the aircraft ). Under normal flight conditions if this happens the plane would usually nosedive amongst other things. However during landing the extra thrust of the engines provides more forward force to stop this happening.
A small light aircraft can glide into land with little or no engine power but the larger the plane the harder it gets as you must be able to keep enough lift to prevent a nosedive and crash.



When the plane actually lands the engines will power even higher and a very complicated arrangements of ducts and flaps on the back of the engine channel a large proportion of the thrust in a (near ) forward direction which in effect slows the plane down ( usually very quickly ). Often you hear of planes overshooting the runway on landing, this usually is because this thrust reversing did not happen for whatever reason.

As this plane came into land the pilot would have slowed the plane down and used the flaps and such to try and reduce the lift over the wings as he approached the runway. He would have asked the engines for more power as he began to rotate the nose upwards in preparation for touchdown. This apparently didnt happen so he had to quickly use what momentum he had to get the plane into a resonable angle and direction to make the best level and non nose first landing he could. He thankfully managed to do this and tbh he deserves a bloody medal for it! :eek:


The Flaps are there to increase the lift at slow speeds but they also create a lot of drag the engines combat this drag by giving more power hence louded noise

flaps arent deployed to reduce lift they give more lift at slower speeds

"frig beat to it lol"
 
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