Compressor Stall - Relight?
Thread Starter
Joined: Jan 2009
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From: Europe
Compressor Stall - Relight?
Hi Folks!
I would like to know your opinion about something. In case you experience a compressor stall (mainly during the TO run), would you consider a relight in flight?
YES or NO? Could you explain your position?
Thanx in advance!
I would like to know your opinion about something. In case you experience a compressor stall (mainly during the TO run), would you consider a relight in flight?
YES or NO? Could you explain your position?
Thanx in advance!
Joined: Jul 2001
Posts: 4,960
Likes: 17
From: Australia
zedoscarro,
There is no yes or no answer, it all depends on circumstances.
If it was a "stall" (if that is what has happened) that shut the engine down, that sound serious to me.
In one personal experience of a really big "backfire at about 120 kt and subsequent abort, examination of the engine revealed that there was serious internal damage ---- even though idle parameters were normal and the engine still made "down line" acceleration checks.
If it was a stall that resulted in something like a stable sub-idle, with no EGT limits exceeded, or other obvious indicated damage, but you needed to shut the engine down to re-establish control of the engine, that would merit much thought.
If it was just a "chuffle", such as you might get with a X-wind gust, or hanging onto reverse a little to long, with no adverse indications, that recovered itself, you would probably leave the engine running.
Tootle pip!!
There is no yes or no answer, it all depends on circumstances.
If it was a "stall" (if that is what has happened) that shut the engine down, that sound serious to me.
In one personal experience of a really big "backfire at about 120 kt and subsequent abort, examination of the engine revealed that there was serious internal damage ---- even though idle parameters were normal and the engine still made "down line" acceleration checks.
If it was a stall that resulted in something like a stable sub-idle, with no EGT limits exceeded, or other obvious indicated damage, but you needed to shut the engine down to re-establish control of the engine, that would merit much thought.
If it was just a "chuffle", such as you might get with a X-wind gust, or hanging onto reverse a little to long, with no adverse indications, that recovered itself, you would probably leave the engine running.
Tootle pip!!
Joined: Jan 2001
Posts: 2,044
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From: UK
In case you experience a compressor stall .... would you consider a relight in flight?
Why do you need to "relight" an engine that has had a compressor stall? By definition it is still running, so what is there to relight?The answer should surely be 100% clear according to type/company procedures, and not a generic pPrune answer. And of course will depend on # of engines you start with / have left.
Certainly on one type I fly I would consider a relight in flight if the engine was shut down... but then with only 1 engine, seems a fairly easy answer
NoD
Joined: Apr 2010
Posts: 89
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From: in the flight deck
hmm I'm still new.
For me, if the procedure requires u to shut it down in the first place, then leave it shut down. There is a reason why it's been shut down.
If the procedure requires ONLY to retard thrust lever to idle and check parameters then leave it running if parameters/procedures allow.
I remember someone once told me , " if u shut it down then leave it. If it flame out due rain/weather then u can consider to relight. The last thing u want is to turn an engine failure into an engine Fire."
For me, if the procedure requires u to shut it down in the first place, then leave it shut down. There is a reason why it's been shut down.
If the procedure requires ONLY to retard thrust lever to idle and check parameters then leave it running if parameters/procedures allow.
I remember someone once told me , " if u shut it down then leave it. If it flame out due rain/weather then u can consider to relight. The last thing u want is to turn an engine failure into an engine Fire."
Joined: Jul 2001
Posts: 4,960
Likes: 17
From: Australia
Most compressor stall conditions are with advancement of throttle
Not true at all, various misbehavior under the generic "compressor stall" can occure in all sorts of circumstances. Come to think of it, most of the ones I have experienced over 35 years have been with a steady throttle setting.
That they will all be covered in SOPs is wishful thinking, given the range of very diverse possibilities. Nigel, indeed your contribution is a really good Nigel effort, are you a Nigel?
Tootle pip!!
Joined: Apr 2010
Posts: 0
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From: Home soon
NEUPILOT,
I vote for your answer.
I believe on 737s, a compressor shall not call for a relight.
Engine stall recall items are to disengage the A/T and reduce the thrust until the engine is stall free.If the thrust lever is retarded to the closed position then the recall items are to follow the engine fire severe damage or separation
and therefore shutting down the engine.
I would opt for a relight in case of an engine failure due to heavy water ingestion or icing.
I vote for your answer.
I believe on 737s, a compressor shall not call for a relight.
Engine stall recall items are to disengage the A/T and reduce the thrust until the engine is stall free.If the thrust lever is retarded to the closed position then the recall items are to follow the engine fire severe damage or separation
and therefore shutting down the engine.
I would opt for a relight in case of an engine failure due to heavy water ingestion or icing.
Joined: Jul 2007
Posts: 610
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From: France
Compressor Stall
In the past, I spent a long, time in jets and as far as I can remember ,was lucky enough not to have experienced a compressor stall on a take - off or in flight.
I dare say that it can happen but happily, not often.
Tmb
I dare say that it can happen but happily, not often.
Tmb
Joined: Aug 1998
Aviation Qualifications: ATPL
Posts: 6,623
Likes: 847
From: Ex-pat Aussie in the UK
My company had an aircraft experience a series of compressor stalls on take-off - noise, banging, ejected visible flame etc. so it isn't THAT "hypothetical"
If you retard the thrust lever (at a safe height) and regain control of the engine, it is best to leave the engine at idle and return. Attempting to continue, even if the engine is fine, may cause a riot in the cabin amongst the passengers (and later, the press)
If you have shut the engine down - which wouldn't be unusual in these circumstances - it is best to leave it shut down & return for engineering assessment unless you NEED the thrust.
If you retard the thrust lever (at a safe height) and regain control of the engine, it is best to leave the engine at idle and return. Attempting to continue, even if the engine is fine, may cause a riot in the cabin amongst the passengers (and later, the press)
If you have shut the engine down - which wouldn't be unusual in these circumstances - it is best to leave it shut down & return for engineering assessment unless you NEED the thrust.
Joined: Mar 2002
Posts: 4,569
Likes: 1
From: Florida
My company had an aircraft experience a series of compressor stalls on take-off - noise, banging, ejected visible flame etc. so it isn't THAT "hypothetical"
but the question as posed seemed to presume that the engine shutdown during takeoff.
I don't believe that it is probable that the two conditions will go together
Joined: Sep 1998
Posts: 1,615
Likes: 1
From: wherever
I'm a little at a loss to understand this term "compressor stall". I'm going to assume you are all referring to an engine surge. The indications of a stall will start with ITT/EGT/TGT rise as the airflow brakes down and could lead to a reversal of airflow (a surge) which would be indicated by a large bang possibly accompanied by flame from either or both the engine exhaust and or inlet. With the surge will come a fluctuation in N1/N2/N3/NG and temperature which may also be the only indication if the stall doesn't develop into a surge.
There is a great video of a Thomson 767? swallowing a bird and suffering a surging engine afterwards. I had something similar on the L1011 on a training flight after a touch and go with simulated engine failure.
The Engine which had been at idle for the last 10 minutes decided to complain after being accelerated for the take off. In the cockpit the only indication we had was a banging so loud we thought we had come under fire. The Aircraft was and RAF tanker fitted with a camera which I used to check the engines and was somewhat concerned when I swung it onto no.3 and saw the engine coughing it's innards out of both ends.
Appropriate checklists were completed and we scrubbed back to the squadron for tea and biscuits. The next day in the engine servicing bay we looked at what was left of the HP compressor. Not Much!
My advice. If it miss behaved to the extent that you had to shut it down, think very carefully before relighting. Of course we can imagine scenarios where you might consider relighting a shutdown engine but in a hundred years of aviation they haven't happened very often.
There is a great video of a Thomson 767? swallowing a bird and suffering a surging engine afterwards. I had something similar on the L1011 on a training flight after a touch and go with simulated engine failure.
The Engine which had been at idle for the last 10 minutes decided to complain after being accelerated for the take off. In the cockpit the only indication we had was a banging so loud we thought we had come under fire. The Aircraft was and RAF tanker fitted with a camera which I used to check the engines and was somewhat concerned when I swung it onto no.3 and saw the engine coughing it's innards out of both ends.
Appropriate checklists were completed and we scrubbed back to the squadron for tea and biscuits. The next day in the engine servicing bay we looked at what was left of the HP compressor. Not Much!
My advice. If it miss behaved to the extent that you had to shut it down, think very carefully before relighting. Of course we can imagine scenarios where you might consider relighting a shutdown engine but in a hundred years of aviation they haven't happened very often.
