Luxembourg Crash 6/11 (Threads Merged)
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F-50 PW-125B engines:
High pressure spool: comprises a centrifugal compressor and a single stage axial turbine (rpm governed by fuel metering)
Low pressure spool: comprises a centrifugal compressor and a single stage axial turbine (ungoverned)
Power turbine: 2-stage axial power turbine drives the propeller via the reduction gearbox.
High pressure spool: comprises a centrifugal compressor and a single stage axial turbine (rpm governed by fuel metering)
Low pressure spool: comprises a centrifugal compressor and a single stage axial turbine (ungoverned)
Power turbine: 2-stage axial power turbine drives the propeller via the reduction gearbox.
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Ignition Override
From day one my airline trained us on the GA engine loss and an engine failure of some sort on final besides the standard V1 cut and reject. I was always of the opinion that everyone trained to this standard.
Are you sure that this is not what the regulator requirement is?
From day one my airline trained us on the GA engine loss and an engine failure of some sort on final besides the standard V1 cut and reject. I was always of the opinion that everyone trained to this standard.
Are you sure that this is not what the regulator requirement is?
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Theory:
Non continuance of approach.
With the crash site being approximately 5-6km from the airport, that would equate to about 4 miles / OM / 1000'
ATRE. If the RVR was below the required minimum then they may well have been executing a missed approach (not
permitted to continue if the RVR was below their minima - which it was, they required 300m, and it was only 250m).
If indeed it turns out to be an icing-induced twin compressor stall (or two in quick succession) then the time to
analyse and deal with the problem would have been minimal. It might also explain why the aircraft was off centerline
and its heading about 80 degrees off the localizer course. A double compressor stall is not improbable, particularly
as the a/c came out of IMC holding to commence the ILS - however it's equally likely that only one engine may have
compressor stalled - and in the rapid shutdown of that problem engine, they may have feathered or fuel-chopped the
wrong engine. Equally, a single-engine go-round from low-speed configured in IMC is a difficult proposition. It is
very significant that photos show the starboard prop virtually undamaged but unfeathered.
Stbd Prop obviously not rotating at impact (nor feathered)
a. At low power, high AoA in a holding pattern, engine bleed-air output may not be sufficient to stop some
ice forming in the intake and on the intake lip.
b. When the pilot made the decision to abandon the approach and go-round (because the RVR was too low), one
or both of the following may have happened:
(i) Engine(s) might compressor stall due to insufficient air-flow through ice-obstructed intake and/or
(ii) Suddenly increased bleed-air flow might dislodge intake and lip ice damaging compressor blades and causing surge/stall/power loss on both.
It would be interesting to know how the new anti-ice control unit was tested as adequate and then certified (see AD
above). F50's may well have been flying for years in similar icing conditions - and landing successfully... but
doing it with an engine intake ice-load that would have caused a dual compressor stall - had they applied go-round
power.
If this was the case, it would be indeed ironic to reflect that, had they continued the approach (even though they
only had 250m RVR vice the required 300m), they may have landed safely and never been any the wiser about the intake
icing (which would only have become a compressor surge/stall problem at go-round power).
Just a theory. I doubt that any extensive testing would have been carried out on the "improved" anti-
ice control unit. It was Fokker - not Boeing or Airbus - and apparently the first anti-ice control unit wasn't up to
it. The "improved" version was probably just an upgraded flow.
http://www.casa.gov.au/avreg/aircraf...50/f50-012.pdf (the AD)
Non continuance of approach.
With the crash site being approximately 5-6km from the airport, that would equate to about 4 miles / OM / 1000'
ATRE. If the RVR was below the required minimum then they may well have been executing a missed approach (not
permitted to continue if the RVR was below their minima - which it was, they required 300m, and it was only 250m).
If indeed it turns out to be an icing-induced twin compressor stall (or two in quick succession) then the time to
analyse and deal with the problem would have been minimal. It might also explain why the aircraft was off centerline
and its heading about 80 degrees off the localizer course. A double compressor stall is not improbable, particularly
as the a/c came out of IMC holding to commence the ILS - however it's equally likely that only one engine may have
compressor stalled - and in the rapid shutdown of that problem engine, they may have feathered or fuel-chopped the
wrong engine. Equally, a single-engine go-round from low-speed configured in IMC is a difficult proposition. It is
very significant that photos show the starboard prop virtually undamaged but unfeathered.
Stbd Prop obviously not rotating at impact (nor feathered)
a. At low power, high AoA in a holding pattern, engine bleed-air output may not be sufficient to stop some
ice forming in the intake and on the intake lip.
b. When the pilot made the decision to abandon the approach and go-round (because the RVR was too low), one
or both of the following may have happened:
(i) Engine(s) might compressor stall due to insufficient air-flow through ice-obstructed intake and/or
(ii) Suddenly increased bleed-air flow might dislodge intake and lip ice damaging compressor blades and causing surge/stall/power loss on both.
It would be interesting to know how the new anti-ice control unit was tested as adequate and then certified (see AD
above). F50's may well have been flying for years in similar icing conditions - and landing successfully... but
doing it with an engine intake ice-load that would have caused a dual compressor stall - had they applied go-round
power.
If this was the case, it would be indeed ironic to reflect that, had they continued the approach (even though they
only had 250m RVR vice the required 300m), they may have landed safely and never been any the wiser about the intake
icing (which would only have become a compressor surge/stall problem at go-round power).
Just a theory. I doubt that any extensive testing would have been carried out on the "improved" anti-
ice control unit. It was Fokker - not Boeing or Airbus - and apparently the first anti-ice control unit wasn't up to
it. The "improved" version was probably just an upgraded flow.
http://www.casa.gov.au/avreg/aircraf...50/f50-012.pdf (the AD)
Moderate, Modest & Mild.
The posting of some people`s hypothetical theories are further making public the LACK of knowledge often displayed by the press.
FYI, Belgique it IS permissible to continue an approach if the RVR/vis drops below the min, as long as it was at or above the minimum at the commencement of the approach.
How about waiting until there`s a bit more HARD evidence from the investigators.
"It is often better to keep one`s mouth closed and APPEAR to be a fool, than to open it - and remove all doubt!"
FYI, Belgique it IS permissible to continue an approach if the RVR/vis drops below the min, as long as it was at or above the minimum at the commencement of the approach.
How about waiting until there`s a bit more HARD evidence from the investigators.
"It is often better to keep one`s mouth closed and APPEAR to be a fool, than to open it - and remove all doubt!"
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First of al: my condolences to all familie and friends of the victims.
For all self declared specialist on a/c.......leave the guessing to the authorities..or at least state accurate facts.
Some people do practise the GA... with n-1 ! realy it has been done.
Actualy Luxair has a very good training program for Cat2 (i've done the cat2 thingy) where the GA in CAT2 is not a spectacular event.
And a compressor stall is a very unlikely possibility with the Fokker50. Even when advancing the throttle quite vast (lets say a pilot new to the plane) would not give mayor hickups warranting this.
What might have been the problem? I'll find out when they publish it!
For all self declared specialist on a/c.......leave the guessing to the authorities..or at least state accurate facts.
Some people do practise the GA... with n-1 ! realy it has been done.
Actualy Luxair has a very good training program for Cat2 (i've done the cat2 thingy) where the GA in CAT2 is not a spectacular event.
And a compressor stall is a very unlikely possibility with the Fokker50. Even when advancing the throttle quite vast (lets say a pilot new to the plane) would not give mayor hickups warranting this.
What might have been the problem? I'll find out when they publish it!
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You are right but....
KAPTIN M
Generally I agree. But please avoid being harsh. Belgique is just offering some guesses. In the past he provided brilliant posts concerning AA 587 or 747 cargo door related threads.
Good night.
Generally I agree. But please avoid being harsh. Belgique is just offering some guesses. In the past he provided brilliant posts concerning AA 587 or 747 cargo door related threads.
Good night.
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Bearcat
Please reread what I wrote, I was not implying anything, just stating a fact that my airline trains and tests to the standard that I described.
I was under the impression that everyone else trains to the same standard.
Since I seem to have touched a nerve, please explain...
By the way, even though I have over 30 years experience as a Airline Captain I wouldn't even comment as to the cause of the accident as I wasn't there and I have only limited time on a turoprop...
Please reread what I wrote, I was not implying anything, just stating a fact that my airline trains and tests to the standard that I described.
I was under the impression that everyone else trains to the same standard.
Since I seem to have touched a nerve, please explain...
By the way, even though I have over 30 years experience as a Airline Captain I wouldn't even comment as to the cause of the accident as I wasn't there and I have only limited time on a turoprop...
Tan: The FAA, which I referred to, only 'oversees' (so to speak) US airlines, and I know nothing about foreign airline requirements. Other than the British CAA, or Dutch RLD (?), I have no idea what the foreign aviation 'authorities' are called. As my remarks attempted to describe, my company, since training me as FO in November '85 (was FO about thirteen years), has only three or four times given me engine failures which were not during takeoff.
As previously stated , only o-n-e such approach 'event' was during a visual: never at an MDA, and never in IMC, even for an ILS, and this was during my four years as Captain.
My company's mainline operates turbofan jets, which range from, generally speaking, 108,000 pounds MTOW up to that of the 747-400.
To repeat, I know nothing about other US airline nor foreign airline requirements, but I suspect that the training for those unfortunate F-50 pilots, no matter what caused the accident, was much better than what many US airlines require on their many jet fleets, most of which carry a larger number of (naive and unsuspecting) passengers per plane.
As previously stated , only o-n-e such approach 'event' was during a visual: never at an MDA, and never in IMC, even for an ILS, and this was during my four years as Captain.
My company's mainline operates turbofan jets, which range from, generally speaking, 108,000 pounds MTOW up to that of the 747-400.
To repeat, I know nothing about other US airline nor foreign airline requirements, but I suspect that the training for those unfortunate F-50 pilots, no matter what caused the accident, was much better than what many US airlines require on their many jet fleets, most of which carry a larger number of (naive and unsuspecting) passengers per plane.
Last edited by Ignition Override; 12th Nov 2002 at 00:28.
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Bearcat
I don't quite get the point of your rather stinging reply to Tan.
The airline that has employed me for the past 29 years has regularly trained and tested us in various 'engine-out' scenarios. Last sim check three weeks ago, given over 2 days, was typical in that among the various exercises, it included engine seizure exiiting a hold, in icing conditions, and subsequent non-percision approach to landing. (We are trained a lot in icing scenarios!)
Also covered, besides the usual engine fire/failure just past V1, were engine flameout in cruise, engine fire + shutdown on vectors, engine flameout with full flap just inside the OM (in icing condiitions) as well as the usual engine failure during missed approach from low level.
These are not 'one-of' sim exercises. They have all been a regular part of every sim syllabus that I have ever taken.
I,too, was under the impression that every airline trained to the same standard. If, as you claim, that the JAR Ops directives do not include scenarios other than the standard 'engine failure after V1', then perhaps those Ops should be re-written and regularily trained for. But I'm willing to bet that, either they do include those exercises, or perhaps that your recurrent training syllabus has become an exercise in checking off the squares on a list of minimum exercises to satisfy some regulatory paperwork. But I hardly think so.
I don't quite get the point of your rather stinging reply to Tan.
The airline that has employed me for the past 29 years has regularly trained and tested us in various 'engine-out' scenarios. Last sim check three weeks ago, given over 2 days, was typical in that among the various exercises, it included engine seizure exiiting a hold, in icing conditions, and subsequent non-percision approach to landing. (We are trained a lot in icing scenarios!)
Also covered, besides the usual engine fire/failure just past V1, were engine flameout in cruise, engine fire + shutdown on vectors, engine flameout with full flap just inside the OM (in icing condiitions) as well as the usual engine failure during missed approach from low level.
These are not 'one-of' sim exercises. They have all been a regular part of every sim syllabus that I have ever taken.
I,too, was under the impression that every airline trained to the same standard. If, as you claim, that the JAR Ops directives do not include scenarios other than the standard 'engine failure after V1', then perhaps those Ops should be re-written and regularily trained for. But I'm willing to bet that, either they do include those exercises, or perhaps that your recurrent training syllabus has become an exercise in checking off the squares on a list of minimum exercises to satisfy some regulatory paperwork. But I hardly think so.
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Someone asked if wake turbulences could have been a factor: I confirm this was not the case as the previous was a Saab 2000 and with increased separation during cat 2 and 3 that Saab was on short finale when the F-50 started its approach.
This A/C asked for holding before the app. They were cleared to DIK to hold as the WX was below their minimas. and then they were cleared for the app...
even the RVR didn't improve in the meantime.
To kaptin M.
I tought you are not allowed to continue the app. if the WX is below the minimas before the OM, thus you have to perform a missed app. You can continue this app only if the RVR goes below your minimas after you already passed the OM. Correct?
Danou_71
This A/C asked for holding before the app. They were cleared to DIK to hold as the WX was below their minimas. and then they were cleared for the app...
even the RVR didn't improve in the meantime.To kaptin M.
I tought you are not allowed to continue the app. if the WX is below the minimas before the OM, thus you have to perform a missed app. You can continue this app only if the RVR goes below your minimas after you already passed the OM. Correct?
Danou_71
Ut Sementem Feeceris
Danou_71
Correct. You must have your required minimum RVR at the OM/1000' ARTE/4 miles or equivalent point. If the RVR is below your minima at this point you must go around.
If you have continued your approach because the RVR was at or above minimum at the OM/1000' ATRE and it subsequently goes below minimum then you can continue the approach down to DH' and land IF you have the required visual reference.
A4
Correct. You must have your required minimum RVR at the OM/1000' ARTE/4 miles or equivalent point. If the RVR is below your minima at this point you must go around.
If you have continued your approach because the RVR was at or above minimum at the OM/1000' ATRE and it subsequently goes below minimum then you can continue the approach down to DH' and land IF you have the required visual reference.
A4
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Insider information indeed. BEE PEE if you are feeding us inside information from your well known Luxembourg source , well then yes , it is garbage. Garbage in, garbage out. Sorry to say that no one except you can take your inside source seriously. Best to disregard any of that information as in my six years of hard experience with said person he never told the truth about anything. And that is an unfortunate smear on Luxembourg and it's aviation community. I thinks that people have to excuse BEE PEE for his gullability because otherwise he does seem to know what he is talking about.
@ palebird
Ut Sementem Feeceris
Can we PLEASE stick to the topic If you wish to get into a slanging match, please do it in private.
This thread is to discuss a serious accident and provides an opportunity to learn about aspects of aviation/aircraft operation we may be unfamiliar with. Please don't let THIS thread degenerate in to a "tit-for-tat" point scoring scenario - it's too important for that.
There's a time and place...........and this isn't it!
A4
If you wish to get into a slanging match, please do it in private. This thread is to discuss a serious accident and provides an opportunity to learn about aspects of aviation/aircraft operation we may be unfamiliar with. Please don't let THIS thread degenerate in to a "tit-for-tat" point scoring scenario - it's too important for that.
There's a time and place...........and this isn't it!
A4
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Icing?
BoxcarWilhomena, you might be right. I just watched the local TV news and they announced that “extreme icing may have played a major role” and “a collision with migrating birds can definitely be ruled out”. It was however left unclear if this was an official statement or not.
A note about the crash site: Within 15m of touchdown the aircraft hit an embankment of about 3-4m height. It is indeed a sad turn of fate that they didn’t have that little extra kinetic energy as the very soft field behind would have been suitable for an emergency landing.
Greetings
BeePee
A note about the crash site: Within 15m of touchdown the aircraft hit an embankment of about 3-4m height. It is indeed a sad turn of fate that they didn’t have that little extra kinetic energy as the very soft field behind would have been suitable for an emergency landing.
Greetings
BeePee
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So much speculation and inuendo - Why not wait for the official results of the accident?
Everyone is so eager to add their hypothesis on what happened, the press would have a field day.
Wait till someone can give you all hard facts, not hypothesis; until then, don't cast aspertions.
Lots of armchair critics here. No worse than a back seat driver wife! We all have (or had) one of those.
Hor
Everyone is so eager to add their hypothesis on what happened, the press would have a field day.
Wait till someone can give you all hard facts, not hypothesis; until then, don't cast aspertions.
Lots of armchair critics here. No worse than a back seat driver wife! We all have (or had) one of those.
Hor
Last Call: Your pilots are fortunate to have received such realistic training scenarios, and let's hope that many other airlines (and military squadrons) now include, or will include, these events in their high-cost simulator periods. Years ago, simply due to cost, some major airlines had no FMC trainer, which could have prepared pilots for each morning's fixed-base sim period in a certain Boeing FMC aircraft, in contrast to pilots showing up after no preparation. The people responsible for training pilots to face the newer type of flying later realized that after many years with many problems, they could then 'justify' the development of a desktop training device, to their "people upstairs". Some FOs at a major US airline actually spent about $5,000 out of their own pockets at Boeing for a course on the same aircraft, having little faith in a certain training department at their own airline. Back then, the company believed in pilots training themselves, to a large extent, don't ya know?
Many valuable simulated events can be done for training, without necessarily being graded by check airmen, if initiated by the Training/Program Managers etc, and allowed by the supervising authorities. Sometimes, the less such situations are graded as "pass/fail", the better the training results, and the lower the stress (better rest) for the pilots when they arrive for an 0500 briefing ().
Many valuable simulated events can be done for training, without necessarily being graded by check airmen, if initiated by the Training/Program Managers etc, and allowed by the supervising authorities. Sometimes, the less such situations are graded as "pass/fail", the better the training results, and the lower the stress (better rest) for the pilots when they arrive for an 0500 briefing (
).