Luxair F50 Crash: Pilot's Fault
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411A, not very impressed by your posts. Worst sort of 'management pilot' by the look of things, from where I sit. ..and I can't help recalling the last 'chap' who posted all over this site with the wonderful plans for his airline...
(...and it took you 35 years to get to the office, did it?)
There are no restrictions on setting idle on the F50, in flight or on the ground (strong tailwinds up the jet pipe gave a problem, but obviously, not in the air).
May I suggest that you, and others, take a look at Dr Simon Bennett's (ahem) seminal 'Human Error - by design?', which gives a good academic brief on much of what is under discussion here...
(...and it took you 35 years to get to the office, did it?)
There are no restrictions on setting idle on the F50, in flight or on the ground (strong tailwinds up the jet pipe gave a problem, but obviously, not in the air).
May I suggest that you, and others, take a look at Dr Simon Bennett's (ahem) seminal 'Human Error - by design?', which gives a good academic brief on much of what is under discussion here...
Last edited by Captain Phaedrus; 18th Nov 2003 at 09:34.
My understanding of the differences between engines is that the Dart is a fixed shaft turbine and the PW 125 is a free turbine. Each engine having different operating characteristics and operating techniques. I also suspect that the prop control systems differ, thus different modes and ranges of prop angles (including beta range).
Whereas the Dart could be safely ‘disced’ in the air other prop engines could not and in some cases the resulting aerodynamic pitch change could be hazardous. In this accident it is inferred that the PW 125 prop should not have been in the beta range in the air, and apparently safeguards were in place, yet it appears that the engines were in the beta range with disastrous effect.
Some of the basics of the different types of turboprop engines are in a specialized turboprop version of the PSM+ICR (Propulsion System Malfunction and Inappropriate Crew Response) Training and Awareness Guide which was issued recently (CD-ROM last year; joint FAA and UK CAA distribution?) any web links out there?
Whereas the Dart could be safely ‘disced’ in the air other prop engines could not and in some cases the resulting aerodynamic pitch change could be hazardous. In this accident it is inferred that the PW 125 prop should not have been in the beta range in the air, and apparently safeguards were in place, yet it appears that the engines were in the beta range with disastrous effect.
Some of the basics of the different types of turboprop engines are in a specialized turboprop version of the PSM+ICR (Propulsion System Malfunction and Inappropriate Crew Response) Training and Awareness Guide which was issued recently (CD-ROM last year; joint FAA and UK CAA distribution?) any web links out there?
411A:
I never flew anything with a Da7 only the larger Da8 and we had no such restrictions.
In fact our normal climb power was 14200/730°TGT so that would have been a bit close to your 14000 limit.
I never flew anything with a Da7 only the larger Da8 and we had no such restrictions.
In fact our normal climb power was 14200/730°TGT so that would have been a bit close to your 14000 limit.
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After carefully reading through the preliminary report incl. ammendment I come to the conclusion that:
1. The crew was not established and not ready for the approach. They tried to bring down the aircraft to lower altitude by all means.
2. The aircraft was not equipped with the newest updates, so it was possible to go in beta mode inflight.
3. After crew tried to descent very steep they came into beta mode and both engines stopped.
It is nearly impossible to restart in such a short period of time.
4. Due to low visibility is was not possible to emergency land the F-50 on the hillside. ROD was too big to keep integrity of the structure.
What do you suggest?
1. The crew was not established and not ready for the approach. They tried to bring down the aircraft to lower altitude by all means.
2. The aircraft was not equipped with the newest updates, so it was possible to go in beta mode inflight.
3. After crew tried to descent very steep they came into beta mode and both engines stopped.
It is nearly impossible to restart in such a short period of time.
4. Due to low visibility is was not possible to emergency land the F-50 on the hillside. ROD was too big to keep integrity of the structure.
What do you suggest?
The way I read the prelim report is like this.
It would seem the crew was indecisive about carrying out the aproach due to fluctuating vis. They postponed the decision to fly the the approach right up until the very last second when the vis came up to landing minimums. As a result, they were high and fast. In order to configure the aircraft for the approach, they pulled the power back to flight idle. It would appear that due to an electrical fault somewhere in the system, with the throttles closed the propeller flight fine pitch stops were removed, allowing either one or both propellers to go into beta range.
I couldn't read the report posted here - kept getting an 'unable to read this document' from Adobe Acrobat - but I read it in French on another board some time ago. How many holes in that analysis?
411A, you're right about the Dart and min torque. RR recommended a minimum of 60 psi torque in flight due to layshaft chatter.
It would seem the crew was indecisive about carrying out the aproach due to fluctuating vis. They postponed the decision to fly the the approach right up until the very last second when the vis came up to landing minimums. As a result, they were high and fast. In order to configure the aircraft for the approach, they pulled the power back to flight idle. It would appear that due to an electrical fault somewhere in the system, with the throttles closed the propeller flight fine pitch stops were removed, allowing either one or both propellers to go into beta range.
I couldn't read the report posted here - kept getting an 'unable to read this document' from Adobe Acrobat - but I read it in French on another board some time ago. How many holes in that analysis?
411A, you're right about the Dart and min torque. RR recommended a minimum of 60 psi torque in flight due to layshaft chatter.
Last edited by pigboat; 20th Nov 2003 at 08:56.
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I've never flown the F50 but with more than a couple of years on turboprops here's my two pence worth.
dani, pigboat
operating at close to minima it is not unusual to commence the appraoch and decide to continue it or not at the last possible moment (final fix or lower if allowed by state approach ban minima) hoping for an improvement in RVR.
Flight idle with discing props is quite normal way of reducing speed/ height rapidly. One of the benifits of a turboprop over a jet is the ability to do this. We used to be able to keep 250 knots clean to 5 miles and still be stable by 500 feet on a visual approach. ( need a bit more space in low vis but the luxair guys had plenty)
once the prop entered beta mode in flight they were effectively dead, the weather becomes irrelevent, loss of control becomes almost inevitable.
The key in this is the failure of Luxair to implement the mod to the antiskid system and the failure of the regulatory authority to mandate the mod.
dani, pigboat
operating at close to minima it is not unusual to commence the appraoch and decide to continue it or not at the last possible moment (final fix or lower if allowed by state approach ban minima) hoping for an improvement in RVR.
Flight idle with discing props is quite normal way of reducing speed/ height rapidly. One of the benifits of a turboprop over a jet is the ability to do this. We used to be able to keep 250 knots clean to 5 miles and still be stable by 500 feet on a visual approach. ( need a bit more space in low vis but the luxair guys had plenty)
once the prop entered beta mode in flight they were effectively dead, the weather becomes irrelevent, loss of control becomes almost inevitable.
The key in this is the failure of Luxair to implement the mod to the antiskid system and the failure of the regulatory authority to mandate the mod.
Dani
Your first point could be made with a different emphasis. The crew had been prepared for an approach, elected for a go around, then changed their minds. A classic human error, but was this aided by a failure to adhere to the approach ban (RVR less than required at FAF), or the manner in which ATC updated the RVR - were ATC trying to be helpful (no blame, just human nature).
As an aside what is the JAA Cat 2 RVR minima, I though that it was 350m? The crew quoted 300m and the JEP gives 300 but with a reservation about US Ops Specs, what does this mean to a JAR-OPS operator?
The crew having recommenced the approach may have faced an unusual technical situation, probably due to error, oversight, or latent failure. The crew may have seen unusual or misleading engine parameters. Assuming the same power lever angles, there were marked differences between power-plants in torque, engine speed, prop speed, and ITT. It is unadvisable for a crew to attempt diagnosis at a late stage of what had become a rushed approach, and they may well have been IMC at that time. However remember the human desire to perform well and help others; in this case was it trying to maintain schedule for an on time arrival? For any accident where it is concluded that pilot error is the cause, then start the investigation again; there is usually a much deeper cause which often involves human error at individual, operator, and organizational levels. Human error, if identified, can be explained and, defenses placed or alleviating action taken. I hope that the investigators identify the errors.
I do not agree that both engines stopped. Both engines had good ITT and HP and LP rotation. Correcting my earlier post; one propeller stopped (not engine), left hand; it was feathered or nearly feathered. What is not clear from the report is whether this was due to crew action or something else. In the report there is some attention to the propeller over-speed system. The FDR indicates that the RH prop was at or near the over-speed limit, which would reduce fuel flow, but the FDR shows the LH fuel flow reducing towards zero with corresponding LH LP/HP turbines and ITT also reducing. I hate to think that DFR data has been transposed, (or even the possibility of engine display data reversed). We must wait until the investigation finally reports, but I hope that all of these issues are explained.
Many of the problems in this accident appear common with those explained in the PSM+ICR project report, well worth reading, if only to remember that not all aircraft/props are the same and that in particular some of the latest big prop engines should not be selected into beta range in flight.
Edit by ALF after final report: both engines were shut down at a late stage; the FDR had stopped due to loss of elect power.
Your first point could be made with a different emphasis. The crew had been prepared for an approach, elected for a go around, then changed their minds. A classic human error, but was this aided by a failure to adhere to the approach ban (RVR less than required at FAF), or the manner in which ATC updated the RVR - were ATC trying to be helpful (no blame, just human nature).
As an aside what is the JAA Cat 2 RVR minima, I though that it was 350m? The crew quoted 300m and the JEP gives 300 but with a reservation about US Ops Specs, what does this mean to a JAR-OPS operator?
The crew having recommenced the approach may have faced an unusual technical situation, probably due to error, oversight, or latent failure. The crew may have seen unusual or misleading engine parameters. Assuming the same power lever angles, there were marked differences between power-plants in torque, engine speed, prop speed, and ITT. It is unadvisable for a crew to attempt diagnosis at a late stage of what had become a rushed approach, and they may well have been IMC at that time. However remember the human desire to perform well and help others; in this case was it trying to maintain schedule for an on time arrival? For any accident where it is concluded that pilot error is the cause, then start the investigation again; there is usually a much deeper cause which often involves human error at individual, operator, and organizational levels. Human error, if identified, can be explained and, defenses placed or alleviating action taken. I hope that the investigators identify the errors.
I do not agree that both engines stopped. Both engines had good ITT and HP and LP rotation. Correcting my earlier post; one propeller stopped (not engine), left hand; it was feathered or nearly feathered. What is not clear from the report is whether this was due to crew action or something else. In the report there is some attention to the propeller over-speed system. The FDR indicates that the RH prop was at or near the over-speed limit, which would reduce fuel flow, but the FDR shows the LH fuel flow reducing towards zero with corresponding LH LP/HP turbines and ITT also reducing. I hate to think that DFR data has been transposed, (or even the possibility of engine display data reversed). We must wait until the investigation finally reports, but I hope that all of these issues are explained.
Many of the problems in this accident appear common with those explained in the PSM+ICR project report, well worth reading, if only to remember that not all aircraft/props are the same and that in particular some of the latest big prop engines should not be selected into beta range in flight.
Edit by ALF after final report: both engines were shut down at a late stage; the FDR had stopped due to loss of elect power.
Last edited by alf5071h; 16th Dec 2003 at 23:03.
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Before you can solve a problem, you need to know what THE problem is. In this case (as usual) a lot of contributing factors were a fact, but not THE problem.
So, what was the problem???? The pilot(s) went below flight-idle, THAT is the problem! Why?? High, close, fast etc....
But why did they go below flight-idle?? Fokker issued a bulletin about this many years ago (after the klc-crash at ams...), warning the pilots!!
And there IS some kind of a detent on the flight-idle setting (and nothing wrong with flight-idle in-flight, you can even select Go-around on the ERP so the props act like speedbrakes).
Sounds like a "get-home-itis" to me, and therefor defenitely piloterror!
My thoughts go to all the family involved!
So, what was the problem???? The pilot(s) went below flight-idle, THAT is the problem! Why?? High, close, fast etc....
But why did they go below flight-idle?? Fokker issued a bulletin about this many years ago (after the klc-crash at ams...), warning the pilots!!
And there IS some kind of a detent on the flight-idle setting (and nothing wrong with flight-idle in-flight, you can even select Go-around on the ERP so the props act like speedbrakes).
Sounds like a "get-home-itis" to me, and therefor defenitely piloterror!
My thoughts go to all the family involved!
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Also seem to recall that the Captain was rather low on experience....age/hours.
The Europeans seem to have the opinion that, it all depends on training. A low hour guy can do just as well as a more experienced type.
What a few seem unable to grasp is that training, altho very concentrated and complete, can not, by itself, substitute for experience and airmanship.
And never will.
Many airlines /corporate operators in the USA found this out a long time ago.
The Europeans seem to have the opinion that, it all depends on training. A low hour guy can do just as well as a more experienced type.
What a few seem unable to grasp is that training, altho very concentrated and complete, can not, by itself, substitute for experience and airmanship.
And never will.
Many airlines /corporate operators in the USA found this out a long time ago.
Gear Down did them in
Extract from preliminary FDR data:
Looks to me that they were doing just fine in Flight Idle for 16 seconds until the gear lowering unblocked the low pitch
9:05:00 Reduction of engine power -- Torque L-17% R-15%
9:05:09 Start lowering Flaps -- Torque 0%
9:05:16 Start lowering gear -- Torque 0%
9:05:17 Left prop blade goes below 10 degrees-- Torque 0%
9:05:18 Right prop blade goes below 10 degrees -- Torque 0%
9:05:09 Start lowering Flaps -- Torque 0%
9:05:16 Start lowering gear -- Torque 0%
9:05:17 Left prop blade goes below 10 degrees-- Torque 0%
9:05:18 Right prop blade goes below 10 degrees -- Torque 0%
RbF, sure looks that way. It would appear there was some kind of electrical fault in the squat switch circuitry that allowed the flight fine pitch locks to be withdrawn while the aircraft was airborne with the throttles closed.
Daysleeper, agree completely with your comment re close in approach decisions. If there are any pilots on the board who hasn't been in that situation, he's indeed fortunate.
Daysleeper, agree completely with your comment re close in approach decisions. If there are any pilots on the board who hasn't been in that situation, he's indeed fortunate.
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411A
four thousand hours with almost three thousand on type at 26 years old is not low experience, the only thing that suprises me about the captain was that he was still on the F50 and hadn't cleared off to a Boeing, just shows how poor the job market has been in the last few years.
four thousand hours with almost three thousand on type at 26 years old is not low experience, the only thing that suprises me about the captain was that he was still on the F50 and hadn't cleared off to a Boeing, just shows how poor the job market has been in the last few years.
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On the other hand Daysleeper, the crew definately seemed unsure of their intensions with regard to the approach (or not)...whereas a more seasoned Captain might well have decided that, due to the airfield conditions, further holding or diversion would have been a better idea.
Company culture plays apart here, as does the fuel state (or lack thereof).
A possible suggestion might be for enhanced LOFT training, so that crews are not rushed into approaches...as they positively never should be.
If you ask yourself...does this picture look right...?, it probably isn't.
Company culture plays apart here, as does the fuel state (or lack thereof).
A possible suggestion might be for enhanced LOFT training, so that crews are not rushed into approaches...as they positively never should be.
If you ask yourself...does this picture look right...?, it probably isn't.
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What's your point 42?
411 "Seasoned"
The bloke has probably made 1000 approaches into luxembourg in the F50 over 7 years, it gets pretty foggy there every winter so if that is not enough experiance then what is.
Back to the point,
Regardless of what the crew did or did not do, if the prop goes into beta when you put the gear down on approach you are going to crash. Whether in VMC or IMC with 5 hours on type or 50,000 it becomes academic.
411 "Seasoned"
The bloke has probably made 1000 approaches into luxembourg in the F50 over 7 years, it gets pretty foggy there every winter so if that is not enough experiance then what is.
Back to the point,
Regardless of what the crew did or did not do, if the prop goes into beta when you put the gear down on approach you are going to crash. Whether in VMC or IMC with 5 hours on type or 50,000 it becomes academic.