Air NZ Perpignan crash reaction
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FISH sauce anyone!
Well pray tell Tartare, what are the lessons we can all learn from?
"QUOTE" Tenerife is an example - a highly experienced, multi-engine heavy rated Captain fixating on getting out and home - I've read that accident report in detail. ( well bugger me gently please, so have I, and probably umteen other crews)
SO what is your definition of G.H.I?
You know this tenerife thing, and the Erebus thing keep coming up, and have done for years, with younger crews, and younger lecturers.
Quite frankly both subjects give me the screaming !&its:
I have never once had Erebus explained as an example in a CRM course as I understand it , and as does alot of NZer's & Aussie's. ( I havnt worked in poverty rocks for years)
As for Tenerife, I feel for poor Capt Van Zanten, all his good gone in an instant with his peer's, so back to my original Question! what is your definition of Get Home Itis?
Havnt been on the boards for awhile! but there is something fishy with Tartare, I fair:
Chr's
H/Snort.
"QUOTE" Tenerife is an example - a highly experienced, multi-engine heavy rated Captain fixating on getting out and home - I've read that accident report in detail. ( well bugger me gently please, so have I, and probably umteen other crews)
SO what is your definition of G.H.I?
You know this tenerife thing, and the Erebus thing keep coming up, and have done for years, with younger crews, and younger lecturers.
Quite frankly both subjects give me the screaming !&its:
I have never once had Erebus explained as an example in a CRM course as I understand it , and as does alot of NZer's & Aussie's. ( I havnt worked in poverty rocks for years)
As for Tenerife, I feel for poor Capt Van Zanten, all his good gone in an instant with his peer's, so back to my original Question! what is your definition of Get Home Itis?
Havnt been on the boards for awhile! but there is something fishy with Tartare, I fair:
Chr's
H/Snort.
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How did both FAC fail at the most critical point during a Normal Law Alpha Max test? The answer to that question is potentially more damaging than the low altitude selected. We must wait for the final report.
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Some of you may remember the crash of an ATR-72 at Roselawn in the USA some years ago. The NTSB investigator, Greg Feith, and his team did a remarkable job of figuring out the cause of this accident. In general terms, the accident was caused by ice flowback on the wings, and in some circumstances, could cause the aircraft to become a brick. It came down to a design flaw in the ATR.
Ironically, at a 1996 ISASI conference in Auckland of all places, the Yanks and the Frogs staged a very public argument about who was to blame. The frogs of course, denied that there could ever be a design flaw with their aircraft.
IMHO, the French accident investigators were unreasonable in this case.
This leads me to be very sceptical about ANY investigation carried out by the French. I'm sure they have some fantastic people, but if they let political or financial interests come before air safety, then the basis of any report is clearly compromised.
Just my 2c worth. Hopefully this accident investigation will come to some worthwhile conclusions.
Ironically, at a 1996 ISASI conference in Auckland of all places, the Yanks and the Frogs staged a very public argument about who was to blame. The frogs of course, denied that there could ever be a design flaw with their aircraft.
IMHO, the French accident investigators were unreasonable in this case.
This leads me to be very sceptical about ANY investigation carried out by the French. I'm sure they have some fantastic people, but if they let political or financial interests come before air safety, then the basis of any report is clearly compromised.
Just my 2c worth. Hopefully this accident investigation will come to some worthwhile conclusions.
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I was going through this thread and wondering when REMOAK would pop up.... and what do we get??
Remoak my lad, you are slipping. Go home, take some nasty pills and have another go. A few of us over here are most concerned about your presumed attack of niceness!!!
Remoak my lad, you are slipping. Go home, take some nasty pills and have another go. A few of us over here are most concerned about your presumed attack of niceness!!!
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I know. I'm pretty ashamed.
Even my kids are concerned that I haven't beaten them with the customary force recently. My wife is in shock after I used the word "please" last week.
I don't know what's happening to my life...
Never mind, I'll be back to normal by the next half-decent thread...
Even my kids are concerned that I haven't beaten them with the customary force recently. My wife is in shock after I used the word "please" last week.
I don't know what's happening to my life...
Never mind, I'll be back to normal by the next half-decent thread...
balance,
The ATR had a problem with aileron reversal which was known at design phase to the engineers. They came up with a half fix in 1989 (VGs in front of the ailerons i think) but it was not sufficient to cover the lack of boot protection ahead of the ailerons. In icing conditions a ridge would form aft of the boots and disturb airflow over the ailerons agrevating the reversal problem. The NTSB and French Investigators blamed mostly poor pilot technique in icing prior to Roselawn and it was pilots who kicked up a fuss for years prior regarding the aircrafts unsafe tendancies in icing. Interesting that the engineers were still not listened to as they requested 23% of chord be covered by boots, I think they increased it to 17-18%.
The ATR had a problem with aileron reversal which was known at design phase to the engineers. They came up with a half fix in 1989 (VGs in front of the ailerons i think) but it was not sufficient to cover the lack of boot protection ahead of the ailerons. In icing conditions a ridge would form aft of the boots and disturb airflow over the ailerons agrevating the reversal problem. The NTSB and French Investigators blamed mostly poor pilot technique in icing prior to Roselawn and it was pilots who kicked up a fuss for years prior regarding the aircrafts unsafe tendancies in icing. Interesting that the engineers were still not listened to as they requested 23% of chord be covered by boots, I think they increased it to 17-18%.
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Thanks 43 for refreshing my memory. You are quite correct. I've never flown the ATR and couldn't quite remember the details.
It was interesting though, watching Greg Feith slug it out with the French very publicly at that conference.
I seem to remember an episide of Air Crash Investigations dedicated to this mishap? Was the French reaction mentioned in the episode?
And for that matter, any other Accident Investigators out there had experience with the French?
It was interesting though, watching Greg Feith slug it out with the French very publicly at that conference.
I seem to remember an episide of Air Crash Investigations dedicated to this mishap? Was the French reaction mentioned in the episode?
And for that matter, any other Accident Investigators out there had experience with the French?
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And for that matter, any other Accident Investigators out there had experience with the French?
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Roselawn? Ice Ridges? Are you sure?
Maybe a bit off topic, but (wrt Roselawn crash), I've seen quite a lot of reference to twin turboprop icing "departures" being more to do with the asymmetric buildup of ice on wings (top and bottom surfaces), empennage (including top and bottom of hoz stabs and elevators), nacelles and fuselage caused by the props both rotating in the SAME DIRECTION.
Think about it. Think helix and helical flows. Think the consequences of different (and higher) stall speeds for port and starboard wings.
Ice builds up, autopilot holds wings level until, at the point of stall (at the new much higher Vs), the draggier, most lift-spoilt wing stalls first.
Even if Pilot then de-selects autopilot and valiantly attempts to pick up the dropping wing with aileron (instinctive - BUT always a no-no at the stall, as it embeds you in autorotation), there's no escaping the autorotation/ensuing spin.
Why? Partly because pilot fails to associate his dilemma with having stalled/entered spin and continues to oppose rapid roll with aileron - and partly because the two wings are now of a completely different airfoil shape and drag index spanwise (because of the dissimilar ice distributions).
This type of icing departure occurs mainly in rain-ice/freezing rain (aka SLD). The Feithster's runback ridge and aileron reversal explanation never ever considered this as a factor, but it's been validated in airborne trials.
Think about it. Think helix and helical flows. Think the consequences of different (and higher) stall speeds for port and starboard wings.
Ice builds up, autopilot holds wings level until, at the point of stall (at the new much higher Vs), the draggier, most lift-spoilt wing stalls first.
Even if Pilot then de-selects autopilot and valiantly attempts to pick up the dropping wing with aileron (instinctive - BUT always a no-no at the stall, as it embeds you in autorotation), there's no escaping the autorotation/ensuing spin.
Why? Partly because pilot fails to associate his dilemma with having stalled/entered spin and continues to oppose rapid roll with aileron - and partly because the two wings are now of a completely different airfoil shape and drag index spanwise (because of the dissimilar ice distributions).
This type of icing departure occurs mainly in rain-ice/freezing rain (aka SLD). The Feithster's runback ridge and aileron reversal explanation never ever considered this as a factor, but it's been validated in airborne trials.
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Shadow,
Nothing to do with props,
As the airplane pitched nose up and the AOA increased through 5 degrees, the airflow in the area of the right aileron began to separate from the wing upper surface because of the ice ridge. As the AOA continued to increase, the airflow separation in the area of the right aileron also increased, causing a reversal of the right aileron hinge moment characteristics. Although the right aileron hinge moment reversal caused the ailerons to deflect rapidly to a right-wing-down (RWD) position, the AOA was not sufficient to activate the stall warning system prior to the aileron deflection. The autopilot could not control the aileron deflection rate, which exceeded that allowed by the autopilot so the autopilot disconnected.
Within 0.25 seconds of the autopilot disconnection, the ailerons fully deflected to the RWD position79 and the airplane rolled rapidly to the right until reaching 77 degrees RWD. An immediate nose down elevator deflection reduced the AOA; and the ailerons were deflected LWD by the flightcrew to counter the right roll. The airplane began to roll back towards a wings-level-attitude. The crew then applied 2 to 3 degrees of left rudder and nose-up elevator. The flightcrew's aileron and rudder control inputs reduced the bank angle to 55 degrees RWD. However, as the AOA increased to more than 5 degrees, the airflow over the right aileron separated again, resulting in a second aileron hinge moment reversal and rapid RWD aileron deflection.
This is directly from the NTSB report, it was a flaw in the aircraft design. The flow separation actually commanded the aileron movement not just a simple wing drop stall. The deflection occured at around 180KIAS and only 5 degrees AoA.
The sad part about the whole scenario is that the aircraft had demonstrated aileron hinge reversal on clean airframes during certification at low AOA and they had adjusted the airflow in the area to increase the angle at which it happened. After the first icing related ATR-42 accident in 1987 they knew that it was most probably ice induced aileron reversal and put out a training package and added more VG's to fix the problem. They did not inform any operators or pilots of the findings. The training package did not cover sudden full aileron control deflection with up to 60lbs of force during apparently normal flight (which was what happened in both accidents).
There was a massive lawsuit against ATR because of this.
Last edited by 43Inches; 6th Jul 2010 at 01:17.
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Make the evidence fit the mould
ATR very specifically advised operators that such conditions could effect roll control forces leading to an autopilot disconnect and a resulting roll to a large bank angle until the crew took over the controls. ATR described appropriate recovery procedures and introduced them into ATR training programs. ATR also modified simulator packages for icing operations to simulate such roll departures.
The NTSB knows of the extensive wind tunnel testing, high speed taxi tests, flight testing, and considerable efforts spent by the manufacturer after Roselawn for the first-ever USAF tanker freezing drizzle/rain testing program for civil or military aircraft at Edwards AFB. The NTSB knows from its own involvement in the testing that the phenomenon of an “ice-induced aileron hinge moment reversal” and its associated flow separation behind the boots at low Angle of Attack was discovered for the very first time as a result of this exhaustive post-Roselawn investigation
The NTSB knows of the extensive wind tunnel testing, high speed taxi tests, flight testing, and considerable efforts spent by the manufacturer after Roselawn for the first-ever USAF tanker freezing drizzle/rain testing program for civil or military aircraft at Edwards AFB. The NTSB knows from its own involvement in the testing that the phenomenon of an “ice-induced aileron hinge moment reversal” and its associated flow separation behind the boots at low Angle of Attack was discovered for the very first time as a result of this exhaustive post-Roselawn investigation
I've re-read the re-issued report for around the fifth or sixth time and I still cannot find anything in there more than the interpretation of uncommanded roll being based upon the specious explanation of runback ice-ridges inducing top surface aileron hinge moment reversal (because nobody had thunk out any other credible explanation).....certainly not the asymmetric icing one leading to a significant (and earlier) stall speed difference between left and right wings.
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Greg Feith has been associated with a number of facile credible explanations including the 1996 Everglades crash of a Valujet DC9 due to the incendiary effect of poorly stowed (and jostled) oxygen cannisters - despite that airframe's known history of electrical faults, including on the flight preceding its crash - and the grandfathered hazardous wiring insulation type (BMS13-13 aka PVC). Feith is a showman and pretty glib and assertively convincing but also echoes the hollow-man - when it comes down to particularizing the science behind the theory.
.
The problem with icing crash theory is not dissimilar to that of wiring-caused crashes. Post-crash, the evidence is just not there and it takes the tea-leaf readers to colorfully interpret and explain the sparse leads available.
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But open-minded as always, please do feel free to point me towards anything that's poignantly tantamount to more than assertions of it having been due to "aileron reversal". We all have our belief systems. I just happen to believe that roll departures that are usually (but not always) in the same direction have a common denominator (and that's the L&R prop rotation direction skewing the ice accumulations asymmetrically and thereby favouring a roll to the right i.e. a stbd wing-drop).
.
43 inches said:
Within 0.25 seconds of the autopilot disconnection, the ailerons fully deflected to the RWD position79 and the airplane rolled rapidly to the right until reaching 77 degrees RWD. An immediate nose down elevator deflection reduced the AOA; and the ailerons were deflected LWD by the flightcrew to counter the right roll. The airplane began to roll back towards a wings-level-attitude
Here is the evidence trail;
1. Recorder data shows the aileron movement in both accidents, the hinge movement was towards the direction of roll, not against which would be the pilots natural reaction.
2. Certification records from flight testing show cause that aileron hinge reversal occured at low AOA on these aircraft to the point where modifications were carried out (only sufficient for flight in clear or light to moderate icing).
3. During the investigation into the first incident by the ATR & DGAC in 1988 the engineers concluded that aileron hinge reversal could be the cause. This was not promulgated to the NTSB at the time.
4. There was intensive wind tunnel testing of the aerofoil which showed that in extreme icing a ridge would form sufficient to cause aileron hinge reversal which created a force of 50lbs or greater. There was also the famous flights behind the tanker, but these flights could only simulate freezing drizzle not freezing rain. On the second runs made in europe they did find some hinge reversal occured but not to the extent found in the wind tunnel.
5. The most important evidence was from the numerous pilots who had experienced and survived the situation. This had occured over the preceding 10 years where pilots recounted stories of the autopilot disconnecting and the aircraft rolling suddenly with large force required to regain aileron control in icing conditions. After the 1988 incident there was a pilot ban on flying the aircraft in icing but the union gave in when ATR came up with the so called fix.
6. The aircraft was never tested in freezing drizzle or rain conditions as the new european certification rules did not require it to. This was an oversight when the aircraft was put on the FAA register.
The NTSB never created the aileron hinge reversal theory, ATR had known about it the entire time (and pilots of the type). The NTSB was finally able to get at the truth about what happened.
All turbo-props are different and suffer slightly differently in icing, know your aircraft!
1. Recorder data shows the aileron movement in both accidents, the hinge movement was towards the direction of roll, not against which would be the pilots natural reaction.
2. Certification records from flight testing show cause that aileron hinge reversal occured at low AOA on these aircraft to the point where modifications were carried out (only sufficient for flight in clear or light to moderate icing).
3. During the investigation into the first incident by the ATR & DGAC in 1988 the engineers concluded that aileron hinge reversal could be the cause. This was not promulgated to the NTSB at the time.
4. There was intensive wind tunnel testing of the aerofoil which showed that in extreme icing a ridge would form sufficient to cause aileron hinge reversal which created a force of 50lbs or greater. There was also the famous flights behind the tanker, but these flights could only simulate freezing drizzle not freezing rain. On the second runs made in europe they did find some hinge reversal occured but not to the extent found in the wind tunnel.
5. The most important evidence was from the numerous pilots who had experienced and survived the situation. This had occured over the preceding 10 years where pilots recounted stories of the autopilot disconnecting and the aircraft rolling suddenly with large force required to regain aileron control in icing conditions. After the 1988 incident there was a pilot ban on flying the aircraft in icing but the union gave in when ATR came up with the so called fix.
6. The aircraft was never tested in freezing drizzle or rain conditions as the new european certification rules did not require it to. This was an oversight when the aircraft was put on the FAA register.
The NTSB never created the aileron hinge reversal theory, ATR had known about it the entire time (and pilots of the type). The NTSB was finally able to get at the truth about what happened.
All turbo-props are different and suffer slightly differently in icing, know your aircraft!
Last edited by 43Inches; 6th Jul 2010 at 01:35.
About the A320 crash;
As with any crash like this there will be many links to the chain and because most people (in the industry anyway) know this full-well, I don't understand why people want to single one out in isolation.
There is a lot to learn from this and I think it would be better to identify a list of what we think the 'causal factors' are and address each one of them.
Here are the things I think need attention based on the interim report;
1/ The test was performed by pilots with no training specific to that test and guided by a pilot with two sim sessions of specific training. (How can the PIC make an accurate assesment of the guidance being offered if he isn't trained for that test) The fact that Airbus have introduced a five day course indicate to me that they think it was a factor, if not in the execution of the maneuver, then in the decision to do it when they did.(would the German Captain have conducted the test at 3000ft if he had completed the five day course?)
2/ XL Airways staff submitted an inaccurate flight plan. This is obviously not what caused the aircraft to crash but I believe it still needs addressing . Do flight plans for 'flight tests' need to be submitted by the PIC? Have airlines cut costs too much in these areas etc.
3/ Europe Aero Services released the aircraft apparently with unservicabilities, what was the error chain within that organisation?
4/The aircraft was intentionally slowed to around 100kts and the test carried out 7000ft below the recommended altitude (shortly after ATC had given them speed control of 180kts), without a clearance from ATC.What combination of commercial pressure, GHI, and ambiguous command environment lead to this action being taken? The Captain was clearly unsure of whether it was wise to do the test but he did it. Why? Thats a CRM PHd right there in itself.
All of these things and probably many others had to occur for the accident to happen in the way that it did (who knows if they would have recovered from 10,000ft), so rather than saying "It was so and so's fault", we should acknowledge that it was a result of many peoples actions or omissions and try to improve the system. Thats what I reckon anyway.
Framer
As with any crash like this there will be many links to the chain and because most people (in the industry anyway) know this full-well, I don't understand why people want to single one out in isolation.
There is a lot to learn from this and I think it would be better to identify a list of what we think the 'causal factors' are and address each one of them.
Here are the things I think need attention based on the interim report;
1/ The test was performed by pilots with no training specific to that test and guided by a pilot with two sim sessions of specific training. (How can the PIC make an accurate assesment of the guidance being offered if he isn't trained for that test) The fact that Airbus have introduced a five day course indicate to me that they think it was a factor, if not in the execution of the maneuver, then in the decision to do it when they did.(would the German Captain have conducted the test at 3000ft if he had completed the five day course?)
2/ XL Airways staff submitted an inaccurate flight plan. This is obviously not what caused the aircraft to crash but I believe it still needs addressing . Do flight plans for 'flight tests' need to be submitted by the PIC? Have airlines cut costs too much in these areas etc.
3/ Europe Aero Services released the aircraft apparently with unservicabilities, what was the error chain within that organisation?
4/The aircraft was intentionally slowed to around 100kts and the test carried out 7000ft below the recommended altitude (shortly after ATC had given them speed control of 180kts), without a clearance from ATC.What combination of commercial pressure, GHI, and ambiguous command environment lead to this action being taken? The Captain was clearly unsure of whether it was wise to do the test but he did it. Why? Thats a CRM PHd right there in itself.
All of these things and probably many others had to occur for the accident to happen in the way that it did (who knows if they would have recovered from 10,000ft), so rather than saying "It was so and so's fault", we should acknowledge that it was a result of many peoples actions or omissions and try to improve the system. Thats what I reckon anyway.
Framer
