Air Nelson Dash Noeswheel Report
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The report spends a lot of time on the associated warnings from the original unsafe gear indication (horn and EGPWS) and is critcal that the crew ignored those warnings. Suggesting they should have gone around and sought further advice. What would that advice have been?
The report does not state if the horn or EGPWS receives indications from both gear indicating systems or just the primary. If it only receives it from the primary then the crew were correct in their assessment of what they expected to hear. If it gets it from both and the horn and EGPWS were an additional bit of important information then why weren't they in the QRH?
The whole point of OEM documents such as the AFM and QRH are so that you don't have to ring the OEM and ask for advice when it is time critical.
My aircraft type has multiple undercarriage indications but the OEM is very clear that only one of them has to indicate a green to be certain that it is down and locked. Nevertheless I would have a sense of unease during the approach, just like these guys did. So the fact they were uneasy should not be miscontrued to mean that they thought that needed more advice.
The report does not state if the horn or EGPWS receives indications from both gear indicating systems or just the primary. If it only receives it from the primary then the crew were correct in their assessment of what they expected to hear. If it gets it from both and the horn and EGPWS were an additional bit of important information then why weren't they in the QRH?
The whole point of OEM documents such as the AFM and QRH are so that you don't have to ring the OEM and ask for advice when it is time critical.
My aircraft type has multiple undercarriage indications but the OEM is very clear that only one of them has to indicate a green to be certain that it is down and locked. Nevertheless I would have a sense of unease during the approach, just like these guys did. So the fact they were uneasy should not be miscontrued to mean that they thought that needed more advice.
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I wonder if this problem goes through to the later Dash models. The Q400 checklist says if any gear indicators fail to illuminate (or come up red) then check the alternate lights. If they are all green then the gear is safe for a normal landing.
Originally Posted by Daysleeper
I wonder if this problem goes through to the later Dash models. The Q400 checklist says if any gear indicators fail to illuminate (or come up red) then check the alternate lights. If they are all green then the gear is safe for a normal landing.
If you have a green light out and no other indications then you would use the LANDING GEAR INDICATOR MALFUNCTION checklist. But if you have other associated warnings such as the red gear unsafe light, and the light in the handle indicating gear not in the position selected, and the gear door open advisory, the only applicable checklist is the ALTERNATE LANDING GEAR EXTENSION checklist. The situation is not covered by either of the other two checklists.
Where Air Nelson differed is that they had their own QRH with an additional checklist for any gear unsafe indication. It first directs you to check the alternate indicators, and if they are green no other action is required. This is not part of Bombardier's QRH and ultimately led the crew to landing with an unsafe nose wheel.
Fair enough. My view on it is that crew did things by the book. The argument is then between Bombardier and Air Nelson to decide who was responsible for the book.
I agree. There seems to be a return to the "pilot error" mindset from our esteemed aviation leaders. Did anyone see the head of the nzcaa on 60 minutes completely denying that there were any systemic failures from the regulator re Fox glacier crash and blaming it solely on the pilot?
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Are you sure about the bold bit? My Dash 8 300 QRH basically has three landing gear checklists. One for the alternate gear extension, one for a failure of a green down and locked light, and one for a door advisory light.
Landing Gear Fail to Indicate Locked Down
(gear lever selected down)
Note > amber and/or red advisory lights may be illuminated.
If any of the instrument panel green gear locked down advisory lights fail to illuminate:
Gear alternate extension door - open
Gear locked down indicator - on / check / off
gear alternate extension door - close
If all three alternate extension green gear locked down advisory lights illuminate
normal landing can be made
end
(gear lever selected down)
Note > amber and/or red advisory lights may be illuminated.
If any of the instrument panel green gear locked down advisory lights fail to illuminate:
Gear alternate extension door - open
Gear locked down indicator - on / check / off
gear alternate extension door - close
If all three alternate extension green gear locked down advisory lights illuminate
normal landing can be made
end
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To add some clarification to the system on the -300, the normal gear indication system is controled by the PSEU (proximity switch electronic unit) and it also provides info the EGPWS to provide "Too Low Gear" callout. The alternate system illuminates the alternate gear verification lights and nothing else.
If the PSEU has a fault then you should get a LDG GEAR INOP caution light and will be required to do an alternate gear extension.
In this case there was no caution light but the evidence suggested that the PSEU was not sensing that the nose gear was down. (the evidence being that the alternate lights indicated down and locked but the normal lights were not)
The Capt knew that if the alternate lights were green the gear was down and locked.
Based on the knowledge that the PSEU must have had some sought of fault that had not illuminated the associated caution light the Capt would not have been surprised to hear the EGPWS warning because it gets its info from the same system, therefore he elected to continue the approach.
Now you can debate that decision till the cows come home but if the PSEU was at fault you would get the same callout every approach until you pulled its circuit breaker so how many times should he have gone around?
If the PSEU has a fault then you should get a LDG GEAR INOP caution light and will be required to do an alternate gear extension.
In this case there was no caution light but the evidence suggested that the PSEU was not sensing that the nose gear was down. (the evidence being that the alternate lights indicated down and locked but the normal lights were not)
The Capt knew that if the alternate lights were green the gear was down and locked.
Based on the knowledge that the PSEU must have had some sought of fault that had not illuminated the associated caution light the Capt would not have been surprised to hear the EGPWS warning because it gets its info from the same system, therefore he elected to continue the approach.
Now you can debate that decision till the cows come home but if the PSEU was at fault you would get the same callout every approach until you pulled its circuit breaker so how many times should he have gone around?
Last edited by aluminium hail; 5th Nov 2012 at 21:44.
I wouldn't have expected them to do anything other than what they did because both the Manufacturer and Air Nelson told them ( through the QRH and verbally ) that the gear was down and locked. The manufacturer was adamant that that the gear was down and locked if three greens showed on the backup system, they designed the system, they tested the system, they have monitored the systems performance through many incidents and accidents while sitting at desks with no fuel induced time pressure. If I was the Capt of that flight I would have felt confident that they were correct.
I fly 737 classics and NG's, in the classic we don't have a back up light system but in the NG'S we do. The NG QRH says
Our company also actively discourages tower fly-bys as well. Can I trust that Boeing has done a better job of testing it's systems? Shall I do a fly by if I have three greens on the standby system? Knowing the "Pilot -Error " mentality of NZ accident investigators I think I will if I'm in Auckland.
I fly 737 classics and NG's, in the classic we don't have a back up light system but in the NG'S we do. The NG QRH says
: If a green landing gear indicator light is illuminated on either the centre main panel or the overhead panel, the related landing gear is down and locked.
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[Asbestos suit on]
And manufacturers are NEVER wrong... 
It's pretty scary to see so many pilots utterly incapable of thinking outside the box. SOPs are great and all, but there have been (and always will be) many scenarios that are not necessarily solvable by slavish obedience to checklists and procedures. As a wise person once said, "rules are for the obedience of fools and the guidance of wise men".
By all means fly by the SOPs and use all the checklists appropriately - I do. However, I have been in situations where strict obedience to the procedures would have had us in a fatal crash scenario. You are allowed to think - a prerequisite for a pilot's licence is not a lobotomy.
As we can see from the incident in question - and many others - the crew should have been able to rely on the information they had, and draw the correct conclusions. But - guess what? There were errors in the systems designed to protect the aircraft and the crew. And I'm not even slightly surprised.
Airmanship used to be about a pilot making a correct decision based on all the available evidence, including such things as taking account of any uneasiness about what the pilot is looking at or sensing. Far better that than slavish obedience to "procedure".
And I don't buy the culpability argument. If you do everything by the book but still crash and kill people, you are just as likely to be hung on the "duty of care" provisions as anything else. There's a lot more to it than "by the book".
I don't think the Air Nelson incident(s) is/are a big deal in themselves, but they do illustrate (in my opinion) a worrying trend towards slavish obedience to procedures by pilots, and a somewhat typical arrogance in NZ aviation circles towards manufacturer's SOPs.
I wouldn't have expected them to do anything other than what they did because both the Manufacturer and Air Nelson told them ( through the QRH and verbally ) that the gear was down and locked. The manufacturer was adamant that that the gear was down and locked if three greens showed on the backup system, they designed the system, they tested the system, they have monitored the systems performance through many incidents and accidents while sitting at desks with no fuel induced time pressure. If I was the Capt of that flight I would have felt confident that they were correct.
It's pretty scary to see so many pilots utterly incapable of thinking outside the box. SOPs are great and all, but there have been (and always will be) many scenarios that are not necessarily solvable by slavish obedience to checklists and procedures. As a wise person once said, "rules are for the obedience of fools and the guidance of wise men".
By all means fly by the SOPs and use all the checklists appropriately - I do. However, I have been in situations where strict obedience to the procedures would have had us in a fatal crash scenario. You are allowed to think - a prerequisite for a pilot's licence is not a lobotomy.
As we can see from the incident in question - and many others - the crew should have been able to rely on the information they had, and draw the correct conclusions. But - guess what? There were errors in the systems designed to protect the aircraft and the crew. And I'm not even slightly surprised.
Airmanship used to be about a pilot making a correct decision based on all the available evidence, including such things as taking account of any uneasiness about what the pilot is looking at or sensing. Far better that than slavish obedience to "procedure".
And I don't buy the culpability argument. If you do everything by the book but still crash and kill people, you are just as likely to be hung on the "duty of care" provisions as anything else. There's a lot more to it than "by the book".
I don't think the Air Nelson incident(s) is/are a big deal in themselves, but they do illustrate (in my opinion) a worrying trend towards slavish obedience to procedures by pilots, and a somewhat typical arrogance in NZ aviation circles towards manufacturer's SOPs.
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Airmanship used to be about a pilot making a correct decision based on all the available evidence, including such things as taking account of any
uneasiness about what the pilot is looking at or sensing. Far better that than
slavish obedience to "procedure".
uneasiness about what the pilot is looking at or sensing. Far better that than
slavish obedience to "procedure".
Remoak, I agree in principle with what you are saying. My only question is, at what point do you decide that you need to act beyond or in addition to the supplied checklist? Of course a checklist can't be provided for every circumstance and if your situation doesn't match the checklist then you have to use your knowledge and experience to make the best of a bad situation. VH-JSI, which took a large bird through the wing root, is a good example of this. These Air Nelson guys, however, seemed to have a checklist that adequately covered their situation and it seemed to them at the time that there was no reason to look further into it. In fact if the alternate indication system was as robust as they'd been lead to believe the checklist they'd followed would have worked fine, but neither Bombardier, Air Nelson, nor the crew, had the vital piece of information that the alternate system was flawed and should only be used to confirm an alternate gear extension or as an alternate to a single green advisory not illuminating. Whether by design or accident, this is actually how the OEM checklist is written, but whoever approved Air Nelson's variation to it didn't seem to see the benefit in the original layout.
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AerocatS2A
For me... after I have completed the abnormal/non normal/emergency checklist, I mentally sit back for a moment and ask myself "am I absolutely certain that I know what's going on, and am I absolutely satisfied that I have done everything that I possibly can to mitigate risk?" If the answer to both is "yes", then job done and let's land this sucker (or whatever). But if there is the slightest doubt - and that can be just an uneasy feeling from either pilot - then it's time to dig a little deeper.
I can recall one incident where we would have shut down an engine out over the North Sea on a stormy night if we had followed the checklist religiously. However, the application of a little lateral thinking led us to the conclusion that what we were looking at (indication-wise) wasn't what was actually happening. The engine continued to run just fine for the rest of the flight...
As I mentioned, I have no difficulty with the crew's actions in this case - although I'm sure the skipper might have second thoughts next time! No, what discourages me is the attitude that "if the book says it, it must be the truth". That is a fallacy that has cropped time and time again in accident investigations. The other is the idea that if you do everything by the book, sit back with a self-satisfied smile on your face and subsequently crash and hurt people, you are automatically immune from blame because you followed the procedure. Anyone who believes that should watch the investigation into the CTV building collapse during the Christchurch earthquake. Plenty of people are being ripped to shreds for not helping as much as they could have, even though they can truthfully say it wasn't their job at the time. The point being made by the investigators is simple - "you were there, it doesn't matter whether it was your job or not, you were in a position to help and you didn't do so to the best of your ability". Duty of care.
When I was doing my F27 and 146 type ratings in the early '90s, our instructors would throw us curve balls constantly to see how we would react. They wanted to see us use the checklists correctly and follow SOPs... but what they REALLY wanted to see is whether we could think outside the box and come up with a solution that wasn't written down anywhere. They wanted to know if there was a mind at work in the pilot's head, as opposed to an automatic procedure-following piece of wetware.
Going back to the incident at hand, could somebody please explain why a) Air Nelson felt it necessary to re-write the checklist; and b) if the re-write was better than the original, why didn't DHC adopt it?
I already know the answer, but I'd be interested to know if anyone else does...
My only question is, at what point do you decide that you need to act beyond or in addition to the supplied checklist?
I can recall one incident where we would have shut down an engine out over the North Sea on a stormy night if we had followed the checklist religiously. However, the application of a little lateral thinking led us to the conclusion that what we were looking at (indication-wise) wasn't what was actually happening. The engine continued to run just fine for the rest of the flight...
As I mentioned, I have no difficulty with the crew's actions in this case - although I'm sure the skipper might have second thoughts next time! No, what discourages me is the attitude that "if the book says it, it must be the truth". That is a fallacy that has cropped time and time again in accident investigations. The other is the idea that if you do everything by the book, sit back with a self-satisfied smile on your face and subsequently crash and hurt people, you are automatically immune from blame because you followed the procedure. Anyone who believes that should watch the investigation into the CTV building collapse during the Christchurch earthquake. Plenty of people are being ripped to shreds for not helping as much as they could have, even though they can truthfully say it wasn't their job at the time. The point being made by the investigators is simple - "you were there, it doesn't matter whether it was your job or not, you were in a position to help and you didn't do so to the best of your ability". Duty of care.
When I was doing my F27 and 146 type ratings in the early '90s, our instructors would throw us curve balls constantly to see how we would react. They wanted to see us use the checklists correctly and follow SOPs... but what they REALLY wanted to see is whether we could think outside the box and come up with a solution that wasn't written down anywhere. They wanted to know if there was a mind at work in the pilot's head, as opposed to an automatic procedure-following piece of wetware.
Going back to the incident at hand, could somebody please explain why a) Air Nelson felt it necessary to re-write the checklist; and b) if the re-write was better than the original, why didn't DHC adopt it?
I already know the answer, but I'd be interested to know if anyone else does...
Last edited by remoak; 8th Nov 2012 at 10:37.
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Remaok...
I'll wholeheartedly agree with you that we take too much for granted. I'd say that our knowledge, as pilots, about our steed doesn't go very far and deep, which needs not be as bad as this phrase suggests. I consider the trick to a long operational life is to know just enough (and recall it promptly) to get one safely out of any conceivable airborne situation - even if the exit is not effected in a neat, elegant or economical manner. I found out that I best remember not the lessons picked up in operating manuals but anecdotes from other pilots, safety publications,(quote)
I would suggest that one reads the NTSB report of the Jetblue incident in KLAX,and take note of the "resources" that the crew used to take care of this issue......at the end of the day,you as the Capt,and F/O.....will be required to prove that you used "all" avenues to deal with the issue at hand...
I'll wholeheartedly agree with you that we take too much for granted. I'd say that our knowledge, as pilots, about our steed doesn't go very far and deep, which needs not be as bad as this phrase suggests. I consider the trick to a long operational life is to know just enough (and recall it promptly) to get one safely out of any conceivable airborne situation - even if the exit is not effected in a neat, elegant or economical manner. I found out that I best remember not the lessons picked up in operating manuals but anecdotes from other pilots, safety publications,(quote)
I would suggest that one reads the NTSB report of the Jetblue incident in KLAX,and take note of the "resources" that the crew used to take care of this issue......at the end of the day,you as the Capt,and F/O.....will be required to prove that you used "all" avenues to deal with the issue at hand...
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I don't think for one second that anyone would disagree with your comments Remoak, particularly the on-going assessment of an issue, the thing is, you and I both know that there is a company culture here at work in the background, and I don't mean with respect to guys on the day.
Rightly or wrongly, most operators train us to rely on the QRH, and for better or worse they tend to be reliable documents....but they contain the usual caveats..this is straight out my 777 QRH, and note the trouble shooting comment.
Damned if you do damned if you don't 
Rightly or wrongly, most operators train us to rely on the QRH, and for better or worse they tend to be reliable documents....but they contain the usual caveats..this is straight out my 777 QRH, and note the trouble shooting comment.
While every attempt is made to supply needed non–normal checklists, it is not possible to develop checklists for all conceivable situations. In some smoke, fire, or fumes situations, the flight crew may need to move between the Smoke, Fire or Fumes checklist and the Smoke or Fumes Removal checklist. In some multiple failure situations, the flight crew may need to combine the elements of more than one checklist. In all situations, the captain must assess the situation and use good judgment to determine the safest course of action.
It should be noted that, in determining the safest course of action, troubleshooting, i.e. taking steps beyond published non-normal checklist steps, may cause further loss of system function or system failure. Troubleshooting should only be considered when completion of the published non-normal checklist results in an unacceptable situation.
It should be noted that, in determining the safest course of action, troubleshooting, i.e. taking steps beyond published non-normal checklist steps, may cause further loss of system function or system failure. Troubleshooting should only be considered when completion of the published non-normal checklist results in an unacceptable situation.
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I think that is pretty clear.
Their QRH clearly told them they did not have a problem.
Further troubleshooting in this situation would have been clearly outside the guidelines of the manufacturer and the operator.
This crew did the right thing.
Their QRH clearly told them they did not have a problem.
Further troubleshooting in this situation would have been clearly outside the guidelines of the manufacturer and the operator.
This crew did the right thing.
Remoak, I agree with what you are saying.
As for this:
I don't know anything about Air Nelson but assume that, as has been alluded to here, there is some cultural thing going on. Perhaps they have a tendency to try and reinvent the wheel? As for B, it wasn't better.
As for this:
Going back to the incident at hand, could somebody please explain why a) Air Nelson felt it necessary to re-write the checklist; and b) if the re-write was better than the original, why didn't DHC adopt it?
Last edited by AerocatS2A; 9th Nov 2012 at 02:40.