Air Nelson Dash Noeswheel Report

[blah blah blah]

Crash pilots ignored cockpit warning alerts - report - National - NZ Herald News

Interesting arguments put forward...

[Bongo Bus Driver]

I had a TCAS descend on the taxiway at Auckland once. I suppose TAIC expected me to react to that as well!

[remoak]

I think TAIC's point is "don't allow strict adherence to procedure - whether correct or not - get in the way of common sense". This is otherwise known as "better to be safe than sorry". A low approach and overshoot is not going to break the bank in a Dash, and if it does reveal an issue, will have been worthwhile. If not, you delayed the flight by two minutes and used a few kilos of fuel, hardly a sack-able offence. Any airline that would discipline a skipper for that should have it's AOC pulled.

Mr Stringer is being somewhat precious with his "crew did everything by the book" line. Whatever happened to airmanship?

It also makes you wonder how DHC could get the procedure so badly wrong. What is it with Dash 8s and undercarriages?

Having said all that - the reporting is somewhat sensationalist and, well, crap. They didn't ignore the warning, they did everything they were required to. I just think that airmanship took a back seat to procedure.

[haughtney1]

The use of the low level fly past or “fly-by” by an aircraft with landing gear, or other condition, for the purpose of ground observation / confirmation does not provide meaningful additional information etc etc etc. Such operations are prohibited.

Remoak old chum, this is straight out of a JAR Ops 1 and I'm assuming EASA compliant OMA. The etc etc etc is my edit to keep the post to one page...
I wonder if the TAIC chap had any relevant access/experience with respect to the legalese that we have to deal with?

[Flt.Lt Zed]

The DASH 8 diverted from Nelson 50 miles away due weather.Maybe the cloudbase and visibility were too low for a fly by ?

[aerostatic]

Personally I am disappointed with this TAIC report. The QRH clearly stated that if either of the gear indicating systems showed the gear to be down and locked then it was down and locked. Given that that is what the manufacturer had to say on the matter, in writing, in a critical operational document (the QRH) it should have been good enough to hang your hat on. I'm all for applying common sense when there is genuine ambiguity but I don't see it applying in this case.

[Roger Greendeck]

So TAIC believes that the pilots should have ignored the manufacturer's advice about the technical performance of their system?

What about if they ignored advice and that caused an incident?

This looks like a classic case of being wise after the event. Maybe, if they had the fuel, they would have been been better off holding and contacting TAIC to ascertain the correct course of action from the investigator.

Come to think of it, I might start adding some margin fuel for accident/incident investigation in the future.

[blah blah blah]

It wasn't necessarily the manufacturers advice.

They had fuel to think about things.

There was a lack of airmanship displayed.

I was surprised that the report was so generous.

[AerocatS2A]

It wasn't necessarily the manufacturers advice.

Yes it is the manufacturers advice. The Dash 8 QRH says that if the gear indicates unsafe, you should check the alternate indicating system, if that indicates down and locked then the gear is down and locked*. Obviously that advice is now known to be wrong on this occasion, but the pilots didn't have any reason to suspect that at the time. They did exactly what they should have done and were let down by both the aeroplane and the TAIC.

*From memory, I don't have it to hand and haven't flown the Dash for 18 months.

[haughtney1]

Gosh Blah, I wish I had your outstanding airmanship qualities, I find the conclusions of the report contradictory at best.
On the one hand..

3.1.5. The landing gear selector lever was left in the DOWN position and the captain directed the first officer to begin the “Landing gear fails to extend” checklist in the operator’s customised QRH (see Appendix 1).

Which is chapter and verse what I would hope we all would do

Followed further on by..

4.17. When the pilots moved the landing gear selector lever to DOWN on the approach to Woodbourne, the “Landing ear Inop” caution light did not illuminate, but the indicators on the landing gear panel told them that the nose landing gear was in an unsafe condition. The use of the “Landing gear fails to extend” procedure in the Air Nelson QRH was the appropriate action for the pilots to take. The procedure stated that if either the advisory indicator on the forward panel or the verification light under the alternate extension flap was green, the corresponding landing gear leg was down and locked. The 2 indication systems were independent of each other.
4.18. The text of the QRH removed any doubt for the pilots. It clearly stated that if either light was green, the relevant landing gear leg was down and locked. When the pilots saw the green verification light for all 3 landing gears, including the nose landing gear, the pilots had every right to believe the verification light, and halt the “Landing gear fails to extend” procedure.
4.19. The captain said that in his capacity as the airline’s flight operations representative at Bombardier customer seminars, he had heard the saying “a green is a green” used to emphasise the dependability of the verification system. His comment that “a green is a green”, made when he declined the first officer’s suggestion to fly past the control tower and have the nose landing gear position checked by the controller, reflected his confidence in the verification system. Most other pilots would have concluded at that point that all of the landing gear was down. Notwithstanding that confidence, shortly afterwards he requested a second check of the verification light, and both pilots confirmed that it was still green.

At this point there has been no reference to the operators operations manual as to whether a flypast is recommended or even allowable in this circumstance (please don't hit me with the airmanship argument...these days it's about avoiding culpability...which is why even QRH's are written the way the are)

Followed by the key findings in all of this..

Findings
With the nose landing gear stuck in a partially extended position, light from the taxi light was likely detected by the sensor for the down-lock verification system, causing it to give a false green light.
The false green light on the verification system misled the pilots of ZK-NEB into believing that the nose landing gear was fully down and locked.
The verification system for checking if the landing gear is down and locked on the Dash 8 series of aircraft is not reliable enough for pilots to place total trust in it when
trying to establish the status of the landing gear.

Quite simply the manufacturers recommendations hung these guys out to dry, yes they COULD have flown past the tower..but there is no guarantee of a successful outcome.
Then a further kick in the nuts for the crew..A none too subtle reference to the investigators opinion..as well as the standard get out clause..just in case it could be hung on him in a later incident...

4.40. A fly-by cannot confirm absolutely that a landing gear leg is locked down, especially at night, but an observer can report the landing gear appearance. In the case of the nose landing gear on the Q300, if the wheels appear down and the forward doors are closed, that is useful information, because the Proximity Switch Electronics Unit must sense that the landing gear is down and locked before it will signal the doors to close.

Followed by..A bit of 20/20 hindsight that supposes all that previously happened..didn't in fact happen and that the crew should have ignored the QRH...

4.41. The pilots could have sought technical advice from the operator and likely would have done so had they gone around in response to the aural warnings. If it had been confirmed that the nose landing gear was not locked down, the checklist would have led the pilots to silence the potentially distracting warnings and they would have instructed the flight attendant to prepare the cabin for an emergency landing.

And lastly....a statement indicative of an operator with potentially a few more deficiencies in its Ops spec....why the need to clarify? shouldn't the course of action be clear for all to see?

4.42. The operator later clarified the action it expected its pilots to take, including making use of an external observer, when there was a disagreement between landing gear position indications.

I wholly agree with the CRM aspects of the report, but these aspects in their isolation had no real bearing on the outcome.
The reality IMHO based on the report is that the Q300 concerned had a defective system that was deficient for the task with which it was designed to do..namely alert the crew as to the state of their landing gear...the fact that this system was given credence over and above the various other warning systems speaks volumes about the manufacturer, their "green is green philosophy"and its poorly concieved design.
The crew did everything that could be reasonably expected of them, notwithstanding the CRM issues...and the now "clarified" company procedure.
The manufacturer and operator however appear to have escaped any censure..other than a couple of recommendations

[remoak]

rmcdonal

Interestingly the message being pushed by CASA (I realise this is a NZ incident) is exactly the opposite, CAR215 would hold the AOC holder accountable for not enforcing a strict adherence to the approved manual.

Does any approved manual over there explicitly prohibit a low-level flypast for the purpose of inspecting an undercarriage?

Haughtney1

Remoak old chum, this is straight out of a JAR Ops 1 and I'm assuming EASA compliant OMA.

Yes mate but we don't live in EASA land, we live in NZ and over here it is actively encouraged, at least by Airways...

At this point there has been no reference to the operators operations manual as to whether a flypast is recommended or even allowable in this circumstance (please don't hit me with the airmanship argument...these days it's about avoiding culpability...which is why even QRH's are written the way the are)

Well... please explain the difference between an approach followed by a missed approach, and a low approach and overshoot? it's the same thing, the only difference is what you call it. Declare that you are carrying out the appropriate approach and go around at DA/MDA... you achieve the same thing and nobody can criticise you, far less prosecute you. However you CAN be blamed (and prosecuted) if you do not take all steps available to you to resolve any ambiguity in what your aircraft is telling you, when the next thing that happens is an accident. It's called "duty of care" and is something all aircraft commanders should be intimately acquianted with. Just think for a minute... what would have happened if the Dash had unexpectedly veered off the runway following a nose gear indication issue, and people had been hurt? Which is exactly what happened to an ATP a few years back in Edinburgh. I'll think you'll find the captain would have been in a world of hurt, irrespective of what the manual might say.

I might be old-school, but airmanship rules and culpability can take a hike...

Flt.Lt Zed

The DASH 8 diverted from Nelson 50 miles away due weather.Maybe the cloudbase and visibility were too low for a fly by ?

If the weather is too bad for a low approach/overshoot, it's also too bad to make an approach... in any case, I was inbound to WB at the time this was happening and the wx wasn't that bad.

[haughtney1]

I might be old-school, but airmanship rules and culpability can take a hike...

Can you imagine how much time in Jail I'd get if I did that.....

Fair points BTW, but it's telling to me the TAIC guy noted that they had to get clarification...and it's also worth noting that the crew whilst uneasy felt that the warnings were nuisance...so in essence, not ambigious..spurious, an easily argued point my Lud given the system faults..and the manufacturers own (most likely attributable) statements...
See its the lawyers...

[AerocatS2A]

Remoak, what's your go-around performance with the landing gear down?

[remoak]

Adequate... why?

You aren't asymmetric... you know your main gear is working fine... you are VMC and can remain so... please explain, using small words and a crayon, what the danger is...

Haughtney old bean...

the crew whilst uneasy felt that the warnings were nuisance...so in essence, not ambigious..spurious

And that's the whole point... if you are not absolutely 100% certain that there is no issue, you ALWAYS err on the side of caution and do whatever you have to do to become 100% certain and 0% uneasy... which is why you use ALL the avenues available to you... including observation from the ground. Which, by the way, has often clarified whether an emergency exists or not in the past.

Oh, and I forgot to mention...

The use of the low level fly past or “fly-by” by an aircraft with landing gear, or other condition, for the purpose of ground observation / confirmation does not provide meaningful additional information etc etc etc. Such operations are prohibited.

In an emergency, as you know, the rule book goes out the window. There is nothing to stop you doing a low pass if you deem it necessary during an emergency. Just don't forget to declare an emergency!

One day, young Skywalker...

[blah blah blah]

It wasn't necessarily the manufacturers advice.

Yes it is the manufacturers advice.

The manufacturers advice, in terms of their QRH, and what the company did, in terms of THEIR QRH were two different things when this event happened.

Gosh Blah, I wish I had your outstanding airmanship qualities

My outstanding airmanship qualities were exactly the same as all the pilots at Air Nelson who also questioned why the Captain didn't take the hint from the FO and why they didn't take the time to have a think about the problem. The EGPWS going off should have been a hint.

[HF3000]

And if something happened while attempting to troubleshoot a problem that their QRH told them didn't exist?

Crew are not generally encouraged to troubleshoot beyond the guidelines in the manual unless a greater emergency exists.

Didn't someone die doing that a while ago?

Oh yes: United Airlines Flight 173 - Wikipedia, the free encyclopedia

[AerocatS2A]

The manufacturers advice, in terms of their QRH, and what the company did, in terms of THEIR QRH were two different things when this event happened.

Did they differ in any meaningful way? I'm not familiar with Air Nelson's QRH, but it doesn't seem like it was saying anything different than Bombardier's.

Edit: Just read the Air Nelson QRH from the report, although laid out differently it is functionally the same as Bombardier's, so the crew were following the manufacturers instructions.

[AerocatS2A]

And now having read the Bombardier QRH, I see where they differ. The Bombardier QRH would have directed you to check the alternate verification system if only a green gear down and locked light had failed to illuminate, but if a green light was out and you had other indications of a failure to extend such as gear door open lights on and the gear unsafe light on, you would carry out the alternate extension procedure. I agree that if they'd followed the OEM QRH rather than the Air Nelson one, the incident would not have happened.

[framer]

The pilots said that they had had enough fuel to go around again. Had they done so, one would expect that they would have asked the controller to report the nose landing gear position, as the first officer had earlier suggested they do.

4.39. Had the controller said that the nose landing gear did not appear to be down, the pilots would have realised that the aural warnings were genuine. It would then have been logical for them to disregard the (false) green verification lights and go back to the “Landing gear fails to extend” checklist. This would have directed them to perform the alternate extension procedure. However, as mentioned above, that procedure would have been unlikely to succeed in this case, because the actuator was jammed.

It seems to me this investigator is giving his opinion of how he might have liked the situation to play out. An opinion formed from a comfy chair with months to assess. I could do the exact same thing....in fact I think I will;

"Had the manufacturer run a thorough risk analysis procedure when relocating the taxi light from the external nose cone to the landing gear strut, they most likely would have determined that the light sensing verification system was no long appropriate. Having realised that the system was no longer appropriate, it would have been logical for the manufacturer to re design the verification system or alternatively, reconsider the relocation of the taxi light.
ZK-NEB had been investigated for landing gear malfunctions twice in the 5 weeks preceding the accident flight. No fault was found on either occasion and the aircraft was returned to service. Had the airlines maintenance system been capable of identifying trends of unresolved malfunctions it is logical to presume that further analysis of ZK-NEB would have resulted in the faulty actuator being replaced."

I'm not suggesting that what I've just written is better than the report, I am suggesting that it is the same as what the Investigator has done. Had X happened, then Y would logically follow, and Z would be the outcome.

[601]

TAIC lead investigator Peter Williams said the actions of the pilots were "understandable'' in terms of the information they had.

On the information presented to the pilots, this statement should read;

TAIC lead investigator Peter Williams said the actions of the pilots were "correct and in accordance with the published procedures'' in terms of the information they had. However, we shall recommend that the CAA require the manufacturer to amend the procedures to prevent conflicting information being presented to the flight crew