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Cougar S-92 Accident: A Case Study in Safety

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Cougar S-92 Accident: A Case Study in Safety

Old 11th Feb 2011, 21:12
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Cougar S-92 Accident: A Case Study in Safety

This accident is worth attention outside the rotorcraft community. There are major issues with CRM and with certification.

Transportation Safety Board of Canada - AVIATION REPORTS - 2009 - A09A0016
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Old 12th Feb 2011, 21:08
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I just wanted to say that this has indeed got my attention (for what it's worth). I think zalt is right about the implications.

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Old 13th Feb 2011, 16:38
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The certification aspects are probably best covered in the 23 month old thread on the accident in Rotorheads.

TSB believed there were clearly CRM and training issues and they really do deserve analysis here. From the TSB findings section:

  • The S-92A rotorcraft flight manual (RFM) MGB oil system failure procedure was ambiguous and lacked clearly defined symptoms of either a massive loss of MGB oil or a single MGB oil pump failure. This ambiguity contributed to the flight crew's misdiagnosis that a faulty oil pump or sensor was the source of the problem.
  • The pilots misdiagnosed the emergency due to a lack of understanding of the MGB oil system and an over-reliance on prevalent expectations that a loss of oil would result in an increase in oil temperature. This led the pilots to incorrectly rely on MGB oil temperature as a secondary indication of an impending MGB failure.
  • By the time that the crew of CHI91 had established that MGB oil pressure of less than 5 psi warranted a "land immediately" condition, the captain had dismissed ditching in the absence of other compelling indications such as unusual noises or vibrations.
  • The captain's decision to carry out pilot flying (PF) duties, as well as several pilot not flying (PNF) duties, resulted in excessive workload levels that delayed checklist completion and prevented the captain from recognizing critical cues available to him.
  • The pilots had been taught during initial and recurrent S-92A simulator training that a gearbox failure would be gradual and always preceded by noise and vibration. This likely contributed to the captain's decision to continue towards CYYT.
  • Rather than continuing with the descent and ditching as per the RFM, the helicopter was levelled off at 800 feet asl, using a higher power setting and airspeed than required. This likely accelerated the loss of drive to the tail rotor and significantly reduced the probability of a successful, controlled ditching.
  • The captain's fixation on reaching shore combined with the first officer's non-assertiveness prevented concerns about CHI91's flight profile from being incorporated into the captain's decision-making process. The lack of recent, modern, crew resource management (CRM) training likely contributed to the communication and decision-making breakdowns which led to the selection of an unsafe flight profile.
Their CRM discussion (including a history of CRM) is extensive:
FACTUAL Transportation Safety Board of Canada - AVIATION REPORTS - 2009 - A09A0016
and
ANALYSIS Transportation Safety Board of Canada - AVIATION REPORTS - 2009 - A09A0016

One reason for the delay in understanding the situation is that the Amber MGB Oil P Caution was rapidly replaced by a Red MGB Oil P Warning, which the Co-Pilot tried to find to no avail in the checklist, because it had also been written assuming only slow leaks and so just listed the Amber.

One thing I find really strange is that the "Cougar checklist" shown by TSB is marked "Flight Safety Inc" and "For Training Purposes Only". Can anyone explan that?

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Old 14th Feb 2011, 02:22
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All Flight Safety checklists are marked "for training purposes only", and my guess would be that's because an operator may operate to an entirely different checklist, plus it may differ from the latest RFM amendment. When you attend Flight Safety there is nothing to prevent you using your own companys checklist should you wish to do so.
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Old 16th Feb 2011, 22:29
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The information I have Sox, is that Cougar just took the laminated FSI checklists and put a cover sheet on the front!

The TSB report does also raise serious questions about the standard of S-92 training FSI give, particularly the negative learning from narrowly scripted emergency exercises.

Of course their SOP manuals differed from the checklist. Both differed from the RFM and TSB also raised serious concerns over the content of the RFM.

There is SO much in this report.
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Old 3rd Apr 2011, 11:48
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This accident reminds me of two high profile airline accidents.

One is the Air Korea 747 CFIT accident in Guam. In both accidents training emphasised certain issues (in that case the visual aspects of the approach, in the Cougar case the indications of MRGB failure), fostering false expectations and not emphasising the hazards. As a result the training did not adequately prepare flight crews for the challenges they faced.

The other is the Transat A330 'flying on empty' accident in the Canaries. In that case poor indicate of the failure state resulted in confusion and assumption of sensor error, just like in the Cougar accident.

Incidentally in the Transat case, TC fined the operator a record amount for the errors that caused the fuel leak. I wonder if TC will fine anyone in this case.

I don't think any competent offshore operator with an SMS would be so lazy as to just use the notes from their sumulator provider as a checklist.
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Old 3rd Apr 2011, 14:19
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SMS, checklist and audit this, sm, you finger wagging *%#!!

It used to be called airmanship and common sense.....

If the accidents that you quoted are the ones that you are personally reminded of, then it is time for you to retire, old boy! You shouldn't be in the industry!

My bolds and brackets.....

"In addition to the regulatory oversight by TC, Cougar Helicopters is subject to a considerable amount of oversight by the companies that it has contractual obligations with. The oil companies independently bring in aviation and safety management specialists to periodically audit Cougar Helicopters. Between 2007 and the date of the occurrence (March 2009), Cougar Helicopters had been subject to 16 external audits........"

"Finally, Cougar Helicopters has its own internal audit processes defined in its SMS. Typically there are four separate internal audits performed each year on each Cougar Helicopters' base of operations. Additional audits or change management processes are completed as necessary when modifications have been made to the operational scope, which could include such things as opening a new base or the addition of a new helicopter. Between 2007 and the date of the occurrence (March 2009), Cougar Helicopters performed 16 internal safety audits."

And later......

"In some extreme situations, pilots may find themselves required to make a decision that goes against the formally established procedure because of some type of extenuating circumstance like weather, darkness, or sea state. If a pilot determines that the risk of ditching is so high that prolonging flight is considered a safer option, careful consideration must be given to the flight profile chosen to reach a safe landing spot. While there is no universally accepted flight profile for prolonging flight with a suspected gearbox malfunction, the investigation determined that many helicopter pilots would opt for a "low" and "slow" profile. It is generally accepted that an altitude of 50 to 200 feet agl and an airspeed between 50 and 80 knots (i.e., at or near the bucket airspeed) reduces stresses on a compromised gearbox while still allowing for a rapid controlled ditch at the first indication of an impending gearbox failure.92

In Canadian Aviation Safety Board (CASB) occurrence 85-H54001, the pilot of a S-61N lost all the MGB oil while only 17 nm offshore. Recognizing the potential for a MGB failure due to a lack of lubrication, the pilot established the helicopter at 100 feet above the water and 100 knots to keep the helicopter in a position from which it could be rapidly ditched if the situation worsened. When unusual noises and vibrations were experienced, the pilot turned into wind, flared to reduce the helicopter's speed and altitude, and carried out a successful ditching from which everyone survived."
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Old 3rd Apr 2011, 14:33
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Did you have a particular point to make about this accident?
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Old 3rd Apr 2011, 15:03
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..................and it was the Azores...............
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Old 3rd Apr 2011, 15:06
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BOAC many thanks for the correction.
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Old 3rd Apr 2011, 23:07
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Between 2007 and the date of the occurrence (March 2009), Cougar Helicopters had been subject to 16 external audits........

I have no comment on the mishap being discussed, nor the specific audits, but the above comment needs to be caveated in a more general sense.

In a past life I participated in a large number of audits such as those to which you refer. The number of hardware and procedural systems major errors I discovered suggested that many, if not all, such audits are a substantial waste of time. At the very least, if such errors had been detected, nothing had been done to fix them ...

For instance, in one FIFO audit which comes to mind, I discovered that the performance calculations for a mid size heavy turboprop operation had been predicated on the wrong critical cases - indeed the relevant critical case had been overlooked totally.

The particular operation had been running for some years and the operator had been subjected to the standard half dozen third party audits or so for this and that customer each year during the period. The error, which amounted to the aircraft's launching significantly overweight EVERY flight out of a particular mine strip was generic within the performance work.

Strangely, no-one amongst the various highly esteemed, experienced and qualified auditors had ever bothered to look at the performance calculations (or, perhaps, they just didn't understand much about what they did look at). Detection of the systemic error took me all of about two minutes (no, closer to a minute and a half) - and then half an hour of check calculations to convince myself that I was, indeed, seeing what I thought I was seeing ....

On this same audit, I also discovered that the aircraft trimsheet loading system was unworkable and that this error followed directly from an editorial error in the approved Flight Manual. Strangely, no-one had ever seen the confusion and variety of different ways to complete this trimsheet in favour with the fleet crew. Clearly a forgiving aircraft for loading or, perhaps, just good luck/skilled crews ?

This operator, otherwise, was basically OK. To their credit, when I raised the problems with them, they fixed them pretty quickly - indeed, our client directed me to make sure they were fixed that day.

I left with a very jaundiced view of a range of Industry audit teams - incompetent idiots at best.

Some years later, when I was running an endorsement program for their pilots in another country, some of the more senior chaps remembered me all too well from that audit .. made for some attentive students in the ground school and during the OEI work in the sim.
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Old 4th Apr 2011, 01:40
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An all too common story with regard to audits John, even those conducted by the regulator. Flew for 27 years without providing for alternates, as demanded by the ops manual and the regulators supplement to the flight manual for each and every flight, and not one audit picked up on the fact. And that was only one operating practice.

Another was the take off charts in the ops manual only considered the reject case, so should you try to continue the take off with the failure after V1, depending on the prevailing circumstances, you may very well have found yourself in deep doo doo.

I always wondered if in the latter case, a pilot came to grief, what accountability he would have for not complying with the flight manual, as the ops manual had a statement

This Manual shall not supersede or countermand any Regulation, Orders or Instructions issued by the Regulator. Compliance only with the terms of this Manual shall not absolve any personnel from the responsibility of abiding by such Regulations, Orders and Instructions.

Such errors management were aware of, but for reasons of their own saw fit not to address same.
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Old 9th Apr 2011, 14:36
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Sadly not all customers apply the level of roigour that certain companies do in training their auditors or aviation advisors.

The FSF BARS scheme was devised as a way to irradicate some of the less competent auditors in Australia and elsewhere.

The problems are the lax regulations outside of the North Sea and the general failure to understand or respect industry best practice.
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Old 13th Apr 2011, 05:26
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There certainly is a variable standard in auditors.

Aero Safety World have an article on this accident:

http://flightsafety.org/asw/mar11/asw_mar11_p19-23.pdf
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Old 13th Apr 2011, 05:47
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There certainly is a variable standard in auditors.

I recall spending some time as an independent advisor to a larger Australian miner which saw a need to review the performance of their aviation auditor and internal management philosophies for FIFO contract work.

I was somewhat bemused when the MD and Operations Manager type folk, having assured me that they took a detailed and active interest in the auditor's work and reports and received periodic safety briefings on the finer points of this and that consideration ... moved to discuss operational safety considerations for the pocket rocket commonly used for executive transport.

These chaps, in all innocence and ignorance, proceeded to confirm that they had not the slightest clue about any of it during the space of a couple of hours' discussion over coffee ...

That is not a criticism of the two chaps but certainly is of the auditors and the aircraft operator who "had provided numerous educational safety briefings to Company executives".

Sometimes I wonder why we bother. Jesus wept ....
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