S76 Accident in California

[Mars]

Was the chosen profile implicated in this accident?

************************************************************ ********************
** Report created 6/30/2008 Record 1 **
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IDENTIFICATION
Regis#: 343AA Make/Model: S76A Description: SIKORSKY S76A
Date: 06/27/2008 Time: 1935

Event Type: Accident Highest Injury: Minor Mid Air: N Missing: N
Damage: Substantial

LOCATION
City: SANTA MARIA State: CA Country: US

DESCRIPTION
N343AA, A SIKORSKY S76A ROTORCRAFT, ON LANDING, TAIL ROTOR MADE CONTACT
WITH THE PLATFORM STRUCTURE AND ROLLED OVER ON THE PLATFORM, OIL PLATFORM
IRENE, 5 MILES FROM SANTA MARIA, CA

INJURY DATA Total Fatal: 0
# Crew: 2 Fat: 0 Ser: 0 Min: 0 Unk:
# Pass: 8 Fat: 0 Ser: 0 Min: 8 Unk:
# Grnd: Fat: 0 Ser: 0 Min: 0 Unk:

WEATHER: NOT REPORTED

OTHER DATA
Activity: Business Phase: Landing Operation: OTHER


FAA FSDO: VAN NUYS, CA (WP01) Entry date: 06/30/2008

[Mars]

...and I guess we are now back to the issue of culture.

If human factors teaches us one thing it is that, whilst the pilot is (almost always) at the controls during the accident sequence, he/she is rarely completely to blame for the accident. Shappell and Wiegmann would have us believe that, amongst the precursors to any accident reside: the organisational influences; unsafe surpervision; preconditions for unsafe acts; and the unsafe acts themselves.

We have no knowledge of the causes of this accident but that should not stop us from discussing one which has cropped up in the past; the potential for error that accompanies a straight-in approach to the helideck (which fits into "Substandard Practices of Operators" - one of the preconditions for unsafe acts). By the very nature of the cockpit layout, the field of view (FOV) of a helicopter - that is the visibility out of the front of the cockpit - will always be obstructed by the instrument panel. During the decelerative landing manoeuvre, this will be made worse by the nose-up attitude (especially in the S76). To compound this combination of factors, most helidecks will rarely be of more than 1D (where D is the maximum length of the helicopter with the rotors turning).

The combination of paucity of view coupled with a small landing surface and a lack of peripheral visual cues, usually results - in the straight-in approach - in an arrival conducted from memory. Because the margins for error are substantially removed in this manoeuvre, it can lead to the tail getting very close and, in some cases, striking the deck surrounds.

Much better that such a manoeuvre is avoided and the landing taken with the FOV that is free of obstructions - i.e. the oblique and side window. Any overcooking of the approach can be rectified by a go-around conducted straight ahead (which also works in the case of an engine-failure on finals - both for a twin and a single).

Mars

[darrenphughes]

No rig landing profile allows for the tail rotor to connect with the platform. It is the pilot flying that causes that to happen.


How insightful! :D Any other pearls of wisdom you'd care to share? :ugh:

[zalt]

Mars

If you are going to use terms like culture around perhaps you should rephrase "he/she is rarely completely to blame for the accident" to "there are many factors that cause accidents".

I can recommend The Field Guide to Understanding Human Error (http://www.amazon.ca/Field-Guide-Understanding-Human-Error/dp/0754648265/ref=sr_1_1?ie=UTF8&s=books&qid=1214954364&sr=1-1)by Sidney Dekker.

Now perhaps JimL will join the debate on profiles;) - but that may be better as different thread. I hope the concept of 'culture' is not going to be abused as an euphemism for regulations.

[Brian Abraham]

This very question regarding this accident was discussed here http://www.pprune.org/forums/rotorheads/330312-cat-profile-cause-crash.html
Perhaps they can be merged Mod?

[Mars]

Flungdung/Brian,

I considered appending this to the thread on the rooftop accident but decided against it because: (a) there was no narrative; (b) the causes are unlikely to be the same; and (c) I wanted to open the discussion to a totally different point. It might transpire that the causes were the same but it is unlikely, because manoeuvring on a helideck is an unusual occurrence.

Zalt,

Thanks for the reference; I have not read the book but I have seen a review of it by Andy Evans of Bristow (for an RAeS conference). Perhaps it would be useful if you could explain to the readers exactly who Sidney Dekker is.

From my perspective, understanding “the new view” is only possible when comparing it with “the old view”; in that sense reading and understanding HFACS by Shappell and Wiegmann is a prerequisite before Dekker’s view can be understood and appreciated. The unfortunate truth is that we work better with labels than with philosophical concepts. However, it was a Dekker contention that I was concentrating on in order to try to make a point:

“Human error is systematically connected to features of people’s tools, tasks and operating environment. Progress on safety comes from understanding and influencing these connections.”

In fact it was the provision of understanding that I was using in an attempt to influence the readers and improve safety.

If there is a connection between the discussion of the rooftop accident and this one, it is that we are preconditioned by our training and manufacturer’s procedures, to certain profiles; the fact that helicopter procedures originate from fixed wing has left a legacy that is only now being re-examined and questioned. For example, take-off procedures that take advantage of an AEO vertical vector (extensive in some cases) have allowed us to move our departure profile way above the obstacle environment and so minimise the effect of a somewhat poor OEI climb gradient.

Benefits can be obtained from revising our thoughts about the landing profile for elevated landing sites – and specifically for offshore operations. In the landing case the offset approach permits us to optimise for the normal (the AEO case) by maximising the pilot’s view of the obstacles and the touchdown-and-positioning-markings - for all approaches. This, at a stroke, removes us from the problems with field of view; it also delays the point at which a commitment to landing has to be made (from an equivalent of the onshore LDP to a committal point much closer to the deck).

As I said earlier, it is not clear that this was the cause of the accident but the opportunity to use it an opener for this discussion was too tempting.

Mars

[Brian Abraham]

Thanks flungdung for pointing out the error of my ways. That'll each me to read the material thoroughly.

[zalt]

For Googlophobes:
Sidney Dekker bio (http://www.lusa.lu.se/research/sidney-dekker-homepage)

[Swamp76]

I've been working offshore for a few years now (some EMS raised helipad work before that) and aiming for the shoulder of the deck until commited and crabbing for visibility in the 76 have been SOP throughout.

Is this a new concept in some locales?

If so, why?

[Mars]

Thanks Zalt; for those who do not wish to pay for the book but are interested in Dekker's theories, go to the publications tab on Dekker's site and pull down the papers.

Swamp76,

Perhaps you would like to tell us why you use that approach profile.

Mars

[JimL]

Clearly Swamp76 is not coming over the parapet so I will take this further.

Just a brief word on the CAT A landing procedures; there appears to be little distinction made between onshore and offshore procedures. The guidance in AC 29-2C still makes the statement that “a safe landing should be possible in case of an engine failure at any point before or after LDP”. Although an offset approach and drop down are now permitted, the inference (of this statement) that there is always a flat-top landing surface to which a non-turning landing approach can always be made, does not reflect restricted approach directions often present at offshore drilling rigs and larger platforms.

Hence, there will be occasions when an OEI transit and landing will not be possible (within crosswind limits). There is little benefit for manufacturers in providing a late and offset LDP because, if the whole of the procedure has to be able to be flown OEI, it will (for aircraft other than the likes of the AW139) reduce the landing masses in the Flight Manual. Worse than that, and bearing in mind the subject of this thread, provision of LDPs set at speeds which ensure that it has to be placed well back from the helideck and at low approach angles requiring a long and continuous OEI transit, give the message that straight-in approaches are not only inevitable but safe.

It is imperative to understand what conditions our consideration of the approach and landing manoeuvre. In my opinion, the main hazards (along with escalation and barriers are):

Hazard:

Collision with obstacles on and around the helideck.

Escalating factors:

Size of helideck and proximity of obstacles.

Barriers (to prevent release of hazard):

Accurate markings provided by the Touch Down and Positioning Marker (TDPM = bum-line);

Absence of the need to manoeuvre when on the helideck;

Approach paths which permit the Best Field of View (FOV) of the TDPM;

Understanding by pilots of the predominant hazards.

Hazard:

Inability to maintain safe flight path on approach and landing.

Escalating factors:

Loss of view of TDPM resulting from poor FOV;

Engine failure on approach;

Turbulence that prevents constant attitude approaches.

Barriers:

An approach path that permits the TDPM to be kept in field of view;

An approach path which retains go-around option until the committal point (CP) has been achieved;

The provision of a CP at the point where a OEI landing manoeuvre to the TDPM can always be achieved;

(Where possible) a landing mass which permits drop-down clear of sea until CP is achieved (at the moment this is achieved: when there is wind – the mean wind in the Northern North Sea is 20kts, the mean temperature is 10ºC and it rarely goes above 20º; or at low landing masses).

There are more but that will suffice for the time being.

There are compensatory conditioning factors which apply to operations in Europe (and in a number of other operating areas):

Two pilots are usually carried (so the obstacles can always be placed on the best side);

Two-way fuel is carried because offshore operations require an onshore alternate;

There is no stigma attached to a go-around and return to base.

From this brief analysis, we can see that any profile that is used must be optimised for the normal – i.e. the thousands of approaches that are conducted every day with AEO. As the main hazard (and the one which is seen in incidents and accidents most often) is striking an obstacle on or around the helideck, the profile should be one where the pilot-flying can keep all obstacles in view, with the TDPM as a clear aiming point – i.e. a sidestep manoeuvre keeping the helicopter into wind with the TDPM in the oblique or side window.

Further, because there is a risk (albeit a small one) of an engine failure with potentially catastrophic consequences, the exposed period - from the point where a go-around is no longer possible and the CP - should be minimised (and reduced to zero if possible). In addition, to avoid a complex manoeuvre, the approach path should be offset from the helideck such that a straight ahead go-around manoeuvre is possible without an avoiding turn.

As was stated in the analysis above, under the conditions where return fuel is carried, no OEI landing on the deck has to be made unless the CP has been reached; all approaches will therefore be made in the knowledge that an OEI recovery to a land base will be possible.

Jim

[Gomer Pylot]

All this is fine for academic discussion, but the reality is that many, if not most, helicopter operations are simply not feasible using Cat A criteria. Many helipads simply don't permit Cat A operations. When making an approach or takeoff, I try to set my priorities on what the most likely cause of bent metal will be, and the most likely cause is seldom engine failure, especially on approach. Having an aircraft with unlimited power and unlimited range would be nice, but it's an illusion. The bigger and more powerful the engines, the shorter the range and the more expensive (and thus unlikely to be purchased) the purchase price and maintenance costs. Cat A is nice in theory, but impractical for use in the real world of helicopter operations, where max possible payload and range are the real drivers. Given the statistical likelihood of engine failure in large modern turbine helicopters, that isn't unrealistic or even unsafe, unless taken to extremes. I use whatever approach technique I consider the safest under the conditions encountered, and that technique often places the possibility of engine failure down on the list.

[JimL]

Gomer,

I fear that in the quest to put an answer on each thread in the Rotorhead forum, you missed the point in this one. Perhaps I could invite you to read it again and then comment accordingly.

The reason for including the the Cat A text was to show that it was impractical in the landing case and in fact had made a negative contribution to safety. A number of us concluded some time ago that Performance Class 1 offshore is not a practical proposition; not for the reasons you have stated, but because engine-failure accountability is not consistently achievable.

Perhaps I have a slightly less jaundiced view of the world than you are showing today. In my flying career I saw real advances in equipment and operational standards; I have also met and worked with a number of aviation managers (even in oil companies) who would be apalled at your characterisation of them as money grabbing tyrants.

Whilst I am on my soapbox, I have to say that a some stage you might wish to spread your wings and look at areas other than the US; you would be surprised at the dedication of the larger HEMS companies - at least in Europe. Companies such as REGA, ADAC, DRF and others in Italy, Scandinavia, Holland and the UK who are working with the best equipment and to the highest standards.

Finally, I have to say that I have always read your posts with interest; you are an experienced operator who often has something important to contribute to any discussion. Perhaps this is an off day for you.

I would like the old Gomer back please.

Jim

[Upland Goose]

What a load of hot air - to touch the tail rotor of an S76 (whichever variant) with the structure of a platform has nothing to do with CAT A unless the landing crumpled the fuselage, following a heavy landing after an engine failure for example. You can only touch the tail rotor if you side swipe the structure.

The S76A in not endowed with stunning performance.

Yes, true CAT A is expensive and costs fuel but when you have enjoyed the performance it provides - as with Agusta machines. You realise that we have been playing "Russian Roulette" with five bullets in the gun for years.

Give me power - at all costs!


UG

[Gomer Pylot]

I don't know where the old Gomer went. I didn't even know he was gone. :rolleyes: I'm not really trying to post on every thread, I just have had some time on my hands. 3 threads or so isn't close to all of them.

I don't say anything about EMS in Europe because I don't know anything about it. I simply can't comment on how or why they do things.

Managers aren't all money-grubbing tyrants, but they are all influenced by the need for money, and their salaries are all based on short-term profit, and they are obliged to act accordingly. That's the same here or in Europe. The difference there is that there are unions with some influence which can rein them in to some degree. In any case, threads are being mixed here.

My point above was only that discussions about Cat A and PC 1 is academic at best, for much of the world. We can debate it ad nauseum here, but it won't make an iota of difference in what happens in the world. Most pilots I know use some variation of the approach posted by Swamp 76. Aim for the far edge of the deck and use whatever it takes to get it down. I tend to make slower and steeper approaches than some others, but not drastically out of line with them. I don't think we really disagree very much on this, other than the utility of the debate on this forum.

[ShyTorque]

Years ago the theme was "care free handling" for helicopters. This included HUMS, data logging, improved engine management and cockpit indications, etc etc. All very expensive and complicated.

Some of us said "For proper carefree handling, instead of all that, just give us more power and a transmission that you can't overstress with that power, either AEO or OEI. We can then look outside the cockpit at all times, during approach and landing, far safer than looking inside at gauges when things go awry".

It still holds true today.

Upland, glad you enjoyed your flights yesterday. Agusta have gone a considerable way towards the above.

[Mars]

First prize to 'Brian Abaham' - another case of putting the tail rotor into obstacles. Strange how these accidents occur in batches.

NTSB Identification: LAX08LA200
Nonscheduled 14 CFR Part 135: Air Taxi & Commuter
Accident occurred Friday, June 27, 2008 in Santa Maria, CA
Aircraft: Sikorsky S-76A, registration: N343AA
Injuries: 1 Minor, 9 Uninjured.

This is preliminary information, subject to change, and may contain errors. Any errors in this report will be corrected when the final report has been completed.

On June 27, 2008, about 1238 Pacific daylight time, a Sikorsky S-76A, N343AA, rolled over following a collision with a steel beam on oil platform Irene, off the coast of Santa Maria, California. Arctic Air Service, Inc., was operating the helicopter under the provisions of 14 Code of Federal Regulations (CFR) Part 135. The airline transport pilot and eight passengers were not injured; the airline transport copilot with a certified flight instructor (CFI) certificate received minor injuries. The helicopter sustained substantial damage. The flight departed Santa Maria Public Airport, (SMX), Santa Maria, about 1202, with planned stops at platforms Hidalgo, Hermosa, and Irene, before returning to Santa Maria. Visual meteorological conditions prevailed for the flight, and no flight plan had been filed.

During a hover for landing, the pilot performed a right pedal turn over the heliport, and the tail of the helicopter collided with a moveable derrick. The pilot lost tail rotor authority and landed immediately. The landing gear collapsed and the helicopter rolled onto the left side. The helicopter received substantial damage to the tail rotor and main rotor, destroying the tail rotor and main rotor blades. The pilot reported that there were no mechanical malfunctions or failures of the helicopter.

[zalt]

"the pilot performed a right pedal turn over the heliport"

I wonder if that could have been to keep the tail rotor from being over the (only) access to the deck?

[Swamp76]

Thanks for answering in my absence. I don't actually come by here that often. I don't really have anything constructive to add except this.

I have noticed that in the current "pilot shortage" I am flying with a lot more "offshore captains" who have little or no knowledge of what helideck markings mean, the fact that there are normally 2 access points to a deck, or any other facet of how the rig actually operates.

It's a little worrying to me. I have always believed that we need to learn as much as practical about the industries we support in order to be both safe and effective.

[zalt]

there are normally 2 access points to a deck

That may be normal in Nigeria but not in the US!

[Swamp76]

Sorry, again the US seems to be in a world of it's own.

Not just Nigeria in my limited experience.

[Brian Abraham]

In Oz many platforms have only one access. But it is a US company.

[Shell Management]

Turns out to have nothing to do with approach profiles just plain old obstacle clearance.In a conversation with a Federal Aviation Administration (FAA) inspector, the copilot stated that he was at the controls for the approach and landing at Platform Irene. He reported that about 99 percent of the time an approach is made to the northeast, but he performed an approach to the southwest that day because of the wind direction.The operator reported that during the landing and a right pedal turn over the heliport at Platform Irene, the tail rotor of the helicopter struck a movable derrick. The copilot lost tail rotor authority and landed immediately. The left main gear collapsed, and the helicopter rolled onto its left side. The helicopter received structural damage to the tail rotor and main rotor assemblies. The operator reported that there were no mechanical malfunctions or failures of the helicopter. They noted that winds were from 220 degrees at 6 knots. They also reported that the movable derrick on the platform had been positioned in the closest possible location to the heliport area. The operator reported that the landing deck on Platform Irene is 50 feet by 50 feet, at an elevation of 110 feet. The decks on the other oil platforms operated on by Arctic Air are larger, about 70 feet by 70 feet.In the section titled RECOMMENDATION (How could this accident have been prevented) of the operator's written report (NTSB Pilot/Operator Report, Form 6120.1), the operator stated that the flight deck on Platform Irene had recently been repainted. The "H" symbol was offset from the previous position, and the reference line had not been repainted. He reported that pilots used the reference line, or "Butt Line," to determine where the pilot seat would have to be located to allow adequate tail rotor clearance when "swinging" the tail around. The operator recommended that the "H" symbol be repositioned, and the reference line be repainted. He also thought that a profile view depiction of the flight deck and surrounding obstacles could be published to help pilots determine possible problems with particular approach paths. Lastly, he recommended that all company pilots be briefed on these changes and the associated hazards and methods to avoid similar accidents in the future. The Arctic Air Service Safety Officer reported that the derrick had been moved to its location adjacent to the southeast edge of the heliport deck 6 days before the day of the accident. She stated that Platform Irene is the only platform Arctic Air operates on with a movable derrick that can be positioned to that location, which is within 7 feet of the heliport deck. The Safety Officer reported that the deck had been stripped and repainted about 2 months before the accident. She stated that the new "H" marking painted on the deck was 23 feet from the southeast edge; the previous location of the "H" was about 1 foot farther from this edge. The markings on the deck of Platform Irene were different than those on all the other decks before being repainted to match the other decks.An FAA representative stated that there are no FAA regulations defining requirements for markings on these offshore heliports.LAX08LA200 (http://www.ntsb.gov/ntsb/brief.asp?ev_id=20080711X01019&key=1)

[JimL]

I'd like to understand what the NTSB had in mind when this text was added as a recommendations:

In the section titled RECOMMENDATION (How could this accident have been prevented) of the operator's written report (NTSB Pilot/Operator Report, Form 6120.1), the operator stated that the flight deck on Platform Irene had recently been repainted. The "H" symbol was offset from the previous position, and the reference line had not been repainted. He reported that pilots used the reference line, or "Butt Line," to determine where the pilot seat would have to be located to allow adequate tail rotor clearance when "swinging" the tail around. The operator recommended that the "H" symbol be repositioned, and the reference line be repainted. He also thought that a profile view depiction of the flight deck and surrounding obstacles could be published to help pilots determine possible problems with particular approach paths. Lastly, he recommended that all company pilots be briefed on these changes and the associated hazards and methods to avoid similar accidents in the future.

Remember that this was a less than 1D deck; (probably) with obstacles closer than permitted in Annex 14 (CAP 437). Is it likely that such a recommendation was written by someone without sufficient knowledge to make such statements?

Jim

[Gomer Pylot]

It was apparently written by someone from Arctic Air. Whether that person knew anything about the operation I don't know, but one would hope so.