Bristow sues over helicopter crash

[Rotorbike]

Taken from the Mail on Sunday (http://www.thisismoney.com/20030413/nm61737.html)

Bristow sues over helicopter crash
13 April 2003, Mail on Sunday

ELICOPTER operator Bristow is suing two American aviation companies for negligence over a crash in which one of its machines plunged into the North Sea last July, killing all 11 people on board.

In a High Court writ, Bristow alleges that repair work on the main rotor blade was faulty. The part had been hit by lightning three years earlier when it was on another Bristow aircraft.

Bristow blames helicopter manufacturer Sikorsky and its partner United Technologies for the crash. The Sikorsky S76A machine was ferrying workers between a gas production platform and a drilling rig when it ditched into the sea off Norfolk. Two pilots and nine passengers were killed.

Bristow alleges that the rotor blade that had been passed as airworthy fractured catastrophically because of fatigue, the result of intense thermal damage caused by the lightning strike. Bristow is being sued by families of the 11 victims. After the disaster, Bristow gave £100,000 between them and set up a disaster fund for further cases of hardship.

The writ says that though the crash was not Bristow's fault, and though it blames the negligence of other companies for the disaster, it might still have to pay compensation to families of the victims.

Bristow is asking the High Court to rule that Sikorsky and United Technologies are liable to indemnify it against the cost of any compensation it might have to pay, including sums already distributed to dependants of the crash victims.

Bristow is also suing another company, Composite Technology, for damages, claiming negligence and breach of contract over the inspection and safety certificate of the rotor blade.

[Old Man Rotor]

I accept its a dog eat dog at commercial level..................but surely any professional engineering group must assume that anything struck by lighting, and hence had a temperature rise of thousands of degree's in milli seconds must question the capacity of that "thing" to ever be normal again???


But of course the all mighty $$$ takes over and for a fraction of the price of a new one....we can get certificates from all sorts of folk that have their finger in the pie, and put the "thing" back in service.....

I bet my salary that the Flightcrew and passengers of that terrible flight had no advice from the owners, that a vital bit of their aircraft had suffered such an event.

I sincerely hope that the families make all parties pay heavily for their actions.

[S76Heavy]

Just as the flight crew had no advice about the blade and its history, nor did anybody else continuing to fly the 76 worldwide in the days after the accident know anything that could have been important.
I still believe it was negligent not to officially ground the type before it was evident which part and partseries were suspect, and why. In the end it was the customer who refused to fly the BHL S76 until there was an investigation result.

[Shawn Coyle]

This is an interesting part of the story of aviation. The long term lesson is that perhaps our non-destructive testing procedures aren't all they could be- so we need to learn how to examine things differently without breaking them apart ('we destroyed it in the inspection, but it was OK...).
I would imagine there are also other rotor blades out there that have been struck by lightning and inspected and have put in many hours of useful service afterwards.
This particular blade appears to have had a manufacturing defect that made the problem worse, and that was undetected in manufacture or the subsequent post-lightning strike inspection as well.
I'm reminded of the story of the Canadian F-18 that was overstressed to 11.2 G (ground static testing had only ever been done to 10.5G) - every non-destructive test known was done on the machine, and no fault found, so it was put back in service. Flew quite nicely for several years, so I understand.

[SASless]

Shawn....

Go to the AAIB reports for the two events...the original lightning strike and the later crash of the second aircraft. When you read the laundry list of damage, destroyed components, and scrapped components from the aircraft that was struck by lightning....I dare say....you will question any explanation for why those blades were even considered to be worth inspecting....much less using. There are a lot of people stirring up the dust over this one and pointing the fingers every which way.

One man's opinion....after the lightning strike, those blades should have been removed from service along with the transmissions and other bits and not placed on an aircraft. The severe damage the aircraft sustained from the strike moved it from an incident to an accident in my book....and alarm bells should have been sounding when it was decided to re-use the blades.

The manufacturer's quality control and the subsequent inspection of the blades also seems suspect as well. I wonder if the people inspecting the blades after the lightning strike were aware of the extent of the damage to the aircraft and would that knowledge have impacted their decision making? Were the blade caps on the blades or had they been removed....that would also have provided more evidence for the inspectors to view while inspecting the blades.

The Operator got about 1600 more hours out of the blade....at the cost of an inspection, some shipping, and one aircraft and eleven lives.

I hope those hours were worth it?

[M/V]

We are all wiser after the event. Those people involved in returning blades to service probably acted with their best intentions.The cost of replacement blades was more than likely the ruling factor in continuing to use original items, I'm sure there has been/will be much `finger pointing',passing the buck etc

[Lu Zuckerman]

Many years ago a little old lady in tennis shoes was assigned to remove the excess bonding agent that extruded from between mating parts on S-55 rotor blades. In the process of performing her job she used a Xacto knife to scrape and cut away the bonding agent from the spar cutting into the anodized coating which set up a stress riser on the spar. The problem manifested itself when two US Marines were folding the blades per base order. On the S-55 (HRS) it was necessary to turn the left blade upside down in order to place the blade in the supporting saddle. This helicopter had just returned from a training mission and when the blade was turned upside down it snapped off at the stress riser.

The entire S-55 fleet including the one I was crewing on was grounded until a Sikorsky rep could inspect the blades. On our blades the Rep used a Dremel grinder in a special jig to grind into the spar to remove the stress riser and then we had a one-time flight to our base from the ship we were on and then the blades were scrapped.

In another case the US Navy was overhauling blades from the HSS fleet (CH-34) and to ensure that the pockets on the blades would not debond the used PK (metal screws) screwing them through the pockets into the rear end of the spar. Needless to say when Sikorsky found out about it the blades were scrapped.

:suspect:

[B47]

Firstly, no apologies for taking this personally, the chief pilot was a friend.

My only printable comment is on the massive disparity between the commercial interests in this case and how they would have been dealt with if the heli was a private machine. The difference being that the customer doesn't have clout.

We are all told to believe that the maintaining engineer's judgement prevails. It certainly does if the blades on any private machine had suffered damage of any kind as serious as a lightning strike. Scrapped without question, no discussion allowed and on a two bladed machine, replace both as a pair. Whinge as much as you like, they won't listen to how you can't afford replacements, and quite right too.

So, tell me, if a commercial machine carries eleven brave young men with families, why the criteria should be any different? A naive question of course, but it illustrates starkly the hypocrasy which operates at this level. Whether the 'repair' should have been willingly carried out or whether it was not done properly is not the only issue. Whilst the blame appears to be directed against those who did this work, can we stop to question any company who with expert knowledge asks for 'repairs' like this to be carried out ?

[Old Man Rotor]

I sort of agree with you, but remeber we were all trying not to jump to conclusions late last year, even thou as soon as the lightning history was stated we had more than an educated guess as to the root cause.

It is now more clear and the worst possibility has been realised, in that a defective part was reinstalled on a machine as operational.

Let me ask just one question----particularly of our Engineers that walk these threads.

"Most engineers have their favourite screwdriver in their tool box. At some time when we needed a small soldering iron to get into that small hole somewhere to solder that wire and the normal heat source is unavailable, for a nano second the thought crosses the mind to heat up my driver and fix that wire. "

But would you???

Not in any lifetime, as we all know that that screwdriver would never be the same again............Metal and heat don't mix....period"

Would Inspections, X-Ray, NDT, be acceptable....of course not. You would never allow it in the first place.

The lightning stroke raises the temperature in narrow channel of air to 30,000° K.

We in our Industry have become used to the concept of, recycling, remanufacture, storing timex parts, running all components to the full extensions possible......and more.

Most of the time it works, but its not an exact science and people died because of the system that operators have manipulated, and remanufactoring shops and recertifying faceless people are complient with.

Yes, you bet I am mad over this. Remember the blade that is on your machine may be one of those [hopefully they are all recalled by now].

[zalt]

S76Heavy: If aircraft types are automatically grounded after accidents there would have been no Sikorsky aircraft flying in the UK last July (an SAR S-61 only just made it after an airborne fire the day before the S-76 accident while searching Poole harbour - I shudder to think what would have happened if it had been a passenger filled S-61 cruising a 1000ft higher over the sea).

Furthermore two days after a Canadian Bell 412 went due to what turned out to be a tail rotor failure (I believe the decendents of Lu's little old lady in tennis shoes may have been involved in that one).

The oil comany 'grounding' was really a rescheduling of movements and a rush charter of AS332s.

Shawn makes a good point about NDT. In that case a manufacturing defect and the lightning damage were both missed.

Remember in all the fuss about the super safe S-92 being designed to the damage tolerant philosophy? Sounds an improvement eh?

Problem is that such components are only tolerant to small amounts of damage (which by definition the manufacturer are happy to let you fly round with) - the trick is to find the damage before it become critical. In many cases that means NDT. After this accident that doesn't sound like leap forward.

Remember how we were told the S-76 didn't need BIMs because the titanium spars were such an improvement.....

[S76Heavy]

Zalt,

So what if there would have been no Sikorskys flying for some time? VX wasn't just an accident, it was a fatal accident due to a catastrophic failure that happened so quickly that there was no chance of survival, for a reason that was unknown for a while.
And I don't give a hoot how you call the oil company's action, they did not fly the 76 for a while. Pure semantics.

Are we really happy to operate an A/C if a similar one has simply dropped out of the sky without a warning, and nobody can as yet tell us why it happened?
At least in the SAR case, the crew survived to tell the tale, and a thorough investigation of the remaining S61s could take place. Therefore, the S61 crews could be reasonably confident that the machines they were flying would not go up in flames that day.

[leading edge]

Zalt

I think you are confusing the argument here. With the exeception of this one very tragic accident, the S76 has had excellent reliablity from its blades. I think that Sikorsky were quite right not to equip the aircraft with a BIM system.

The aircraft concerned was equipped with Hums, and if that didn't pick up any problems in time for corrective action, there is no way that a BIM would have shown anything in time to prevent this accident.

I think that those who suggest that any blade which shows any evedence of a lightening strike are correct. Of course, we all know that now as a result of those lives lost. Blame the operator, yes, if you like, but that operator did send the blade back for an "authorised repair" by the manufacturer. Perhaps it is Sikorsky who should have scrapped it.

LE

[zalt]

LE - On your last paragraph - totally agree - sorry if I implied otherwise - there was nothing in the MM that would allowed the operator to have picked this up in service. So the key Q in court is: was the R&O inspection done adequate?

On BIMs: strictly until the details of the fracture come out in the AAIB report it is difficult to confirm if they would have helped - but considering the cracks I have seen found with BIMs I remain moderately confident ther would have been a pressure drop pre-flight.

Disagree partly on the 76 blade record, though admittedly spindle/cuff rather than spar failures: G-BGXY 12/3/81, 4 fatalities and the identical PT-HKB 20/3/1980, 14 fatalities. Same problem twice in one year.

S76Heavy - You have missed the point on the S-61.

The S-76 needed three events (one a goof in manufacture + a strike + passing an inspection afterwards), so few aircraft in the fleet would have been at risk. Although I agree it took a few days for the localised nature to become clear. I just don't believe a knee-jerk grounding (when the hazard is still unknown) has ever prevented another accident.

Note the AAIB did not recommend the CofAs were withdrawn a la Concorde - do the oilcos know more than them? Or are they just managing a potential industrial relations problem?

The S-61 problem is inherent in the design, and still is today. It has happened before and can happen again on any S-61. The odds of it happening again are surprisingly high. Sikorsky still haven't managed to issue a mod with a box with some light bulbs and a 12ft cable to bodge a warning system. This sort of continued and unnecessary exposure to a known and avoidable but excessive risk is where I sweat. The only good news is AAIB/CAA/FAA are all getting impatient I'm told.

[S76Heavy]

Zalt,

I'm not familiar with S61s apart from flying past them when they lumber through the sky. So I cannot comment on it.

But in general, as a driver and not a management type, why are we bothering with relatively minor items in the MEL that stop us from getting airborne, when we continue to operate machines that have either known or unknown deficiencies that have led to fatalities or may well have? Somebody please explain the logic to me, as I am unable to find it.
:confused:

[Lu Zuckerman]

It was stated above that the main spar of the S-76 rotor blade is made from Titanium. One of the properties of Titanium is that when a low level of DC is passed through it an Oxide will form on the surface of the material. The Oxide will have a color and the density of the color and the shade of the color is dependent on two things. The strength of the DC passing through the Titanium, and, the length of the application of the DC. This change in color is caused by the application of a low level of DC,which alters the surface chemistry. It can only be imagined what happens to both the surface and the matrix of the Titanium when exposed to many thousands of volts DC.

:rolleyes:

[zalt]

S76Heavy - Try JAR-39's ACJ on sufficiency of corrective action, a real gem which is a damn sight better reading than an MEL! Its a question of managing risk. We could avoid risk turn the clock back to pre-Kittyhawk when the Wright Bros still made push-bikes.

I wonder what safety targets they will use for aircraft to the latest FARs/JARs? At least the old BCARs, that helicopters like the L2 and 101 had to meet did have very explicit numeric safety targets.

[Blue Rotor Ronin]

Management points the finger as soon as the fourth bean cost the lives of eleven good men , whilst still asking Jack to get him a fifth, in order to score him a giant. Inevitable. Drivers know this and live in the hope that one day bean counters will realise that life isn't cheap.

[Dantruck]

I still can't get over the fact that a safety critical, load bearing, complex moving part that was known to have been struck by lightning was refitted to a helicopter. Yes I understand the 'cost saving' argument, but somehow I doubt all the money ever saved by rotor blade inspection would cover the cost of this tragedy even if all the cash could somehow be pooled, which it can't. And that's without counting all the legal and other knock-on costs, and before we even get to the much weightier personal cost to the families and friends involved.

As a young engineer I was taught about lightning and what it can do, from first principles. Above all I remember the warning that science does not fully understand lightning, and that engineers cannot therefore fully predict the effects a strike might have on any mechanical component, its metalurgy and characteristics. I was also taught always to remember that, by definition, all forms of non-destructive testing are, and will always be, fallible, ie: not to be relied on totally where safety might be an issue.

OK, I know I'm having a rant, and I know the realities of commercial operations are such that not every decision maker can be trained in every aspect of the disciplins involved, but please god let safety-v-cost lessons be learned from this terrible episode.

I'm all for going flying to MAKE money, but never just to SAVE money. The cost is simply too high.

[leading edge]

DanTruck and others

I agree that this subject is emotive because of the loss of lives. I too lost a friend in that accident and I too can get emotional about it.

The aircraft operator suffered a lightning strike when a given set of 4 blades were fitted to BHBF 3 years ago. They obviously removed them post strike. Then, maintenance management would have gone to Sikorsky, the OEM and said "what can we do with these blades, should we scrap them or can they be repaired?"

I don't think any of us know whether any of the other 3 blades in the set of 4 on BF were scrapped or whether they were all repaired. It might even be that this was the least damaged and the others were scrapped, I dont know.

The OEM had the call as to whether the blades were repaired or not. If they said "scrap them", Bristow would have scrapped them without question.

The implication by some in this thread is that there was a conspiracy betweeen Bristow and Sikorsky to "save a buck" by returning an essentially unairworthy blade to service. That is absolutely not correct. The blade conecrned was believed by all involved to be airworthy at the time of re installation onto BJVX.

Furthermore, the lightning strike caused further development of a pre-existing manufacturing fault. That fault had been present since the blade was new. Without the strike but with the fault, or without the fault but with the strike, the failure may not have propogated as quickly, who knows.

Bristow is a good operator and would not knowingly risk the lives of passengers to save a buck or even several bucks. People who run companies know the costs of having an accident and to suggest that they would risk lives by saving money on a new versus repaired blade is asonine.

LE

[Old Man Rotor]

If your suggestion is in reference to my comments, No I don't suspect any collusion between the two principals.

The question perhaps has never been asked, either deliberately or not.

The question that should have been asked was: can any piece of metal that has been heated to around 30,000K ever be the same.

Any metalurgist will confirm the common sense answer to that one.

"Metal and heat don't mix....period"

Why then could any operator or re-manufacture ever think otherwise. Oh of course the almighty $$$$

It has already been an expensive hardship for the friends and relatives.

It's also an expensive mistake that the operator and re-manufacture will never make again.

Metal and heat don't mix....period"

[Flight Safety]

Lu and I were basically in agreement (in another thread) about the cause of the rotor blade failure when this accident happened, namely that the titanium spar would not take kindly to a lightning strike, due to the unique properties of titanium.

I noticed that after the accident, the FAA and Sikorsky were involved in an AD to recall all S-76 rotor blades in service that had suffered previous lighting strikes. If memory serves me, there were 8 known blades in service at that time with this history.

I doubt after this accident, that ANY titanium spar rotor blade will EVER be returned to service after a lightning strike. Again Shawn is right, a foolproof NDT method of testing would be required to properly certify a titanium spar rotor blade for return to service after a lightning strike, and no such method exists at this time. Until such a method is developed, the only prudent course of action is to ALWAYS remove such a rotor blade from service, permanently.

[Red Wine]

I think your 100% correct.....

So I guess the owners of those blades have cut them into many pieces...?

Or stored them in the storeroom awaiting the day that someone reckons they have a "new" foolproof test to recertify them?