Weather leaves 300 oil workers stuck in North Sea

[SFIM]

they didn’t have triggered lightning, when I was full time North Sea, or rather they did have it but nobody talked about it or stopped you flying because of it, I am inclined to think it’s all gone a bit too far, am I alone ?

https://www.bbc.co.uk/news/uk-scotland-64043030 (http://www.bbc.co.uk/news/uk-scotland-64043030)

[ApolloHeli]

they didn’t have triggered lightning, when I was full time North Sea, or rather they did have it but nobody talked about it or stopped you flying because of it, I am inclined to think it’s all gone a bit too far, am I alone ?

https://www.bbc.co.uk/news/uk-scotland-64043030 (http://www.bbc.co.uk/news/uk-scotland-64043030)

The customers tend to lack an appetite for 'having a go' and seeing if areas can be operated through visually (by day) due to the odds of having to RTB without fulfilling the flight, and different crews have different levels of enthusiasm when it comes to offering flights that operate through areas affected by TL. At the end of the day it is just a planning tool, one that is still being improved and balanced against commercial desires to crack on. I understand the frustration for the workers stuck offshore but if this were January and Christmas wasn't around the corner I doubt it would be newsworthy. I doubt Santa checks the TL forecast though so hopefully Christmas is still on.

[Variable Load]

TL rules are driven by the regulator and customers. Crews just do what they're told by the Ops manual. Same as it always was I hope, certainly my 30+ years have been spent following the rules.

Must be a slow news day at the BBC. Next .....

[helicrazi]

TL rules are driven by the regulator and customers. Crews just do what they're told by the Ops manual. Same as it always was I hope, certainly my 30+ years have been spent following the rules.

Must be a slow news day at the BBC. Next .....

TL isn't regulatory, tail wags dog

[SFIM]

I don’t know where TL came from, but I come from the “have a go” generation, it seems a shame to me that this has gone, these days I fly in Africa, and we sometimes delay flights for weather but we have never lost a day…and nobody knows what TL is 🤣

[helicrazi]

2011/12 at request of UK O&G. I must admit it was news to me that Denmark bother with it. Norway are much more pragmatic.

[212man]

I don’t know where TL came from, but I come from the “have a go” generation, it seems a shame to me that this has gone, these days I fly in Africa, and we sometimes delay flights for weather but we have never lost a day…and nobody knows what TL is 🤣
Maybe talk to the crew of G-TIGK! The fact that you are talking about TL and Africa suggests you don’t know much about lightning. It is generated around the zero degree level, so by definition it has already been triggered naturally around 15,000 ft in Africa and you just observe it, but cannot be the trigger.

https://www.skybrary.aero/articles/helicopter-triggered-lightning-strikes

[Variable Load]

TL isn't regulatory, tail wags dog

I didn't say regulatory, I said driven by the regulator. The rules we work with are not in regulation, but the Met Office tool and the associated ruleset are all put in place with CAA oversight, encouragement, etc.

212man makes reference to TIGK. This was the start of a very long journey. Some of the initial research was very interesting, including that TL was mainly "positive" rather than "negative" and carried much more energy than traditional lightning. The positive lightning strike energy far exceeded the certification requirements back in the 90s, and I suspect still does.

[212man]

I didn't say regulatory, I said driven by the regulator. The rules we work with are not in regulation, but the Met Office tool and the associated ruleset are all put in place with CAA oversight, encouragement, etc.

212man makes reference to TIGK. This was the start of a very long journey. Some of the initial research was very interesting, including that TL was mainly "positive" rather than "negative" and carried much more energy than traditional lightning. The positive lightning strike energy far exceeded the certification requirements back in the 90s, and I suspect still does.
I remember HC telling me years ago that the ion trail from the exhausts was like flying along with several hundred metres of copper wire behind you!

[helicrazi]

My point was more of compliance being optional to the algorithm output, by optional I mean operators including it in ops manuals, not crews choosing to adhere.

I'm aware of more strikes trying to dodge outdated info rather than applying airmanship.

It's a planning tool and barely suitable even at the planning stage given the picture can radically change every 30 mins or so.

Even the operators got bored of it and wrote rules to operate around the red areas

[212man]

I come from the “have a go” generation

​​​​​​​Whilst driving your pax to and from their normal place of work, and home. I’m sure they’d love to hear that. Do you expect the same when being flown with your family on holiday?

[piperpa46]

I'm confused why they are specifically mentioning Tyra II. It's an issue for all of Totals fields in the Danish sector, and has been ongoing the last two weeks. I've had colleagues stuck out there, as well as colleagues unable to go to a rig to perform a scheduled job.
There was also a prolonged period of time 2-3 years ago iirc.

[SFIM]

Quote:
I come from the “have a go” generation

​​​​​​​Whilst driving your pax to and from their normal place of work, and home. I’m sure they’d love to hear that. Do you expect the same when being flown with your family on holiday?

I should clarify, that it was normal practice in the noughties for the customer to often request flights when the weather offshore was below ARA limits, as there was no approach ban, so yes we would “have a go” at the customer request.

[212man]

I should clarify, that it was normal practice in the noughties for the customer to often request flights when the weather offshore was below ARA limits, as there was no approach ban, so yes we would “have a go” at the customer request.
I know, but I think the gamble of doing an ARA and diverting to Bergen is not quite the same as getting struck by lightning and ditching!

[jimf671]

... I come from the “have a go” generation ... ...

Sometimes that means the "Before we knew what we were doing generation."?

===================

I have been following the triggered lightning story because it affects availability for SAR training flights. The G-TIGK story already mentioned raised the conductivity issue and that has been mentioned by a number of people. The idea is that the changes in materials over the years has made susceptibility to TL damage worse because it affects the flow of an electrical charge around the airframe or can result in explosive vapourisation of materials. So those who say that 'we never had that in my day' may indeed be correct.

[Variable Load]

Sometimes that means the "Before we knew what we were doing generation."?

===================

I have been following the triggered lightning story because it affects availability for SAR training flights. The G-TIGK story already mentioned raised the conductivity issue and that has been mentioned by a number of people. The idea is that the changes in materials over the years has made susceptibility to TL damage worse because it affects the flow of an electrical charge around the airframe or can result in explosive vapourisation of materials. So those who say that 'we never had that in my day' may indeed be correct.The change in manufacturing from traditional metal to composites and honeycombs has resulted in aircraft that are much more susceptible to significant damage when subject to a lightning strike. It's a well known phenomena that water is gradually absorbed into these structures over time. Introduce the massive energy of a lightning strike and the water than vaporises and expands, with the potential for some real and substantial damage. Add in the cost of replacing powertrain components following a strike and the corporate need to reduce risks and cost naturally kicks in.

S-61s used to get struck a lot, but apart from pinholes in blades nobody really blinked. I can remember seeing some very interesting photo’s of Bristow S76 blades when that was subject to a lightning strike and hobbled it’s way back into Aberdeen (I think it was Aberdeen).

The current TL MetOffice tool is a pain, mainly due to the lack of forecast stability. However it’s all we have and the real risks associated with being struck are only getting worse with modern aircraft.

[The Sultan]

I can remember seeing some very interesting photo’s of Bristow S76 blades when that was subject to a lightning strike and hobbled it’s way back into Aberdeen (I think it was Aberdeen).
.

You mean this one?

https://assets.publishing.service.gov.uk/media/5422fe4240f0b6134200089f/G-BJVX_Pub_version_inc_annexes.pdf

11 dead.

[ericferret]

I know, but I think the gamble of doing an ARA and diverting to Bergen is not quite the same as getting struck by lightning and ditching!

There exists a photograph of a Super Puma at Bergen that suffered a lightning strike to a main rotor blade. It blew a hole aft of the spar large enough for the chief engineer to put his head through it.
Wish I had kept a copy. This would have been circa 1995.

[212man]

There exists a photograph of a Super Puma at Bergen that suffered a lightning strike to a main rotor blade. It blew a hole aft of the spar large enough for the chief engineer to put his head through it.
Wish I had kept a copy. This would have been circa 1995.

Not seen it but at a similar time we had one get struck flying back to Aberdeen. It was after GK and the crew prepared for the worst after the strike, only to find no effects and everything was smooth. After shutdown all four blades had holes the size of 20mm cannon shells!

[212man]

You mean this one?

https://assets.publishing.service.gov.uk/media/5422fe4240f0b6134200089f/G-BJVX_Pub_version_inc_annexes.pdf

11 dead.
Of course not - what crass post! The blades had been subjected to a lightning strike on a different airframe and then sent to the factory for inspection and recertification. This process failed to identify a latent defect from new, that had exacerbated the effects of the strike, but they remained undetected. Clearly, the aircraft that suffered the strike did ‘hobble’ home or it would have been clear that the blades were not salvageable.

[Asturias56]

There exists a photograph of a Super Puma at Bergen that suffered a lightning strike to a main rotor blade. It blew a hole aft of the spar large enough for the chief engineer to put his head through it.
Wish I had kept a copy. This would have been circa 1995.

https://www.fss.aero/accident-reports/dvdfiles/GB/1995-01-19-UK.pdf refers to

another AS332L helicopter suffered a high energy lightning strike. This Norwegian aircraft, LN-OLB, was inbound to Bergen on the 27 February 1996 when it was struck, resulting in heavy airframe vibration. The commander elected to continue to land at Bergen where subsequent inspection revealed marked damage to its main rotor blades, with further damage to its hydraulic system components and airframe, although the tail rotor showed no evidence of lightning attachment

Oddly it doesn't seem to figure in the Norwegian official list of reports

https://www.nsia.no/Aviation/Published-reports?sortby=idate&sortorder=desc&page=1&lcid=1033

[HeliComparator]

Other than G-TIGK which had arguably sub standard (as in an inappropriate certification standard) tail rotor blades - and 332L tail rotor blades were subsequently improved - I don’t think there have been any loss of life or loss of aircraft incidents from TL. However each strike is VERY EXPENSIVE as it generally requires replacement of blades, head, main rotor gearbox etc. And can be pretty alarming when you see the damage.

I have always thought the forecasting algorithms were pretty blunt but then again I can’t design a better one! My own TL strike was from stratus cloud, absolutely no turbulence at all. Then zap. A pretty minor one but resulted in a burnt rotor blade.

With regard to the current publicity there is “defence” that de-icing wouldn’t help. But surely if you can climb above -2C then you are clear of the TL zone. Maybe it depends on the specifics of a particular aircraft’s de-icing system?

[PlasticCabDriver]

Other than G-TIGK which had arguably sub standard (as in an inappropriate certification standard) tail rotor blades - and 332L tail rotor blades were subsequently improved - I don’t think there have been any loss of life or loss of aircraft incidents from TL. However each strike is VERY EXPENSIVE as it generally requires replacement of blades, head, main rotor gearbox etc. And can be pretty alarming when you see the damage.

I have always thought the forecasting algorithms were pretty blunt but then again I can’t design a better one! My own TL strike was from stratus cloud, absolutely no turbulence at all. Then zap. A pretty minor one but resulted in a burnt rotor blade.

With regard to the current publicity there is “defence” that de-icing wouldn’t help. But surely if you can climb above -2C then you are clear of the TL zone. Maybe it depends on the specifics of a particular aircraft’s de-icing system?

I’m sure a CHC S-92 from a few years ago had one. The path of the current from point of entry through the blade, right through the MGB, down the TR drive train, through those GBs to the point of exit could be clearly seen. As you said, complete replacement of the entire transmission.

If you can get below -10°C then red areas can be treated as amber, which would most often be achieved by getting high enough to get that cold, so the S-92 can do this IMC if it has the RIPS working, 175 needs to be VMC below -10° (like the Puma) so a bit more limited in trying that option. Question always is though, if I am flying above a red area because it is < -10° outside, what happens if I suddenly have to descend?

[HeliComparator]

I’m sure a CHC S-92 from a few years ago had one. The path of the current from point of entry through the blade, right through the MGB, down the TR drive train, through those GBs to the point of exit could be clearly seen. As you said, complete replacement of the entire transmission.

If you can get below -10°C then red areas can be treated as amber, which would most often be achieved by getting high enough to get that cold, so the S-92 can do this IMC if it has the RIPS working, 175 needs to be VMC below -10° (like the Puma) so a bit more limited in trying that option. Question always is though, if I am flying above a red area because it is < -10° outside, what happens if I suddenly have to descend?


Its coming up to 10 years since I retired but when the whole TL thing was being investigated, an analysis of all NS lightning strikes was carried out and every one of them was with an OAT of +-2 degC. So if the current rules require going to -10c then that seems extremely over-cautious. What science is that based on?

As to the need for an unexpected descent then one should bear in mind that safety is all about probability, not absolutes. For many years people flew for thousands of hours in the “danger zone” and there were just a few strikes a year. So if you have to descend through the “danger zone”, taking 2 or 3 minutes to do so, the probability of getting struck is extremely remote and much less likely than other catastrophes.