Major safety boost for offshore helicopters moves closer

[CharlieOneSix]

From the CAA website, dated 25 March:

A new technical standard for 'Terrain Awareness & Warning Systems' fitted to helicopters operating offshore (Offshore HTAWS) has been published in Europe and North America. The upgrade will significantly enhance safety levels by increasing the warning time helicopter pilots receive of a potential impact by up to 600 per cent, affording flight crews a much better chance of avoiding accidents. Developed by a joint helicopter industry working group instigated by the UK Civil Aviation Authority (CAA), the new standard can now be adopted by regulators and applied by equipment manufacturers to their products installed in helicopter fleets globally.

In aviation, TAWS are on-board systems aimed at preventing unintentional impacts by airworthy aircraft under pilot control with the ground or sea, known in the industry as controlled flight into terrain accidents, or CFIT.

The initiative began as a response to a number of accidents involving helicopters operating in the North Sea. Subsequent analysis of the HTAWS fitted to helicopters showed that pilots were often being alerted unnecessarily, but then either too late or not at all when an impact actually happened. An earlier joint CAA-industry research project used flight data from normal operations and actual accidents to better define when accidents were likely to happen. Honeywell, the avionics manufacturer involved with the research, was then able to produce a prototype system for further testing in flight simulators, leading to the production of an interim standard which formed the basis of the comprehensive new technical standard.

The new standard has now been published by EUROCAE in Europe and RTCA in the USA and will be adopted by aviation regulators allowing manufacturers to implement the improvements in new products or as modifications to existing equipment.

Dave Howson, Research Project Manager at the CAA, said: “We are delighted to see the publication of the new standard which represents a significant milestone in rolling out this major safety benefit for helicopters flying in difficult conditions, where accidents are more likely to occur.

“This has been a great collaborative effort by regulators and the industry to achieve a real positive outcome, hopefully pointing the way to further joint aviation safety projects in the future.”

[Undried Plum]

Does it work if a crane suddenly moves its jib?

[FD2]

A few things puzzle me C16. If this system increases potential impact warnings sixfold, won't it perhaps give a lot more false warnings? The Sumburgh ditching was due to lack of training or currency with coupled systems. The Scillies crash was due to either a lack of a height warning bug or it being wrongly set or ignored, which is the worst CFIT incident that springs to mind. It will be interesting to see how the system works when more details are released - a new 'standard' is a bit vague from the CAA - but of course any real improvement in safety is welcome.

Apart from disabling cranes remotely by the HLO or Radio Op there might still be scope for crane incidents but I would have hoped that one had been sorted after 50 years plus of North Sea ops! I've been out of it for 15 years now so not exactly current.

[CharlieOneSix]

I agree FD2 - I don't understand the 600% increase in warning time statement. Like you I am way too far away from being current - almost 22 years since I retired - so it's difficult to comment. The Scillies crash - 1983 I think - resulted in the compulsory fitting of the AVAD system to offshore helicopters and from what I understand Offshore HTAWS is the modern replacement. If it had been available then AVAD would almost certainly have saved the Scillies S-61 with its "Check height" and "100ft" call as long as they hadn't muted it. Can't remember - was it impossible to mute the 100ft call? Would HTAWS have prevented the Sumburgh accident - I don't know. They were already on the wrong side of the drag curve when they realised what was happening and unsuccessfuly pulled in power.

I only had one moving crane incident and it was almost a brown trouser occasion. At least it would have been kept in the goon suit!

[FD2]

Wracking the remaining brain cell about muting the AVAD - will try and find an old checklist from SNS days.

The goon suits were also good for holding in farts but it wasn't nice in the changing room later.

[CharlieOneSix]

Just looked at the incident to S76 G-BHYB here when it touched the sea at night in 1987 and it appears the 100ft warning could not be inhibited.

[FD2]

Yes C16 - I'm sure you're right on that - the bugs were wound down to zero once committed to landing. The history of terrain awareness warning systems and lead up to this announcement is mentioned in Annex G page 20 (para 3.10) to CAP1145 from 2014.

https://publicapps.caa.co.uk/modalappli ... il&id=6088 (leads to PDF download).