Focus on Offshore Helicopter Safety

A focus on offshore helicopter safety happens for me every time I get on one.  They are the blessing and curse of any offshore worker’s rotation. Nothing is more disappointing than to be psyched up ready for off and then we get the dreaded delay.  Once on board , though familiarity puts risk to the back of my mind to some extent it is always there.

In recent years there have been many changes to operating helicopters offshore, so do any preventable risks still exist?

What Tends to Go Wrong

It is tempting to turn this article into a memorial piece. Our hearts go out to the people who both are killed and injured when a helicopter goes down and the people they love left behind. Maybe I lament these accidents so much because of the nature of these tragedies. I love my job but I get on those aircraft in order to earn a living, not for leisure. They are the scene of elation at the thought of a trip home and sometimes shear determination at the tasks awaiting at sea.

However, forefront of my mind while writing this is the reality that such accidents are rare and for example it is still statistically safer than a drive to the supermarket..

The last oil and gas related air accident to occur (North Sea) was when thirteen were killed while travelling to Bergen, Norway from the Gullfaks B Platform.  A sudden failure of the planet gears caused the rotor to detach.

Safety issues that are peculiar to offshore air transport were not really relevant in this case. The weather was good, the pilots were not challenged regarding visibility and the loss of life was not due to the peculiarities of operating over a hostile sea. Sadly the stricken aircraft crashed onto a small island.

This sudden catastrophic failure was caused by a previous fault that was unknown  to the pilot and remains of an unknown origin at the time of writing.

Previous accidents, however, have driven the search for improved safety features and operating parameters.

A look at accidents that have forced a helicopter down while on North Sea operations shows they were primarily caused by mechanical failure. In almost all cases, though warned that something awful had occurred, crew had no chance to rectify the situation before the aircraft had to descend. In cases where the primary cause was not mechanical, such things as lightening strikes and poor visibility featured significantly.

The thing is we in this region are not exclusively at risk. Wherever offshore air transport is used the same issues occur. The last such tragedy happened only a month ago off the coast of Angola. Six people lost their lives when a  chopper came down in the sea while flying in poor weather.

So What About the Future?

In many cases it is not the impact that kills. Rather it is the conditions you find yourself in.

First there is the escape. After studying other accidents the CAA ( UK Civil Aviation Authority) required improvements in planning for an emergency. The most significant was that Cat A emergency breathing systems (EBS) were required for passengers. This was because taking enough breath in order to escape a capsized aircraft was not always possible based on the physical condition of both the personnel and aircraft post impact. More time was needed.

The limitations of types of aircraft were examined and the weather they could fly in was restricted to improve the likely hood of the chopper remaining upright and floating. In addition, it became mandatory that operators ensure the flotation systems could be deployed automatically if needed and that all seating should be adjacent to an escape point.

full rig of a life jacket and cat A  EBS system
Cat A EBS uses compressed air as opposed to the old re breather systems. This means they are easier to use especially when deployed under water.

Particular attention was given to the issue of the buoyancy of the helicopter itself.

I think it would be fantasy to look at the dynamics of chopper design and believe you could get them to behave in a heaving sea just like a boat. However, how long that lump of metal floats for is the main issue when it comes to surviving a ditching.

A good example of this was when in Feb 2009  all hands were rescued after the chopper they were in deployed flotation and ditched. The sea was relatively calm and as a result the aircraft remained upright about 120 miles offshore of Aberdeen.

It is when the aircraft rolls over that things become critical. This happens for a variety of reasons, the flotation system, being low down, can be damaged on impact or the angle of descent makes it unlikely it will float upright in the first place.

So the CAA pointed to systems where a flotation device acts as back up to the conventional ones already fitted. This second line of defence is encased high up on the air frame. In heavier seas as the chopper tilts in order to capsize the secondary air bags may prevent it turning over. If it does go over tests show it will tilt leaving an escape gap and possible access to air. This means there is a  significant angle in the water, it is not perfect, but for those battling to escape it could provide vital minutes to clear into life rafts.

So Here is the Rub

Chapter 9  ( P39) of the CAA – Safety review of offshore public transport helicopter operations deals with the ditching of choppers in the sea.

In ‘actions’ it lists many of the changes we might have noticed since mid 2014.  There are quite a few and all the easier ones were given time limits that have since passed. However, the side flotation devices that would back up the main floats and minimise the danger of capsize were only recommendations.

I am not dismissing the positive effect and action regarding this report or the improvements the operators have made. I am saying that given surviving in these situations is difficult then any and all measures to increase the likely hood of survival should be taken and should be mandatory.

It was found that there were designs of helicopter that could likely float in gentle sea states, but any weather above sea state 5 presented problems for all. This is due to the high centre of gravity caused by the position of the engine, gears and transmission.

 

So it is acknowledged that in conditions like the above helicopters will struggle to stay upright using standard emergency flotation. The below shows how in good conditions a chopper behaves post ditching.

 

In the EASA research (below) they anticipate that even with the additional floats the helicopter will partially capsize, however, tests show that an air pocket and open gap would be available to aid escape. If that gap exists, granted it would be terrifying, then extra time would be afforded to at least some of those trapped inside.

What do you think? Do you know of any such systems fitted? At the time of writing I can find no mention of them on the web nor is there a mention of calls for them to be introduced beyond the recommendations of two plus years ago.

The only useful thing I can say from reading the documents I have put links to is that being familiar with the particular aircraft you find yourself in is vital. If a new or unfamiliar type lands on the helideck then take extra time to look at the devices for opening emergency escape points.

It was found that in past accidents even the unfamiliar way a release system operates has cost lives.

Thanks

Chris Hodge

 

 

 

Source information Skybrary.com, CAA report, EASA final report,

 

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