Obtaining accurate medical information on the casualty and the severity of the injury is often an issue, particularly when English is not the mother tongue of the crew. Often the fishing fleets in the Atlantic are not from home shores.

Which is why declining a task on the basis of sketchy information is a concern. Ideally - as in this case - a shore-based doctor can advise, or in the case of large cruise ships, a doctor is part of the crew. Lacking this, the advice of our own Paramedic is invaluable and helps in the decision making process.

It is ultimately the Commander's (often both pilots are Captains) responsibility to make the go/no go decision but I want to be happy that, either way, the other crew believe we are making the correct decision.

Even if this was the case the accident could have also happened if this was a training mission. I'm not sure this is the right path to pursue when trying to learn lessons from this tragedy. Flying (and thus training) less frequently under challenging conditions doesn't make the job less risky. Compared to other missions/training scenarios this one wasn't even particularly challenging/risky. That is what makes it so mysterious.
There will be more to learn from CVR/FDR.

Moot point.(Happy Now)....Might as well say if only the Aircraft wasn't serviceable. I wouldn't have taken off.
It was tasked and it happened, stay on track.
It's a SAR Heli

Re: questions around lack of NVG etc, there is a tender request in the EU Journal at present for third-party heli-SAR consultancy to the Irish Coastguard to liaise between them and CHC and to advise on matters of contractual adherence, future strategy, regulation, practices and equipment.

The CHC contract is currently at its mid-point so it makes sense to start looking forward to the next big supply tender. However I do wonder if it will move back from private sector to a more integrated state-provided package. The 2012 contract award was controversial at the time and will be no less so in five years.

Henra
I was not suggesting at all that the potentially unnecessary despatching of R166 was anything to do with the cause of the accident - which of course it wasn't. I raised the issue as a separate, though related, point. The reality is the no doubt generally excellent SAR services are funded by tax payers and as such need to continually look to provide best value for money. It is quite possible that investment in improved information communication with vessels might help this process - which in itself would protect the SAR industry. I can see that even unnecessary missions are still good training, but there is clearly a limit to how much of this is sensible.

Buzz66 - as above, you misunderstood my post.

https://twitter.com/patmcgrath/statu...51476543475712

https://www.rte.ie/news/regional/201...st-guard-mayo/

Heartbreaking.

RIP Captain Mark Duffy

Simply because the crash dynamics may have been more favourable to some than others. In car crashes some passengers come out unscathed, whilst others are fatally injured. Aircraft accidents are no different.

They will be using inflatable airbags to try to raise the wreckage to search for the remaining two crew members this morning.

I wonder why they just don't manually pop the floats and let it float to the surface by itself...probably a good technical reason why...I don't know.

Probably because the machine is spread over an area the size of a football field

Would the arming devices still be serviceable after prolonged submersion? Also you have no control over the lift at all, even if it works, I'd imagine it would pop up like a cork disturbing valuable evidence.

gulliBell

The reason that popping the floats won't work is that the aircraft is lying under 40 metres of water. The air pressure required to inflate a float at that depth is four times that at the surface, so the volume of gas required to just provide bouyancy at depth is four times greater that that required at the surface due to compression effects. The floats would burst on the way up in all likelyhood.

The standard method of recovery is to use open ended bags that are filled with just sufficient air to supply bouyancy. The volume of gas in the bags is adjusted by divers as the object is brought to the surface to strictly control the rate of ascent. An uncontrolled rise to the surface would be dangerous to personnel in the water, surface recovery vessels and risks further damaging or losing the object being recovered.

Bouyancy bags have been used for centuries as a way of recovering heavy valuable objects such as bronze cannon from the sea, so the methods are well understood even if they seem a bit low tech for the modern era of remotely controlled submarines.

Not sure they would inflate at that depth? (though I agree with your other points)

It's possible the bags went off as soon as the immersion switches were exposed to water if the system was armed. This is unlikely, but could explain spreading of the wreckage.

Assuming the bags are uninflated, the system is electrically actuated, and since it sounds like the circuit breaker panels in the cockpit are separated from the rest of the wreckage, the system would not function even if it was triggered.

The primary reason this wouldn't be entertained as a viable solution is because the floats are not designed to raise a broken airframe from under water, but are rather intended to keep an intact airframe (and it's occupants) safely on the surface. Raising anything from the bottom of the sea is a delicate and calculated exercise. Float bags are placed at key points to maintain the structure's orientation as it is raised, and are slowly inflated to control the rate of ascent. This prevents the structure from shifting and further disintegrating, which would risk losing important information that would aid the investigation, as well as making a big mess to clean up.

If we go full mythbusters on this idea, lets assume a perfectly good S92 is sitting in 40m of water with a fully functional emergency flotation system. The float bottles are serviced with a nitrogen and helium mix to around 2500PSIG. I don't know the exact number offhand, but I think the floats are around 5PSIG when fully inflated. So while the pressure at 40m is around 60psi, the bags might still inflate enough to raise the aircraft to the surface. Again, though, I think the weight of the QCA (rotorhead and MGB) would cause it to flip upside-down along the way.

Actually, the total pressure at 40m depth would make a 5psi at surface only fill the floats to 27%, making the lifting force only 27% of the 'on surface floating force'.
As we can be sure that the floats don't work now, and that that way of lifting stuff in water would be a bad idea, its only a theoretical discussion. Nevertheless, could be nice to know, cause the same fenomena applies also to inflatable floating jackets and so on( not exactly 27%, but the principle)

Actually the float bottles are filled with just nitrogen and the bags are inflated to 3.5 psi.

For those who are not involved in SAR - here's how the tasking process works for us:


In Canada, at JRCC Halifax, the radio-medical consultations are (or were when I was a RCAF SMC there) routed to a contracted civilian Doctor in the provincial health care system who takes what information may be gleaned, often through a language barrier, and makes a decision whether the injury is worthy of a helo extraction.


The SMC then contacts (frequently conference calls) a RCAF Flight Surgeon who either concurs with the decision or not. The idea being that, unlike the civilian Doc, the RCAF Doc understands the risks associated with a helo hoist extraction and can therefore make an educated risk assessment. If the RCAF Doc concurs that a helo extraction is warranted then the helo crew is fully briefed with all details of the injury and tasked with the mission.


With the knowledge of the level of injury, the aircraft commander and crew then assesses the weather, aircraft, crew, mission and threats; they make a yea/nea decision and either spin up and go or make a plan for when they can go in the future - when the weather/range to vessel or whatever has changed (risk level, essentially) enough to make mission success most likely.


Did we have what I considered unwarranted missions? Definitely.


Am I a Doctor? No.


I have, however, had my hands on the controls and my guys on a hoist in risk/return situations that I would describe as...asymmetric. Maybe we should be hoisting more doctors from boats at night in sea state 5, 180NM out! :p


To my knowledge our EMS/lifeflight crews are not briefed on the details of the injury until they make the weather call to accept the mission, but I'm sure there is a Canuck air ambulance guy out there who can confirm that.


We almost always send a fixed wing top cover platform out with the rescue bird to provide eyes on in case of an accident as well as a comms platform. We use Hercs here (for the moment) and they will commonly orbit and drop flares to try to give a horizon for hoisting. It works sometimes.


I find the idea of the SARTech/Flight Engineer (hoist operator) having a say in the go/no go decision interesting but I think it would only work when you're on top the vessel with the door open, hook in hand and they can see what they are getting into. Even then I don't think it would work as it's been my experience that those guys will jump into lava to rescue someone.

Yes, as described by survivors from the Australian SF Blackhawk accident who, escaping at some depth and pulling the life jacket inflation tabs, experienced the shock of finding nothing happened and they had to swim to the surface!