Ditching
Join Date: Sep 2010
Location: London
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I’m a long term lurker and, more recently, PPL student who’s never posted before as I’ve never really been able to contribute substantial content but this thread has driven me to put keyboard to ether. Whilst I’m at the bottom of the learning curve in planes I’ve spent many years mucking about in boats and teaching others to do so. I’ve also been actively involved in the sharp end of marine SAR for the last ten years or so.
In no particular order:
· I’ve no idea how many ditched aircraft float for any length of time or come to rest the right way up but liferafts are big and heavy. Yachts (and their safety regulators, where regulated) are moving to carrying them secured with hydrostatic releases on the open deck so that they are automatically released when submerged. I’d not want to have one between me and the door (in say a PA28) but equally I’d not want to be on the outside trying to get one out unless it was in the doorway – it would be even harder in a high wing plane where you’d inevitably be in the water. I can barely lift a six man offshore raft – especially out of an awkward space/locker.
· Getting into a raft from the water is a challenge and there is a knack to be learnt. After only 2 or 3 attempts even a fit adult may well be too tired to continue. Training is a must: using a sea survival pool such as the RNLI one in Poole with a wave machine running with meter plus waves is a real eye opener. Even the English channel is very rarely mill pond flat: expect your plane, even if firmly afloat, to have short wavelength half metre high waves washing along/over it at the very least – it’s a bonus if it doesn’t!
· Cold water shock kills. I once had a first aid instructor who was a winchman at Zeebrugge: he reported that most of the people who jumped from the ship into the water died from cold water shock almost immediately – he recovered none alive. As I understand it the sudden cold causes an increase in heart rate at the same time as vaso-constriction pushes peripheral and surface blood back to the core leading to a massive spike in blood pressure.
· Drysuits are great as protection against cold shock and at extending survival times in the water but, as someone who has spent a lot of time wearing them, they can, especially on a hot day, bring their own problems with heat exhaustion – and that’s before you consider peterh’s views on bodily functions in flight
(told you I’d been lurking). Unless you have full aircrew spec nomex ones they are about the last thing I’d want to be near a fire in. As others have said drysuits are only any use if you wear them done up – what proportion of your flight has a ditching risk rather than a risk of a ‘conventional’ forced landing with its fire risk?
· As others have pointed out it is essential you do all you can to initiate and reduce the duration search phase of SAR. I’d got as far as to say that once you’re committed to ditching Communicate becomes more important than Navigate (possibly even if you don’t know where you are) in the hierarchy and almost joint with Aviate. There’s no point in surviving a ditching offshore if no one is looking for you. It wasn’t so long ago that a Cornish fishing crew spent nearly 24h in a raft in sight of land before they were spotted. 406MHz EPIRBS are good, waterproof marine VHF’s are also a help as most modern lifeboats (even the larger inshore ones) can DF on VHF or 121.5 (which all EPIRBS put out for local homing). GPS based EPIRBS reduce the initial search area even further. Flares help in the final phase but only use if you think someone will see them – also think carefully before using them if you’re happily sat on a floating plane. Half a kilo of burning phosphorus wouldn’t my first choice of companion when sitting on/in 100LL. Smokes are best in daylight and might well be less of an ignition risk – bigger ones are designed to be thrown clear into the water and float free.
· If you’re in the water stay together. You’re a bigger search target (and you can help each other stay afloat) – an individual in the water is often invisible at 20m or less, especially if there is any sea running. Searches can take a LONG time, even when centred on a good datum such as a GPS EPIRB hit or floating wreckage. Don’t expend energy unnecessarily – hypothermia will set in faster.
· Don’t expect the cavalry to be there immediately if you’re offshore. Most lifeboats would be underway within ten minutes of the call but won’t steam at much more than 20-30kts. Helicopters are often on 20mins notice by day unless they’re already up and have sufficient fuel. At night you can be looking at 40mins notice for a helicopter, plus flying and search time. You might well be in/on the water for over an hour in the best case even in the narrower parts of the English channel.
· If you can ditch within sight of a boat that’s got to be the best option. I don’t think it makes any real difference what sort of boat: any well run boat (commercial or recreational) will have a practised plan for getting people out of the water. They will also be able to call for help with a confirmed position.
Well that’s possibly the longest first post ever… and is only my 2p’s worth, it certainly is not official advice from anyone!
Tom
In no particular order:
· I’ve no idea how many ditched aircraft float for any length of time or come to rest the right way up but liferafts are big and heavy. Yachts (and their safety regulators, where regulated) are moving to carrying them secured with hydrostatic releases on the open deck so that they are automatically released when submerged. I’d not want to have one between me and the door (in say a PA28) but equally I’d not want to be on the outside trying to get one out unless it was in the doorway – it would be even harder in a high wing plane where you’d inevitably be in the water. I can barely lift a six man offshore raft – especially out of an awkward space/locker.
· Getting into a raft from the water is a challenge and there is a knack to be learnt. After only 2 or 3 attempts even a fit adult may well be too tired to continue. Training is a must: using a sea survival pool such as the RNLI one in Poole with a wave machine running with meter plus waves is a real eye opener. Even the English channel is very rarely mill pond flat: expect your plane, even if firmly afloat, to have short wavelength half metre high waves washing along/over it at the very least – it’s a bonus if it doesn’t!
· Cold water shock kills. I once had a first aid instructor who was a winchman at Zeebrugge: he reported that most of the people who jumped from the ship into the water died from cold water shock almost immediately – he recovered none alive. As I understand it the sudden cold causes an increase in heart rate at the same time as vaso-constriction pushes peripheral and surface blood back to the core leading to a massive spike in blood pressure.
· Drysuits are great as protection against cold shock and at extending survival times in the water but, as someone who has spent a lot of time wearing them, they can, especially on a hot day, bring their own problems with heat exhaustion – and that’s before you consider peterh’s views on bodily functions in flight
(told you I’d been lurking). Unless you have full aircrew spec nomex ones they are about the last thing I’d want to be near a fire in. As others have said drysuits are only any use if you wear them done up – what proportion of your flight has a ditching risk rather than a risk of a ‘conventional’ forced landing with its fire risk?· As others have pointed out it is essential you do all you can to initiate and reduce the duration search phase of SAR. I’d got as far as to say that once you’re committed to ditching Communicate becomes more important than Navigate (possibly even if you don’t know where you are) in the hierarchy and almost joint with Aviate. There’s no point in surviving a ditching offshore if no one is looking for you. It wasn’t so long ago that a Cornish fishing crew spent nearly 24h in a raft in sight of land before they were spotted. 406MHz EPIRBS are good, waterproof marine VHF’s are also a help as most modern lifeboats (even the larger inshore ones) can DF on VHF or 121.5 (which all EPIRBS put out for local homing). GPS based EPIRBS reduce the initial search area even further. Flares help in the final phase but only use if you think someone will see them – also think carefully before using them if you’re happily sat on a floating plane. Half a kilo of burning phosphorus wouldn’t my first choice of companion when sitting on/in 100LL. Smokes are best in daylight and might well be less of an ignition risk – bigger ones are designed to be thrown clear into the water and float free.
· If you’re in the water stay together. You’re a bigger search target (and you can help each other stay afloat) – an individual in the water is often invisible at 20m or less, especially if there is any sea running. Searches can take a LONG time, even when centred on a good datum such as a GPS EPIRB hit or floating wreckage. Don’t expend energy unnecessarily – hypothermia will set in faster.
· Don’t expect the cavalry to be there immediately if you’re offshore. Most lifeboats would be underway within ten minutes of the call but won’t steam at much more than 20-30kts. Helicopters are often on 20mins notice by day unless they’re already up and have sufficient fuel. At night you can be looking at 40mins notice for a helicopter, plus flying and search time. You might well be in/on the water for over an hour in the best case even in the narrower parts of the English channel.
· If you can ditch within sight of a boat that’s got to be the best option. I don’t think it makes any real difference what sort of boat: any well run boat (commercial or recreational) will have a practised plan for getting people out of the water. They will also be able to call for help with a confirmed position.
Well that’s possibly the longest first post ever… and is only my 2p’s worth, it certainly is not official advice from anyone!
Tom
Join Date: Jul 2010
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They said NO because the gas comes out of the cylinder very cold and makes the rubber brittle.
Join Date: Dec 1999
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my theory is that the less fuel you have, the longer you'll float (thanks to the fuel tanks being full of air)
Join Date: Dec 2011
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Does this mean that the liferaft is a use-once-only item and that once inflated using the gas cylender must be thrown away?
Though hopefully that is not WHY you are floating around in the sea!
I think most ditchings are caused by running out of fuel. Especially on the Jersey runs which people tend to do with nearly empty tanks so they get the biggest benefit of the cheaper fuel
They just neglect the fact that if they left the UK with full tanks and claimed the duty drawback, they would make a similar saving and have a much safer trip and would in most cases avoid a pointless stop in Jersey which is just unnecessary hassle.
