Ditching a helicopter: (incl pictures)
I did the Royal Navy dunker course at HMS Dolphin (as a civvy travelling out to Grey Funnel Line ships) many years ago and I can heartily concur with Thomas Coupling - it is an experience which you will never forget. Four dunks, last in the dark with darkened visors down: wait until you're upside down (less chance of the 'fish bait' scenario, Paulo) then exit through a defined exit in a set order. Scary. Having 'died' twice, I'm none too happy about helos over water ever since (not good for a North Sea wannabe!! 
)
But, it has focussed my mind on getting out of anything in an emergency. All these years later, whenever I get in an aircraft (airliner or light aircraft) I make damn sure I know how to get off it again in a hurry, operate emergency exits, etc. Some years after the dunk, I got on an airliner with a colleague who'd been on the same course as me. Just after we'd sat down I asked him where the nearest emergency exit was. Without looking or hesitation he pointed over his shoulder at it saying: "there and I'm going that way". He, like me, had automatically, nearly subconsciously, looked as soon as we'd found our seats. The training worked.
)But, it has focussed my mind on getting out of anything in an emergency. All these years later, whenever I get in an aircraft (airliner or light aircraft) I make damn sure I know how to get off it again in a hurry, operate emergency exits, etc. Some years after the dunk, I got on an airliner with a colleague who'd been on the same course as me. Just after we'd sat down I asked him where the nearest emergency exit was. Without looking or hesitation he pointed over his shoulder at it saying: "there and I'm going that way". He, like me, had automatically, nearly subconsciously, looked as soon as we'd found our seats. The training worked.
It's not just an adventure....
it's just a job!
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Chopper Dr:
If you deploy the floats on a 212 in flight, you are in for a very big suprise!
Furthermore, if you are doing an auto in a 212, you probably have your hands full so to take your hand of the collective and reach over and pull the lever it may be a little distracting. This system is designed for a water contact deployment, hence the water sensors.
Cheers
Offshore Igor
If you deploy the floats on a 212 in flight, you are in for a very big suprise!
Furthermore, if you are doing an auto in a 212, you probably have your hands full so to take your hand of the collective and reach over and pull the lever it may be a little distracting. This system is designed for a water contact deployment, hence the water sensors.
Cheers
Offshore Igor
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The lateral roll on entering the water
There have been a number of posts talking about whether or not the gearbox will come forward with blade impact. This same topic came up on a news group a while back, particularly in relation to Robinsons. This was especially pertinent because the flight manual says roll left while the various mathmatical types on the NG suggested this would force the gear box forward into the cabin.
I wrote to Robinson for clarification and one of their engineers wrote back and said that there was no likelihood of the MR Gbx coming forward as the blades were shown to disintegrate first. The roll to the left was to make sure the pilots door was uppermost to make egress easier.
I wrote to Robinson for clarification and one of their engineers wrote back and said that there was no likelihood of the MR Gbx coming forward as the blades were shown to disintegrate first. The roll to the left was to make sure the pilots door was uppermost to make egress easier.
Robborider,
Having rolled over in an R22 on land, to the left, I can heartily endorse the Robinson advice - the rotor blades will disintegrate/distort on initial impact leaving you in a broken but substantially intact helicopter.
Having rolled over in an R22 on land, to the left, I can heartily endorse the Robinson advice - the rotor blades will disintegrate/distort on initial impact leaving you in a broken but substantially intact helicopter.
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Ditching - which way to roll?
If you have to ditch a helicopter and have a choice of rolling it right or left, which side should you chose?
I've heard some say rolling to the left to reduce the chances of the retreating blade entering the cabin (with a counter clockwise rotor). Is this true, and if so, does the benefit from that outweigh the problem that would cause when you're flying from the left seat?
Thanks for your comments
I've heard some say rolling to the left to reduce the chances of the retreating blade entering the cabin (with a counter clockwise rotor). Is this true, and if so, does the benefit from that outweigh the problem that would cause when you're flying from the left seat?
Thanks for your comments
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I think it would really depend on your helicopter, and who your passengers are. I know in the robbies that the blades would certainly not survive their contact with the water no matter which side you put them in, and that it is easier for the pilot to get out if you roll left. But if there is someone you care about in the left seat you'll probably want to roll right, as you likely have much more exp./familiarity with the helicopter. just my 2 cents.
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Here's another angle to it. Before ditching should you undo your seatbelts? High time pilots confident with their autorotation skills might undo seat belts before, knowing they can put her down gently and so not have to undo seatbelts under water which I'm told is not as easy as one would imagine. I've heard stories of people completely unable to get their seatbelts open under water. On the other hand if you make a mess of it and go in heavy, you'll probably wish you had your seatbelt on. My own opinion is keep them on, and after surviving touchdown pray you have the presence of mind to get yours and your passenger's (should he/she need help) undone. My instructor however seems to prefer the first method. Obviously has more confidence in his autorotational ability than I do in mine. 
Any ideas?
Irlandés
Any ideas?
Irlandés
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I'm with Nick on this one. Why roll if you don't have to? I plan on my floats keeping me dry, should worse come to worst. You do have floats on your ship while flying over the ocean, don't you?
Unfastening the seatbelt isn't that hard, & you should have plenty of time to get them undone, if you do the auto correctly. I've gone through the 'dunker' training, & if you stay calm, it really isn't that bad. Easy to say, probably harder to do.
Unfastening the seatbelt isn't that hard, & you should have plenty of time to get them undone, if you do the auto correctly. I've gone through the 'dunker' training, & if you stay calm, it really isn't that bad. Easy to say, probably harder to do.
ditching
A few points to consider from way back ;
use all of the collective on "landing", for control and it also gets rid of the rotor energy as you ditch,
the tail-rotor might break,so you will lose yaw control and might roll either way,even if pre-planned,
the doors may provide some rigidity to the fuselage ,so,it may not be a good idea to open them too early.They will also prevent water coming in and may provide a bit of buoyancy time.
keep the as/c as level as you can as blades striking the water can turn the a/c over,before they break.
having briefed the pax. prior to flight-Do not release your harness until the a/c has settled,you may end up upside down or get flung around and unconscious/injured,
release your harness as the water fills the cockpit/cabin to your chest BUT dont let go of the strap on the out-board side,as it provides you with an orientation point/reference,as you will lose all sense of orientation ,if the a/c turns over.Release doors/em.exits,take a deep breath at the same time and grab a door-frame to pull yourself out-let go if you are free;if not try another route-if you release your harness too early you will float up,whichever way that is!I know as I`ve done it in the Dunker-from the cockpit ,under the pilot`s`seat and out thru` the cabin!
;;Want to try it at night??
use all of the collective on "landing", for control and it also gets rid of the rotor energy as you ditch,
the tail-rotor might break,so you will lose yaw control and might roll either way,even if pre-planned,
the doors may provide some rigidity to the fuselage ,so,it may not be a good idea to open them too early.They will also prevent water coming in and may provide a bit of buoyancy time.
keep the as/c as level as you can as blades striking the water can turn the a/c over,before they break.
having briefed the pax. prior to flight-Do not release your harness until the a/c has settled,you may end up upside down or get flung around and unconscious/injured,
release your harness as the water fills the cockpit/cabin to your chest BUT dont let go of the strap on the out-board side,as it provides you with an orientation point/reference,as you will lose all sense of orientation ,if the a/c turns over.Release doors/em.exits,take a deep breath at the same time and grab a door-frame to pull yourself out-let go if you are free;if not try another route-if you release your harness too early you will float up,whichever way that is!I know as I`ve done it in the Dunker-from the cockpit ,under the pilot`s`seat and out thru` the cabin!
;;Want to try it at night??
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ditching and various sub-topics
A couple of comments about some of the posts:
The question of which way to roll (or not) arises fairly regularly on rec.aviation.rotorcraft and as a result of varying opinions I contacted robinson helicopter company and got the lowdown on their opinion.
I can't speak with any knowledge on other types though.
The theory of some maths whiz pilots was you should impact the blade so the forces would transmit to the MR gearbox and dislodge it backwards, not forwards into the cabin. This would mean a right roll (in counter clockwise turning blades). Some others said "no, the impact needed to be on the left side after a left roll". The maths was a bit over my head when they started getting so contradictory.
Robinson's answer was. "We have tested the theory and none of it applies. Robinson blades bend up and distort or break and the MR gearboxes never dislodged." So they maintain the roll to the left as dictated in their handbook is purely to provide easier exit for the pilot as the aircraft submerges.
I guess if you have a passenger then which way to roll is dependant on whether you think they they will find it easier to get out than you will.
I suspect that some other types of helicopter with beefier blades may have more strict guidelines on rolling to avoid MR gearbox dislodgment.
Floats:
It would be nice to think that the situation would never arise where you would be over water without floats. But reality is there are planty of times where the only place you can land may be wet. A lake, creek or river in a heavily tree covered area, tracking along the coast and have to turn back into the wind and suddenly find your glide distance is a few metres short of the beach etc. In Oz is quite legal for private ops to be over water and out of auto distance provided you have lifejackets on.
Seatbelts:
On one of my many dunker courses we were shown a video with footage and interviews with people who had been in ditchings and their comments were interesting.
Firstly seatbelts. One guy undid his first for the same sort of arguments put forward above. When he touched down with what he thought was a zero speed auto he was slammed into the dash as the real zero speed was reached very rapidly. He was hurt but not enough to stop him getting out. His comment was that your perception is distorted because you are just so busy and stressed. He said he would never undo his belt again till everything stopped in the water.
Water entry and time to get orientated.
Two separate pilots told of how the cabin instantaneously filled with froth. Not a second to get organised and it was completely disorientating because all those suggested things like seeing which way the bubbles rise or things float was no help at all. In full daylight and "clear water" theywere completely blinded by bubbles. Sounds like you need to treat every ditching as the equivalent of a night ditching.
The average time I heard quoted at each course I did was less than 10 seconds from engine problem to swimming clear of the aircraft. Doesn't leave any time for much at all.
My advice 9 for what its worth) is do as many dunker courses as you can. Besides they are great fun.
The question of which way to roll (or not) arises fairly regularly on rec.aviation.rotorcraft and as a result of varying opinions I contacted robinson helicopter company and got the lowdown on their opinion.
I can't speak with any knowledge on other types though.
The theory of some maths whiz pilots was you should impact the blade so the forces would transmit to the MR gearbox and dislodge it backwards, not forwards into the cabin. This would mean a right roll (in counter clockwise turning blades). Some others said "no, the impact needed to be on the left side after a left roll". The maths was a bit over my head when they started getting so contradictory.
Robinson's answer was. "We have tested the theory and none of it applies. Robinson blades bend up and distort or break and the MR gearboxes never dislodged." So they maintain the roll to the left as dictated in their handbook is purely to provide easier exit for the pilot as the aircraft submerges.
I guess if you have a passenger then which way to roll is dependant on whether you think they they will find it easier to get out than you will.
I suspect that some other types of helicopter with beefier blades may have more strict guidelines on rolling to avoid MR gearbox dislodgment.
Floats:
It would be nice to think that the situation would never arise where you would be over water without floats. But reality is there are planty of times where the only place you can land may be wet. A lake, creek or river in a heavily tree covered area, tracking along the coast and have to turn back into the wind and suddenly find your glide distance is a few metres short of the beach etc. In Oz is quite legal for private ops to be over water and out of auto distance provided you have lifejackets on.
Seatbelts:
On one of my many dunker courses we were shown a video with footage and interviews with people who had been in ditchings and their comments were interesting.
Firstly seatbelts. One guy undid his first for the same sort of arguments put forward above. When he touched down with what he thought was a zero speed auto he was slammed into the dash as the real zero speed was reached very rapidly. He was hurt but not enough to stop him getting out. His comment was that your perception is distorted because you are just so busy and stressed. He said he would never undo his belt again till everything stopped in the water.
Water entry and time to get orientated.
Two separate pilots told of how the cabin instantaneously filled with froth. Not a second to get organised and it was completely disorientating because all those suggested things like seeing which way the bubbles rise or things float was no help at all. In full daylight and "clear water" theywere completely blinded by bubbles. Sounds like you need to treat every ditching as the equivalent of a night ditching.
The average time I heard quoted at each course I did was less than 10 seconds from engine problem to swimming clear of the aircraft. Doesn't leave any time for much at all.
My advice 9 for what its worth) is do as many dunker courses as you can. Besides they are great fun.
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Seatbelts...
If there is a chance of the aircraft rolling over, undoing your seatbelt prior to entering the water is not advisable. When the aircraft rolls inverted or part thereof, being strapped into your seat provides you with a great orientation/reference point in which to find the appropriate exit point (The window/door that was on your right will still be on your right while upside down) As a HUET instructor so many people try to get out the 'other side' when put upside down, so my advice is not to undo the seatbelt/harness.
If there is a chance of the aircraft rolling over, undoing your seatbelt prior to entering the water is not advisable. When the aircraft rolls inverted or part thereof, being strapped into your seat provides you with a great orientation/reference point in which to find the appropriate exit point (The window/door that was on your right will still be on your right while upside down) As a HUET instructor so many people try to get out the 'other side' when put upside down, so my advice is not to undo the seatbelt/harness.
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This is a great thread, like so many on pprune!
A comment on the question of transmission coming unglued - This is a weakness of some designs, but not a pervasive helicopter problem. Most helos keep the gearbox in place when blades contact objects and break off. The exception seems to be the 2 bladed Huey family, whose transmission does unseat when blade strikes occur.
I strongly suggest that a roll will help disorient the occupants, and also make blade-water contact occur at higher rpm (more energy, more damage). Keep the aircraft level as long as possible, pull off the rpm with collective and settle in. Do not release belts until aircraft motion had stopped, a slight head injury makes you an unconscious sinker, not a conscious swimmer.
On the way down before water landing, spot the belts, and even lay your hands on the release. This muscle memory trick is important for performing the act while shockingly cold, blind, underwater and scared. If you rotate the aircraft during water settling, the sharp roll and even upside down aircraft are very disorienting, up is hard to identify, and you are much more likely to go down with your ship.
A comment on the question of transmission coming unglued - This is a weakness of some designs, but not a pervasive helicopter problem. Most helos keep the gearbox in place when blades contact objects and break off. The exception seems to be the 2 bladed Huey family, whose transmission does unseat when blade strikes occur.
I strongly suggest that a roll will help disorient the occupants, and also make blade-water contact occur at higher rpm (more energy, more damage). Keep the aircraft level as long as possible, pull off the rpm with collective and settle in. Do not release belts until aircraft motion had stopped, a slight head injury makes you an unconscious sinker, not a conscious swimmer.
On the way down before water landing, spot the belts, and even lay your hands on the release. This muscle memory trick is important for performing the act while shockingly cold, blind, underwater and scared. If you rotate the aircraft during water settling, the sharp roll and even upside down aircraft are very disorienting, up is hard to identify, and you are much more likely to go down with your ship.
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Nav procedures would be to maintain the aircraft upright and allow to settle, I wouldn't roll IMO.
Belts release is after all motion has stopped. Certainly after water contact.
As for those familiar with ditching, I already have a point of referance selected for exiting (not to hard in a robbie, but one could have several for a CH-53E).
Anyone else use HEEDS? If I'm going over long patches I take mine with me.
[Edited: Thomas has a point, I've been trained. You would need to know how to use one. While I do not believe in the ditch situation that you will get the bends from ascending too fast with HEEDS, not enough time for nitrogen to build (I'm a diver as well) but if you didn't exhale during ascent, he is correct, you could damage yourself, etc.]
I know similar units are available in most diving shops, not too expensive either. If one were faced with a real situation, the ability to breathe for 5-6 minutes after going in can make a real difference in how you react.
I'd also advise if anyone has the ability to attend a class whch includes a dunker, to do so, darn, I remember my 9D5 rides, fun, but a good learning experience.
[Edited: USN requires a dunker ride every 4 years, don't know if that has changed since I left.]
Belts release is after all motion has stopped. Certainly after water contact.
As for those familiar with ditching, I already have a point of referance selected for exiting (not to hard in a robbie, but one could have several for a CH-53E).
Anyone else use HEEDS? If I'm going over long patches I take mine with me.
[Edited: Thomas has a point, I've been trained. You would need to know how to use one. While I do not believe in the ditch situation that you will get the bends from ascending too fast with HEEDS, not enough time for nitrogen to build (I'm a diver as well) but if you didn't exhale during ascent, he is correct, you could damage yourself, etc.]
I know similar units are available in most diving shops, not too expensive either. If one were faced with a real situation, the ability to breathe for 5-6 minutes after going in can make a real difference in how you react.
I'd also advise if anyone has the ability to attend a class whch includes a dunker, to do so, darn, I remember my 9D5 rides, fun, but a good learning experience.
[Edited: USN requires a dunker ride every 4 years, don't know if that has changed since I left.]
Last edited by RW-1; 21st Aug 2002 at 19:23.
Concur with most of the above:
Seat belts: definitely keep locked.
Disorientation hand remains on QRB, and (if pax) other hand on escape handle(door handle) - DONT LET GO until all motion has ceased.
DO NOT inflate Mae West inside cockpit!
Most light twins (2-3 tonnes) are estimated to sink at 8'/second
Most roll over (due to high C of G) and rotate through the fore/aft plane (i.e. nose dive)
Dunker is the most valuable form of insurance and should be repeated often (2-3 yearly?).
DONT buy STASS or HEEDS from your corner shop and stick it in your pocket while flying over water!!! You MUST do a training course for this as it is compressed gas at depth. Use it without training and pulmunary embolisms will get you if drowning doesn't
If you think sea floats will keep you upright in anything other than mill pond conditions...think again
Autorotating into water with the engine(s) off will almost certainly take your TR out, unless of course you flare too early
A powered approach to the hover then settling vertically into the water just after the swell is the aim...and that requires precision
Seat belts: definitely keep locked.
Disorientation hand remains on QRB, and (if pax) other hand on escape handle(door handle) - DONT LET GO until all motion has ceased.
DO NOT inflate Mae West inside cockpit!
Most light twins (2-3 tonnes) are estimated to sink at 8'/second
Most roll over (due to high C of G) and rotate through the fore/aft plane (i.e. nose dive)Dunker is the most valuable form of insurance and should be repeated often (2-3 yearly?).
DONT buy STASS or HEEDS from your corner shop and stick it in your pocket while flying over water!!! You MUST do a training course for this as it is compressed gas at depth. Use it without training and pulmunary embolisms will get you if drowning doesn't
If you think sea floats will keep you upright in anything other than mill pond conditions...think again
Autorotating into water with the engine(s) off will almost certainly take your TR out, unless of course you flare too early
A powered approach to the hover then settling vertically into the water just after the swell is the aim...and that requires precision
I've never ditched, but the accepted teaching when I learned to fly rotary was to get the rear doors open, then to zero-speed into the water, hold it upright as long as possible, and then if there was a choice, roll it so that the advancing blade would hit the water, supposedly reducing the likelihood of the transmission ripping off its mounts and taking out the passengers strapped onto the centre rear cabin wall (this was in B204/205s).
Sounded fair to me at the time.
Sounded fair to me at the time.
Guys
I always have a spare air system attached to my life jacket, it gives you about 2 mins of air for about £200. Having experienced cold water sudden emersion and having seen test results you are unlikely to hold your breath for more than 20 seconds !!
I am always shocked at the number of people who cross water with no life jackets or emersion suits, I have even heard emersion suits are too expensive ! and this from someone flying a new squirrel - what price your life ? Shame to auto in and get out and the drown waiting to be picked up !
I always have a spare air system attached to my life jacket, it gives you about 2 mins of air for about £200. Having experienced cold water sudden emersion and having seen test results you are unlikely to hold your breath for more than 20 seconds !!
I am always shocked at the number of people who cross water with no life jackets or emersion suits, I have even heard emersion suits are too expensive ! and this from someone flying a new squirrel - what price your life ? Shame to auto in and get out and the drown waiting to be picked up !
Avoid imitations
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All good stuff; the only further advice I can give is
1) Do underwater escape training as often as possible. Even once is very worth while because it can quickly dispel some pre-conceived ideas of what to expect! Many people say afterwards they would probably have panicked in the real situation, having experienced being upside down under water in the trainer's controlled conditions.
2) Preferably ditch on land. If not, always ditch near a lifeboat.
1) Do underwater escape training as often as possible. Even once is very worth while because it can quickly dispel some pre-conceived ideas of what to expect! Many people say afterwards they would probably have panicked in the real situation, having experienced being upside down under water in the trainer's controlled conditions.
2) Preferably ditch on land. If not, always ditch near a lifeboat.