Water Ditching
It depends on how quickly you breathe
The Dunker staff said they have seen one emptied in 20 seconds! The cold water shock will tend to make you hyperventilate and adrenaline will have everything in your body running pretty quickly anyway. In a controlled, benign environment the bottles can last for several minutes.
The Dunker staff said they have seen one emptied in 20 seconds! The cold water shock will tend to make you hyperventilate and adrenaline will have everything in your body running pretty quickly anyway. In a controlled, benign environment the bottles can last for several minutes.
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My company teaches ambulance paramedics, aircrewmen, pilots and police officers HUET for their operational circumstances. With paramedics and aircrewmen the final exit has them at the critical stage of bringing a stretcher into the cabin, on wander-leads stretcher halfway in, and then we initiate the ditch. The results are varied: saved patient, left patient, needed saving by diver – we give the trainee the option as to whether they want to try and save the patient.
Before leaving us, all trainees are advised that the most important part of any ditching, real or training, is to GET OUT. If you hang around to assist, you will either become disorientated, or impeded someone else making egress. As for re-entering, we strongly advise against it.
Before leaving us, all trainees are advised that the most important part of any ditching, real or training, is to GET OUT. If you hang around to assist, you will either become disorientated, or impeded someone else making egress. As for re-entering, we strongly advise against it.
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From FH1100
In my case, the internal part of my Bell 212 Rotor Brake Input Quill detached inside the Main Transmission 65 Nm from anywhere dry!.
The Chip light did not stay on constantly probably because the loose ball & roller bearings were probably too heavy to be held by the magnets but the noise of these bearings being "mashed" between various trannie teeth suggested to me that ditching might be a sensible option.
In descent it was necessary to maintain power to keep the disintegrating transmission turning. Passengers were warned and floats armed.
On water entry (6 - 8 foot swell) the floats inflated and the aircraft settled in a level attitude maintained with cyclic. On slowly retarding the throttles, the blades came to a fairly rapid stop without rotor brake application due to now completely f
d Main Transmission.
Exit windows and pilot door were jettisoned and liferaft launched. All pax climbed into raft (which we kept attached to the floating helicopter for ease of visual identification by rescuers although we were prepared to cut away at any sign of helicopter sinking)) I made a further Mayday call on 121.5 using the upper VHF Aerial relayed by a overflying plank then joined pax in raft where we spent a jolly 2 hours smoking, telling sea stories and awaiting rescue. I helped recover the still floating Helicopter with the assistance of a crane equipped supply vessel. We carried out a thorough fresh water wash of the machine on the supply vessel deck and less than a month later the helicopter was returned to service.
A happy ending
It's all a pretty silly exercise, really. Why on earth would anyone intentionally ditch a helicopter under power? Perhaps you can, but I cannot think of a reason...any reason.
The Chip light did not stay on constantly probably because the loose ball & roller bearings were probably too heavy to be held by the magnets but the noise of these bearings being "mashed" between various trannie teeth suggested to me that ditching might be a sensible option.
In descent it was necessary to maintain power to keep the disintegrating transmission turning. Passengers were warned and floats armed.
On water entry (6 - 8 foot swell) the floats inflated and the aircraft settled in a level attitude maintained with cyclic. On slowly retarding the throttles, the blades came to a fairly rapid stop without rotor brake application due to now completely f
d Main Transmission.Exit windows and pilot door were jettisoned and liferaft launched. All pax climbed into raft (which we kept attached to the floating helicopter for ease of visual identification by rescuers although we were prepared to cut away at any sign of helicopter sinking)) I made a further Mayday call on 121.5 using the upper VHF Aerial relayed by a overflying plank then joined pax in raft where we spent a jolly 2 hours smoking, telling sea stories and awaiting rescue. I helped recover the still floating Helicopter with the assistance of a crane equipped supply vessel. We carried out a thorough fresh water wash of the machine on the supply vessel deck and less than a month later the helicopter was returned to service.
A happy ending
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Helicopter ditching - information only
Not the most pleasant subject and there has been no incident yet before people start worrying!
I am looking for information on the ditching characteristics of a helicopter depending on whether you have one/two or no cabin doors open. The present policy where I work is for the crewman to open one cabin door when carrying out deck landings. Personally I would not want any doors open such that in the event of a controlled ditching perhaps due to engine failure the in rush of water from one side will cause massive disorientation to the guy(s) in the back and cause the aircraft to capsize.
I can understand if 2 doors are open then this is less likely as the in rush of water will occur from both sides simultaneously so reduced chance of capsize.
If both doors are closed, there is less likely to be a capsize and the occupants can escape through the emergency windows.
Any thoughts/comments welcome.
I am looking for information on the ditching characteristics of a helicopter depending on whether you have one/two or no cabin doors open. The present policy where I work is for the crewman to open one cabin door when carrying out deck landings. Personally I would not want any doors open such that in the event of a controlled ditching perhaps due to engine failure the in rush of water from one side will cause massive disorientation to the guy(s) in the back and cause the aircraft to capsize.
I can understand if 2 doors are open then this is less likely as the in rush of water will occur from both sides simultaneously so reduced chance of capsize.
If both doors are closed, there is less likely to be a capsize and the occupants can escape through the emergency windows.
Any thoughts/comments welcome.
The thing will capsize anyway unless you have floats. Therefore you want it to fill with water as fast as possible because it is almost impossible to get out with the water rushing....
Open all the doors and/or windows is my philosophy... And I just did my Huet renewal training a month ago....
Open all the doors and/or windows is my philosophy... And I just did my Huet renewal training a month ago....
Sorry Gordy, would have to disagree whole heartedly with you on this one.
Even little helo's with no flot bags on them - if they ditch; those precious few moments of air trapped inside the cockpit could just be enough to give the occupants time to re-orientate themselves after impact (provided it is a controlled landing) and egress the cab.
Leaving doors/large windows open would speed the capsize process up and also massively disorientate someone who is getting tons of water in their face.
Even after capsizing, some cabs have been known to stay afloat because of the trapped ai pockets. These provide support to the survivors while awaiting rescue.
Open panels would exacerbate this.
Even little helo's with no flot bags on them - if they ditch; those precious few moments of air trapped inside the cockpit could just be enough to give the occupants time to re-orientate themselves after impact (provided it is a controlled landing) and egress the cab.
Leaving doors/large windows open would speed the capsize process up and also massively disorientate someone who is getting tons of water in their face.
Even after capsizing, some cabs have been known to stay afloat because of the trapped ai pockets. These provide support to the survivors while awaiting rescue.
Open panels would exacerbate this.
Last edited by Thomas coupling; 9th May 2013 at 13:08.
and egress the cab
time to re-orientate themselves after impact
I thought you are supposed to help turn it over to stop things! Just like the HUET machine does.
No floats and power off of course.
Even little helo's with no flot bags on them - if they ditch; those precious few moments of air trapped inside the cockpit could just be enough to give the occupants time to re-orientate themselves after impact (provided it is a controlled landing) and egress the cab.
Leaving doors/large windows open would speed the capsize process up and also massively disorientate someone who is getting tons of water in their face.
Leaving doors/large windows open would speed the capsize process up and also massively disorientate someone who is getting tons of water in their face.
The method they found worked best involved opening the door as soon as possible so there was no build up in differential pressure to fight against.
In a helicopter ditching/crash there's also the problem of the airframe warping to consider which may actually prevent you opening the door post impact.
Taking all that into account, and having heard from people who have ditched, I'd rather have nothing between me and the outside world pre-impact than hope there might be a handy air pocket I could spend my last few minutes in.
Bing - you have obviously not done any HUET have you?
Ever heard of jettisonable doors?
Hoping for an air pocket as you sink rapidly Vs guaranteeing an air pocket while you think about what you are going to do next.....hmmmmmm
Go do a HUET and come chat again.
RVDT: None of the dozen or so HEUT courses I've done have taught the pilot to purposely roll the cab over...where do you do your training?
The ones I used taught: ditch / flot bags (if fitted) / shut rotors down / jettison doors / disorientation arms / egress.
["Walking all over you" suggests you are used to a troop carrier/lots of pax. I am talking about GA light helo and or 2+ pax.
Ever heard of jettisonable doors?
Hoping for an air pocket as you sink rapidly Vs guaranteeing an air pocket while you think about what you are going to do next.....hmmmmmm
Go do a HUET and come chat again.
RVDT: None of the dozen or so HEUT courses I've done have taught the pilot to purposely roll the cab over...where do you do your training?
The ones I used taught: ditch / flot bags (if fitted) / shut rotors down / jettison doors / disorientation arms / egress.
["Walking all over you" suggests you are used to a troop carrier/lots of pax. I am talking about GA light helo and or 2+ pax.
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Water Bird
Having taught on the water bird in the USN, the one thing that always struck you was how far the a/c sank into the water on landing and thus how close to the swell the rotors were, even in a sponson fitted SH3-D. I would suggest in many cases, therefore, you are not in control of your destiny re which way you roll unless you have a very slight sea state and the gearbox is still lubricated!
The other weird part was due to tail rotor thrust the a/c will not taxy in a straight line on the water..
The other weird part was due to tail rotor thrust the a/c will not taxy in a straight line on the water..
Can't imagine why anyone would want to purposely roll the helicopter onto its side to stop the blades .... I would want to stay upright for as long as possible to reduce the inertia before the blades hit !! Would you try to use rotor brake as soon as you touch down ??
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Definitely keep off the rotor brake! Will speed up the roll over - use some pitch if you really have the time to control the blades. So many variables - flots/no flots, gearbox (s) still running OK, seastate, etc
Abso-bloody-lutely no 
Not unless you want to turn turtle, of course..... ! Rule one after a successful ditching, don't use the rotorbrake as it will impart as much torque back through the trannie and try to turn the fuselage as much as stop the rotors.
sbdorset, I must confess that water taxiing the S61 didn't seem as much as a problem in a straight line: but using the brakes when turning never seemed to have very much effect
Not unless you want to turn turtle, of course..... ! Rule one after a successful ditching, don't use the rotorbrake as it will impart as much torque back through the trannie and try to turn the fuselage as much as stop the rotors.
sbdorset, I must confess that water taxiing the S61 didn't seem as much as a problem in a straight line: but using the brakes when turning never seemed to have very much effect
Bing - you have obviously not done any HUET have you?
Ever heard of jettisonable doors?
Ever heard of jettisonable doors?
Hoping for an air pocket as you sink rapidly Vs guaranteeing an air pocket while you think about what you are going to do next.....hmmmmmm
None of the dozen or so HEUT courses I've done have taught the pilot to purposely roll the cab over...where do you do your training?
Yes I have jettisonable doors.
Read a few Bell flight manuals. A few military flight manuals................
All have the same instructions.
And from the US Army who have no doubt done it more than most.
HOW TO CRASH A HELICOPTER
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Bing
There was a fatal accident with a Bell 212 in the Maldives some years ago where one causal factor was (it is believed) the co-pilot jettisoning a door early and it took out the tail rotor.
There is some merit to opening a door prior to a 'controlled' or 'anticipated' ditching but not jettisoning it unless in a controlled hover.
Yes and yes, and I've seen plenty of accident reports where the doors were jammed in position post impact. The jettison isn't a magic cure all so if I had the option I'd want to jettison the door before hitting the water.
There is some merit to opening a door prior to a 'controlled' or 'anticipated' ditching but not jettisoning it unless in a controlled hover.
That's a good point, although I'd like the door gone before ditching that's obviously only really practicable in a power on ditching when you know it's going to fall clear from a hover. In a power off ditching I doubt I'd have the capacity to switch hands on the cyclic, jettison the door and then change back again while auto-rotating anyway! In that case it's the first thing I'm getting rid of once all violent motion has ceased.
Youtube clip of Richard Hammond trying to get out of a car, the first time waiting for the pressure to equalise the second without. Not directly transferable to helicopters but food for thought non the less.
Youtube clip of Richard Hammond trying to get out of a car, the first time waiting for the pressure to equalise the second without. Not directly transferable to helicopters but food for thought non the less.
Last edited by Bing; 10th May 2013 at 16:42.
Not directly transferable to helicopters but food for thought non the less.
RVDT: I've done HUET all my military and all my civilian flying life. Each year in fact of the 30 yrs of flying. Secondly, I taught as a Waterbird Instructor in Canada. In all, I have probably 'impacted the water' in a helo about 150-200 times.
If I may be permitted therefore...I may know a little about the subject matter.
As 'bing' stated, here is the real "food for thought":
Provided you are entering the water in a controlled fashion (and upright):
Attempt to rotate to the level attitude after the flare and immediately prior to touchdown. This gives you the greatest chance of remaining 'intact' (keeping the TR away from the water.
DO NOT jettison panels prior to landing. A controlled landing 'normally' results in preventing the frame around the jettisonable door from 'jamming'. It can occur, but very rarely (and Bing you haven't seen "plenty" of accident reports where the cab has come down 'safely' where the door misaligns due to hard impact damage - it's only common in uncontrollable landings - you've probably read the odd couple
). Jettison immediately after landing and only if you believe you are sinking.Never shut the rotors down using the rotor brake for all the reasons previously mentioned. Bring the throttle(s) back slowly.
Rolling a cab over intentionally is inviting trouble:
With some helos, if the advancing blade tip strikes first, the gearbox will depart from its mountings and move backwards away from the cockpit area. If the retreating blade tip strikes - the gearbox will come fwd and possibly enter the cockpit area.
There is a great video of the guys in Vietnam bringing their huey's back to the USS Forrestal, I think and - unable to land on board, due to lack of space, drop their pax off first (from the hover) and then taxi over the side, to about 3 feet over the water. The pilot then climbs out of his door space and kicks the cyclic away so that the advancing blade strikes first, thus reducing collateral damage from the flailing blades and gearbox striking him once he falls into the water.
Rolling a helo over into the water speeds up the sinking process, whereas leaving it sitting on the surface affords you precious seconds/minutes to make decisions (one of those decisions could be to remain upright in a stable condition and wait for rescue!!),
Rolling a helo purposely will cause the helo to (a) invert and (b) pitch fwd nose down and inverted as it sinks and (c) cause all your "lights" to go out! This is an extremely alien dimension to be in whilst attempting egress from a confined space under enormous time pressure. It inevitably results in failure as the pilot becomes disorientated and doesn't know which way is up. This experience is exacerbated if the victim hasn't done HUET.
IF the helo is going to roll, let it do it of its own accord and in its own time if and when one of the blades strikes the incoming swell. Again precious seconds are afforded waiting for this to happen and for the pilot to 'prepare' mentally and physically. Anything above SS 2-3 will guarantee a roll over anyway if floats aren't used.