Water Ditching

[TwinHueyMan]

Some legit statements... I know I won't be able to stay down forever, but that little safety net the bottle provides makes me feel assured that what I've got in my lungs when I go down is not all that I'm going to have. Lowers the stress and reduces the chances of freaking out... hearing stories of others that have done the real dunker ride without any training or equipment, and how they all managed to calm down and work their way out rationally, makes me think that the bottle helps people get out period, not just gives them more time. Put air in a scared crashed pilot's lungs and I gaurentee you that the lowered fear and increased confidence they get will help him/her out quicker... not to mention give them some more air. And the bends or a possible air embolism vs. never getting out is an easy decision, at least in my mind... it's like sending someone to a gunfight without a gun because he never learned to shoot it. I think you've got a better chance with the thing, even if it's not ideal.

The instructors also stated the bottle helps you to get out, but after seeing what the bottle that I carry can do, I know I've got enough time to spend a second or two helping someone else out, or (more likely) swimming to the engine compartment to see why the damn hunk of sh*t let me down. Even if you can't go to the class, I say get the best equipment you can afford/find/figure out how to use, get familiar with it's capabilities, and use it to it's most when the unfortunate arises...

Mike

[Rich Lee]

The question should not be which way you roll a helicopter after a power off landing to water; but why you would be flying a civil helicopter over water, beyond autorotative glide distance to land, without floats?

In the case where the helicopter lands in the water after hitting a tail rotor on the edge of a heli-deck or hitting a main rotor against the mast of the ship, or LTE on approach, or due to spatial disorientation, the chances or rolling to one direction or another are rather slim.

With properly deployed emergency floats or fixed utility floats there should be no reason an upright landing cannot be made power-on or power-off.

[rotors88]

Well Rich Lee have you not ever done circuits/patterns, or an approach over water to a pad/airport which is perfectly legal & regularly done? Or what if the floats fail to deploy, or if your doing aerial work or private ops over water which you do NOT require floats? Or your within auto distance to land but the beach is packed with people, or for some other reason not suitable? So there are plenty of legit what ifs over water? The question is what if the noise stops during over water flight & you HAVE to ditch in the drink; then what are the options & alternatives? Based on some great valid responses here, then given a ditching in a anti-clockwise rotating machine the safer option is after the flare level cushion... settle in, then roll the machine to the RIGHT, hence reducing the chance of the tranny & engine joining you in the cockpit for a little tea & crumpet. Thanks heaps for the constructive responses. Cheers

[oldpinger]

I was told by some bloke who ditched a 206 into sydney harbour, right between the headlands and too far from each, that if you roll the advancing blade (I think) into the water, the resulting massive torque back through the system will spit the gearbox out backwards away from the cockpit.

Well he said it worked anyway. I'm sure someone knows the full story.

I did the 'waterbird' course on the US Sea King- great aircraft to take off again from water if you've got 1 engine left. The ditching at 30kts fwd speed was fun also with the aircraft coming to a stop in about a length and a half!!

[mark sicknote]

Great tale OP!

And a classic "handle" if I judge your line of work correctly.


Best.

Sicknote

PS

Off to start a similar thread on the GA boards.

[FH1100 Pilot]

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.

If you think about it a little (and those Vietnamese pilots surely did not but we can forgive them if they were so, um, preoccupied with other things to wonder, "Now how would Nick Lappos do this?"), you absolutely do not want to have power to the rotor if it's going to contact anything. Thus, engine-OFF for water ditching.

Once you take the torque away from the main rotor and slow it as much as possible with pitch, it really won't matter which way the helicopter rolls. I know of a certain ship with a two-blade system that rolled over after landing on uneven ground. As it was going over, the pilot managed to get the engine off so the rotor was no longer driven. The transmission stayed put. The blades were trashed but after inspection, the hub, grips and drag links are flying on another ship to this day...somewhat unbelievably to me but there you go.

Perhaps ditching theory was important in the UH-1, with that long mast and that big, tall transmission. (Ever look at/think about that? Yikes! What a poor design.) But in other helicopters with better trans mount designs, it just doesn't matter. If it's a controlled ditching, get the ship down onto the water level and then, keeping it that way, pull the pole up as high as it'll go to slow the MR. Let it roll and don't worry about it. That trans ain't going anywhere.

But let's not kid ourselves into thinking that there would ever be an occurrence where it would be necessary to ditch a helicopter in the water while it's still under power, okay?

[oldpinger]

FH1100

Ok, ask the guys who had a internal fire caused by a 3000psi utility hydraulic leak, VERY large fireball inside the aircraft, ditched it, rolled it over putting the fire out and all the crew got out. The Jaguar pilot who had ejected that they were about to rescue got a bit of a shock when the rescue aircraft needed rescuing however.

Also- any impending catastrophic gearbox oil problem over water away from land- offshore ops anyone?? I can think of at least two RN ditchings caused by this.Granted all happened with older aircraft- ok, Seakings, but not outside the realms of possibility even with newer offshore aircraft with cabin fires etc. I would rather use the big wet fire extinguisher than get crisped airborne....

[Spanish Waltzer]

O-P - ISTR in that particular instance the aircraft was rolled to the right because the handling pilot was in the left seat and he wanted his boss in the right seat to get wet first!

I also seem to recall the handling pilot was well looked after by the nurses when he got to hospital....but thats a story for another time

Not that it matters but just for accuracy the jag pilot had actually been rescued some time before. The seaking crew had been tasked to locate the wreckage on the seabed using their sonar.

[Rich Lee]

Well Rich Lee have you not ever done circuits/patterns, or an approach over water to a pad/airport which is perfectly legal & regularly done?

Yes I have. In my younger days I even used to ferry long distances across water in a single engine helicopter without emergency or fixed floats. That doesn't make it right. Now I would probably insist on floats if I needed to fly over water in a single engine helicopter.

Or what if the floats fail to deploy

Good question. Of course that begs all the other questions like what do you do if the hydraulics fail, or if the controls become stuck, or if the pilot panics, or electrical system fails and the battery is dead and that causes all the electronic displays to fail, or you are in a sea state that cause your blades to hit the water before you land, or you can't align properly with the swells? All perfectly legitimate questions alone or in conjunction with each other. Secondary and subsequent failures of multiple systems do occur, but I would still rather have properly serviced floats as opposed to none when flying over water.

The bottom line is you do what you can do get the aircraft into the water at a vertical descent rate and horizontal speed that allows the best survival opportunities. I am a believer in following manufacturers recommended procedures. If you are in an aircraft with a transmission that wanders about when the blades strike something, and a manufacturer like Bell says to roll the helicopter a certain way, then do what Bell tells you to do. You can't be faulted for doing what the manual tells you to do.

There are plenty of legal operations that fly over water without floats. However, do something within legal boundaries doesn't mean one is always exercising the best possible judgment. Imagine the case of a pilot carrying passengers over water and the engine or engines fail. Imagine the pilot did all the right things but the passengers drowned, what would the pilot's justification to their families be .... 'it was legit'? Please do not get me wrong. I am have been involved in operations that were perfectly legal and standard operating procedure only to realize years later that there were safer ways to do things. I have learned that there is a safer way to fly over water and that is to do so with floats. With or without floats, every passenger should be briefed on how to exit in a water landing, and how to use personal flotation devices; and they should be wearing those personal flotation devices.

If I made a decision to accept the risk of flying over water in an aircraft without floats, I know that in the event of an engine failure, I will fly the aircraft all the way to the water, and on the way down I will make sure I have a door open. I will use full collective on water entry to dissipate as much main and tail rotor energy as possible. If at that point I have enough control power in the main rotor to roll the helicopter, I might make the attempt if that is what the manufacturer recommends, but I really wouldn't expect too much from the rotor at that point.

[Thomas coupling]

Fire, main gearbox oil loss, serious vibration. Just a couple of reasons why one would "fly" a serviceable helo into the water under power, I would suggest.

Provided the pilot still had control of the aircraft after landing (Sea state <3) then he might have the option to shut down before the blades make contact with the swell and decide for themselves which blade impacts first (adv / retr).

The gearbox would disconnect and depart the airframe in the opposite direction and there have been numerous incidents which reflect this.

The bottom line is to alight on the surface of the water with minimum force, inflate the flot bags, slow the rotors gently and depart the aircraft.

[[email protected]]

Twin Huey Man - speaking as one of the most current HUET qualified pilots in NATO (I did my requal this morning) your chances of 'swimming around' and helping someone else are somewhere between none and F-all. You can see almost nothing in a benign environment like a swimming pool without goggles or a mask and you would see even less in the sea, and that's in good light. The bottle is there as a secondary escape system should you fail to get out quickly - not to make you Marine-Boy/Navy Diver/Hero of the day.

The bottle should give confidence to dispel fear, not breed over-confidence.

[Phrogman]

To chime in with "oldpinger" the transmission scenario is one of the prevalent reasons you would ditch with power with the notion that the impending failure (indicated by chip light with perhaps torque spikes, yaw kicks, the sound of marbles in the transmission) means you will probably lose the ability to generate lift altogether very soon. The warnings I have seen state that entering into an autorotation with an impending transmission failure may cause the transmission to seize earlier than if you maintained power input from the engine (mainly at the point you are pulling to cushion and the turns begin to bleed off). Another possibility is folks who get offshore and become disoriented and then run themselves out of gas or get caught in weather that runs them out of gas (MH60 crew flying in "The Perfect Storm"...quite the story if you aren't familiar- night time ditch into 75' waves- good times there). Knowing it was a matter of time, I would look to get rid of my pax in an air taxi, get all set up with doors gone, floats blown (in that order),and perhaps target the crest of a wave. I would rather have the opportunity to land in the water on my terms vice trying to see how well I could auto to a particular sea state.
As far as which way to roll, I think the sea will decide that for you, but I am happy to listen to any test pilot who has the answers from experience...the three pilots I have met who have ditched power on stated it wasn't a prevalent thought at the time.

[Phil77]

That EMS EC135 that crashed the other night (http://www.pprune.org/forums/showthread.php?t=329188) got me thinking about this thread and the theory of the gearbox departing the airframe in the oposite direction of rotorblade impact...

How come that the gearbox on that EC135 (it rolled over after clipping a trailer on (forced) landing) moved a mere 5 inches towards the side of impact?!?
Last time I checked dirt is a lot harder than water - or was the crew just lucky not beeing beheaded by a flying gearbox? (pardon my sarkasm).

[TwinHueyMan]

"Twin Huey Man - speaking as one of the most current HUET qualified pilots in NATO (I did my requal this morning) your chances of 'swimming around' and helping someone else are somewhere between none and F-all. You can see almost nothing in a benign environment like a swimming pool without goggles or a mask and you would see even less in the sea, and that's in good light. The bottle is there as a secondary escape system should you fail to get out quickly - not to make you Marine-Boy/Navy Diver/Hero of the day.

The bottle should give confidence to dispel fear, not breed over-confidence."

Congrads on your trip to the dunker. Always a fun day when we go.

I understand what a lot of the instructors say, and why they say it, and by all means I don't think one guy on a bottle will save an entire bus load of scared people, but when you've got that much of a safety net, it's not worth it to me to not at least give a look to make sure my buddy is getting out. When we do our briefs before flying overwater, the two crew on each side of the aircraft are told to "make your best effort" to make sure your co-aircraft-sider is getting out, and if we have passengers, we're to do the same for them. We did so in the dunker, hell our instructors would breathe the same heeds bottles we did!

Also, I'm think one of the bigger HUET companies has classes for HEMS guys that fly overwater, and they train to extract a patient during the ride.

As for the visibility, I know it can be pretty bad at times, but I'm also a guy who cruises down to 100 feet on the weekend and I've never had a problem seeing at least a bit in front of me at those depths on a murky day doing mask drills. I've also been caught on the most innocent of things down there, unable to free myself, without 2 seconds of help from my buddy. We have loads of crap hanging all over in the back of our aircraft, plenty of stuff to get hung up on, and the simple help of someone who is already out, with a good view of the problem, and the calmness that comes from getting out may be all the help someone needs to make it through.

By the way, I'm not arguing that everyone should have the same attitude, but the thought that people should be allowed have a heeds bottle without expensive, sometimes hard to find training, and that it is capable of only very limited things, is a pretty pessimistic view on things.

Mike

[[email protected]]

TwinHuey - I cannot see how anyone is going to have a good view of any problem underwater without a mask - if you are caught up inside and they are outside they will, at best, be able to see a blurred mess. If you are talking about a realtively controlled ditching where the aircraft has inverted but not sunk because the floats have inflated then there is possibly a case for trying to extricate others but the situation we train for is where the aircraft has inverted and is sinking - no-one should ever consider going back into that.

Unfortunately, letting people believe they can save others in this scenario is more likely to cost lives. BTW does your dunker training include night ditching?

[TwinHueyMan]

I agree that "going back" is not the safe thing to do. Reaching across while still maintaining a reference point is more like it. We also brief that, if you end up on the surface, you don't go back down. On the way out, after having sorted yourself but still with the wreck, do your best to ensure your buddy made it out. I think it might be different in a larger airframe where you can't just reach out and grab your entire crew...

We didn't do night dunks, but we don't do much of any night over water work. Pretty frowned upon unless it's rather important. I think if the event happened at night, it would be a miracle of anyone made it out expediently let alone did buddy checks on the way out.

Mike

[Bravo73]

Originally Posted by Phil77

How come that the gearbox on that EC135 (it rolled over after clipping a trailer on (forced) landing) moved a mere 5 inches towards the side of impact?!?
Last time I checked dirt is a lot harder than water - or was the crew just lucky not beeing beheaded by a flying gearbox? (pardon my sarkasm).

Phil77,

I am by no means a physicist but wouldn't the fact that dirt is much harder than water be a contributory factor?

When a blade hits the ground, isn't it more likely to shatter or break in some way? (See the photo of the Philly EC135 - all of the blades are sheared at the root.) This will dissipate most of the remaining kinetic energy.

However, when a blade hits the water, isn't it just as likely to decelerate rapidly? This means that a lot of the energy will be transferred along the blade until it gets to the end ie the gearbox.

Although saying that, maybe it comes down to the more modern design of the EC135? I remember from the video of that ENG AS350 which came down on a New York roof that the pax were very lucky not to get clobbered by the gearbox when it came away from the aircraft.

[[email protected]]

TwinHuey - unfortunately, we do spend a lot of time at night over the water so one run is conducted in half light and one in the dark - we do 6 runs altogether, 4 without STASS/HEEDs and 2 with.

On the 2 STASS runs we end up swimming inside the aircraft (Sea King size) to escape from an alternate exit (cabin door for example).

On the last run I had to get from the RHS to the air stairs door (about 5 feet in my 8 o'clock position) - sounds easy and I correctly orientated as we hit the water but, by the time I was upside down, had released my safety harness and was breathing on the STASS, I was completely lost and tried just about every exit on the aircraft until I finally found the one I was supposed to get out of. It was difficult and disorientating and that was in a swimming pool in daylight after 5 other runs and only in 4m of water.

In the real case you are very unlikely to be able to do anything other than just get yourself out - if your training lets you believe otherwise, your training isn't hard enough.

[Helinut]

Don't forget that the rate of consumption of bottled air will be significantly greater in a real emergency than in the HUET: the application of extra adrenalin and cold water will see to that! It could easily half the endurance.

[IntheTin]

How long could you expect from these bottles of air?