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Ditching a helicopter: (incl pictures)

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Ditching a helicopter: (incl pictures)

Old 28th Aug 2002, 17:20
  #181 (permalink)  
 
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sirs: concerning rafts and access to them upon ditching, apical industries has developed and received faa certification for a raft system that deploys when the emergency floats are deployed. the rafts themselves are contained within the floats bags and then are fired seperatley from the floats themselves, so as not to inflate until a.c is on the water. to date the system is available on the md 902, shortly on the a119, and in testing for the bell 407, 412, eurocopter 350, 120,130.
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Old 29th Aug 2002, 14:22
  #182 (permalink)  
 
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Interesting thread, as are most in the Rotorheads forum.

Story:

On one of several visits to the dunker, I was sampling the variety of seats. Strapped in the back of a "Lynx" with the seat athwartships, I felt that the egress would be simple... right up to the point that I tried to release my harness. I had a lungfull of air, I had a reference point, I had divers close by, but the stress that set in immediately was overpowering. I tried as hard as I could to rip this harness buckle open but it was not going to unlock. Panic... you bet I did.

A friendly diver who was behind me reached over, calmed me down, and tried to open the buckle. Not a chance, this thing had locked and was not going to play the game. We were now at about 30 seconds in the water and I was fighting the desire to breath in.

The diver calmly reached for the harness anchor point and unclipped the whole thing, releasing me from the seat and allowing me to surface.

The point that was forced home to me, was that, even under controlled circumstances, panic, disorientation, stress and a bit more panic, set in very quickly. I could easily have unclipped the harness at the anchor point, but I didn't have the presence of mind. I can only imagine how difficult the exercise would have been if I had just autorotated to ditch, with parts still splashing around me, and possibly with an injury and a passenger to take care of.

Bottom line for me... if I am flying a single-engine helicopter without floats, I fly around anything bigger than a puddle.
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Old 29th Aug 2002, 15:35
  #183 (permalink)  
 
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R44 Ditching

A couple of years ago I knew of an R44 that was flying between Cancun and Cozumel (carribean) had engine failure, auto'd into the water, no floating devices for heli or pax, the thing just sank inmediately in about 30 FT of crystal clear water, the pilot came out alone and noticed his pax (3 germans) were still in the helicopter, he then dove down, unstrapped them, and they all swam to shore, the pilot says the germans biggest concern was their wet cameras around their necks.
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Old 29th Oct 2002, 14:13
  #184 (permalink)  
 
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Question Job Stability in The Emirates

I've just been offered a job as a helicopter pilot in UAE. It's on a rotation, but the pay seems quite low compared to other overseas jobs I've heard about and the 8:4 schedule isn't very attractive. I've also heard quite a lot of rumours that there is a very high turnover of pilots out there. Is there anybody out there with recent experience of the place who can tell me if the rumours of pilot turnover are really true, and if so, what's the reason? I'd quite like to go, but I don't want to find myself out of work again in a few months.
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Old 3rd Dec 2002, 13:47
  #185 (permalink)  

I don't want to be the best pilot in the world - Just the oldest
 
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Will a helicopter sink upright?

My reason for the above question is that as a HUET instructor our organisation is constantly being bombarded by companies demanding that we practice this competency as part of the course.

My thoughts on the matter are that a helo will, in a well controlled autorotation situation with correctly functioning floatation and a relatively calm sea, remain upright. However if one of the favourable circumstances above are removed then in all probability the airframe will roll over.

The only scenario I can imagine of a helicopter sinking upright would be a controlled autorotation and failure of the floatation to inflate. My question though is whether or not it is feasable to sink in this attitude given the high centre of gravity? Also is it feasable that a main rotor blade striking the water would transfer torque forces through the airframe and twist it at least onto its side?

It appears that the design of the METS HUET system is driving the training competencies rather than what is statistically shown to be the oucome of a ditching.

Would appreciate views from anyone with HUET training or crews with ditching experience. Also where I can find any authoritative statistics on the subject.
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Old 3rd Dec 2002, 14:05
  #186 (permalink)  

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Question Autorotation and ditching.

I do not know if any records were kept or if they were if they still exist but in the summer of 1949 the US Coast Guard ran a series of autorotation and ditching of a large number of Sikorsky HOS-1s. The pilot Cdr. Mc Dermid (spelling may not be correct) intentionally crashed the helicopters into the Albemarl Sound at the Elizabeth City, NC Airstation. He hit the water in various attitudes to determine the best way for the pilots and crew of other helicopters to evacuate from the fuselage. In most cases he intentionally moved the cyclic in order to dissipate the energy of the blades by hitting the water. From what I understand he would move the cyclic in all directions to determine the most effective way of dissipating the rotational energy of the rotor system.

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Old 3rd Dec 2002, 17:27
  #187 (permalink)  
 
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If the autorotation is successful, the sea is calm and all the floats inflate, the aircraft will remain upright for a while.

Sinking is generally caused by the sea state rolling the aircraft over, or a float bag slowly deflating and causing a rollover.

One of the large Gulf of Mexico operators who have recently lost some aircraft, all which have had successful autorotations, is looking into ways of increasing the longevity of the aircraft floating so that they increase the chances of aircraft recovery.

In the cases which occurred recently, the aircraft was lost, and the operator believes that improved floats or supplementary floats could prevent hull losses.

Brother
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Old 3rd Dec 2002, 22:22
  #188 (permalink)  
 
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Ditchings

All the ditchings I have seen on film or TV have rolled to one side and floated for a while. Think back to that footage of the Hueys ditching beside the aircraft carrier when Saigon was lost. Big splashes as rotors thrashed about, fuselages floated long enough for crews to exit if they were conscious.
Two ditchings around NSW involved a twin and a single, both had the same story, roll onto right side, float, sink.

I have no doubt that HUET courses saved lives in those 2 cases. It is great training for the basic principles, which can then be applied to each situation. Very few helos in Oz have floats, so we can expect them to follow the laws of physics and put the heavy bits (transmission, engine, rotor heads) under the empty light bits (cabin, fuel tank) and thus be upside down.

Helicopters: a triumph of science and technology over common sense..
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Old 3rd Dec 2002, 22:39
  #189 (permalink)  
Straight Up
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On the two HUET courses I've done (one at Sale in Vic, Aus, and one run by the Royal Navy in th UK) we were told that if the floats work, it'll stay upright and you can get out (sea state permitting).

If the floats don't work/are not fitted to aircraft/high sea state, it will roll over and either float belly up or sink, either way you'll need the HUET training.

The pictures etc that we were shown at the naval dunker (to keep us amused until it was our turn), showed a lot of belly up aircraft.

I think Ascend Charlie has it spot on with the heavy bits at the top, and light/empty bits at the bottom. Not sure how it would work for Wessex style aircraft, with the engine down low in the nose, and some transmission up top.
 
Old 3rd Dec 2002, 23:18
  #190 (permalink)  
 
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Cool Topsy Turvy?

I have been told of a urban myth that a Blackhawk with external wings and jugs, will stay upright for a few minutes before it rolls or sinks, (providing your entry was not to rough).

But hey my hat goes off to that hard [email protected] who deliberately ditched all those Sik horseys into the ocean........

-----------------------------
If it don't hover Don't Bover........
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Old 4th Dec 2002, 00:00
  #191 (permalink)  

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Question That was only the beginning.

To: bigdog 1971

But hey my hat goes off to that hard [email protected] who deliberately ditched all those Sik horseys into the ocean........
Several years later that same pilot was promoted to Captain and was the Skipper of the Coast Guard Air Station in San Diego. The US Navy had commissioned several PBM-5As and they turned them over to the Coast Guard to test them to destruction. The Captain would walk through the hangar and pick out a crew from the available personnel.

He would then take the PBMs to the roughest water and make all types of open seas landings including stalling the aircraft out and coming straight down. He accomplished what the Navy wanted and destroyed both aircraft. After his demonstration the Navy scuttled plans to build more PBM-5As.

Needless to say the crew was not too thrilled to be picked out for the tests.

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Old 4th Dec 2002, 00:47
  #192 (permalink)  

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Thanks for the responses folks.

If I may ask you to be a little more direct. In your knowledge or experience, would you forsee a circumstance where a helicopter would / could sink vertically?

Straight Up,
we have a brief summary of the RAN Wessex ditching in the Bass Straight in 1993. Reports were that after inflight vibration was felt, both the airspeed and altitude were reduced whilst trying to reach the coast. Upon a fairly catastrophic transmission failure it was reported that the airframe rolled almost upside down and struck the water in a nose down attitude. There apparently was no pause on the surface and at least two survivors escaped via the gaping opening at the rear of the cabin where the tail boom had torn away.
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Old 4th Dec 2002, 01:54
  #193 (permalink)  
 
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As an ex waterbird Instructor (S61) and now current dunker victim, stats then and now show that helos will remain upright up to sea state 1 without floats and SS3 with floats. If SAS is kept in, it will increase the risk of a tip strike with the swell as the tip path plane hunts for the level attitude. Because of the lack of a water anchor the helo will float beam on also increasing the chance of a tip strike.
Unless the a'c is designed to float for prolonged periods (S61 / Sea Sprite etc), you will most certainly sink within seconds without floats. In a calm SS there is a good chance it will sink vertically without toppling, especially if the lower section fills with water quickly. But the sea is never calm!!! So it is almost a certainty that it will (a) roll over inverted and (b) dive nose down after it is fully submerged [For light helos it is estimated that it could sink up to 8'/second....all in the dark, too

If in doubt...do the dunker...Duty of care and all that for the establishment, tremendous confidence for the crew.
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Old 4th Dec 2002, 03:55
  #194 (permalink)  

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Islander,

Does your HUET company offer courses for walk in private (H) pilots or are you just for the offshore/commercial world? I have been looking for a course in Asia/Aus for a while.

Email me if you feel the moderators might think it advertising.

Thnkx
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Old 4th Dec 2002, 04:12
  #195 (permalink)  

I don't want to be the best pilot in the world - Just the oldest
 
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Thomas coupling,

thanks for the info. Much appreciated.

moosp,

will email you later with details.
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Old 5th Dec 2002, 17:40
  #196 (permalink)  
 
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Angry Wessex

Having ditched a Wessex 1 in Sea State 1 in which the bags did not inflate on water entry; I can assure you that it did roll to the right - causing a blade tip hit the water and wrap around the cockpit - until inverted and then sink nose first.

The RN dunker training was almost a perfect simulation.

BTW: it was a Friday the 13 th.
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Old 6th Dec 2002, 00:03
  #197 (permalink)  
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Floats Good - No floats bad!

A colleague of mine called Art Swain gave an SAR demo off Lyme Bay which ended up with rapturous applause from the crowd on the beach when the engine stopped at the end of the display. Calm sea - floats popped as advertised and he climbed into his dinghy from the wheel strut dryshod.

Colin Bates did a great demo some years back of a 206 on floats autorotating into the water - nice stable floating platform on flat calm water.

BUT if one of the floats doesn't inflate or bursts, it'll roll, a blade will hit the water and you won't know if it'll dig in or flip the aircraft over onto its other side. In any event lots of thrashing about.

If in doubt do the dunker!
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Old 6th Dec 2002, 04:08
  #198 (permalink)  
 
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I'd say the best answer to the question is that it might float upright. But it also might flip over. With odds like that I'd say egress training is necessary for any who do extended overwater flights.

I ditched an H46 under controlled conditions (power on landing...in-flight fire). As it took on water, it also began to roll. If left alone I think it would have been on it's side or inverted prior to the last piece of metal going below the surface.

Without floats...you're on your own. With floats, if they work you should be okay in advertised sea conditions and entries.
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Old 6th Dec 2002, 14:29
  #199 (permalink)  
 
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A bit that was missed here is that most flight manuals include in the procedure for ditching sans floatation to roll the aircraft prior to losing control effectiveness to intentionally stop all the flailing bits lest it sit there upright with the blades skipping around on the surface once it sinks to that level and you exit to resurface amongst them.

Full touchdowns with floats is best learnt watching ducks land!
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Old 7th Dec 2002, 21:38
  #200 (permalink)  
 
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a well-known british pilot and instructor tells a great story about ditching following and engine failure...

the bags inflate.....

the heli sits there happily while the nearest destroyer launches a cutter to pick up VIP Admiral passenger and the crew...

the cutter comes alongside...

the sailor on the cutter uses a boathook to make contact with the heli...

boathook goes through bags...

time to go swimming, including said Admiral

I don't suppose that sailor got promotion that year. Probably fiction, but did make me laugh.
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