Ditching techniques...?!?!?!

[skyraider]

This is not something I am planning to test out if I can help it, but I was reading a POH the other day and I have a question on ditching that I wonder if anyone can answer.

It's the part about not rounding out fully and rather flying the plane into the water.:confused:

Why not the round out ?

This assumes a reasonably calm surface b.t.w.

Sky

[FlyingForFun]

I believe this is to do with the momentum of the aircraft after the impact with the water.

Imagine a fixed-gear tricycle such as most basic trainers. If you were to flare as you impacted the water, the first part of the aircraft to impact would be the main wheels. The aircraft's momentum would then force the nose of the aircraft down fairly violently - a bit like landing with the parking brake on. This could cause substantial damage to the aircraft, which would mean it's less likely to float and/or stay water-tight.

The effect would be less pronounced with retractible undercarriage - but even with the gear up, if you flare, the back of the aircraft will be landing first, and the momentum will force the nose down violently into the water.

If you "fly the aircraft in", the nose will impact first. The momentum of the aircraft will try to cause the tail to continue moving forwards - and therefore up - while gravity will cause the tail to go down. These two will cancel each other out to a certain extent, and the overall effect will be a much smooter arrival.

Like you, I've never tested these theories, and I have no particular desire to! It would be interesting to hear from anyone with practical experience...

FFF
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[sennadog]

Would it not be better to try to flare the aircraft to the point of stall so that it bellyflops down onto the water? That way, there may be less chance of injury to the pilot/crew without the full frontal impact of the nose into the water.

I know it's all hypothetical and I know diddly squat but it's just a theory.:D

[swahili]

>Would it not be better to try to flare the aircraft to the point of stall so that it bellyflops down onto the water?

Again, I have never tried this for real, but ISTR that judging height over water is difficult. Thus the possibility of stalling at a considerable height would make this more dangerous.

[englishal]

I'd rather stall (no higher than)3-4m above the water than fly nose first into it.

EA

[Julian]

Yep, flying nose first into the water sounds like it would jettison your body out of the canopy !
Suffering major concussion is more than likely going to render you unable to make an effective escape.

Stalling sounds softer.

Anyone have any first hand experience on whats the best way?

[FlyingForFun]

I'm surprised we haven't had an "expert" view on this yet - maybe it's worth posting a link to this thread on the Technical forum? But, for what it's worth, some more uneducated thoughts from me regarding stalling:

Remember, when you're stalled, you're still doing (depending on aircraft type, of course) around 50kts. You could approach at, say, 10% above the stall speed, and it really wouldn't make that much difference to the total amount of energy the aircraft has at impact.

If you fly nose-first into the water, all the deceleration will be horizontal relative to your body - this is the direction in which the body can withstand most force. If you approach nose-high, when the tail impacts, the nose will be forced down with considerable vertical force, which the body is not capable of withstanding.

It really would be nice to hear the "real" reason why the advice is to fly into the water - the reasons I'm giving are from logically thinking the problem through, but I haven't read that much on the subject, so it wouldn't surprise me if I'm completely wrong. But one thing I do know is that all the advice I've ever read, whether in books, POH's or magazine articles, is to fly the aircraft in - and I doubt that everyone would be giving the same advice unless there was a good reason for it.

FFF
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[skyraider]

Sennadog has given me an idea after mentioning bellyflops....

The ideal approach angle in life seems to be 3 degrees but we all know that if you hit water at speed, it's not a whole helluva lot softer than the ground, so if you hold that approach into the water, well thats not a good idea IMHO. Also, the POH did say words to the effect of... "DO NOT ROUND OUT FULLY"... so if you hold the approach until close to the water, taking careful note of the difficulty in judging height above water :D and round out until you have a level deck, you can pancake onto the surface with the greatest surface area available at the lowest speed..and skip along like a stone on a pond :confused: :) , effectively doing a wheelsup on water....

I think this would hold true for fixed gear as well. Once the gear touches the water, as FFF pointed out, she is going to pitch forward onto her nose. If you are flared into a nose up attitude you have further to fall and more chance of cartwheeling....

so after all of that hot air :D , my decision is to arrive as slow and as level as possible.... oh yes, I also expect to find religion at that point :D :D

Sky

[Spacer]

All I know is that according to the RAF training instructions and FRCs, it seriously recommends abandoning the a/c rather than ditching. I know it may not always be an option, but in private flying I like to try and keep my options as open as possible.

[englishal]

Slow and flat sounds good, although the decelleration forces will increase exponentially with speed. Besides, I was watching discovery the other night, and this crazy doctor was shooting himself off on a rocket sled, and decellerating with over 50g's. He was ok, apart from a few temporary detatched retina, so I think the moral is to have a good tight seat belt.

The CAA do a good 'safety sense' information book on ditching, which can be downloaded from their website....


Cheers
EA

[Danza]

Seen as though nobody has brought the subject up yet, what is the effect of swell and waves, and how does this factor in with ditching. From what I can gather from reading random books the best idea seems to be to lose altitude into the wind and just before ditching turn to land across the swell. Anyone got any better ideas? (or knows what you should do) :confused:

[Final 3 Greens]

What A/c was the recommendation for?

The types I fly recommend flaring hard to make the first point of contact the tail.

Must say, Its always struck me that the chanes of survival are pretty slim with the deceleration forces involved.

[skyraider]

F3G...for myself, it's a PA-28... I wonder if the tactics would be different for high wing aircraft...

Danza... thats in line with what I have read as well, along the crest of the swell in rough water...

[andrewc]

You might like to take a look at this article
http://www.avweb.com/articles/ditching/ from
Avweb which gives plenty of good advice.

It also is optimistic about your chances, quoting that
>90% of ditchings are survivable.

-- Andrew

[ILS27R]

I'm no expert but I heard that you should stall the aeroplane in with full flap and land along the swell- even if it means not flying into the wind. Also prepare for that second impact.

[GonvilleBromhead]

Think I'd rather go along with Skyraider's theory, level and slow until it just belly's onto the surface, reducing chances of flipping or catapulting yourself out of the shield due to excessive nose down, but good question, and one we've (hopefully) all at least thought "What if..." at some time or other.

Scary thing is, none of us have a real answer to it, just subjective opinions. Maybe worth writing to Flyer for the defininitive.

[Evo7]

Wasn't a discussion of ditching in Flyer recently? I'm sure I've read an article somewhere.

[pulse1]

For most UK pilots I guess that the most likely bit of wet stuff we are likely to ditch in is the English Channel. From too many hours spent trying not be seasick sailing across said channel I would make the following observations:

1. The Engish Channel is rarely calm enough to allow any kind of precision fly in.

2. Due to tidal effects, there is rarely any really regular wave pattern although it should normally be possible to land roughly across the waves. This will depend on the relative directions of wind and tide.

3. I seem to remember being told to try to land, across the waves, aiming for the back of the wave. With the irregular chop you tend to get in the channel I think that is going to be a matter of luck.

4. Those of us who do fly across water should know before hand what is the best way. It's a bit late to change your mind when you get close to the water.

I do hope that this thread attracts some informed opinion. I guess that, at the moment I would land crosswind, across the waves. At least the drift would be in the direction of the waves and might reduce the impact force.

[GonvilleBromhead]

"Those of us who do fly across water should know before hand what is the best way. It's a bit late to change your mind when you get close to the water."

That's exactly it though Pulse, I think this question having been raised shows exactly the opposite, that most of us in actual fact have opinions to go by but no definitive answer. I know I for one have thought about it, as I hope most PPL's who have ever crossed water have.

Still not sure I know the best way, whichever looks the "safest" at the time given the conditions etc I guess is the best answer, and if it came to it, I don't think science would come in to play too much anyhow, more a bit of luck perhaps.