Emergency water landings are worse than one on land. Advection can cause fog to linger over water near coastal areas.
“Flat light can completely obscure features of the terrain, creating an inability to distinguish distances and closure rates.”
The safest way to fly over water is with an all-airframe parachute….and if over long stretches of cold water like the N. Atlantic a raft, vests and emergency kit are a must.
The water temperature does not fluctuate that much in the Northern Hemisphere, and unless fully equipped, the chances of survival, unless picked up quickly, are slim.
That depends what you mean by that much. The mean variation in the channel for example is 8C or nearly doubles throughout the year. That equates to a really huge difference in projected survival times. At 10C you will be lucky to be conscious after an hour, and likely to be dead in 2 hours. At 17C with luck you will go 5 hours or more, and could live considerably longer. Certainly in the channel it brings the chances of rescue from very unlikely to likely without taking further precautions.
I watched the helicopter recover some divers around the Greenwich Mer. bouy this year who were in the most urgent need of recovery. The launch was from Lee and by the time the operation had been co-ordinated and the asset resourced and launched in the winter you would almost certainly be dead, in the summer you would almost certainly survive.
Given the ditching is survived it is all about avoiding hypothermia which really cannot be under estimated.
Sorry Fuji, not sure about that large temp variation. My investigation show-
“The average night time temperature during the swimming season ranges from 10.6°C to 13.9°C. The yearly average night time temperature is 6.7°C. When your pilot tells you that it is warmer in than out, he is telling the truth. 2012 was a particularly brutal and exceptional year and in some days is mid summer the night temperatures fell to 6-8°C.”
The source states an annual swing of only 3 degrees, and that dependent on air temp. Frankly, when bobbing about on the surface, that is nothing. It is still only 59 degrees.
Also, that is the Channel, a much different proposition than the North Sea, the Atlantic, Irish Sea, etc. I frankly, would never wish to experience a sea ditching. I also don’t relish an engine failure over land, so, be prepared would be my guiding motto.
BeechBaby wrote:
The water temperature does not fluctuate that much in the Northern Hemisphere, and unless fully equipped, the chances of survival, unless picked up quickly, are slim.Well… The Baltic sea is in the Northern Hemisphere and temperatures vary between as much as 20°C in the summer and freezing in winter.
USFlyer wrote:
Emergency water landings are worse than one on land.They are not. In fact studies show that ditchings with SEPs are about 90% survivable. I would say those odds are better than for an emergency “landing” in a forest or urban area. Not to mention at night. The problem is staying alive after the ditching until you are picked up.
DMEarc wrote:
Has anyone worked out a way of determining the actual risk of such legs or reasonable personal minima for such?
No. What most of us do is put measures in place that may mitigate any potential risk. Personally, I feel far less comfortable at night or in cloud over mountainous terrain. Do I worry about it? No. I just put sensible measures in place.
For example, I’ll soon fly from UK to Amman in Jordan via Malta, Crete and Egypt (the task demands that route). The risks that I’ll not normally experience are:
Mountainous terrain (S. France and Sinai)
Water, lots of it. Somewhere near 10hrs of flying.
Desert, lots of it.
No guarantee that the rescuers will be in the mood to rescue. Some may be bearing one piece orange suits.
How do I mitigate? Lift rafts, vests, PLBs, satcom, long-winded routes avoiding higher risk terrorist areas etc etc. Does it truly mitigate? Not so sure although it does make one feel less vulnerable.
Airborne_Again wrote:
The problem is staying alive after the ditching until you are picked up.
Exactly, ditchings may be 90% survivable, but for how long? Minutes in Winter?
Most of us would prefer an emergency landing over land, taking all factors into account (terrain, season, aircraft type, day/night, ballistic ’chute etc.).
Airborne_Again wrote:
Well… The Baltic sea is in the Northern Hemisphere and temperatures vary between as much as 20°C in the summer and freezing in winter.
Airborne I will apologise, I am not really a pedant, but…….
“The temperature around the islands in the archipelagos and along shallow beaches is often higher than out at sea. The surface water warms more quickly as there is less mixing. In the shallow water, the sun’s rays can even warm the sea floor.”
The actual temperature of the Baltic, deeper layers, remains constant at 4-6 degrees. Admittedly, the surface temperature varies, anywhere between 4-25 degrees, but this can be very isolated, and is wholly dependent on air temperature, and weather. And is totally seasonal. The problem lies in the salinity, and brackishness, of the Baltic Archipelago.
Sorry, I did warn you. I did well in geography at school. 
That all said, I think we have agreement that ditching could be a much more tragic experience than attempting to land, on solid ground, after an engine failure.
I have flown the north Atlantic in an SEP, SET and a Jet. If you exclude fuel starvation and poor maintenance I think your chance of a ditching goes down by an order of magnitude. You control both of those factors. Most ditchings IMHO are pilot induced.
BeechBaby
Here are some ideas of the range. This one coastal North Sea.
http://www.seatemperature.org/europe/united-kingdom/lowestoft-august.htm
