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Assuming Malaysia Airlines Flight 370 ditched in the ocean, and surviving passengers and crew were floating around in their inflatable vests, how long could they survive?

Is there data about the longest survival under such conditions?

There are a few examples of people surviving for months in tiny boats, but there they could gather rainwater and catch fish, obviously impossible in just a lifejacket.

Edit: although I mentioned a specific flight and lifejackets, the question is intended to be general for ditching in the ocean.

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    $\begingroup$ Well, they have rafts on board too. In just a life vest it would depend on the temperature of the water, but it isn't all that long.... $\endgroup$ – Lnafziger Mar 20 '14 at 18:27
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    $\begingroup$ and assuming they ditched south of australia it would be very cold water $\endgroup$ – ratchet freak Mar 20 '14 at 18:35
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    $\begingroup$ If you are in the water and it is below 21 C, you'll be dead within three hours. In above 27 C water, you won't die of cardiac arrest due to hypothermia. Links: 1, 2, 3. (I'm not an expert.) $\endgroup$ – Keep these mind Mar 20 '14 at 20:07
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    $\begingroup$ I don't know where they are searching now, but you can find up-to-date surface temperatures here. (Main page.) $\endgroup$ – Keep these mind Mar 20 '14 at 20:25
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Well, your scenario is a bit unlikely because if the aircraft did ditch in the ocean they would have the emergency rafts and slides to take cover in instead of "floating around in their inflatable vests".

However, if someone were floating in the ocean without any protection, how long they could survive depends on various factors. Temperature is the biggest factor in the amount of time before they would succumb to hypothermia.

Take a look at this chart to figure out the average temperature of the area in question. If we go by the latest news, that is going to be somewhere in the neighborhood of 14C.

This page says that the Expected Time of Survival is 1 to 6 hours.

The same page also says:

Maximize your chances of surviving by:

  • Wearing a personal flotation device (PFD)
  • Adopting a survival position
  • Keeping clothing on
  • Getting as much of body out of the water as possible
  • Remaining still and in place UNLESS a floating object, another person, or the shore is nearby
  • Keeping a positive mental outlook (a will to survive really does matter)

Swimming isn't recommended unless there is little chance of being rescued and shore is less than a mile away. Putting on a PFD after falling into cold water is almost impossible – SO WEAR IT. If you find yourself in cold water without a PFD and nothing to climb onto, tread water. Traditional drown-proofing by repeatedly lowering your head into the water and floating speeds up heat loss.

Lots more information is available on that page!

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    $\begingroup$ So, in general, just lifejackets would mean a few hours in cold water, a few days in warm water, and on rafts up to a few months? $\endgroup$ – vsz Mar 21 '14 at 7:16
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    $\begingroup$ @vsz make that minutes in cold water, hours in temperate water, days in warm water. And after days you'd be dead from dehydration anyway. Rafts? Depends on weather and supplies. People have been rescued from lifeboats after 6 months, but they had means to generate fresh water, emergency food supplies, and managed to make fishing gear to procure more food from the ocean. $\endgroup$ – jwenting Mar 21 '14 at 10:01
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Well, there chances for extended survival is not exceedingly generous, according to the FARs 91.509 and 135.167. Bear in mind that it probably wouldn't take so long for a larger aircraft before they notice that it was missing.

FARs 135.167:

(a) Except where the Administrator, by amending the operations specifications of the certificate holder, requires the carriage of all or any specific items of the equipment listed below for any overwater operation, or, upon application of the certificate holder, the Administrator allows deviation for a particular extended overwater operation, no person may operate an aircraft in extended overwater operations unless it carries, installed in conspicuously marked locations easily accessible to the occupants if a ditching occurs, the following equipment:

(1) An approved life preserver equipped with an approved survivor locator light for each occupant of the aircraft. The life preserver must be easily accessible to each seated occupant.

(2) Enough approved liferafts of a rated capacity and buoyancy to accommodate the occupants of the aircraft.

(b) Each liferaft required by paragraph (a) of this section must be equipped with or contain at least the following:

(1) One approved survivor locator light.

(2) One approved pyrotechnic signaling device.

(3) Either— (i) One survival kit, appropriately equipped for the route to be flown; or

(ii) One canopy (for sail, sunshade, or rain catcher);

(iii) One radar reflector;

(iv) One liferaft repair kit;

(v) One bailing bucket;

(vi) One signaling mirror;

(vii) One police whistle;

(viii) One raft knife;

(ix) One CO2 bottle for emergency inflation;

(x) One inflation pump;

(xi) Two oars;

(xii) One 75-foot retaining line;

(xiii) One magnetic compass;

(xiv) One dye marker;

(xv) One flashlight having at least two size “D” cells or equivalent;

(xvi) A 2-day supply of emergency food rations supplying at least 1,000 calories per day for each person;

(xvii) For each two persons the raft is rated to carry, two pints of water or one sea water desalting kit;

(xviii) One fishing kit;

(xix) One book on survival appropriate for the area in which the aircraft is operated.

So I'd guess the answer is around three or four days perhaps. If they got to the galley onboard within an hour before the aircraft flooded, they might have a bit more...

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    $\begingroup$ Useful information, but what is your guess of 3-4 days+ based upon? The current record for life raft survival is 133 days. $\endgroup$ – Keep these mind Mar 20 '14 at 21:32
  • $\begingroup$ Well, the question specifically asks about "floating around in their lifevests", so being in the raft doesn't really apply here. $\endgroup$ – Lnafziger Mar 20 '14 at 21:43

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