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According to an article published in the New York Daily News a few months after the "Miracle on the Hudson", when US Airways flight 1549 safely landed (watered?) on the Hudson River to the survival of all 155 souls on board, this incident was only the second ever emergency water landing that did not result in significant injuries and casualties in commercial aviation history.

And yet, the safety briefing at the beginning of every commercial flight adhering to aviation regulations spends more time discussing water landings than nearly any other topic, focussing on how to use life jackets, where to find them, where to inflate and where not to inflate them, how to use the emergency rafts, and so on.

Further, a very large amount of weight on commercial aircraft is devoted to equipment chiefly or entirely present to aid in water landings, with most commercial aircraft today having four or six emergency life rafts, hundreds of life jackets, and even the design of the aircraft itself adhering to minimum float time requirements.

With water landings so rarely attempted and even more rarely successful, why is there so much emphasis put on the current, ineffective methods? In other words, if water landings with current methods and technology generally don't work, why hasn't this changed?

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    $\begingroup$ No modern aircraft has "four or six" dedicated emergency life rafts. The escape slides also serve as rafts. At most there is one additional raft and that's usually found on aircraft that make you evacuate off the wing without a slide (737, MD-80). Further, if you want an aircraft to be able to be pressurized, it will naturally float. There's no weight lost in that. $\endgroup$ – user71659 Mar 30 '18 at 0:53
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    $\begingroup$ Because, as has been practically demonstrated (see the article you mention) water landings can be quite survivable if procedures are followed, whereas most other crashes aren't. $\endgroup$ – jamesqf Mar 31 '18 at 4:02
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    $\begingroup$ I would say that more time is spent on water landings because there's more for you to deal with during a water landing. A non-water landing basically involves unbuckling your seatbelt and getting out an exit (leaving your luggage behind). Water landings add the need for life vests (where are they, how to put them on, inflate them--don't do that until outside or you may not get out), and rafts. More stuff to talk about takes longer. $\endgroup$ – Gerry Mar 31 '18 at 16:30
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    $\begingroup$ The only thing you can do to increase your survival likelihood in a non water landing is to scream loudly and/or have a chat with your preferred deity(ies.) In the case of a water landing - there are things you can do in addition to the afore mentioned. Thus the briefing. $\endgroup$ – Mike Brass Jul 23 '18 at 6:19
  • $\begingroup$ @user71659: According to this safety card, at least some 737-800s do have four dedicated emergency life rafts. $\endgroup$ – Sean Apr 4 at 0:05
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The entry doors to an aircraft that is required to have life rafts are equipped with "slide rafts," which are dual purpose (land/water) so there is not any material difference in the weight. Some aircraft will also have perhaps one (maybe two) rafts in the cabin overhead (depending on the need for extra life raft capacity not covered in the entry door slide/raft).

I imagine, if controlled water landings were more frequent, design and technology might be modified in some way to make successful evacuations more efficient if that were necessary. But, as you point out, controlled water landings are relatively rare, so likely the cost/benefit of creating an entirely different fuselage/wings/evac system would not be justified.

Of course, the fairly recent successful controlled water landing and evacuation into the Hudson is ample justification for having personal flotation devices (life vests, etc.) and associated emergency equipment designed primarily for water survival. Also, the design of that aircraft apparently provided for adequate flotation and evacuation as can be seen from the photographs.

The safety briefing before each flight by the Flight Attendants is relatively short and maybe 60 seconds are dedicated to explaining the operation of emergency equipment specific to water landings.

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