January 16th, 2009

The Economist said so:

In the history of aviation the number of wide-bodied aircraft that have made successful landings on water is zero. (September 2006)….

The life jackets … have little purpose other than to make passengers feel better. (2005)

Wikipedia supplies a long list of ditchings by narrow-bodied planes, with gratifyingly high survival rates, so the life jackets do make a difference. But just suppose yesterday’s brilliant airliner ditching in the Hudson was an outlier, and there really had been no precedents. Would that mean that life jackets fail a rational cost-benefit analysis (CBA)?


Like many other laymen, I’m uneasy about CBA when it’s applied to safety across a broad sweep, maximising “quality adjusted life years” regardless of context. It strips out our prior contractual relationships, legitimate and unreasonable expectations, agency and dependence, and rational or imaginary anxieties. But within a narrow field like aviation safety it should generate a fair list of priorities.

Without proper data, I surmise that since aircraft lifejackets save few lives but don’t cost much, they would go fairly well down a blank-sheet CBA list of safety measures. There are several things which commercial aviation could do and doesn’t that would probably come higher up:

* defibrillators on all larger planes

* training of one member of each cabin crew to paramedic standard

* infirmaries and low-impact exercise rooms on superjumbos

* backwards-facing seats as on military transport aircraft

* no sales of hard liquor (I stop there because I usually drink wine on flights).

Even if lifejackets come low down, that doesn’t mean they should be dropped. The Economist seems to think it unimportant to “make passengers feel better”. One in ten of us is seriously anxious about flying, and anxiety can turn to panic, so reassurance is vital. The flight jacket demonstration ritual does just that, adding a little indoctrination for everybody into the aviator’s attitude to danger: keep calm and always do something however small the chance of it working. Thinking about putting on a lifejacket makes the passenger into an agent fighting for life, not just a potential victim of tragedy. “Do not go gentle into that good night.

The danger of such rituals is that they can stop you thinking about about better plans. That’s where cold-blooded CBA becomes useful.

Admiring congratulations to Captain Sullenberger and his 155 passengers.

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