This is making my head spin.

In February 2011 the FAA issued an Airworthiness Directive calling for removal of chemical oxygen generators from airplane lavatories, or emptying the generator and restowing the masks. (By the way, no one told the passengers that there was no longer any supplemental oxygen supply in the bathrooms.) While security wasn’t mentioned in the AD, apparently there was a safety problem. Or as the FAA so confoundingly put it in the new final rule, which rescinds the 2011 AD, “This AD was prompted by reports that the current design of the oxygen generators presents a hazard that could jeopardize flight safety. We are issuing this AD to eliminate a hazard that could jeopardize flight safety [our italics] and to ensure that all lavatories have a supplemental oxygen supply.”

The original AD was the result, I think, of somebody somewhere in the government waking up in the middle of the night worrying that terrorists would go the toilet during a flight, pull out the oxygen generator, activate it (which generates heat) and somehow use it to take down the airplane. The AD took effect immediately because it was so important and applied to aircraft with 20 seats or more. Chemical oxygen generators have been used for years in airliners, and if these items were so dangerous, why did it take so long for the FAA to do something about them? (There is, of course, the tragic 1996 ValuJet DC-9 accident, in which the NTSB determined that loose oxygen generators being transported in the cargo compartment caused the fire that downed the airplane.)

So anyway, now, after airlines spent who knows how much on complying with the 2011 AD, they have to spend even more money to undo the AD and restore their bathrooms back to normal. Incidentally, the FAA determined in issuing the 2011 AD that there was no significant impact “on a substantial number of small entities” so therefore no need to worry about the cost of compliance. I’m sure the “big” airlines didn’t like having to spend that money, and they like even less having to spend it again. The FAA estimates the cost of complying with the new AD at about $45 million for the 5,500 aircraft affected.

Airlines will have 37 months to comply with the new AD. It should be noted, sarcasm aside, that it may not be a simple matter of restoring chemical oxygen generators that were never removed to their original condition. The new AD points out that airlines must “install a supplemental oxygen system that meets all applicable sections of Parts 25 and 121 of the Federal Aviation Regulations.”

I still would like to know where the original impetus for last year’s AD came from, and why the FAA decided to backtrack. And I do prefer to have access to oxygen in case I’m in the bathroom during a decompression. But, really, $45 million isn’t chump change. And I also worry, if this was a security issue, all this has done is tell everyone in the world, including potential harm causers, where these things are, why you can't find them now, what they do, when they'll be back and where to find them. Talk about unintended consequences.