AIN Blog: Warning: Airliner Lavatories no Longer Have O2 Supply

 - April 5, 2011, 6:02 AM

The FAA is abdicating its safety responsibility.

The FAA’s primary job is safety, but ever since the 9/11 terrorist attacks, the FAA has allowed the ever-growing Homeland Security bureaucracy to bulldoze the agency into putting security above safety. TFRs, for example, have thus far resulted in hundreds of pilots, many of whom were intercepted by fast-moving military jets, being snagged for innocent airspace violations. One pilot ran out of gas trying to negotiate with a controller to fly into the Washington, D.C., special flight rules area. The latest example is the FAA’s ill-considered move to force airlines to remove oxygen masks from airline lavatories.

The FAA has issued an airworthiness directive (AD 2011-04-09), which is law and must be complied with. This particular AD requires airlines to disable the chemical oxygen generators that supply the oxygen masks inside airline lavatories. Airlines can either empty the oxygen generator and reinstall it or they can remove the generator. (Note to the airlines: don’t throw all the generators into a box! Remember the ValuJet Flight 592 accident!).

Now here’s the weird safety part. The AD allows airlines to restow the oxygen mask inside the mask dispenser in the lavatory. So a passenger who happens to be stuck in the lav during a decompression incident might reach for that mask and find that there is no oxygen available. Time of useful consciousness at 35,000 feet is 30 to 60 seconds. That’s barely enough time to grab the mask in the lav if it was even working.

According to the AD, flight crews have been made aware of this situation. And presumably during a decompression incident, someone would go knock on the lav door and make sure anyone inside gets oxygen. By that time, of course, the hapless passenger is going to be unconscious. Hopefully the pilots will have descended the airplane to thicker air before the oxygen-less lav user becomes brain dead.

The FAA doesn’t specifically cite security issues as a reason for issuing this AD, but claims, “This AD was prompted by reports that the current design of chemical oxygen generators in the lavatories presents a hazard that could jeopardize flight safety. We are issuing this AD to eliminate this hazard.” Reading the AD gives no idea of the nature of this hazard, but it must be serious enough that it is safer to remove access to life-giving oxygen from a passenger in a lav during decompression than to leave the oxygen generator in place.

Decompression events are relatively rare. Although now I can’t help wondering whether someone was in the lavatory when the Southwest Airlines 737 fuselage popped open on April 1. Probably not, the jet was only 18 minutes into its flight out of Phoenix.

To be fair to the FAA, the airlines never used to tell passengers during the briefing, “Oh, by the way, if you’re stuck in the lav and we lose pressure, please use the handy oxygen mask provided.” So now should we expect flight attendants to brief passengers that, “By the way, if you’re stuck in the lav and if we lose pressure, good luck!”

In the long run, it probably won’t make that much of a difference. But honestly, I’d like to know the real reason why the FAA issued this AD. Was it pressure from some anal analyst in Homeland Security, who wondered what havoc a terrorist could wreak by using the heat generated by an oxygen generator to do…what?

Oxygen generator canisters can heat up to 500 degrees F when activated, and they run for 15 to 20 minutes. I’m still not sure how a terrorist could use this. Maybe someone from the FAA could shed some light on this.

June 2017
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