A few months back, a statement was issued by the Federal Aviation Administration FAA in the US about chemical oxygen generators being disabled or removed from lavatories because they posed a ‘security vulnerability’ and could potentially be used to start a fire.  The problem of course is that if you happen to be in the lavatory of an American commercial aircraft thousands of metres above ground, and there is a loss of cabin pressure, it could lead to hypoxia — when the body is deprived of adequate oxygen supply — causing injury or death.

While loss of cabin pressure itself seems a rarity nowadays, this recent regulation shows that risks posed by terrorism can transform how we view other risks, such as health.  And while releasing information about eliminating this security risk definitely seems reasonable, will other airlines outside the US have to follow suit since the risk has been made available publicly?  Where do the boundaries lie between security, risk and national law?  When does making something secure create new risks while preventing others?  Obviously, preventing the possibility of terrorist attacks through various means has priority, as these risks can lead to disasters resulting in the loss of many lives and tremendous damage.

Removing oxygen generators from lavatories could be seen as another example of how authorities attempt to sanitise our risk-laden environments to ensure everyone’s ‘safety’.  But merely weighing up the risks against the benefits has also been show to be overly reductive in practice, often provoking disasters rather than mitigating them.  On the extreme end of this, you have technological hazards such as the Deepwater Horizon oil spill and the nuclear meltdown at Fukushima, along with many others, that show why new forms of analyses that account for complex systems need to be used as well, to account for what traditional top-down risk management approaches fail to acknowledge.

Last month, Southwest Airlines Flight 812 in the US experienced a rapid depressurisation at 10,485 m altitude and was forced to make an emergency landing.  There was later found to be a ‘hole’ in the top of the aircraft that caused the cabin to depressurise, leading to a loss of oxygen for people to breathe.  This wasn’t the first incident for Southwest as there was another one only two years before.

Below is a list of notable uncontrolled decompression ‘accidents’ and ‘incidents’ listed in a Wikipedia article about the topic:

Event↓ Date↓ Pressure vessel↓ Event Type↓ Fatalities/number on board↓ Decompression Type↓ Cause↓
Soyuz 11 re-entry 1971 American Airlines Flight 96 1972 Douglas DC-10-10 Accident 0/67 Rapid decompression[17] Cargo door failure
National Airlines Flight 27 1973 Douglas DC-10-10 Accident 1/116 Explosive decompression[18] Crew tripping circuit breakers; engine overspeeding and disintegrating, pieces striking fuselage
Turkish Airlines Flight 981 1974 Douglas DC-10-10 Accident 346/346 Explosive decompression[19] Cargo door failure
Tan Son Nhut C-5 accident 1975 C-5 Galaxy Accident 155/330 Explosive decompression Improper maintenance of rear doors, cargo door failure
Far Eastern Air Transport Flight 103 1981 Boeing 737 Accident 110/110 Explosive decompression Corrosion
Byford Dolphin accident 1983 fail-safe in the design
Korean Air Lines Flight 007 1983 Boeing 747-230B Shootdown 269/269 Rapid decompression[20][21] Intentionally fired http://en.wikipedia.org/wiki/Air-to-air_missile”>air-to-air missile after aircraft strayed into prohibited airspace; 12 minutes of flight after damage from missile shrapnel caused the cabin to decompress.[22]
Japan Airlines Flight 123 1985 Boeing 747-SR46 Accident 520/524 Explosive decompression Structural failure of rear pressure bulkhead
Aloha Airlines Flight 243 1988 Boeing 737-297 Accident 1/95 Explosive decompression[23] Metal fatigue
Boeing 747-121 Terrorist bombing 259/259 Explosive decompression Bomb explosion in cargo hold
United Airlines Flight 811 1989 Boeing 747-122 Accident 9/355 Explosive decompression Cargo door failure
British Airways Flight 5390 1990 [24] Incorrect windscreen fasteners used
Boeing 747-131 Accident 230/230 Explosive decompression Explosion in fuel tank
Lionair Flight LN 602 1998 MANPAD shootdown
South Dakota Learjet 1999 Australia “Ghost Flight” 2000 Beechcraft Super King Air Accident 8/8 Decompression suspected (Undetermined)
Fokker 100 Accident 1/82 Rapid decompression Window ruptured by shrapnel after engine failure[25]
China Airlines Flight 611 2002 Boeing 747-200B Accident 225/225 Explosive decompression Metal fatigue
Helios Airways Flight 522 2005 Boeing 737-31S Accident 121/121 Gradual decompression The pressurization system was set to manual for the entire flight, resulting in a failure to pressurize the cabin.[26]
Alaska Airlines Flight 536 2005 McDonnell Douglas MD-80 Incident 0/140 + crew Rapid decompression Failure of operator to report collision involving a baggage loading cart at the departure gate. Decompressed at 26,000 feet
Qantas Flight 30 2008 [27] Fuselage ruptured by explosion of an oxygen cylinder
Southwest Airlines Flight 2294 2009 Boeing 737-300 Incident 0/126 + 5 crew Rapid decompression 1-square-foot (0.1 m2) hole blown in fuselage during flight.[28] Metal fatigue
Southwest Airlines Flight 812 2011 Boeing 737-300 Incident 0/118 + crew Rapid decompression 5-square-foot (0.5 m2) hole blown in fuselage during flight due to metal fatigue[29]

The point of presenting all this is that decompression inside commercial aircraft in flight, although rare, still occurs and the decision to remove oxygen generators where they could be needed by passengers seems more reactive than intelligent.  Critical thinking seems absent when addressing the potential new risks that could result from regulations.  Anyone who travels by air is reminded again and again about oxygen masks being deployed during a loss of cabin pressure.  In the future though, the next time I travel by air in the US, I might make my trips to the lavatory as quick as possible.

Further Reading

FAA Press Release: https://www.faa.gov/news/press_releases/news_story.cfm?newsId=12518

FAA technical document on removal of chemical oxygen generators from lavatories: http://www.airweb.faa.gov/Regulatory_and_Guidance_Library/rgAD.nsf/0/9f88c7760144bb948625784d0050a787/$FILE/2011-04-09.pdf

‘Southwest’s Scare’. http://newsfeed.time.com/2011/04/05/southwests-scare-when-a-plane-decompresses-what-happens/. Time

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