Safety Recommendation A-74-007

The National Transportation Safety Board 1 s continuing investigation of the National .Airlines DC-10 accident near Albuquerque, New Mexico, on November 3, 1973, has disclosed unsafe conditions in the passenger oxygen system, portable oxygen system, and cabin pressurization system. The Board believes that these unsafe conditions merit your immediate attention and the attentions of all air carriers which operate aircraft with this equipment.

When the aircraft lost a cabin window and the passenger cabin decompressed, many of the passenger's oxygen-generating units were activated. Three oxygen canisters came out of their mountings in the seatback oxygen compartment and fell onto passenger seat cushions. Two of these canisters, which become very hot when operating, scorched the cushions and burned fingers when seat occupants tried to remove them. The third reportedly caused a small fire. The canisters came out of their mounting brackets because of the pulling force exerted on either the initiation lanyard of the canisters or the oxygen supply hose.

The Safety Board believes that these canisters constitute a potential fire and injury hazard when they are not retained properly in their mountings.