NTSB · Safety Recommendation
Safety Recommendation A-76-020
Recommendation
REQUIRE, AFTER A CERTAIN DATE, THAT PASSENGER EMERGENCY SUPPLEMENTAL OXYGEN SYSTEMS HAVE READILY DISCERNIBLE MEANS TO INDICATE THAT OXYGEN IS FLOWING.
Safety Issue and Context
SEVERAL RAPID DECOMPRESSION MISHAPS INVOLVING DC-10 AND L-1011 AIRCRAFT HAVE DISCLOSED PROBLEMS WITH CHEMICALLY GENERATED PASSENGER SUPPLEMENTAL OXYGEN SYSTEMS. THE NATIONAL TRANSPORTATION SAFETY BOARD'S SPECIAL STUDY, "CHEMICALLY GENERATED SUPPLEMENTAL OXYGEN SYSTEMS IN DC-10 AND L-1011 AIRCRAFT"1/INDICATES THAT THESE PROBLEMS ARE PRIMARILY THE RESULT OF A LACK OF UNDERSTANDING OF THE SYSTEM BY BOTH PASSENGERS AND FLIGHT ATTENDANTS.
Response History
June 17, 1985 · NTSB Correspondence · FAA
In its ltr dtd 2/21/78, the faa offered the issuance of ac 121- 24, passenger safety information briefing and briefing cards, in fulfill- ment of this recommendation. This ac requested that flight attendants provide passengers, as part of the pretakeoff oral briefing with informa- tion concerning the amount of inflation of the oxygen bag. The safety board notes that most airlines now include this information as part of their recommendation. The board recommended that the systems incorporate a positive means to detect flow. Discussions with the faa staff have failed to persuade the faa to consider requiring oxygen flow indicators as required
by the british and australian aviation authorities. Safety recommendation a-76-20 is still considered to be appropriate action to enhance safety board on the information gathered by the safety board. Since the safety board has not additional information to provide in support of this recommendation, safety recommendation a- 76-20 has been classified as closed--unacceptable action. However, the safety board will continue to stress this safety issue in future pertinent accident investigations and in safety studies.
February 21, 1978 · Recipient Response · FAA
FAA LTR: ADVISORY CIRCULAR AD-121-24 WAS ISSUED JUNE 23, 1977.
February 11, 1977 · Recipient Response · FAA
FAA LETTER: FAA DISAGREES WITH THE BOARD'S RECOMMENDATION AND RESTATES THAT "THE CURRENT RESERVOIR BAG WILL GIVE A GOOD FLOW INDICATION AS THE CABIN ALTITUDE IS INCREASED TO THE HIGHER LEVELS WHERE THE NEED FOR SUPPLEMENTAL OXYGEN IS GREATEST." THE FAA PLANS TWO SPECIFICATIONS. THEY WILL: (1) EVALUATE THE BASIS FOR THE BRITISH AND AUSTRALIAN REQUIREMENT FOR A DISCERNIBLE FLOW INDICATOR. (2) ISSUE AN AC TO PROVIDE THE PRINCIPAL INSPECTORS WITH GUIDELINES FOR STANDARDIZATION OF PASSENGER BRIEFING CARD INFORMATION.
December 29, 1976 · NTSB Correspondence · FAA
With regard to recommendation a-76-20, which recommends that passenger supplemental oxygen systems have a means to indicate oxygen flow when the system is operating, a variety of sensitive, reliable, and simple flow-indicating devices are available today to perform this function. In fact, such devices are required by the united kingdom and by australia on certain components of chemically generated oxygen systems.
August 2, 1976 · Recipient Response · FAA
FAA LTR: THE FAA DOES NOT CONCUR WITH THIS RECOMMENDATION. A FLOW DETECTOR TO BE RECOGNIZABLE TO PASSENGERS WOULD NEED TO BE VERY SENSITIVE AND RELIABLE TO INDICATE THE EXTREMELY LOW OXYGEN FLOW RATE OF THE LOWER CABIN ALTITUDES. REGARDLESS OF FLOW INDICATORS, AT LOW CABIN ALTITUDES LAY PASSENGERS MAY NOT BE AWARE THAT THEY ARE RECEIVING A NORMAL FLOW OF OXYGEN.