Safety Recommendation A-76-027

The safety board finds that safety recommendation a-77-58 is met by the release of technical standard order (tso) c-64a, oxygen mask assembly, continuous flow, passenger. This tso utilizes society of automative engineers aerospace standard (as) 8025 for technical descriptions of these oxygen masks, their function, and testing. Safety recommendaitons a-76-21 and -23 are met by as 8025, paragraphs 4.2 and 3.9, respectively. Recommendation a-76-27, which calls for use of established human factors engineering principles and which calls for use of established human factors engineering principles and system design concepts, is not directly addressed by any one area of the tso or as.

However, the use of such principles and concepts is evident throughout the as 8025 document in such areas as ease of use, service life, and lack of maintenance. Therefore, safety recommendation a-76-21, -23, and a-77-58 are classified as "closed--acceptable action." safety recommendation a-76- 27 is classified as "closed--acceptable alternate action."

On 8/25/89, the faa issued technical standard order (tso) c-64a, oxygen mask assembly, continuous flow, passenger. This tso prescribes the minimum performance standards that these oxygen mask devices must meet in order to be identified with the applicable tso marking. I have enclosed a copy of the tso for the board's information. I consider the faa's action to be completed on these safety recommendations, and i plan no further action.

The safety board is reviewing the proposed revisions to technical standard order (tso) c-64a, oxygen mask assembly, continuous flow, passenger, and will provide comments to the faa on the responsiveness of the tso to the safety recommendations in the near future. Safety recommendations a-76-21, -23, and -27, and a-77-58 will remain in an open--unacceptable action status to underscore our concern with the inactivity which has been displayed by the faa during the 12 years since their issuance.

ON JULY 19, 1988, THE FAA ISSUED A NOTICE OF AVAILABILITY OF TECHNICAL STANDARD ORDER (TSO) C-64A, OXYGEN MASK ASSEMBLY, CONTINUOUS FLOW, PASSENGER, IN THE FEDERAL REGISTER FOR PUBLIC COMMENT. I HAVE ENCLOSED A COPY FOR THE BOARD'S INFORMATION. I WILL PROVIDE THE BOARD WITH A COPY OF THE FINAL ACTION AS SOON AS IT IS ISSUED.

While we are pleased that the faa will propose a revision to technical standard order (tso) c64a as soon as the aerospace council committee approves the draft society of automotive engineers aerospace standard 8025, continuous flow oxygen mask this information is identical to that contained in the faa's response to these recommendations dated january 13, 1986. The safety board believes that the action described could satisfy the intent of these recommendations when completed.However, because of the extended delay in moving forward with the revision to tso c64a, these safety recommendations will be held in an open--unacceptable action status pending

the completion of the tso revision. We appreciate your keeping the safety board apprised of progresson these actions and look forward to an expeditious resolution of these recommendations.

A DRAFT SAE AEROSPACE STANDARD 8025 "CONTINUOUS FLOW OXYGEN MASK" HAS BEEN DEVELOPED. THE DRAFT AS ADDRESSES THE ADJUSTMENT TABS, SERVICE LIFE AND PERIODIC INSPECTION REQUIREMENTS, AND HUMAN FACTORS ENGINEERING PRINCIPLES AND DESIGN CONCEPTS IN THE DESIGN OF PASSENGER SUPPLEMENTAL OXYGEN SYSTEMS. THE DRAFT AS HAS BEEN SENT TO THE AEROSPACE COUNCIL COMMITTEE FOR APPROVAL. AS SOON AS THE DRAFT HAS BEEN APPROVED, THE FAA WILL PROPOSE A REVISION TO TSO C64A TO INDICATE THE STANDARD.

The safety board is pleased to learn that the society of automotive engineers (sae) aerospace standard (as) 8025 draft, continuous flow oxygen mask, has been developed which addresses safety recommendations a-76-21, -23 and -27. Pending approval of the draft as a specification andthe subsequent revision to technical standard order c64a, safety re- commendations a-76-21, -23, -27, and a-77-58 have been classified as open--acceptable action.

IN RESPONSE TO THESE RECOMMENDATIONS, A SOCIETY OF AUTOMOTIVE ENGINEERS (SAE) AEROSPACE STANDARD (AS) 8025, CONTINUOUS FLOW OXYGEN MASK, HAS BEEN DEVELOPED AND IS IN COORDINATION WITH THE SAE COMMITTEE. THE DRAFT AS-8025 ADDRESSES THE ADJUSTMENT TABS (A-76-21), SERVICE LIFE AND PERIODIC INSPECTION REQUIREMENTS (A-76-23), AND HUMAN FACTORS ENGINEERING PRINCIPALS AND DESIGN CONCEPTS IN THE DESIGN OF PASSENGER SUPPLEMENTAL OXYGEN SYSTEMS (A-76-27). I HAVE RECENTLY ASKED THE SAE TO EXPEDITE THE ACTION CONCERNING THE APPROVAL OF THE DRAFT AS 8025 SPECIFICATION. WHEN AS 8025 HAS BEEN APPROVED BY THE SAE COMMITTEE, THE FAA WILL PROPOSE A REVISION TO TSO C64A TO INDICATE THE STANDARD.

FAA LTR: WE ARE INITIATING A STUDY OF HUMAN FACTORS ENGINEERING PRINCIPLES AND SYSTEM DESIGN CONCEPTS RELATING TO PASSENGER SUPPLEMENTAL OXYGEN SYSTEM. THE STUDY WILL BE DONE AT OUR CIVIL AEROMEDICAL INSTITUTE IN OKLAHOMA CITY AND WILL DRAW ON ALL CURRENTLY AVAILABLE DATA, INCLUDING SAE DATA.

Recommends development of design standards for passenger supplemental oxygen systems which would include accepted human factors engineering principles and system design concepts for use by designers of these systems.

FAA LTR: THIS RECOMMENDATION IS NOT CLEAR AS TO WHAT NTSB EXPECTS AS AN END PRODUCT. HUMAN FACTORS ARE THE PRIME CONSIDERATION IN THE DESIGN OF SYSTEMS SUCH AS OXYGEN SYSTEMS. WE CANNOT SEE THAT THESE CONSIDERATIONS WERE NEGLECTED IN THE DC-10 OR L-1011 SYSTEMS.