AWB 25-10 Issue 1 - Pacific Scientific rotary seatbelt buckles
Pacific Scientific rotary seatbelt buckles
AWB 25-10 Issue 1, 3 April 2006
All aircraft fitted with unguarded rotary seatbelt buckles manufactured by the Pacific Scientific Company.
The purpose of this bulletin is to alert operators and maintainers of aircraft to a problem of inadvertent release of rotary seatbelt buckles manufactured by the Pacific Scientific Company. Also, to advise that an approved replacement guarded seatbelt buckle is manufactured by Pacific Scientific, and to advise that fitment of the guarded seatbelt buckle is strongly recommended.
Investigation of a fatal aircraft accident in 2003 showed that the captain had been ejected from her seat upon impact as a result of uncommanded release of a rotary seatbelt buckle which was made by Pacific Scientific. Other uncommanded releases of the same type of rotary seatbelt buckle have been reported.
As a consequence, and at the request of the Boeing Company and the UK CAA, Pacific Scientific Company have designed and manufactured a replacement rotary buckle which incorporates a protective guard to prevent inadvertent release of the buckle.
The guard was designed in conjunction with Boeing, who have issued Service Bulletins relating to replacement of the buckle on B737 and B757 series aircraft. (As well as inadvertent release, Pacific Scientific rotary seat belt buckles also have a history of possible failure to release under emergency conditions. AD/RES/12 refers).
The following figure depicts the Pacific Scientific rotary seatbelt buckle:
It is recommended that operators and maintainers determine whether rotary seatbelt buckles manufactured by Pacific Scientific Company are fitted to any aircraft which they own or are responsible for.
If so, in each instance it should be determined whether the new guarded seatbelt buckle, as specified in Pacific Scientific Service Bulletin 1117032-25-02 (which was issued specifically in respect to Boeing aircraft) is fitted. If not, it is strongly recommended that the guarded rotary seatbelt buckle, as specified in the above Service Bulletin, be fitted in each instance.
Enquiries with regard to the content of this Airworthiness Bulletin should be made via the direct link e-mail address included on the Airworthiness Bulletin web site, AirworthinessBulletin@casa.gov.au or in writing to the Manufacturing, Certification and New Technology Office, GPO Box 2005, Canberra, ACT, 2601