COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY
SCHEDULE OF AIRWORTHINESS DIRECTIVES
Boeing 767 Series Aeroplanes
AD/B767/47 Hydraulic Power Transfer Unit System 12/90
All model B767-200 and B767-300 series aeroplanes on which Production Revision Record (PRR) B-11777 has not been incorporated.
1. Aeroplanes identified in Boeing Alert Service Bulletin 767-29A0039, dated 11 May 1989, shall be modified in accordance with this Service Bulletin, and
2. All other aeroplanes, in accordance with Boeing Alert Service Bulletin 767- 29A0039, Revision 1, dated 2 November 1989.
FAA AD 90-18-04 Amendment 39-6714 also refers.
Prior to 9 April 1992.
Boeing has advised, analysis indicates that if both left and centre hydraulic systems of applicable aircraft become inoperative, and with adverse centre-of-gravity and gross weight combination, pitch control during approach and landing is marginal. The addition of the power transfer unit (PTU) system will provide stabiliser pitch control and additional landing flare capacity in the event of such a situation.