Air New Zealand Technial Operations

Air New Zealand requests the FAA review the following issue with regards the embodiment of Boeing Alert Service Bulletin 777-55A0016 Rev 01 as terminating action to the proposed FAA AD. SB777-55A0016 has been released as an airframe bulletin, but the SB modifies the elevator as a standard alone component and does not affect the airframe. Accomplishment of SB 777-55A0016 , leaves the elevator assembly P/N unaffected but the elevator data plate has the service bulletin added to it (see 777-55A0016 Rev 01, Part C., 3 ‘Parts Modified and Re-identified’, Note (b). The Elevator assembly is an interchangeable component however the current IPC does not show a one-way part interchangeability with pre and post embodiment 777-55A0016 terminating action assemblies due to the part number remaining unchanged. If an operator embodies SB 777-55A0016 rev 01 the repeat inspections of SB 777-55A0015 are terminated per AD 2007-26-05. The risk is that if an unscheduled maintenance occurs that replaces the elevator the operator could potentially install a pre-modified elevator and not reinstate the repeat mandatory inspections per SB 777-55A0015 due no part number changed and no IPC interchangeability information. The implications of installing a pre-modified elevator and not re-instating the repeat inspection per SB 777-55A0015 would be an unsafe condition and the aircraft would be out of compliance to the current and proposed AD. AirNZ suggests the installed P/N should be amended to reflect embodiment of 777-55A0016 instead of the current data plate modification. The benefit of Boeing re-numbering the modified elevator assembly would be to ensure the effective airplane shows very clear pre/post modification configuration of the elevator assemblies. The part number changes will also add further clarity to inspection requirements when fitting pre/post 777-55A0016 modified assemblies, reducing the potential for human error in management of the airplane maintenance