COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Boeing 727 Series Aeroplanes AD/B727/121 Takeoff Configuration Warning System 9/90 Applicability: All model Boeing 727 series aircraft not equipped with a system incorporating engine pressure ratio (EPR) logic for activation of the takeoff warning system. Requirement: 1. For 727 series aircraft with auto-speedbrakes operative: Modify the logic which enables the Takeoff Configuration Warning Systems (TOCWS) in accordance with Boeing Service Bulletin 727-31-29; 727-31-33; 727-31-35; or 727-31-36 as appropriate. 2. For 727 series aircraft not equipped with auto-speedbrakes or with the auto- speedbrakes deactivated: 1. Modify the logic which enables the Takeoff Configuration Warning System(TOCWS) in accordance with Boeing Service bulletin 727-31-29; 727- 31-33; 727-31-35; or 727-31-36 as appropriate; OR b. Adjust the takeoff warning thrust lever actuated switches to operate at 19.5 degrees from the idle stop for takeoff configuration warning system arming in accordance with Boeing Service bulletin 727-31-30. Install a circuit breaker guard (cover) on the TOCWS circuit breaker, and safety wire the guard. Operation of the aircraft must be in accordance with the limitations of the TOCWS specified in Appendix 39 or 51 (as appropriate) of the aircraft Flight Manual. Note: FAA AD 90-03-18 refers. Compliance: Prior to 6 September 1992. Background: Compliance with this AD is required in order to prevent takeoff configuration warning system nuisance warnings when taxi operations are conducted with the flaps intentionally retracted.