COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Fokker F28 Series Aeroplanes AD/F28/70 Amdt 1 Horizontal Stabilizer Actuator Servo Valve Assembly 5/95 Applicability: 1. All model F28 (except Mk 0100) S/N 11003 thru 11241, 11991 and 11992. 2. All spare Menasco actuators P/No 11100. Requirement: Unless previously carried out, action in accordance with Fokker Service Bulletin SB F28/27-183. Note 1: RLD AD 1992-077/2 (A) refers. Note 2: Fokker SB F28/27-183 refers to Menasco SB 11100-27-105. Compliance: 1. a. By 01 August 1995 for Part 1 of the Requirement Document. 1. b. For Part 2 of the Requirement Document: At next removal of the stabilizer control unit or by 01 January 1998, whichever occurs first. 2. Prior to installation on an aircraft. Background: A crew on an overseas F28 experienced a horizontal stabilizer malfunction where the stabilizer trim slowly ran away. The auto pilot disengaged and the aircraft started to pitch up and climb. Although both pilots held the control column fully forward, the aircraft continued to climb to 31,000 feet. The crew reduced engine power after which the climb stopped and the aircraft started to descend. At the same time the centre of gravity had been moved forward by reseating the passengers. The aircraft diverted and carried out an emergency landing at the nearest airport. This amendment is being raised to mandate actuator modification following advice that a F28 horizontal stabilizer moved to the full nose down position after engine shut-down.