AD/LEARJET 35/15 - Automatic Flight Control Systems - Inspection and Modification (Cth)

COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES

Gates Learjet 35 and 36 Series Aeroplanes

AD/LEARJET 35/15 Automatic Flight Control Systems - Inspection and Modification

9/80

Applicability: All models 35, 36, 35A, 36A with S/Nos. 35-001 and subsequent and 36-001 and subsequent.

Requirement: Conduct the following inspections to assure capability of manually overriding the Automatic Flight Control Systems:

1. Energize the aircraft electrical system by applying 28 VDC electrical power.

2. Roll Axis

(a) On aircraft equipped with FC-110 autopilot, remove the electrical power from the FC-110 Autopilot Computer. Open the computer and identify the Roll Calibration Board. On the Roll Calibration Board, temporarily install, in parallel with R18 (82 ohm) resistor, a 39 ohm, one watt resistor. Restore the electrical power and engage the autopilot with the control wheel centered and verify that the roll slip clutch breakaway occurs by rotating the control wheel briskly (45 degrees per second) in both directions. If slippage is not verified, remove the capstan and adjust to proper torque per the appropriate Gates Learjet Service Manual. Return Autopilot Computer to original configuration and accomplish a functional check of the autopilot.

(b) On aircraft Models 35, 35A, 36 and 36A, conduct the following inspection of the FC-200 autopilot roll axis to assure capability of manually overriding that axis of Automatic Flight Control Systems:

Check and adjust the roll capstan slip clutch for proper torque in accordance with the appropriate Gates Learjet Service Manual.