Another strange one on the 135.
Have a look at the screws that attach the SEMA's (Smart Electro Mechanical Actuator) to the flight control runs. The number of SEMA's fitted varies with VFR SAS/IFR Autopilot configuration.
According to type certificate requirements they should have 2 methods of locking.
Part 27
(a) Each removable bolt, screw, nut, pin, or other fastener whose loss could jeopardize the safe operation of the rotorcraft must incorporate two separate locking devices. The fastener and its locking devices may not be adversely affected by the environmental conditions associated with the particular installation.
The 135 clearly does not.
The 155 which uses the same or similar actuator clearly does as the attaching screws are cross drilled and wire locked.
Am I missing something? Does it mean that ONE fastener can fall out and its OK because you have three left?
There were issues recently where the fasteners used were too long. Screws were torqued OK but they had bottomed out in the thread allowing play in the control run.
see ASB EC135-22A-015 - Applicable ALL models.