AD 50-05-02

50-05-02 SHAKESPEARE CONTROLS: Applies to Shakespeare Vernier Type Flexible Push-Pull Controls, Models 3A-42 and 3A-81, Installed in Beech Models 35 and A-35, Navion, and Any Other Certified Aircraft.

To be accomplished not later than April 1, 1950.

A serious accident recently occurred on an aircraft employing a Vernier throttle control of the above type due to unscrewing of the male thread adapter which secures the outer casing of the flexible control to the body tube, at the instrument panel end. This resulted in the pilot's being unable to control the throttle. The means employed in these controls to secure this connection is the machining of some imperfect threads on the brass adapter. This method of locking is not considered satisfactory, as assembly and disassembly of these components can result in rendering this locking means ineffective. The control manufacturer has advised that a staking operation to positively secure this connection is now being incorporatedon all their Vernier type flexible controls during manufacturer.

To prevent the possibility of the adapter becoming separated from the body tube on aircraft in service equipped with the subject Vernier control, all such controls must be inspected to ascertain whether these components are positively secured by staking, drilling and lock-wiring, or equivalent means. If the adapter is not found to be so secured in the body tube, it should be locked by one of the foregoing locking means.

(Beech Engineering Service Bulletins Nos. 35-16 and A35-7, dated November 23, 1949, cover this subject as it applies to their Models 35 and A-35 airplanes.)