76-001 - GA8

Applicability:

All Gippsland GA8 Airvan aircraft.

Purpose:

This Continued Airworthiness Notice (CAN) alerts operators of Gippsland GA8 Airvan aircraft to inspect the throttle cable P/N GA8-761012-11 to throttle lever P/N GA8 -714011-11 installation. 

Background:

This CAN is prompted by a report from an operator of a Gippsland GA8 Airvan aircraft finding a sluggish feel to the aircraft throttle operation.

Investigation revealed that the throttle cable female rod end P/N GA8-270021-31 to throttle lever P/N GA8-7140-11-11 attachment was found to be very loose. When nut P/N MS21042-3 was retightened, it was noted that the female rod end P/N GA8-270021-31 was in contact with the penny washer P/N AN970-3 due to the approach angle of the throttle cable being too sharp relative to the throttle lever. Movement of the throttle control transferred rotational forces to the penny washer which resulted in rotation of the bolt causing the lightweight locknut to loosen.

The CAA is concerned that the throttle cable to throttle lever attachment on other Gippsland GA8 Airvan aircraft may be loose, and eventually result in detachment and loss of engine throttle control.

Recommendation:

To minimise the potential of contact between the female rod end and the penny washer, replace the rod end spacer P/N GA8-710011-17 on the penny washer side of the female rod end with a thicker spacer of the same specification.

To reduce the angle between the throttle cable and the throttle lever replace the rod end spacer P/N GA8-710011-17 on the throttle lever side of the female rod end with a longer spacer of the same specification.  The longer spacer increases the clearance between the female rod end and the throttle lever and reduces the angle of approach of the throttle cable.

To prevent loosening of the bolt and nut, replace bolt P/N AN3-11 with a drilled bolt P/N AN3-11 and replace nut P/N AN3-11 with a castellated nut P/N MS17825-3 and a split pin.

Move the throttle control through the full range of movement to ensure adequate clearance between the female rod end, penny washer, throttle lever and other engine parts.

The photo below shows the reconfigured installation to achieve adequate clearance between the female rod end, the penny washer and the throttle lever.

A thicker spacer fitted to allow sufficient clearance to avoid contact between the penny washer and the female rod end.

Nut P/N MS17825-3

Longer spacer fitted. Rod Spacer

Enquiries:

All other enquires regarding this CAN should be made to:

Owen Olls

Airworthiness Specialist

Email: ollso@caa.govt.nz

Phone: 04 560 9569