Aviation safety issues and actions

Insufficient joint clamping

Issue number: AO-2013-046-SI-02
Who it affects: All owners and operators of Jabiru J230 & J430 aircraft
Issue owner: Jabiru Aircraft Pty Ltd
Operation affected: Aviation: General aviation
Background: Investigation Report AO-2013-046
Date: 19 August 2014

Safety issue description

The manufacturer’s specified procedure for assembling and torqueing of the crankshaft/propeller flange fasteners was ineffective in ensuring resistance against subsequent joint movement in service.

Proactive Action

Action organisation: Jabiru Aircraft Pty Ltd
Action number: AO-2013-046-NSA-015
Date: 19 August 2014
Action status: Closed

The manufacturer has issued a revised Propeller Flange Attachment Service Bulletin. It no longer specifies the multi-step torqueing procedure, instead referring to the correct procedure in the Engine Overhaul Manual i.e. single-step torqueing. 

An additional requirement has been introduced for mounting surfaces to be free from paint, thread-locking compound or other contaminants before assembly. The relevant painting process specification now requires that all three faying surfaces of the flange be masked plus an illustrative diagram accompanies the text.

Current issue status: Adequately addressed
Status justification:

The documentary changes should ensure the increased reliability of the propeller flange/crankshaft joint and the reduced likelihood of propeller loss due to joint fastener failure.

Last update 19 August 2014