The engine manufacturer’s documents with respect to the propeller mounting flange were technically inconsistent with regard to painting and torqueing procedures.
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.
On the matter of avoiding paint on all the propeller-mounting flange’s faying surfaces – additional text has been included within the engine overhaul manual to emphasise and strengthen the requirement. Additionally, the latest revision of the process specification, covering surface preparation and painting, unambiguously specifies the manuals’ requirement for nil paint below the cap screw washers and the crank and propeller faying surfaces. On the subject of consistency for the torqueing procedure, this has been amended in both relevant manuals to solely specify the one-step, dynamic torqueing process.
