Output Number
Approval Date
Published Date Time
Recommendation type
Mode
Date released

The Australian Transport Safety Bureau recommends that the Civil
Aviation Safety Authority alert helicopter maintenance
organisations and all aircraft maintenance engineers to the
potentially detrimental effects of painting engine-cooling
fans.



As a result of technical analysis of the fan blade failures, the
Bureau simultaneously issues the following recommendations:



R19990195



The Australian Transport Safety Bureau recommends that the Civil
Aviation Safety Authority alert all aircraft maintenance engineers,
especially those conducting nondestructive inspections, to the
detrimental effects that may be created in critical components by
the abrasion of surfaces during general cleaning or cleaning in
preparation for nondestructive inspection.



R19990197



The Australian Transport Safety Bureau recommends that Kawasaki
Heavy Industries clarify the bolt-tightening instructions contained
in Service Bulletin 305 to establish if an allowance should be made
for the frictional torque effects of self-locking nuts.

Organisation Response
Date Received
Organisation
Civil Aviation Safety Authority
Response Text

CASA accepts the recommendation and advises that the following
action has been taken.



A direction under CAR 38 (1) of the Civil Aviation Regulations 1988
was forwarded to all Certificate of Registration holders of
Kawasaki-Bell 47G3B-KH4 and 47G2 helicopters and Bell 47
helicopters on 14 January 1998. The direction requires that all
maintenance undertaken complies with the maintenance data produced
by the helicopter manufacturer and other approved data. It also
requires that engine cooling fans fitted to helicopters be checked
to ensure that the fan is the correct part number for the
helicopter.



More recently, CASA has prepared an Airworthiness Bulletin (AWB) to
alert the industry to the issues raised in the recommendation (the
effect of fan painting and surface preparation prior to
nondestructive testing). AWB 75-001 Issue 1, Cooling Fans in Piston
Engine Helicopters, was issued on 15 March 2002