Executive summary
An engine failure, and subsequent forced landing, occurred to an Aerospatiale AS 350D helicopter during a scenic flight over the Fox Glacier on 17 March 1993. The safety issues discussed in the report are related to the promulgation and implementation of manufacturer's Service Letters and the inspection of unmodified fuel pump assemblies.
Related Recommendations
Alert owners/operators of LTS 101 series gas turbine engines to the circumstances of the accident to AS 350D ZK-HGV and the potentially serious consequences of complete power loss resulting from failure of the fuel pump drive.
Draw attention of owners/operators to Textron Lycoming Commercial Service Letter 102 (dated 23 June 1992) to inform or remind them of the series of modifications and improvements that may be made to existing fuel pumps with particular reference to Chandler Evans Service Bulletin SB 73-98 "Improved internal spline lubrication resulting in reduced spline wear and extended pump service life".
Give consideration to mandatory action such as the publication of an Airworthiness Directive to require the installation of fuel pumps modified or manufactured to the latest improved status on LTS 101 gas turbine engines, or to require specific modifications to be incorporated, including SB 73-9, on existing fuel pumps currently at a lower modification status.
Dependent on action taken, in 062/93 above, give consideration to requiring an inspection of fuel pump drive shaft internal/external splines in affected Chandler Evans fuel pump assembled installed on the LTS 101 gas turbine engines to ensure that spline wear will not compromise the integrity of the fuel pump drive before the assembly is withdrawn from service for overhaul.