COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 106 CIVIL AVIATION SAFETY AUTHORITY
SCHEDULE OF AIRWORTHINESS DIRECTIVES
Rolls Royce Turbine Engines - Viper Series
AD/VIPER/4 Blow-Off Valve 3/90
Applicability: Viper Mk. 521, 522 engines.
Requirement: 1. Action in accordance with Rolls Royce Service Bulletin No. 75-31, or
2. CAO 106 AD/RRT-V/14. Compliance: Effective 22 March 1990.
Background: This Directive has been reissued to require repetitive inspection of the blow-off valve.
Engine surge/stall events have been attributed, in part, to stiction of the blow-off valve.