COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY
SCHEDULE OF AIRWORTHINESS DIRECTIVES
Bell Helicopter Textron Canada (BHTC) 222 Series Helicopters
AD/BELL 222/5 Ng Operating Speed Restrictions 11/85
Applicability: Bell 222U helicopters with Lycoming LTS101-750C-1 engines installed which have not been modified in accordance with LYC SB 101C-72-00-0079.
Requirement: Install engine operating speed restriction placard/ decal P/N 222-075-221-101 or similar, which reads:
AVOID CONT OPS 86% to 90% Ng
beneath gas producer speed indicators in accordance with Bell Helicopter Textron Alert Service Bulletin No. 222U-85-6.
Note: Temporary Revision No. 85-1 to Model 222U Flight Manual BHT-222U-FM-1 is required whilst this restriction is effective.
Effective: Forthwith.
Background: A number of contained turbine blade failures have occurred due to fatigue caused by vibration stresses when engines are operated in the 86% to 90% speed range. This Directive is issued restricting operation in this range until gas producer turbine wheels are modified in accordance with LYC SB 101C-72-00-0079.