Comment from United Airlines
United AirlinesSupportBusiness
Summary: United Airlines supports the Airworthiness Directive but requests the inclusion of specific Accomplishment Instructions from a Pratt & Whitney Service Bulletin. They argue that because EEC timers can be unreliable, the AD should allow for calculating operational hours based on years in service or average annual utilization.
The sensor replacement times based on operational hours is tracked by the EEC timer. Industry experience indicates a significant quantity of units at shop visits with suspect/unrealistic EEC times, that cannot be used to determine operating hours. United Airlines requests that the Accomplishment Instructions in PW SB PW4ENG 73-221 be included in this AD, specifically, that the EEC operational hours can also be established by multiplying years in service by 3,048 hours or average utilization per year.