AD propsed to end JT15D flameouts
The FAA and Pratt & Whitney Canada believe they have found the cause of at least three high-
altitude, dual-engine flameouts on Pratt & Whitney Canada JT15D-5-powered airplanes operating in certain meteorological conditions. In a proposed Airworthiness
Directive issued on August 22, the FAA said its investigation into these incidents revealed that the engine’s fuel control hydromechanical unit (HMU) P3 servo can be exposed to excessive moisture and freezing, subsequently causing the flameouts. To preclude P3 servo freezing, P&WC has issued a JT15D alert service bulletin to reroute compressor delivery air to the HMU and improve moisture separation. The FAA’s proposed AD would mandate the incorporation of the SB on affected JT15D-5 engines within 200 flight hours after the effective date of this AD or by December 31, whichever occurs first. The JT15D-5 turbofan powers Cessna 500-series Citations, Mitsubishi Diamonds and Beechjet 400s/Hawker 400XPs.