Airworthiness Directive · Amendment 39-17070 · Honeywell International, Inc. Turbofan Engines
Honeywell International, Inc. Turbofan Engines
This AD applies to Honeywell International, Inc. ALF502L-2C; ALF502R-3; ALF502R-3A; ALF502R-5; LF507-1F; and LF507-1H turbofan engines.
We are adopting a new airworthiness directive (AD) for all Honeywell International, Inc. ALF502L-2C; ALF502R-3; ALF502R-3A; ALF502R-5; LF507-1F; and LF507-1H turbofan engines. This AD was prompted by two reports of engines experiencing uncontained release of low-pressure (LP) turbine blades. This AD requires operational checks of the engine overspeed trip system. We are issuing this AD to prevent LP turbine overspeed leading to uncontained release of the LP turbine blades and damage to the airplane.
Within 30 operating hours after the effective date of this AD, perform an initial check of the overspeed trip system, in accordance with the applicable paragraphs for your engine as follows:
(i) With engine operating at 65 percent NL (N1) speed (28 to 30 percent if overspeed controller 2-303-052-04 or later is installed), pull toggle lever of cockpit OVERSPEED TEST/RESET switch and hold in the OVERSPEED TEST position.
(ii) Activation of the engine overspeed system shall be verified by:
(A) Engine OVERSPEED TRIP light illuminated in cockpit.
(B) Reduction of engine NH (N2) speed.
(C) When engine NH (N2) speed begins to decrease, retract engine power lever to fuel cutoff position and turn off fuel boost pumps.
(D) Release lever of engine cockpit OVERSPEED TEST/RESET Switch.
(E) When engine is completely shut down, reset the engine Overspeed System by momentarily holding the engine cockpit OVERSPEED TEST/RESET switch on the RESET position.
(F) If engine does not shut down, manually shut down engine and perform a detailed functional test of the overspeed system. Guidance on performing a detailed functional test of the overspeed system can be found in the applicable engine maintenance manual instructions.
(i) With engine operating at ground idle, set engine NL (N1) speed to 30 to 35 percent.
(ii) Press cockpit OVERSPEED TEST switch and hold.
(iii) Activation of the engine overspeed system shall be verified by:
(A) Engine OVERSPEED TRIP light illuminated in cockpit.
(B) Shutdown of the engine [zero NH (N2) speed].
(iv) Release cockpit OVERSPEED TEST switch and retract power lever to fuel cutoff position.
(v) When the engine is completely shut down, reset the engine overspeed system.
(vi) If engine does not shut down, manually shut down engine and perform a detailed functional test of the overspeed system. Guidance on performing a detailed functional test of the overspeed system can be found in the applicable engine manual instructions.
(i) With engine operating at ground idle, set engine NL (N1) speed to 30 to 35 percent.
(ii) Activate cockpit overspeed test circuit (GRND TEST ENG OVSPD).
(iii) After NL (N1) speed begins to decay, retard the throttle to the fuel cutoff position.
(iv) Verify the following conditions:
(A) Engine shutdown.
(B) Overspeed system light (ENG OVSPD) is illuminated in cockpit.
(v) Reset overspeed system circuit power.
(vi) If engine does not shut down, manually shut down engine and perform a detailed functional test of the overspeed system. Guidance on performing a detailed functional test of the overspeed system can be found in the applicable engine manual instructions.
(1) For ALF502L-2C engines, perform repetitive checks of the overspeed trip system at 100-hour intervals of operation, as specified in paragraph (f)(1) of this AD.
(2) For ALF502R-3; ALF502R-3A; ALF502R-5; and LF507-1H engines, perform repetitive checks of the overspeed trip system once every flight day, as specified in paragraph (f)(2) of this AD.
(3) For LF507-1F engines, perform repetitive checks of the overspeed trip system once every flight day, as specified in paragraph (f)(3) of this AD.
For the purpose of this AD, a flight day is a 24-hour period during which at least one flight is indicated.
Upon starting the daily repetitive checks, only one sign-off is required attesting to the daily check implementation.
