AD 2006-09-13 Airworthiness Directives; Honeywell International Inc. ALF502L Series and ALF502R Series Turbofan Engines

This AD applies to Honeywell International Inc. (formerly AlliedSignal, Inc. and Textron Lycoming) ALF502L, ALF502L-2, ALF502L-2A, ALF502L-2C, and ALF502L-3 series turbofan engines with third stage turbine disc and shaft assemblies that have operated in the Honeywell Pre SB No. ALF502L 72-232 configuration. This AD also applies to ALF502R series engines. These engines are installed on, but not limited to, BAe Systems AVRO 146 and Bombardier (Canadair) CL600-1A11 series airplanes.

You are responsible for having the actions required by this AD performed within the compliance times specified unless the actions have already been done. ALF502L Series Turbofan Engines Determination of Third Stage Turbine Disc and Shaft Assembly Drawdown Schedule (f) For ALF502L series turbofan engines, determine if the third stage turbine disc and shaft assembly is currently operating in the Pre SB No. ALF502L 72-232 configuration as follows: (1) If a third stage turbine nozzle assembly, part number (P/N) 2-141-120R56/-57 is installed, then Honeywell SB No. ALF502L 72-232 has been complied with. Proceed to the drawdown schedule in paragraph (h) of this AD. (2) If any other third stage turbine nozzle assembly is installed, then the engine is in the Pre SB No. ALF502L 72-232 configuration. Proceed to the drawdown schedule in paragraph (g) of this AD. Drawdown Schedule for Third Stage Turbine Disc and Shaft Assemblies That Are Operating in the Pre SB No. ALF502L 72-232 Configuration (g) For ALF502L series turbofan engines, use the drawdown schedule described in the following Table 1, and replace with serviceable parts: Table 1.—Drawdown Schedule for Third Stage Turbine Disc and Shaft Assemblies in Pre SB ALF502L 72-232 Configuration For third stage turbine disc and shaft assembly P/Ns: If hours-in-service (HIS) on the effective date of this AD are: Then remove: 2-143-030-05, 2-143-030-08, 2-143-030-14, 2-143-030R21, 2-143-030-22, 2-143-030-23 (1) 5,200 or more HIS. (2) 5,001 to 5,199 HIS. (3) 2,551 to 5,000 HIS. (4) 2,550 or fewer HIS. Within 50 additional HIS. Before reaching 5,250 HIS. Within 250 additional HIS. Before reaching 2,800 HIS. Determination of Drawdown Schedule for Third Stage Turbine Disc and Shaft Assemblies That Have Operated in Pre and Post SB No. ALF502L 72-232 Configurations (h) For ALF502L series turbofan engines, with third stage turbine disc and shaft assemblies converted from Pre SB No. ALF502L 72-232 configuration to Post SB No. ALF502L 72-232 configuration, do the following: (1) Determine the total HIS accumulated on the third stage turbine disc and shaft assembly at time of installation of third stage turbine nozzle assembly, P/N 2-141-120-R56/-57. (2) If the total is 2,800 HIS or more, use the drawdown schedule in Table 1 of this AD to remove the assembly from service. (3) If the total is fewer than 2,800 HIS, calculate the remaining service life using paragraphs 2.A. through 2.B.(4)(i) of the Accomplishment Instructions of Honeywell SB No. ALF502 72-0004, Revision 17, dated January 16, 2005. (i) For ALF502L series turbofan engines, use the drawdown schedule described in the following Table 2 to remove the assembly from service: Table 2.—Drawdown Schedule for Third Stage Turbine Disc and Shaft Assemblies Operated In Pre and Post SB No. ALF502L 72-232 Configuration For third stage turbine disc and shaft assembly part numbers: If HIS on the effective date of this AD are: Then: (1) 2-143-030-05, 2-143-030-08, 2-143-030-14 (i) 30,000 or more HIS. (ii) 27,250 to 29,999 HIS. (iii) Fewer than 27,250 HIS. Remove within 50 additional HIS. Remove within 250 additional HIS. Remove using Tables 1 through 5 of Honeywell SB No. ALF502 72-0004, Revision 17, dated January 16, 2005. (2) 2-143-030R21, 2-143-030-23 (i) 24,650 or more HIS. (ii) 22,150 to 24,649 HIS. (iii) Fewer than 22,150 HIS. Remove within 50 additional HIS. Remove within 250 additional HIS. Remove using Tables 1 through 5 of Honeywell SB No. ALF502 72-0004, Revision 17, dated January 16, 2005. (3) 2-143-030-22 (i) 50,000 or more HIS. (ii) 49,750 to 49,999 HIS. (iii) Fewer than 49,750 HIS. Remove within 50 additional HIS. Remove within 250 additional HIS. Remove using Tables 1 through 5 of Honeywell SB No. ALF502 72-0004, Revision 17, dated January 16, 2005. ALF502R Series Turbofan Engines Requirements Brought Forward, and Unchanged From AD 95-04-11 (j) For ALF502R series turbofan engines, remove from service and replace with a serviceable part third stage turbine disks, P/Ns 2-143-030-05, 2-143-030-08, and 2-143-030-14, as follows: (1) For disks that have been installed only with third stage turbine nozzles P/Ns 2-141-130-52 or 2-141-120-53, remove from service as follows: (i) For disks that have accumulated 13,220 or more hours time in service (TIS) since new on April 13, 1995 (the effective date of AD 95-04-11), within the next 80 hours TIS after December 11, 1990, but not to exceed the existing cyclic life limit. (ii) For disks that have accumulated less than 13,220 hours TIS since new on April 13, 1995, before accumulating more than 13,300 hours TIS since new, but not to exceed the existing cyclic life limit. (iii) Thereafter, remove disks before accumulating more than 13,300 hours TIS since new, but not to exceed the existing cyclic life limit. (2) For disks that have been installed only with third stage turbine nozzles, P/Ns 2-141-120-57 or 2-141-120-R56, remove from service as follows: (i) For disks that have accumulated 27,420 or more hours TIS since new on April 13, 1995, within 80 hours TIS after April 13, 1995, but not to exceed the existing cyclic life limit. (ii) For disks that have accumulated less than 27,420 hours TIS since new on April 13, 1995, before accumulating more than 27,500 hours TIS since new, but not to exceed the existing cyclic life limit. (iii) Thereafter, remove disks before accumulating more than 27,500 hours TIS since new, but not to exceed the existing cyclic life limit. (3) For disks that have been installed with both third stage turbine nozzles, P/Ns 2-141-120-52 or 2-141-120-120-53, and third stage turbine nozzles P/Ns 2-141-120-57 or 2-141-120-R56, remove from service as follows: (i) Determine the prorated hourly life limit using the procedure defined in the Accomplishment Instructions, Section 2.B.(2) of Textron Lycoming SB No. ALF 502 72-0002, Revision 22, dated December 23, 1992. From this prorated hourly life limit, subtract 80 hours TIS to determine the compliance threshold. (ii) For disks that have equaled or exceeded the compliance threshold on April 13, 1995, within the next 80 hours TIS, but not to exceed the existing cyclic life limit. (iii) For disks that have accumulated fewer than the compliance threshold on April 13, 1995, before accumulating more than the calculated prorated hourly life limit. (iv) Thereafter, remove disks at or before accumulating the prorated hourly life limit, but not to exceed the existing cyclic life limit. Alternative Methods of

This AD results from a report of failure of a third stage turbine disc and shaft assembly, leading to turbine blade release and separation of the exhaust nozzle. We are issuing this AD to prevent total loss of engine power, in-flight engine shutdown, release of turbine blades, separation of the exhaust nozzle, and possible damage to the airplane.