AD 2005-25-10 Airworthiness Directives; Dowty Propellers Type R321/4-82-F/8, R324/4-82-F/9, R333/4-82-F/12, and R334/4-82-F/13 Propeller Assemblies

Makes named: dowty. Models named: 3101, 3201, Fairchild Aircraft, Inc, Merlin IIIC, Merlin IVC/Metro III. Read the applicability below — it usually turns on serial or part numbers too.

This AD applies to Dowty Propellers Type R321/4-82-F/8, and R324/4-82-F/9, R333/4-82-F/12 propeller assemblies with propeller hubs part number (P/N) 660709201, installed on, but not limited to, British Aerospace Regional Aircraft Jetstream Models 3101 and 3201, Fairchild Aircraft, Inc., Merlin IIIC, and Merlin IVC/Metro III airplanes, and to Type R334/4-82-F/13 propeller assemblies with hubs P/N 660709201, installed on Construcciones Aeronauticas, S.A. (CASA) 212 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. (f) Propeller hubs, P/N 660709201, previously inspected using Dowty Mandatory Service Bulletins (MSBs) listed in Table 1 or an earlier issue of those MSBs, are already in compliance with paragraph (g) of this AD and do not need another initial inspection. Table 1.—Applicable MSB for Propeller Type Propeller assembly type Initial inspection within the earlier of * * * Repeat inspection within * * * Applicable MSB (1) R334/4-82-F/13 10 flight hours (FH) time-in-service (TIS) or 20 days after the effective date of this AD 300 FH time-since-last-inspection (TSLI) or 300 flight cycles-since-last-inspection, whichever occurs sooner Alert MSB No. 61-1119, Revision 4, dated September 14, 2005. (2) R321/4-82-F/8 50 FH TIS or 60 days after the effective date of this AD 1,000 FH TSLI MSB No. 61-1125, Revision 1, dated October 9, 2002. (3) R324/4-82-F/9 50 FH TIS or 60 days after the effective date of this AD 1,000 FH TSLI MSB No. 61-1126, Revision 1, dated October 9, 2002. (4) R333/4-82-F/12 50 FH TIS or 60 days after the effective date of this AD 1,000 FH TSLI. MSB No. 61-1124, Revision 1, dated October 8, 2002. Initial Ultrasonic Inspections (g) Perform an initial ultrasonic inspection of the rear wall of the rear half of the propeller hub for cracks within the compliance time specified in the following Table 1. Use Appendix A or Appendix D of the applicable Dowty Mandatory Service Bulletin (MSB) listed in Table 1 of this AD. (h) For hubs and propellers in storage, perform an initial ultrasonic inspection of the rear wall of the rear half of the propeller hub for cracks, before placing in service. Use Appendix A or Appendix D of the applicable Dowty MSB listed in Table 1 of this AD. Repetitive Ultrasonic Inspections (i) Thereafter, perform a repetitive ultrasonic inspection of the rear wall of the rear half of the propeller hub for cracks within the compliance time specified in Table 1 of this AD. Use Appendix A or Appendix D of the applicable Dowty Mandatory Service Bulletin (MSB) listed in Table 1 of this AD. Inspection Reporting Requirements (j) Within 10 days after each inspection, record the inspection data on a copy of Appendix B of the applicable MSB listed in Table 1 of this AD. Report the findings to the Manager, Boston Aircraft Certification Office, FAA, Engine and Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803-5299. The Office of Management and Budget (OMB) approved the reporting requirements and assigned OMB control number 2120-0056. Alternative Methods of

This AD results from comments received on AD 2005-20-12. We are issuing this AD to prevent propeller hub failure due to cracks in the hub, which could result in loss of control of the airplane.