Airworthiness Directive · Amendment 39-13681 · Dowty Aerospace 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
Dowty Aerospace 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
Superseded. A later AD replaced this one: AD 2005-20-12. Comply with the one in force.
This airworthiness directive (AD) applies to Dowty Aerospace Propellers (Dowty) Type R321/4-82-F/8, R324/4-82-F/9, R333/4-82-F/12, and R334/4-82-F/13 propeller assemblies with propeller hubs part number (P/N) 660709201. These propeller assemblies are installed on, but not limited to, Construcciones Aeronauticas, S.A. (CASA) 212, British Aerospace Regional Aircraft Jetstream Models 3101 and 3201, Fairchild Aircraft, Inc., Merlin IIIC, and Merlin IVC/Metro III airplanes.
Note 1: This AD applies to each propeller identified in the preceding applicability provision, regardless of whether it has been modified, altered, or repaired in the area subject to the requirements of this AD. For propellers that have been modified, altered, or repaired so that the performance of the requirements of this AD is affected, the owner/operator must request approval for an alternative method of compliance in accordance with paragraph (f) of this AD. The request should include an assessment of the effect of the modification, alteration, or repair on the unsafe condition addressed by this AD; and, if the unsafe condition has not been eliminated, the request should include specific proposed actions to address it.
This amendment supersedes an existing airworthiness directive (AD) that applies to Dowty Aerospace Propellers (Dowty) Type R334/4-82- F/13 propeller assemblies. That AD currently requires a one-time ultrasonic inspection of propeller hubs, part number (P/N) 660709201, for cracks. This amendment requires initial and repetitive ultrasonic inspections of propeller hubs, P/N 660709201, that are installed on airplanes, and for hubs and propellers in storage, initial ultrasonic inspection of propeller hubs before placing in service. Propeller hubs, P/N 660709201, are installed on Type R321/4-82-F/8, R324/4-82-F/9, R333/4-82-F/12, and R334/4-82-F/13 propeller assemblies. This amendment results from the manufacturer's reevaluation of potential hub failure on Type R321/4-82-F/8, R324/4-82-F/9, R333/4-82-F/12, and R334/4-82-F/ 13 propeller assemblies. 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.
Compliance with this AD is required as indicated, unless already done.
To prevent propeller hub failure due to cracks in the hub, which could result in loss of control of the airplane, do the following:
Within 50 flight hours time-in-service (TIS) after the effective date of this AD, or within 60 days after the effective date of this AD, whichever occurs earlier, perform an initial ultrasonic inspection of the rear wall of the rear half of the propeller hub for cracks in accordance with Appendix A of the applicable Dowty Mandatory Service Bulletin (MSB) listed in the following Table 1:
| Propeller assembly type | Applicable MSB |
|---|---|
| (1) R334/4-82-F/13 | MSB No. 61-1119, Revision 3, dated March 8, 2002. |
| (2) R333/4-82-F/12 | MSB No. 61-1124, Revision 1, dated October 8, 2002. |
| (3) R321/4-82-F/8 | MSB No. 61-1125, Revision 1, dated October 9, 2002. |
| (4) R324/4-82-F/9 | MSB No. 61-1126, Revision 1, dated October 9, 2002 |
(b) 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, in accordance with Appendix A of the applicable Dowty MSB listed in Table 1 of this AD.
(c) Propeller hubs, P/N 660709201, used on Type R334/4-82-F/13 propeller assemblies that have been previously inspected using a Dowty MSB listed in Table 1 or earlier issue of those MSBs, are considered to be in compliance with paragraph (a) of this AD.
Thereafter, within 1,000 flight hours TIS after each ultrasonic inspection, perform an ultrasonic inspection of the rear wall of the rear half of the propeller hub for cracks in accordance with Appendix A of the applicable Dowty MSB listed in Table 1 of this AD.
For each inspection, record the inspection data on a copy of Appendix B of the applicable MSB listed in Table 1 of this AD, and report the findings to the Manager, Boston Aircraft Certification Office, FAA, Engine and Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803-5299 within 10 days after the inspection. Reporting requirements have been approved by the Office of Management and Budget (OMB) and assigned OMB control number 2120-0056.
The aircraft, engines and makers this AD names, by the model designations in its text. A model listed here may still be outside the AD's serial ranges.
Propellers
