AD 2003-04-25

This amendment adopts a new airworthiness directive (AD), that is applicable to Dowty Aerospace Propellers, R354/4-123-F/13, R354/4- 123-F/20, R375/4-123-F/21, R389/4-123-F/25, R389/4-123-F/26, and R390/ 4-123-F/27 propellers. This amendment requires a one-time inspection of the hub joint mating surfaces for fretting. This amendment is prompted by reports of fretting on the joint mating faces of propeller hubs. The actions specified by this AD are intended to prevent failure of the hub due to loose hub through bolts.

Final rule.

2003-04-25 Dowty Aerospace Propellers: Amendment 39-13074. Docket No. 2000-NE-18-AD.

Applicability: This airworthiness directive (AD) is applicable to Dowty Aerospace Propellers, R354/4-123-F/13, R354/4-123-F/20, R375/4-123-F/21, R389/4-123-F/25, R389/4-123-F/26, and R390/4-123-F/ 27 propellers. These propellers are installed on, but not limited to, SAAB 340A and 340B 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 (b) of this AD. The request should include an assessment of the effect of the modification, alteration, or repair on the unsafe condition addressed by thisAD; and, if the unsafe condition has not been eliminated, the request should include specific proposed actions to address it.

Compliance: Compliance with this AD is required within 1,800 flying hours after the effective date of this AD, unless already done.

To prevent failure of the hub due to loose hub through bolts, do the following:

One-Time Inspection of the Propeller Hub

(a) If the propeller hub has not been disassembled since it was received from Dowty Aerospace Propellers, no further action is required. Otherwise, do the following:

(1) Within 1,800 flying hours after the effective date of this AD, perform a one-time inspection of the hub for loose hub through bolts in accordance with 3.A.(1) through 3.A.(10) of the Accomplishment Instructions of Dowty Aerospace Propellers mandatory service bulletin (MSB) SF340-61-96, dated April 18, 2000.

(2) If wear exceeds the limits specified in 3.A.(8) of the Accomplishment Instructions of Dowty Aerospace Propellers MSB SF340- 61-96, dated April 18, 2000, replace the hub with a serviceable part.

Alternative Methods of Compliance

(b) An alternative method of compliance or adjustment of the compliance time that provides an acceptable level of safety may be used if approved by the Manager, Boston Aircraft Certification Office (ACO). Operators must submit their request through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, Boston ACO.

Note 2: Information concerning the existence of approved alternative methods of compliance with this airworthiness directive, if any, may be obtained from the Boston ACO.

Special Flight Permits

(c) Special flight permits may be issued in accordance with 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199) to operate the airplane to a location where the requirements of this AD can be done.

Documents That Have Been Incorporated by Reference

(d) The inspection must be done in accordance with Dowty Aerospace Mandatory Service Bulletin (MSB) SF340-61-96, dated April 18, 2000. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from Dowty Aerospace Propellers, Anson Business Park, Cheltenham Road, East Gloucester GL2 9QN, UK; telephone 44 (0) 1452 716000; fax 44 (0) 1452 716001. Copies may be inspected at the FAA, New England Region, Office of the Regional Counsel, 12 New England Executive Park, Burlington, MA; or at the Office of the Federal Register, 800 North Capitol Street, NW, suite 700, Washington, DC.

Note 3: The subject of this AD is addressed in CAA airworthiness directive 005-04-2000, dated April 18, 2000.

Effective Date

(e) This amendment becomes effective on April 8, 2003.

A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to include an AD that is applicable to Dowty Aerospace Propellers, R354/4-123-F/13, R354/4-123- F/20, R375/4-123-F/21, R389/4-123-F/25, R389/4-123-F/26, and R390/4- 123-F/27 propellers was published in the Federal Register on March 22, 2002 (67 FR 13294). That action proposed to require a one-time inspection of the hub joint mating surfaces for fretting in accordance with Dowty Aerospace Propellers Mandatory Service Bulletin (MSB) SF340- 61-96, dated April 18, 2000. The Civil Aviation Authority (CAA) issued AD 005-04-2000 in order to ensure the airworthiness of these Dowty propellers in the United Kingdom (UK).

Comments

Interested persons have been afforded an opportunity to participate in the making of this amendment. Due consideration has been given to the comment received.

One commenter states that extensive experience and service history had been recorded whileoperating a large fleet of aircraft in excess of 25,000 flight hours over the past 17 years. The operator states that the AD would impose undue cost and maintenance requirements that would not increase the propeller safety or reliability, and that the AD would not do anything positive such as eliminating the problem or creating a safer hub component.

The FAA does not agree with the commenter. The FAA considers the one-time inspection to be a necessary safety-related inspection to guard against possible propeller hub failure as the result of loss of hub bolt preload torque that may well foster hub cracking and complete propeller loss.

After careful review of the available data, including the comment noted above, the FAA has determined that air safety and the public interest require the adoption of the rule as proposed.

Economic Analysis

There are approximately 418 Dowty Aerospace Propellers, R354/4-123- F/13, R354/4-123-F/20, R375/4-123-F/21, R389/4-123-F/25, R389/4-123-F/ 26, and R390/4-123-F/27 propellers, of the affected design in the worldwide fleet. The FAA estimates that 169 propellers installed on airplanes of U.S. registry will be affected by this AD, that it will take approximately 6 work hours per propeller to perform the required actions, and that the average labor rate is $60 per work hour. There are no required parts per propeller. Based on these figures, the total cost of the AD to U.S. operators is estimated to be $60,840.

Regulatory Analysis

This final rule does not have federalism implications, as defined in Executive Order 13132, because it would not have a substantial direct effect on the States, on the relationship between the national government and the States, or on the distribution of power and responsibilities among the various levels of government. Accordingly, the FAA has not consulted with state authorities prior to publication of this final rule.

For the reasons discussed above, I certify that this action (1) is not a "significant regulatory action" under Executive Order 12866; (2) is not a "significant rule" under the DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and (3) will not have a significant economic impact, positive or negative, on a substantial number of small entities under the criteria of the Regulatory Flexibility Act. A final evaluation has been prepared for this action and it is contained in the Rules Docket. A copy of it may be obtained by contacting the Rules Docket at the location provided under the caption ADDRESSES.

List of Subjects in 14 CFR Part 39

Air transportation, Aircraft, Aviation safety, Incorporation by reference, Safety.

Adoption of the Amendment

Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration amends part 39 of the Federal Aviation Regulations (14 CFR part 39) as follows:

PART 39--AIRWORTHINESS DIRECTIVES

1. The authority citation for part39 continues to read as follows:

Authority: 49 U.S.C. 106(g), 40113, 44701.

39.13 [Amended]

2. Section 39.13 is amended by adding a new airworthiness directive to read as follows: