00-21167. Airworthiness Directives; Dowty Aerospace Propellers Model R381/6-123-F/5 Propellers

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Notice of proposed rulemaking.

SUMMARY:

This document proposes to revise an existing airworthiness directive (AD) that is applicable to Dowty Aerospace Propellers Model R381/6-123-F/5 propellers. That action currently requires initial and repetitive visual and ultrasonic inspections of propeller blades for cracks across the camber face, and, if blades are found cracked, replacement with serviceable blades. This proposed revision would increase the time-in-service (TIS) intervals between required visual and ultrasonic inspections. This proposal is prompted by an engineering analysis of field service data and certification testing that indicate that the repetitive inspection interval can be safely increased. The actions specified in this proposed revision are intended to prevent propeller blade cracks and propagation, which could result in propeller blade separation and possible aircraft loss of control.

DATES:

Comments must be received by September 20, 2000.

ADDRESSES:

Submit comments to the Federal Aviation Administration (FAA), New England Region, Office of the Regional Counsel, Attention: Rules Docket No. 99-NE-43-AD, 12 New England Executive Park, Burlington, MA 01803-5299. Comments may also be sent via the Internet using the following address: “[e-mail]”. Comments sent via the Internet must contain the docket number in the subject line.

The service information referenced in this AD may be obtained from Dowty Aerospace Propellers, Anson Business Park, Cheltenham Road East, Gloucester GL29QN, England; telephone: [phone], fax: [phone]. This information may be examined 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.

FOR FURTHER INFORMATION CONTACT:

Frank Walsh, Aerospace Engineer, Boston Aircraft Certification Office, FAA, Engine and Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803-5299; telephone [phone], fax [phone].

SUPPLEMENTARY INFORMATION:

Comments Invited

Interested persons are invited to participate in the making of the proposed rule by submitting such written data, views, or arguments as they may desire. Communications should identify the Rules Docket number and be submitted to the address specified above. All communications received on or before the closing date for comments, specified above, will be considered before taking action on the proposed rule. The proposals contained in this notice may be changed in light of the comments received.

Comments are specifically invited on the overall regulatory, economic, environmental, and energy aspects of the proposed rule. All comments submitted will be available, both before and after the closing date for comments, in the Rules Docket for examination by interested persons. A report summarizing each FAA-public contact concerned with the substance of this proposal will be filed in the Rules Docket.

Commenters wishing the FAA to acknowledge receipt of their comments submitted in response to this notice must submit a self-addressed, stamped postcard on which the following statement is made: “Comments to Docket Number 99-NE-43-AD.” The postcard will be date stamped and returned to the commenter.

Availability of NPRM's

Any person may obtain a copy of this NPRM by submitting a request to the FAA, New England Region, Office of the Regional Counsel, Attention: Rules Docket No. 99-NE-43-AD, 12 New England Executive Park, Burlington, MA 01803-5299.

Discussion

On August 25, 1999, the FAA issued 99-NE-43-AD, Amendment 39-11284, (64 FR 47661, September 1, 1999), applicable to Dowty Aerospace Propellers Model R381/6-123-F/5 propellers to require initial and repetitive visual and ultrasonic inspections of propeller blades for cracks across the camber face, and, if blades are found cracked, replacement with serviceable blades. That action was prompted by a report of a crack that had developed on a deiced propeller blade assembly across the camber face at a blade station of approximately 13.5″ up from the base of the blade cuff. That condition, if not corrected, could result in propeller blade cracks and propagation, which could result in propeller blade separation and possible aircraft loss of control. The FAA received no comments to the current AD, issued as a final rule, request for comments.

Since that AD was issued an engineering analysis of field service data and certification testing indicate that the repetitive inspection interval can be safely increased. As a result, the manufacturer has revised Dowty Service Bulletin No. S2000-61-75 (Rev. 3, dated September 30, 1999), to increase the repetitive visual inspection interval from 50 to 300 hours time in service (TIS) since last inspection and repetitive visual and ultrasonic inspections of propeller blades for cracks from 200 to 600 hours TIS.

Since an unsafe condition has been identified that is likely to exist or develop on other Dowty Aerospace Propellers Model R381/6-123-F/5 propellers of the same type design, the proposed AD would revise AD 99-18-18 to increase the TIS intervals between required visual and ultrasonic inspections.

Regulatory Impact

The proposed revision would not increase the economic burden on US operators as set out in the economic analysis published for the current AD.

The regulations adopted herein will 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. Therefore, it is determined that this final rule does not have federalism implications under Executive Order 13132.

The FAA has determined that this regulation is not a “significant regulatory action” under Executive Order 12866. It has been determined further that this action involves an emergency regulation under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979). If it is determined that this emergency regulation otherwise would be significant under DOT Regulatory Policies and Procedures, a final regulatory evaluation will be prepared and placed in the Rules Docket. A copy of it, if filed, may be obtained from the Rules Docket at the location provided under the caption ADDRESSES.

List of Subjects in 14 CFR Part 39

• Air transportation
• Aircraft
• Aviation safety
• Safety

The Proposed 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 part 39 continues to read as follows:

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

§ 39.13

[Amended]

2. Section 39.13 is amended by removing Amendment 39-11284 (64 FR 47661, September 1, 1999), and by adding a new airworthiness directive (AD), to read as follows:

Dowty Aerospace Propellers: Docket 99-NE-43-AD. Revises AD 99-18-18, Amendment 39-11284.

Applicability: Dowty Aerospace Propellers Model R381/6-123-F/5 propellers, installed on but not limited to SAAB 2000 series airplanes.

Note 1:

This airworthiness directive (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 (c) 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.

Compliance: Required as indicated, unless accomplished previously.

To prevent propeller blade cracks and propagation, which could result in propeller blade separation and possible aircraft loss of control, accomplish the following:

Visual Inspections

(a) Perform initial and repetitive visual inspections of propeller blades for cracks across the camber face in accordance with the Accomplishment Instructions of Dowty Aerospace Propellers Service Bulletin (SB) No. S2000-61-75, Revision 3, dated September 30, 1999, as follows:

(1) Initially, conduct a visual inspection within 50 hours time-in-service (TIS) after the effective date of the original AD.

(2) Thereafter, inspect at intervals not to exceed 300 hours TIS since last inspection.

(3) Replace cracked propeller blades prior to further flight with serviceable blades.

Ultrasonic Inspections

(b) Perform initial and repetitive ultrasonic inspections of propeller blades for cracks across the camber face in accordance with the Accomplishment Instructions of Dowty Aerospace Propellers SB No. S2000-61-75, Revision 3, dated September 30, 1999, as follows:

(1) Initially inspect within 200 hours TIS after the effective date of the original AD.

(2) Thereafter, inspect at intervals not to exceed 600 hours TIS since last inspection.

(3) Replace cracked propeller blades prior to further flight with serviceable blades.

Alternative Method of Compliance

(c) 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 shall submit their requests 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

(d) Special flight permits may be issued in accordance with sections 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199) to operate the aircraft to a location where the inspection requirements of this AD can be accomplished.

Issued in Burlington, Massachusetts, on August 14, 2000.

David A. Downey,

Assistant Manager, Engine and Propeller Directorate, Aircraft Certification Service.