AD 99-18-18 SUPERSEDED

This amendment adopts a new airworthiness directive (AD) that is applicable to Dowty Aerospace Propellers Model R381/6-123-F/5 propellers. This action requires initial and repetitive visual and ultrasonic (UT) inspections of propeller blades for cracks across the camber face, and, if blades are found cracked, replacement with serviceable blades. This amendment is prompted by reports of a cracked composite propeller blade. The actions specified in this AD are intended to prevent propeller blade cracks and propagation, which could result in propeller blade separation and possible aircraft loss of control.

Final rule; request for comments.

99-18-18 DOWTY AEROSPACE PROPELLERS: Amendment 39-11284. Docket 99-NE-43-AD. Issued August 25, 1999.

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 1, dated June 11, 1999, as follows:

(1) Initially inspect within 50 hours time-in-service (TIS) after the effective date of this AD.

(2) Thereafter, inspect at intervals not to exceed 50 hours TIS since last inspection.

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

Ultrasonic (UT) Inspections

(b) Perform initial and repetitive UT 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 1, dated June 11, 1999, as follows:

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

(2) Thereafter, inspect at intervals not to exceed 200 hours TIS since last inspection.

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

(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.

(d) Special flight permits may be issuedin 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.

(e) The actions required by this AD shall be performed in accordance with Dowty Aerospace Propellers SB No. S2000-61-75, Revision 1, dated June 11, 1999. 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 GL29QN, England; telephone +44 1452 716000, fax +44 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.

(f) This amendment becomes effective on September 16, 1999.

The Civil Aviation Authority (CAA), which is the airworthiness authority for the United Kingdom (UK), recently notified the Federal Aviation Administration (FAA) that an unsafe condition may exist on Dowty Aerospace Propellers Model R381/6-123-F/5 propellers. The CAA advises that they have received a report of a crack that had developed on a de-iced propeller blade assembly across the camber face at a blade station of approximately 13.5" up from the base of the blade cuff. Engineering evaluation of X-ray examination and subsequent CAT scan inspections of the camber face of the spar indicated a crack had developed internally from a composite defect in the spar and had propagated outward through the blade skin. The defective blade was found visually during a pre- flight pilot walk-around inspection. The results of this pre-flight inspection resulted in removal of the propeller and replacement of the de-iced propeller blade assembly by maintenance crews.This 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.

Service Information

Dowty Aerospace Propellers has issued Service Bulletin (SB) No. S2000-61-75, Revision 1, dated June 11, 1999, that specifies procedures for visual and ultrasonic (UT) inspections of propeller blades for cracks across the camber face, and provides reject procedures for cracked blades. The CAA classified this SB as mandatory and issued Airworthiness Directive (AD) 003-05-99 in order to assure the airworthiness of these propellers in the UK.

This propeller model is manufactured in the UK and is type certificated for operation in the United States under the provisions of section 21.29 of the Federal Aviation Regulations (14 CFR 21.29) and the applicable bilateral airworthiness agreement. Pursuant to this bilateral airworthiness agreement, the CAA has kept the FAA informed of thesituation described above. The FAA has examined the findings of the CAA, reviewed all available information, and determined that AD action is necessary for products of this type design that are certificated for operation in the United States.

Required Actions

Since an unsafe condition has been identified that is likely to exist or develop on other propellers of the same type design registered in the United States, this AD requires initial and repetitive visual inspections for blade cracks at intervals of 50 hours time-in-service (TIS), and UT inspections at intervals of 200 hours TIS. Blades found cracked must be replaced with serviceable blades prior to further flight. The actions would be required to be accomplished in accordance with the SB described previously.

Interim Action

The manufacturer is reviewing the design of the propeller blades and changes to the manufacturing process; hence future rulemaking may be forthcoming requiring installation of improved blades or changes to the inspection procedures.

Since a situation exists that requires the immediate adoption of this regulation, it is found that notice and opportunity for prior public comment hereon are impracticable, and that good cause exists for making this amendment effective in less than 30 days.

Comments Invited

Although this action is in the form of a final rule that involves requirements affecting flight safety and, thus, was not preceded by notice and an opportunity for public comment, comments are invited on this rule. Interested persons are invited to comment on this rule by submitting such written data, views, or arguments as they may desire. Communications should identify the Rules Docket number and be submitted in triplicate to the address specified under the caption "ADDRESSES." All communications received on or before the closing date for comments will be considered, and this rule may be amended in light of the comments received. Factual information thatsupports the commenter's ideas and suggestions is extremely helpful in evaluating the effectiveness of the AD action and determining whether additional rulemaking action would be needed.

Comments are specifically invited on the overall regulatory, economic, environmental, and energy aspects of the rule that might suggest a need to modify the 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 that summarizes each FAA-public contact concerned with the substance of this AD 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.

The regulations adopted herein will not have substantial direct effects 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, in accordance with Executive Order 12612, it is determined that this final rule does not have sufficient federalism implications to warrant the preparation of a Federalism Assessment.

The FAA has determined that this regulation is an emergency regulation that must be issued immediately to correct an unsafe condition in aircraft, and 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, 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 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 adding the following new airworthiness directive:

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: "9-ane-adcomment@faa.gov". 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 +44 1452 716000, fax +44 1452 716001. 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.

Frank Walsh, Aerospace Engineer, Boston Aircraft Certification Office, FAA, Engine and Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803-5299; telephone (781) 238-7158, fax (781) 238-7199.