01-3674. Airworthiness Directives; Bombardier Model DHC-8-102, -103, -106, -201, -202, -301, -311, -314, and -315 Series Airplanes

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

This document proposes the adoption of a new airworthiness directive (AD) that is applicable to all Bombardier Model DHC-8-102, -103, -106, -201, -202, -301, -311, -314, and -315 series airplanes. This proposal would require revising the Bombardier maintenance program to incorporate repetitive inspections to detect fatigue cracking in certain structures; and corrective actions, if necessary. This proposal is prompted by issuance of mandatory continuing airworthiness information by a foreign civil airworthiness authority. The actions specified by the proposed AD are intended to ensure that fatigue cracking of certain principal structural elements is detected and corrected; such fatigue cracking could adversely affect the structural integrity of these airplanes.

DATES:

Comments must be received by March 16, 2001.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2000-NM-45-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056. Comments may be inspected at this location between 9:00 a.m. and 3:00 p.m., Monday through Friday, except Federal holidays. Comments may be submitted via fax to [phone]. Comments may also be sent via the Internet using the following address: [e-mail]. Comments sent via fax or the Internet must contain “Docket No. 2000-NM-45-AD” in the subject line and need not be submitted in triplicate. Comments sent via the Internet as attached electronic files must be formatted in Microsoft Word 97 for Windows or ASCII text.

The service information referenced in the proposed rule may be obtained from Bombardier, Inc., Bombardier Regional Aircraft Division, 123 Garratt Boulevard, Downsview, Ontario M3K 1Y5, Canada. This information may be examined at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the FAA, New York Aircraft Certification Office, 10 Fifth Street, Third Floor, Valley Stream, New York.

FOR FURTHER INFORMATION CONTACT:

Serge Napoleon, Aerospace Engineer, ANE-171, FAA, New York Aircraft Certification Office, 10 Fifth Street, Third Floor, Valley Stream, New York 11581; 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 shall identify the Rules Docket number and be submitted in triplicate 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 action may be changed in light of the comments received.

Submit comments using the following format:

• Organize comments issue-by-issue. For example, discuss a request to change the compliance time and a request to change the service bulletin reference as two separate issues.
• For each issue, state what specific change to the proposed AD is being requested.
• Include justification (e.g., reasons or data) for each request.

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 action must submit a self-addressed, stamped postcard on which the following statement is made: “Comments to Docket Number 2000-NM-45-AD.” The postcard will be date stamped and returned to the commenter.

Availability of NPRMs

Any person may obtain a copy of this NPRM by submitting a request to the FAA, Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2000-NM-45-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.

Discussion

Transport Canada Civil Aviation (TCCA), which is the airworthiness authority for Canada, notified the FAA that an unsafe condition may exist on all Model DHC-8-102, -103, -106, -201, -202, -301, -311, -314, and -315 series airplanes. TCCA advises that fatigue cracks have been found in the outer closing angles at both front and rear spar locations on the airplane fuselage. The closing angles consist of three segments (left, center, and right), which are part of the structure that connects the fuselage to the wing front and rear spar webs located in the wing/fuselage interface area. Reports received by the FAA indicate that cracks were detected in the closing angles on a number of in-service Model DHC-8-102 and -103 series airplanes. Investigation revealed that those cracks were generated by metal fatigue due to cyclic loading on the wing. Cracking of any closing angles identified as principal structural elements (PSE's) could adversely affect the structural integrity of the airplanes.

Explanation of Relevant Service Information

The manufacturer has issued de Havilland Temporary Revisions (TR's) to the DHC-8 Maintenance Program Manuals, as listed in Table 1 of this AD. The TR documents include inspection procedures of the Airworthiness Limitations List, Structural Inspection Program Task No. 5310/31A, which specify threshold and repetitive inspections. Those documents are to be incorporated into the DHC-8 Maintenance Program Manuals to revise the Bombardier maintenance program.

TCCA has approved the TR documents and has issued Canadian airworthiness directive CF-2000-07, dated March 3, 2000, to assure the continued airworthiness of these airplanes in Canada. The Canadian airworthiness document includes procedures for revising the Bombardier maintenance program and detecting and correcting fatigue cracking in the wing/fuselage PSE closing angles.

Accomplishment of the actions specified in these documents is intended to adequately address the identified unsafe condition.

FAA's Conclusions

These airplane models are manufactured in Canada and are 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 TCCA has kept the FAA informed of the situation described above. The FAA has determined that the DHC-8 Maintenance Program Manuals, Airworthiness Limitations List (AWL), must be revised by incorporating the threshold and repetitive inspection intervals of the AWL, Structural Inspection Program Task No. 5310/31A, specified by the TR documents, into the Bombardier maintenance program. The FAA has examined the findings of the TCCA, 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.

Explanation of Requirements of Proposed Rule

Since an unsafe condition has been identified that is likely to exist or develop on other airplanes of the same type design registered in the United States, the proposed AD would require accomplishment of the actions specified in the TR documents and in this proposed AD, except as discussed below.

Difference Between Proposed Rule and Canadian Airworthiness Directive

Operators should note that the previously referenced Canadian airworthiness directive specifies contacting the manufacturer for the disposition of any cracking found in any closing angle identified as a principal structural element. However, this proposal would require the repair of any such cracking or replacement of the closing angles per a method approved by the FAA.

Difference Between TR Document, and Canadian Airworthiness Directive and Proposed Rule

Operators should note that TR AWL-71, dated September 3, 1999, lists Model DHC-8-101 series airplanes in the table of the Structural Inspection Program included in that TR. However, that airplane model is not cited in the Canadian airworthiness directive or in the applicability of the proposed rule. In addition, the manufacturer has informed the FAA that Model DHC-8-101 no longer exists, as it was converted into Model DHC-8-102 in 1986.

Cost Impact

The FAA estimates that 195 Model DHC-8-102, -103, -106, -201, -202, -301, -311, -314, and -315 series airplanes of U.S. registry would be affected by this proposed AD.

It would take approximately 1 work hour per airplane to revise the Bombardier maintenance program, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of the proposed AD on U.S. operators is estimated to be $11,700, or $60 per airplane.

It would take approximately 5 work hours per airplane to accomplish the structural inspections, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of the proposed AD on U.S. operators is estimated to be $58,500, or $300 per airplane.

The cost impact figures discussed above are based on assumptions that no operator has yet accomplished any of the proposed requirements of this AD action, and that no operator would accomplish those actions in the future if this AD were not adopted. The cost impact figures discussed in AD rulemaking actions represent only the time necessary to perform the specific actions actually required by the AD. These figures typically do not include incidental costs, such as the time required to gain access and close up, planning time, or time necessitated by other administrative actions.

Regulatory Impact

The regulations proposed herein 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. Therefore, it is determined that this proposal would not have federalism implications under Executive Order 13132.

For the reasons discussed above, I certify that this proposed regulation (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) if promulgated, 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 copy of the draft regulatory evaluation prepared for this action 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
• Safety

The Proposed Amendment

Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration proposes to amend 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:

Bombardier, Inc. (Formerly de Havilland, Inc.): Docket 2000-NM-45-AD.

Applicability: Model DHC-8-102, -103, -106, -201, -202, -301, -311, -314, and -315 series airplanes, certificated in any category.

Note 1:

This AD applies to each airplane 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 airplanes 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 (d) 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 ensure continued structural integrity of these airplanes, accomplish the following:

(a) Within 30 days after the effective date of this AD, accomplish the actions required by either paragraph (a)(1) or (a)(2) of this AD, as applicable.

Maintenance Program Revisions

(1) Revise the Bombardier maintenance program by incorporating the threshold and repetitive inspection intervals specified in the Temporary Revisions (TR's) to the DHC-8 Maintenance Program Manuals, Airworthiness Limitations List (AWL), Structural Inspection Program Task No. 5310/31A, into the Bombardier maintenance program. The TR's for specific airplane models are listed in Table 1, as follows:

Table 1.—List of Temporary Revisions

Bombardier models	TR number	Date
DHC-8-102, -103, and -106 series airplanes	TR AWL-71	September 3, 1999.
DHC-8-102, -103, -106, -201, -202, -301, -311, -314, and -315 series airplanes	TR AWL 2-15	September 3, 1999.
DHC-8-301, -311, -314, and -315 series airplanes	TR AWL 3-78	November 19, 1999.

Note 2:

When the TR documents listed in Table 1 in paragraph (a)(1) of this AD are incorporated into the general revisions of the DHC-8 Maintenance Program Manual, you may insert the general revisions into the Bombardier maintenance program, provided that the information contained in the general revisions is identical to that specified in the TR documents.

Structural Inspections

(2) For airplanes having closing angles that are identified as principal structural elements: Do the inspections specified by the applicable TR listed in Table 1 of paragraph (a) of this AD. Thereafter, repeat the inspection at intervals not to exceed 10,000 flight cycles at the time specified in paragraph (a)(2)(i), (a)(2)(ii), or (a)(2)(iii) of this AD, as applicable.

(i) For airplanes that have accumulated less than 8,000 flight cycles as of the effective date of this AD: Do the threshold inspection prior to the accomplishment of 10,000 flight cycles, or within 2,000 flight cycles after the effective date of this AD, whichever occurs later.

(ii) For airplanes that have accumulated 8,000 flight cycles or more as of the effective date of this AD: Do the threshold inspection within 2,000 flight cycles after the effective date of this AD.

(iii) For airplanes on which a 40,000 flight cycle inspection specified by the applicable TR listed in Table 1 of paragraph (a) of this AD has been done, no cracks have been found, and/or the closing angles have been replaced: Start the 10,000 flight cycle repetitive inspection at the time specified by either paragraph (a)(2)(iii)(A) or (a)(2)(iii)(B) of this AD, as applicable.

(A) From the date at which the 40,000 flight cycle inspection was done.

(B) From the date the closing angles were replaced.

Corrective Actions

(b) If any crack is detected during any structural inspection required by paragraph (a)(2) of this AD, before further flight, repair any such cracking or replace the closing angles per a method approved by the Manager, New York Aircraft Certification Office (ACO), FAA, or the Transport Canada Civil Aviation (or its delegated agent). For a repair or replacement method to be approved by the Manager, New York ACO, as required by this paragraph, the Manager's approval letter must specifically reference this AD.

(c) Except as provided by paragraph (d) of this AD: After the actions specified in paragraphs (a) and (b) of this AD have been accomplished, no alternative inspections or inspection intervals may be approved for the structural elements specified by the documents listed in Table 1 of paragraph (a)(1) of this AD.

Alternative Methods of Compliance

(d) 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, New York ACO. Operators shall submit their requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, New York ACO.

Note 3:

Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the New York ACO.

Special Flight Permits

(e) 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 airplane to a location where the requirements of this AD can be accomplished.

Note 4:

The subject of this AD is addressed in Canadian airworthiness directive CF-2000-07, dated March 3, 2000.

Issued in Renton, Washington, on February 7, 2001.

Dorenda D. Baker,

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.