Airworthiness Directives; Bombardier Model DHC-8-100 and -300 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 certain Bombardier Model DHC-8-100 and -300 series airplanes. This proposal would require revising the Aircraft Log Book to correct the airplane Production Modification List; performing an inspection to determine which bonded skin panels on the airplane require bonding integrity inspections (BII); and revising the Airworthiness Limitations List of the Approved Maintenance Plan to include the BII requirements. This proposal also would, for certain airplanes, require repetitive ultrasonic bond inspections to detect disbonding of airplane skin panels, and repair, 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 prevent damage to bonded skin panels to go undetected, which could result in failure of the bonded skin panels, and consequent loss of controllability of the airplane.

DATES:

Comments must be received by May 1, 2000.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 98-NM-380-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.

The service information referenced in the proposed rule may be obtained from Bombardier, Inc., Bombardier Regional Aircraft Division, 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, Engine and Propeller Directorate, New York Aircraft Certification Office, 10 Fifth Street, Third Floor, Valley Stream, New York.

FOR FURTHER INFORMATION CONTACT:

Franco Pieri, Aerospace Engineer, Airframe and Propulsion Branch, ANE-171, FAA, Engine and Propeller Directorate, New York Aircraft Certification Office, 10 Fifth Street, Third Floor, Valley Stream, New York 11581; telephone (516) 256-7526; fax (516) 568-2716.

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 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 98-NM-380-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. 98-NM-380-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 certain Bombardier Model DHC-8-100 and -300 series airplanes. TCCA advises that, during a Bombardier investigation of an operator query, inconsistencies were found between the effectivity tables for the bonding integrity inspection (BII) in the non-destructive testing manuals and the modification status record in the airplane Modification Log. As a result of these inconsistencies, some of the bonded skin panels on affected DHC-8 aircraft were not being inspected under the BII program even though they were manufactured with panels that require a bonding integrity inspection. Failure to conduct these inspections could allow damage to bonded skin panels to go undetected, which could result in failure of the bonded skin panels, and consequent loss of controllability of the airplane.

Explanation of Relevant Service Information

Bombardier has issued Service Bulletin S.B. 8-51-2, Revision ‘A,’ dated September 19, 1998, which describes procedures for revising the Aircraft Log Book to correct the airplane Production Modification List; performing an inspection to determine which bonded skin panels on the airplane require the BII program; and revising the Airworthiness Limitations List of the Approved Maintenance Plan to include the BII requirements.

Bombardier also has issued Part 5, sections 55-00-01 and 57-30-01 of Bombardier Production Support Manual (PSM) 1-8-7A, dated December 15, 1998 (for Model DHC-8-100 series airplanes); and Part 5, sections 55-00-01 and 57-30-01 of Bombardier PSM 1-83-7A, dated April 30, 1999 (for Model DHC-8-300 series airplanes) which describe procedures for repetitive ultrasonic bond inspections to detect disbonding of the affected airplane skin panels and repair, if necessary.

Accomplishment of the actions specified in the service bulletin and service information is intended to adequately address the identified unsafe condition. TCCA classified this service bulletin and service information as mandatory and issued Canadian airworthiness directive CF-98-31, dated September 1, 1998, in order to assure the continued airworthiness of these airplanes in Canada.

FAA's Conclusions

These airplane models are manufactured in Canada and are type certificated for operation in the United States under the provisions of § 21.29 of the Federal Aviation Regulations (14 CFR 21.29) and the applicable bilateral airworthiness agreement. Pursuant to this bilateral airworthiness agreement, TCCA has kept the FAA informed of the situation described above. The FAA has examined the findings of 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 service information described previously, except as discussed below.

Differences Between Proposed Rule and Service Information

Operators should note that, although the service information specifies that the manufacturer may be contacted for disposition of certain repair conditions, this proposal would require the repair of those conditions to be accomplished in accordance with a method approved by the FAA.

Operators also should note that, although the Canadian airworthiness directive affects Bombardier Model DHC-8-314 series airplanes, Bombardier Model DHC-8-314 series airplanes are not type certificated in the United States. Therefore, the proposed AD does not affect those airplanes.

Cost Impact

The FAA estimates that 41 airplanes of U.S. registry would be affected by this proposed AD, that it would take approximately 1 work hour per airplane to accomplish the proposed revisions to the Aircraft Log Book, Approved Maintenance Plan, and inspection, and that the average labor rate is $60 per work hour. Based on these figures, the cost impact of the actions proposed by this AD on U.S. operators is estimated to be $2,460, or $60 per airplane.

The cost impact figure discussed above is 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.

Regulatory Impact

The regulations proposed herein would 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 proposal would not have sufficient federalism implications to warrant the preparation of a Federalism Assessment.

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.