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Proposed Rule

Airworthiness Directives; Bombardier Model DHC-8-400 Series Airplanes

Document Details

Information about this document as published in the Federal Register.

Published Document

This document has been published in the Federal Register. Use the PDF linked in the document sidebar for the official electronic format.

Start Preamble

AGENCY:

Federal Aviation Administration (FAA), Department of Transportation (DOT).

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

The FAA proposes to adopt a new airworthiness directive (AD) for certain Bombardier Model DHC-8-400 series airplanes. This proposed AD would require an inspection of the laminated shims for cracks, damage, or extrusion between the forward attachment fittings of the horizontal stabilizer and the top rib of the vertical stabilizer; a torque check of the attachment bolts in the attachment fittings of the front, middle, and rear spars; and corrective actions if necessary. This proposed AD results from a report indicating that delaminated shims extruded from the interface between the forward attaching fittings of horizontal stabilizer and the top rib of the vertical stabilizer, and that inadequate torque values of some bolts were found. We are proposing this AD to prevent reduced structural integrity of the horizontal stabilizer, and consequent loss of controllability of the airplane.

DATES:

We must receive comments on this proposed AD by October 14, 2005.

ADDRESSES:

Use one of the following addresses to submit comments on this proposed AD.

  • DOT Docket Web site: Go to http://dms.dot.gov and follow the instructions for sending your comments electronically.
  • Government-wide rulemaking Web site: Go to http://www.regulations.gov and follow the instructions for sending your comments electronically.
  • Mail: Docket Management Facility, U.S. Department of Transportation, 400 Seventh Street SW., Nassif Building, Room PL-401, Washington, DC 20590.
  • Fax: (202) 493-2251.
  • Hand Delivery: Room PL-401 on the plaza level of the Nassif Building, 400 Seventh Street SW., Washington, DC, between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.

Contact Bombardier, Inc., Bombardier Regional Aircraft Division, 123 Garratt Boulevard, Downsview, Ontario M3K 1Y5, Canada, for service information identified in this proposed AD.

Start Further Info

FOR FURTHER INFORMATION CONTACT:

George Duckett, Aerospace Engineer, Airframe and Propulsion Branch, ANE-171, FAA, New York Aircraft Certification Office, 1600 Stewart Avenue, suite 410, Westbury, New York 11590; telephone (516) 256-7525; fax (516) 794-5531.

End Further Info End Preamble Start Supplemental Information

SUPPLEMENTARY INFORMATION:

Comments Invited

We invite you to submit any relevant written data, views, or arguments regarding this proposed AD. Send your comments to an address listed in the ADDRESSES section. Include the docket number “FAA-2005-20403; Directorate Identifier 2005-NM-144-AD” at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of the proposed AD. We will consider all comments received by the closing date and may amend the proposed AD in light of those comments.

We will post all comments we receive, without change, to http://dms.dot.gov, including any personal information you provide. We will also post a report summarizing each substantive verbal contact with FAA personnel concerning this proposed AD. Using the search function of that Web site, anyone can find and read the comments in any of our dockets, including the name of the individual who sent the comment (or signed the comment on behalf of an association, business, labor union, etc.). You may review the DOT's complete Privacy Act Statement in the Federal Register published on April 11, 2000 (65 FR 19477-78), or you may visit http://dms.dot.gov. Start Printed Page 54317

Examining the Docket

You may examine the AD docket on the Internet at http://dms.dot.gov, or in person at the Docket Management Facility office between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The Docket Management Facility office (telephone (800) 647-5227) is located on the plaza level of the Nassif Building at the DOT street address stated in the ADDRESSES section. Comments will be available in the AD docket shortly after the Docket Management System receives them.

Discussion

Transport Canada Civil Aviation (TCCA), which is the airworthiness authority for Canada, notified us that an unsafe condition may exist on certain Bombardier Model DHC-8-400 series airplanes. TCCA advises that delaminated shims extruded from the interface between the forward attaching fittings of horizontal stabilizer and the top rib of the vertical stabilizer. In addition, during removal of the horizontal stabilizer for replacing the laminated shims with solid shims, inadequate torque values of some bolts at the six attachment locations (two each at the front, middle, and rear spars) were found on some airplanes. This can cause increased load on the bolts and consequent reduction in fatigue life of the bolts. These conditions, if not corrected, could result in reduced structural integrity of the horizontal stabilizer, and consequent loss of controllability of the airplane.

Relevant Service Information

Bombardier has issued Service Bulletin 84-55-02, Revision “A,” dated January 12, 2005. The service bulletin describes doing the following procedures:

  • A detailed inspection of the laminated shims for cracks, damage, or extrusion between the forward attachment fittings of the horizontal stabilizer and the top rib of the vertical stabilizers;
  • A breakaway torque check of the six attachment bolts in the attachment fittings of the front, middle, and rear spars; and
  • Corrective actions if necessary. The corrective actions include replacing the laminated shims, between the forward attachment fittings of the horizontal stabilizer and the top rib of the vertical stabilizer, with solid shims and replacing the corresponding barrel nut and retainer with new parts.

Accomplishing the actions specified in the service information is intended to adequately address the unsafe condition. TCCA mandated the service information and issued Canadian airworthiness directive CF-2005-07, issued March 21, 2005, to ensure the continued airworthiness of these airplanes in Canada.

FAA's Determination and Requirements of the Proposed AD

This airplane model is manufactured in Canada 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, TCCA has kept the FAA informed of the situation described above. We have examined TCCA's findings, evaluated all pertinent information, and determined that we need to issue an AD for airplanes of this type design that are certificated for operation in the United States.

Therefore, we are proposing this AD, which would require accomplishing the actions specified in the service information described previously, except as discussed under “Difference Between the Proposed AD and the Service Bulletin.”

Difference Between the Proposed AD and Service Bulletin

Operators should note that, although the Accomplishment Instructions of the referenced service bulletin describe procedures for submitting a sheet recording torque values to the airplane manufacturer, this proposed AD would not require that action. We do not need this information from operators.

Costs of Compliance

The following table provides the estimated costs for U.S. operators to comply with this proposed AD.

Estimated Costs

ActionWork hoursAverage labor rate per hourPartsCost per airplaneNumber of U.S.-registered airplanesFleet cost
Detailed inspection and torque check2$65None$13019$2,470
Replacement3065Free of charge1,9501937,050

Authority for this Rulemaking

Title 49 of the United States Code specifies the FAA's authority to issue rules on aviation safety. Subtitle I, Section 106, describes the authority of the FAA Administrator. Subtitle VII, Aviation Programs, describes in more detail the scope of the Agency's authority.

We are issuing this rulemaking under the authority described in Subtitle VII, Part A, Subpart III, Section 44701, “General requirements.” Under that section, Congress charges the FAA with promoting safe flight of civil aircraft in air commerce by prescribing regulations for practices, methods, and procedures the Administrator finds necessary for safety in air commerce. This regulation is within the scope of that authority because it addresses an unsafe condition that is likely to exist or develop on products identified in this rulemaking action.

Regulatory Findings

We have determined that this proposed AD would not have federalism implications under Executive Order 13132. This proposed AD 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.

For the reasons discussed above, I certify that the 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. 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.

We prepared a regulatory evaluation of the estimated costs to comply with this proposed AD and placed it in the Start Printed Page 54318AD docket. See the ADDRESSES section for a location to examine the regulatory evaluation.

Start List of Subjects

List of Subjects in 14 CFR Part 39

End List of Subjects

The Proposed Amendment

Accordingly, under the authority delegated to me by the Administrator, the FAA proposes to amend 14 CFR part 39 as follows:

Start Part

PART 39—AIRWORTHINESS DIRECTIVES

1. The authority citation for part 39 continues to read as follows:

Start Authority

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

End Authority
[Amended]

2. The Federal Aviation Administration (FAA) amends § 39.13 by adding the following new airworthiness directive (AD):

Bombardier, Inc. (Formerly de Havilland, Inc.): Docket No. FAA-2005-20403; Directorate Identifier 2005-NM-144-AD.

Comments Due Date

(a) The FAA must receive comments on this AD action by October 14, 2005.

Affected ADs

(b) None.

Applicability

(c) This AD applies to Bombardier Model DHC-8-400 series airplanes, certificated in any category; serial numbers 4001, and 4003 through 4081 inclusive.

Unsafe Condition

(d) This AD results from a report indicating that laminated shims were delaminated and extruded from the interface between the forward attaching fittings of horizontal stabilizer and the top rib of the vertical stabilizer, and that inadequate torque values of some bolts were found. We are issuing this AD to prevent reduced structural integrity of the horizontal stabilizer, and consequent loss of controllability of the airplane.

Compliance

(e) You are responsible for having the actions required by this AD performed within the compliance times specified, unless the actions have already been done.

Service Information

(f) The term “service bulletin,” as used in this AD, means the Accomplishment Instructions of Bombardier Service Bulletin 84-55-02, Revision ‘A,’ dated January 12, 2005.

(g) Accomplishing a detailed inspection, a breakaway torque check, and corrective actions if necessary before the effective date of this AD in accordance with Bombardier Service Bulletin 84-55-02, dated December 11, 2003, is acceptable for compliance with the corresponding requirements of this AD.

(h) Accomplishing the repair before the effective date of this AD in accordance with the Bombardier repair drawings in Table 1 of this AD is acceptable for compliance with the requirements of this AD.

Table 1.—Repair Drawings

Bombardier repair drawingRD issueDated
RD 8/4-55-0833April 16, 2003.
RD 8/4-55-0841May 5, 2003.
RD 8/4-55-0892June 6, 2003.
RD 8/4-55-0903August 26, 2003.
RD 8/4-55-0932June 20, 2003.
RD 8/4-55-0943September 4, 2003.
RD 8/4-55-1062July 31, 2003.
RD 8/4-55-1103October 1, 2003.
RD 8/4-55-1381October 29, 2003.

Detailed Inspection and Torque Check

(i) Within 4,000 flight hours after the effective date of this AD, do the actions specified in paragraphs (i)(1) and (i)(2) of this AD in accordance with Part A of the service bulletin.

(1) Do a detailed inspection of the laminated shims for cracks, damage, or extrusion between the forward attachment fittings of the horizontal stabilizer and the top rib of the vertical stabilizer.

Note 1:

For the purposes of this AD, a detailed inspection is: “An intensive examination of a specific item, installation, or assembly to detect damage, failure, or irregularity. Available lighting is normally supplemented with a direct source of good lighting at an intensity deemed appropriate. Inspection aids such as mirror, magnifying lenses, etc., may be necessary. Surface cleaning and elaborate procedures may be required.”

(2) Do a breakaway torque check of the six attachment bolts in the attachment fittings of the front, middle, and rear spars.

Corrective Actions

(j) If, during the inspection required by paragraph (i)(1) of this AD, any cracked, damaged, or extruded laminated shim is found, before further flight, replace the discrepant laminated shim with a solid shim, and replace the attachment bolts, barrel nuts, and retainers of both front spars with new parts, in accordance with Parts A and B of the service bulletin.

(k) If, during the torque check required by paragraph (i)(2) of this AD, any attachment bolt is found with a breakaway torque value outside the limits specified in the service bulletin, before further flight, replace the attachment bolt and its corresponding barrel nut and retainer with new parts, in accordance with Part A of the service bulletin.

Replacement of Laminated Shims

(l) Within 8,000 flight hours after the effective date of this AD, unless previously accomplished in accordance with paragraph (j) of this AD, replace the laminated shims, between the forward attachment fittings of the horizontal stabilizer and the top rib of the vertical stabilizer, with solid shims and replace the corresponding barrel nut and retainer with new parts, in accordance with Part B of the service bulletin.

No Reporting

(m) Although the service bulletin referenced in this AD specifies to submit certain information to the manufacturer, this AD does not include that requirement.

Alternative Methods of Compliance (AMOCs)

(n) The Manager, New York Aircraft Certification Office, FAA, has the authority to approve AMOCs for this AD, if requested in accordance with the procedures found in 14 CFR 39.19.

Related Information

(o) Canadian airworthiness directive CF-2005-07, issued March 21, 2005, also addresses the subject of this AD.

Start Signature

Issued in Renton, Washington, on September 6, 2005.

Kalene C. Yanamura,

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.

End Signature End Part End Supplemental Information

[FR Doc. 05-18208 Filed 9-13-05; 8:45 am]

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