05-24245. Airworthiness Directives; Bombardier Model DHC-8-400 Series Airplanes

AGENCY:

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

ACTION:

Final rule.

SUMMARY:

The FAA is adopting a new airworthiness directive (AD) for certain Bombardier Model DHC-8-400 series airplanes. This AD requires 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 AD results from a report indicating that delaminated shims extruded from the interface between the forward attaching fittings of the 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.

DATES:

This AD becomes effective January 25, 2006.

The Director of the Federal Register approved the incorporation by reference of a certain publication listed in the AD as of January 25, 2006.

ADDRESSES:

You may examine the AD docket on the Internet at http://dms.dot.gov or in person at the Docket Management Facility, U.S. Department of Transportation, 400 Seventh Street SW., Nassif Building, Room PL-401, Washington, DC.

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

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 [phone]; fax [phone].

SUPPLEMENTARY INFORMATION:

Examining the Docket

You may examine the airworthiness directive (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 [phone]) is located on the plaza level of the Nassif Building at the street address stated in the ADDRESSES section.

Discussion

The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 to include an AD that would apply to certain Bombardier Model DHC-8-400 series airplanes. That NPRM was published in the Federal Register on September 14, 2005 (70 FR 54316). (An NPRM correction was published in the Federal Register on September 30, 2005 (70 FR 57221).) That NPRM proposed to 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.

Comments

We provided the public the opportunity to participate in the development of this AD. We have considered the comment received.

Request for Credit for Doing Bombardier All Operator Message (AOM)

One commenter requests that operators be given credit for doing the procedures in accordance with Bombardier AOM 096B, dated June 12, 2003, before the effective date of the AD, as an alternative method of compliance (AMOC) with the requirements of paragraphs (i)(1) and (i)(2) of the NPRM.

We agree with the commenter that accomplishing the actions specified in Bombardier AOM 096B before the effective date of this AD is acceptable for compliance with the detailed inspection and torque check required by paragraphs (i)(1) and (i)(2) of the AD. We also have determined that those actions are also acceptable for the replacement requirements of the AD. We have revised paragraph (g) of the final rule accordingly and reidentified subsequent paragraphs.

Explanation of Change to Identified Repair Drawings

We have revised paragraph (h) of the final rule to refer to the correct revisions and dates of Bombardier Repair Drawing RD 8/4-55-090 and RD 8/4-55-094.

Clarification of AMOC Paragraph

We have revised this action to clarify the appropriate procedure for notifying the principal inspector before using any approved AMOC on any airplane to which the AMOC applies.

Conclusion

We have carefully reviewed the available data, including the comment received, and determined that air safety and the public interest require adopting the AD with the changes described previously. We have determined that these changes will neither increase the economic burden on any operator nor increase the scope of the AD.

Costs of Compliance

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

Estimated Costs

Action	Work hours	Average labor rate per hour	Parts	Cost per airplane	Number of U.S.-registered airplanes	Fleet cost
Detailed inspection and torque check	2	$65	None	$130	19	$2,470
Replacement	30	$65	Free of charge	$1,950	19	37,050

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 AD will not have federalism implications under Executive Order 13132. This AD 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.

For the reasons discussed above, I certify that this AD:

(1) Is not a “significant regulatory action” under Executive Order 12866;

(2) Is not a “significant rule” under 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 AD and placed it in the AD docket. See the ADDRESSES section for a location to examine the regulatory evaluation.

List of Subjects in 14 CFR Part 39

• Air transportation
• Aircraft
• Aviation safety
• Incorporation by reference
• Safety

Adoption of the Amendment

Accordingly, under the authority delegated to me by the Administrator, the FAA amends 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. The Federal Aviation Administration (FAA) amends § 39.13 by adding the following new airworthiness directive (AD):

2005-26-05 Bombardier, Inc. (Formerly de Havilland, Inc.): Amendment 39-14426. Docket No. FAA-2005-22403; Directorate Identifier 2005-NM-144-AD.

Effective Date

(a) This AD becomes effective January 25, 2006.

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; or Bombardier All Operator Message 096B, dated June 12, 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 applicable 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 drawing	RD issue	Dated
RD 8/4-55-083	3	April 16, 2003.
RD 8/4-55-084	1	May 5, 2003.
RD 8/4-55-089	2	June 6, 2003.
RD 8/4-55-090	8	October 9, 2003.
RD 8/4-55-093	2	June 20, 2003.
RD 8/4-55-094	4	October 20, 2003.
RD 8/4-55-106	2	July 31, 2003.
RD 8/4-55-110	3	October 1, 2003.
RD 8/4-55-138	1	October 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 Part A of the service bulletin.

Replacement of Laminated Shims

(1) 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)(1) 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.

(2) Before using any AMOC approved in accordance with § 39.19 on any airplane to which the AMOC applies, notify the appropriate principal inspector in the FAA Flight Standards Certificate Holding District Office.

Related Information

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

Material Incorporated by Reference

(p) You must use Bombardier Service Bulletin 84-55-02, Revision ‘A,’ dated January 12, 2005, to perform the actions that are required by this AD, unless the AD specifies otherwise. The Director of the Federal Register approved the incorporation by reference of this document in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Contact Bombardier, Inc., Bombardier Regional Aircraft Division, 123 Garratt Boulevard, Downsview, Ontario M3K 1Y5, Canada, for a copy of this service information. You may review copies at the Docket Management Facility, U.S. Department of Transportation, 400 Seventh Street SW., room PL-401, Nassif Building, Washington, DC; on the Internet at http://dms.dot.gov;​; or at the National Archives and Records Administration (NARA). For information on the availability of this material at the NARA, call [phone], or go to http://www.archives.gov/​federal_​register/​code_​of_​federal_​regulations/​ibr_​locations.html.

Issued in Renton, Washington, on December 13, 2005.

Ali Bahrami,

Manager, Transport Airplane Directorate, Aircraft Certification Service.