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Proposed Rule

Airworthiness Directives; Bombardier Model DHC-8-100, DHC-8-200, and DHC-8-300 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-8-100, DHC-8-200, and DHC-8-300 series airplanes. This proposed AD would Start Printed Page 14722require, for certain airplanes, modification of the upper bearing of the main landing gear (MLG) shock strut. This proposed AD would also require, for certain airplanes, revising the DHC-8 Maintenance Program Manual to include the MLG shock strut servicing task. This proposed AD results from reports of over-extension of the MLG shock strut piston, which allows the torque links to go over-center and rest on the piston. We are proposing this AD to prevent loss in shock absorption during touchdown and failure of the shock strut housing, which could result in a subsequent loss of directional control.

DATES:

We must receive comments on this proposed AD by April 30, 2007.

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:

Mazdak Hobbi, 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) 228-7330; 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-2007-27713; Directorate Identifier 2006-NM-240-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.

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-8-100, DHC-8-200, and DHC-8-300 series airplanes. TCCA advises that there have been six cases reported in which the main landing gear (MLG) shock strut piston over-extended, allowing the torque links to go over-center and rest on the piston. Investigation has revealed that over-extension of the shock strut resulted from damage to the upper bearing and seal carrier, caused by a loss of internal damping.

Over-extension of the MLG shock strut piston, if not corrected, could result in loss in shock absorption during touchdown and failure of the shock strut housing, which could result in a subsequent loss of directional control.

Relevant Service Information

Bombardier has issued Service Bulletin 8-32-144, Revision ‘A,' dated April 29, 2002, including Messier-Dowty Service Bulletin M-DT SBDHC8-32-82, Revision 1, dated July 5, 2001 (for Model DHC-8-311, -314, and -315 airplanes). The service bulletin describes procedures for modifying the upper bearing in each MLG. The modification includes an inspection of the two halves of the upper bearing for wear and damage, the removal of the needle roller from the upper bearing, an inspection of the cylinder bore for damage and wear, and corrective action if necessary. The corrective action includes replacing the upper bearing with a new bearing and contacting the parts manufacturer if damage or wear that exceeds the maximum diameter is found on the cylinder bore.

Bombardier has issued the following de Havilland Dash 8 maintenance task cards to the applicable Bombardier DHC-8 Maintenance Program Manual (Program Support Manuals 1-8-7, 1-82-7, and 1-83-7). These tasks describe procedures for servicing the MLG shock struts:

  • Dash 8 Series 100 Maintenance Task Card 3210/15, dated June 22, 2005;
  • Dash 8 Series 200 Maintenance Task Card 3210/15, dated June 22, 2005; and
  • Dash 8 Series 300 Maintenance Task Card 3210/15, dated November 29, 2005.

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-2006-14, effective July 21, 2006, to ensure the continued airworthiness of these airplanes in Canada.

FAA's Determination and Requirements of the Proposed AD

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, 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, for certain airplanes, accomplishing the actions specified in the service bulletin described previously, and, for certain airplanes, revising the applicable DCH-8 Maintenance Program Manual to include the MLG shock strut servicing Task 3210/15, except as discussed Start Printed Page 14723under “Difference Between the Proposed AD and the Service Bulletin.”

Difference Between the Proposed AD and the Service Bulletin

The service bulletin specifies to contact the manufacturer for instructions on how to repair certain conditions, but this proposed AD would require repairing those conditions using a method that we or TCCA (or its delegated agent) approve. In light of the type of repair that would be required to address the unsafe condition, and consistent with existing bilateral airworthiness agreements, we have determined that, for this proposed AD, a repair we or TCCA approve would be acceptable for compliance with this proposed AD.

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
Modification4$80$274$594Up to 135Up to $80,190.
Manual Revision180080135$10,800.

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 AD 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-2007-27713; Directorate Identifier 2006-NM-240-AD.

Comments Due Date

(a) The FAA must receive comments on this AD action by April 30, 2007.

Affected ADs

(b) None.

Applicability

(c) This AD applies to Bombardier Model DHC-8-101, -102, -103, -106, -201, -202, -301, -311, -314, and -315 airplanes, certificated in any category; serial numbers 003 through 618 inclusive.

Unsafe Condition

(d) This AD results from reports of over-extension of the main landing gear (MLG) shock strut piston, which allows the torque links to go over-center and rest on the piston. We are issuing this AD to prevent loss in shock absorption during touchdown and failure of the shock strut housing, which could result in a subsequent loss of directional control.

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.

Modification of the Upper Bearing

(f) For Model DHC-8-311, -314, and -315 airplanes, serial numbers 202 through 516 inclusive, with MLG shock struts having any serial number DCL3501/90 through DCL3768/97 inclusive installed: Within 3,000 flight hours after the effective date of this AD, modify the upper bearing in each MLG (including doing inspections of the upper bearing and cylinder bore for wear and damage, and doing all applicable corrective actions) in accordance with the Accomplishment Instructions of Bombardier Service Bulletin 8-32-144, Revision ‘A,’ dated April 29, 2002, including Messier-Dowty Service Bulletin M-DT SBDHC8-32-82, Revision 1, dated July 5, 2001, except if wear exceeds the maximum diameter specified in the service bulletin for the cylinder bore or if damage is found on the cylinder bore, before further flight, repair using a method approved by either the Manager, International Branch, ANM-116, Transport Airplane Directorate, FAA; or Transport Canada Civil Aviation (TCCA) (or its delegated agent). Do all applicable corrective actions before further flight.

Revision of the Maintenance Program Manual

(g) For Model DHC-8-101, -102, -103, -106, -201, -202, -301, -311, -314, and -315 airplanes, serial numbers 003 through 614 inclusive: Within 30 days after the effective date of this AD, revise Part 1 of the applicable DHC-8 Maintenance Program Manual by incorporating the applicable MLG shock strut servicing Task 3210/15 specified in Table 1 of this AD.

Note 1:

This may be done by inserting copies of the applicable task into the applicable maintenance program manual. When these tasks have been included in the general revisions of the applicable Start Printed Page 14724maintenance program manual, the general revisions may be inserted in the applicable maintenance program manual and the copy of the task may be removed from the maintenance program manual.

Table 1.—Tasks

Task—Dated—To the program support manual (PSM)—For model—
Dash 8 Series 100 Maintenance Task Card 3210/15June 22, 20051-8-7DHC-8-100 Series Airplanes.
Dash 8 Series 200 Maintenance Task Card 3210/15June 22, 20051-82-7DHC-8-200 Series Airplanes.
Dash 8 Series 300 Maintenance Task Card 3210/15November 29, 20051-83-7DHC-8-300 Series Airplanes.

Parts Installation

(h) After the effective date of this AD, no person may install a part identified in paragraphs (h)(1) and (h)(2) of this AD, as a replacement during the repair or overhaul of any shock strut assembly, on any airplane.

(1) Upper bearing, part number 10130-3 or 10130-551.

(2) Damper ring, part number 10129-3 or 10129-551.

(i) After the effective date of this AD, only the parts identified in paragraphs (i)(1) and (i)(2) of this AD may be installed on any airplane as replacement upper bearings and damper rings during the repair or overhaul of any shock strut assembly, except as provided by paragraph (j) of this AD.

(1) Upper bearing, part number 10130-5.

(2) Damper ring, part number 10129-5 or 10129-533.

(j) After the effective date of this AD, only MLGs with a reworked, oversize cylinder bore (part number identified in the applicable component maintenance manual (CMM)) that have parts identified in paragraphs (j)(1), (j)(2), and (j)(3) of this AD used in accordance with the applicable CMM may be installed on any airplane.

(1) Upper bearing, part number CRS85-167-11.

(2) Damper ring, part number CRS85-167-31 or CRS85-167-33.

(3) Seal carrier, part number CRS85-167-21.

Credit for Actions Done Using Previous Service Information

(k) Modifications accomplished before the effective date of this AD in accordance with Bombardier Service Bulletin 8-32-144, dated August 10, 1998, including Messier-Dowty Service Bulletin M-DT SBDCH8-32-82, dated March 9, 1998, are considered acceptable for compliance with the corresponding actions specified in this AD.

Alternative Methods of Compliance (AMOCs)

(l)(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

(m) Canadian airworthiness directive CF-2006-14, effective July 21, 2006, also addresses the subject of this AD.

Start Signature

Issued in Renton, Washington, on March 20, 2007.

Ali Bahrami,

Manager, Transport Airplane Directorate, Aircraft Certification Service.

End Signature End Part End Supplemental Information

[FR Doc. E7-5668 Filed 3-28-07; 8:45 am]

BILLING CODE 4910-13-P