05-6248. Airworthiness Directives; Bombardier Model DHC-8-400, -401, and -402 Airplanes

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, -401, and -402 airplanes. This proposed AD would require repetitive inspections to detect discrepancies of the attachment fittings of the outboard flap front spar at flap track Number 4 and Number 5 locations, and corrective actions if necessary. This proposed AD also would require eventual replacement of the attachment fittings as terminating action for the repetitive inspections. This proposed AD is prompted by the discovery of several airplanes that have loose flap front spar attachment fittings at flap track Number 4 and Number 5 locations. We are proposing this AD to prevent the attachment fittings from becoming detached, and consequent loss of control of the airplane.

DATES:

We must receive comments on this proposed AD by April 29, 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.
• By fax: [phone].
• 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.

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

You can examine the contents of this AD docket on the Internet at http://dms.dot.gov,, or at the Docket Management Facility, U.S. Department of Transportation, 400 Seventh Street, SW., room PL-401, on the plaza level of the Nassif Building, Washington, DC. This docket number is FAA-2005-20727; the directorate identifier for this docket is 2004-NM-148-AD.

FOR FURTHER INFORMATION CONTACT:

David A. Lawson, 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:

Comments Invited

We invite you to submit any written relevant data, views, or arguments regarding this proposed AD. Send your comments to an address listed under ADDRESSES. Include “Docket No. FAA-2005-20727; Directorate Identifier 2004-NM-148-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 submitted 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 our docket 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 can review the DOT's complete Privacy Act Statement in the Federal Register published on April 11, 2000 (65 FR 19477-78), or you can visit http://dms.dot.gov.

Examining the Docket

You can 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 [phone]) 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 DMS 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, -401, and -402 airplanes. TCCA advises that, during inspections and flap modifications, several airplanes were found to have loose flap front spar attachment fittings at flap track Number 4 and Number 5 locations. When the fittings were removed, it was discovered that the fittings and the flap front spar web to which they were mounted had elongated attachment holes. In addition, the lugs of certain attachment fittings were found to be chafing with flap track Number 4. Loose fittings can damage the front spar web and result in the fitting becoming detached, and consequent loss of control of the airplane.

Relevant Service Information

Bombardier has issued Alert Service Bulletin (ASB) A84-57-06, Revision “B” dated March 9, 2004. That ASB describes procedures for repetitive visual inspections to detect discrepancies of the attachment fittings of the outboard flap front spar, track Number 4 and Number 5. For flap track Number 4, discrepancies include damage caused by fouling with a flap track, loose fittings, and nonconforming blind fasteners. For flap track Number 5, discrepancies include loose fittings, a gap between any fitting and the front spar web that exceeds 0.002 inches, and nonconforming blind fasteners.

The alert service bulletin refers to the following Bombardier Repair Drawings (RD) as additional sources of service information for doing corrective actions/temporary repairs/terminating action:

• 8/4-57-226, Issue 2, dated November 11, 2003.
• 8/4-57-228, Issue 1, dated October 27, 2003.
• 8/4-57-220, Issue 2, dated October 15, 2003.

The temporary repair procedures involve opening up the holes on original centers in both the brackets and front spar to allow for installation of oversize fasteners, inspecting the areas around the holes for cracks and/or other signs of damage, installing oversize Hi-Lite Pins with corresponding collars in lieu of original standard MS-type blind bolts at all repair locations, and applying corrosion inhibiting compounds as required.

The alert service bulletin also refers to Modification Summary Package IS4Q5750002, Revision D, released December 1, 2003, as an additional source of service information for doing a permanent repair. The permanent repair involves replacing four blind bolts with certain oversize fasteners having certain collars, and installing a repair patch and solid shim. Accomplishing the permanent repair eliminates the need for the repetitive inspections described previously.

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-2004-11, dated June 28, 2004, 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 § 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 AD action is necessary for products of this type design that are certificated for operation in the United States.

Therefore, we are proposing this AD, which would require repetitive inspections to detect discrepancies of the attachment fittings of the outboard flap front spar at flap track Number 4 and Number 5 locations, and corrective actions if necessary. This proposed AD also would require eventual replacement of the attachment fittings as terminating action for the repetitive inspections. The proposed AD would require you to use the service information described previously to perform these actions, except as discussed below.

Differences Between Proposed Rule and Alert Service Bulletin

The alert service bulletin specifies that you may contact the manufacturer for instructions on how to repair certain conditions, but this proposed AD would require you to repair those conditions using a method that we or TCAA (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 TCAA approve would be acceptable for compliance with this proposed AD Operators should note that, although the Accomplishment Instructions of the alert service bulletin describe procedures for submitting inspection results to the manufacturer, this proposed AD would not require that action.

Costs of Compliance

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

Estimated Costs

Action	Work hours	Average labor rate per hour	Parts	Cost per airplane	Number of U.S.-registered airplanes	Fleet cost
Inspections (per inspection cycle)	1	$65	$0	$65	22	1 $1,430
Permanent repair	20	65	0	1,300	22	28,600
1 Per inspection cycle.

Authority for This Rulemaking

The FAA's authority to issue rules regarding aviation safety is found in Title 49 of the United States Code. 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.

This rulemaking is promulgated 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. 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
• Safety

The Proposed Amendment

Accordingly, under the authority delegated to me by the Administrator, the FAA proposes to amend 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 FAA amends § 39.13 by adding the following new airworthiness directive (AD):

Bombardier, Inc. (Formerly de Havilland, Inc.): Docket No. FAA-2005-20727; Directorate Identifier 2004-NM-148-AD.

Comments Due Date

(a) The Federal Aviation Administration must receive comments on this AD action by April 29, 2005.

Affected ADs

(b) None.

Applicability

(c) This AD applies to Bombardier Model DHC-8-400, -401 and -402 airplanes, certificated in any category; serial numbers 4001 and 4003 through 4093 inclusive.

Unsafe Condition

(d) This AD is prompted by the discovery of several airplanes that have loose flap front spar attachment fittings at flap track Number 4 and Number 5 locations. We are issuing this AD to prevent the attachment fittings from becoming detached, and consequent loss of control 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 Bulletin Reference

(f) The term “service bulletin,” as used in this AD, means the Accomplishment Instructions of Bombardier Alert Service Bulletin A84-57-06, Revision ‘B,’ dated March 9, 2004.

Inspections of Flap Track Number 4

(g) For any front spar attachment fitting at the flap track Number 4 location on which Bombardier Repair Drawing (RD) 8/4-57-228, Issue 1, dated October 27, 2003; in combination with RD 8/4-57-173, Issue 2, dated June 17, 2003, or RD 8/4-57-180, Issue 2, dated September 22, 2003, or RD 8/4-57-226, Issue 2, dated November 11, 2003; has not been done prior to the effective date of this AD: Within 400 flight hours after the effective date of this AD, do a general visual inspection to detect discrepancies of the front spar attachment fittings at the flap track Number 4 location on both the left and right outboard flap assemblies. Do the inspection in accordance with the service bulletin. Repeat the inspection thereafter at intervals not to exceed 800 flight hours until the terminating action required by paragraph (j) of this AD is done.

Note 1:

For the purposes of this AD, a general visual inspection is: “A visual examination of an interior or exterior area, installation, or assembly to detect obvious damage, failure, or irregularity. This level of inspection is made from within touching distance unless otherwise specified. A mirror may be necessary to ensure visual access to all surfaces in the inspection area. This level of inspection is made under normally available lighting conditions such as daylight, hangar lighting, flashlight, or droplight and may require removal or opening of access panels or doors. Stands, ladders, or platforms may be required to gain proximity to the area being checked.”

Inspections of Flap Track Number 5

(h) Within 400 flight hours after the effective date of this AD, do a general visual inspection to detect discrepancies of the front spar attachment fittings at the flap track Number 5 location on both the left and right outboard flap assemblies. Do the inspection in accordance with the service bulletin. Repeat the inspection thereafter at intervals not to exceed 800 flight hours until the terminating action required by paragraph (j) of this AD is done.

Corrective Actions

(i) If any discrepancy is found during any inspection required by paragraph (g) or (h) of this AD, before further flight, repair the discrepancy in accordance with the service bulletin. Where the service bulletin says to contact the manufacturer for repair instructions, before further flight, repair in accordance with a method approved by either the Manager, New York Aircraft Certification Office (ACO), FAA; or Transport Canada Civil Aviation (TCCA) (or its delegated agent).

Terminating Action—Permanent Repair

(j) Within 4,000 flight hours after the effective date of this AD, do the permanent repair required by paragraphs (j)(1) and (j)(2) of this AD. Completing the permanent repair constitutes terminating action for the requirements of this AD.

(1) Modify the attachment of the front fittings of flap track Number 4 on both the left and right outboard flap assemblies in accordance with Bombardier Repair Drawing (RD) 8/4-57-226, Issue 2, dated November 11, 2003. Fittings on which the repairs specified in RD 8/4-57-173, Issue 2, dated June 17, 2003, or RD 8/14-57-180, Issue 2, dated September 22, 2003, have been done do not require that RD 8/4-57-226 be incorporated at those fitting locations.

(2) Modify the attachment of the front fittings of flap track Number 5 on both the left and right outboard flap assemblies in accordance with Bombardier Modification Summary Package IS4Q5750002, Revision D, dated December 1, 2003.

Inspections Accomplished According to Previous Issue of Service Bulletin

(k) Inspections accomplished before the effective date of this AD in accordance with Bombardier Alert Service Bulletin A84-57-06, dated November 5, 2003; or Revision ‘A,’ dated December 16, 2003; are acceptable for compliance with the inspections required by this AD.

No Reporting Requirement

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

Alternative Methods of Compliance (AMOCs)

(m) 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

(n) Canadian airworthiness directive CF-2004-11, dated June 28, 2004, also addresses the subject of this AD.

Issued in Renton, Washington, on March 18, 2005.

Ali Bahrami,

Manager, Transport Airplane Directorate, Aircraft Certification Service.