E7-22103. Airworthiness Directives; Bombardier Model DHC-8-400 Series Airplanes

AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

We propose to adopt a new airworthiness directive (AD) for the products listed above. This proposed AD results from mandatory continuing airworthiness information (MCAI) originated by an aviation authority of another country to identify and correct an unsafe condition on an aviation product. The MCAI describes the unsafe condition as:

There has been a reported case of failure of a bracket (P/N 85217732-108) of the over-centering spring assembly inside the translating door of the forward baggage compartment. * * * Failure of the bracket caused the eyebolt at the bottom of the spring assembly to become loose, resulted in damage of the support beam during normal door handle movement. Damage of the support beam, which is dormant, in combination with failure of a doorstop attached to any remaining undamaged support beam will degrade the structural integrity of the door, resulting in possible depressurization or loss of the door.

The proposed AD would require actions that are intended to address the unsafe condition described in the MCAI.

DATES:

We must receive comments on this proposed AD by December 13, 2007.

ADDRESSES:

You may send comments by any of the following methods:

• Federal eRulemaking Portal: Go to http://www.regulations.gov. Follow the instructions for submitting comments.
• Fax: [phone].
• Mail: U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue, SE., Washington, DC 20590.
• Hand Delivery: U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-40, 1200 New Jersey Avenue, SE., Washington, DC, between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.

Examining the AD Docket

You may examine the AD docket on the Internet at http://www.regulations.gov;​; or in person at the Docket Operations office between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The AD docket contains this proposed AD, the regulatory evaluation, any comments received, and other information. The street address for the Docket Operations office (telephone [phone]) is in the ADDRESSES section. Comments will be available in the AD docket shortly after receipt.

FOR FURTHER INFORMATION CONTACT:

Pong K. Lee, 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 send any written relevant data, views, or arguments about this proposed AD. Send your comments to an address listed under the ADDRESSES section. Include “Docket No. FAA-2007-0183; Directorate Identifier 2007-NM-146-AD” at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of this proposed AD. We will consider all comments received by the closing date and may amend this proposed AD based on those comments.

We will post all comments we receive, without change, to http://www.regulations.gov,, including any personal information you provide. We will also post a report summarizing each substantive verbal contact we receive about this proposed AD.

Discussion

Transport Canada Civil Aviation (TCCA), which is the aviation authority for Canada, has issued Canadian Airworthiness Directive CF-2007-05, effective April 24, 2007 (referred to after this as “the MCAI”), to correct an unsafe condition for the specified products. The MCAI states:

There has been a reported case of failure of a bracket (P/N 85217732-108) of the over-centering spring assembly inside the translating door of the forward baggage compartment. This condition can exist on other translating doors on the aircraft. Investigation concluded that an insufficient gap between the bottom eyebolt and the barrel of the spring assembly caused an increase of tension load on the bracket and resulted in subsequent failure of the bracket. Failure of the bracket caused the eyebolt at the bottom of the spring assembly to become loose, resulted in damage of the support beam during normal door handle movement. Damage of the support beam, which is dormant, in combination with failure of a doorstop attached to any remaining undamaged support beam will degrade the structural integrity of the door, resulting in possible depressurization or loss of the door.

Corrective actions include a one-time inspection for damage of the spring support bracket and support beam of the forward baggage door, aft service door, and aft passenger door; repetitive inspections for integrity (corrosion, damage, cracking, and looseness or misalignment) of the doorstops of support beams found to be within damage limits; repair of support beams, or replacement of damaged brackets, support beams, or doorstops, as applicable; and removal of certain washers and nuts. You may obtain further information by examining the MCAI in the AD docket.

Relevant Service Information

Bombardier has issued Service Bulletin 84-52-51, Revision A, dated September 8, 2006, including Service Bulletin 8-MHI0084, Revision C, dated September 6, 2006; and Repair Drawing RD 8/4-52-202, Issue 1, dated December 2, 2005. The actions described in this service information are intended to correct the unsafe condition identified in the MCAI.

FAA's Determination and Requirements of This Proposed AD

This product has been approved by the aviation authority of another country, and is approved for operation in the United States. Pursuant to our bilateral agreement with the State of Design Authority, we have been notified of the unsafe condition described in the MCAI and service information referenced above. We are proposing this AD because we evaluated all pertinent information and determined an unsafe condition exists and is likely to exist or develop on other products of the same type design.

Differences Between This AD and the MCAI or Service Information

We have reviewed the MCAI and related service information and, in general, agree with their substance. But we might have found it necessary to use different words from those in the MCAI to ensure the AD is clear for U.S. operators and is enforceable. In making these changes, we do not intend to differ substantively from the information provided in the MCAI and related service information.

We might also have proposed different actions in this AD from those in the MCAI in order to follow FAA policies. Any such differences are highlighted in a NOTE within the proposed AD.

Costs of Compliance

Based on the service information, we estimate that this proposed AD would affect about 29 products of U.S. registry. We also estimate that it would take about 5 work-hours per product to comply with the basic requirements of this proposed AD. The average labor rate is $80 per work-hour. Required parts would cost about $0 per product. Where the service information lists required parts costs that are covered under warranty, we have assumed that there will be no charge for these costs. As we do not control warranty coverage for affected parties, some parties may incur costs higher than estimated here. Based on these figures, we estimate the cost of the proposed AD on U.S. operators to be $11,600, or $400 per product.

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 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 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. 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.

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 AD:

Bombardier, Inc. (Formerly de Havilland, Inc.): Docket No. FAA-2007-0183; Directorate Identifier 2007-NM-146-AD.

Comments Due Date

(a) We must receive comments by December 13, 2007.

Affected ADs

(b) None.

Applicability

(c) This AD applies to Bombardier Model DHC-8-400, DHC-8-401, and DHC-8-402 airplanes; certificated in any category; having serial numbers 4001 and 4003 through 4102.

Subject

(d) Air Transport Association (ATA) of America Code 52: Doors.

Reason

(e) The mandatory continuing airworthiness information (MCAI) states:

There has been a reported case of failure of a bracket (P/N 85217732-108) of the over-centering spring assembly inside the translating door of the forward baggage compartment. This condition can exist on other translating doors on the aircraft. Investigation concluded that an insufficient gap between the bottom eyebolt and the barrel of the spring assembly caused an increase of tension load on the bracket and resulted in subsequent failure of the bracket. Failure of the bracket caused the eyebolt at the bottom of the spring assembly to become loose, resulted in damage of the support beam during normal door handle movement. Damage of the support beam, which is dormant, in combination with failure of a doorstop attached to any remaining undamaged support beam will degrade the structural integrity of the door, resulting in possible depressurization or loss of the door.

Corrective actions include a one-time inspection for damage of the spring support bracket and support beam of the forward baggage door, aft service door, and aft passenger door; repetitive inspections for integrity (corrosion, damage, cracking, and looseness or misalignment) of the doorstops of support beams found to be within damage limits; repair of support beams, or replacement of damaged brackets, support beams, or doorstops, as applicable; and removal of certain washers and nuts.

Actions and Compliance

(f) Unless already done, do the following actions.

(1) Within 1,000 flight hours after the effective date of this AD, perform a one-time inspection for damage of the spring support bracket and support beams of the forward baggage door, aft service door, and aft passenger door, as applicable, in accordance with Bombardier Service Bulletin 84-52-51, Revision A, dated September 8, 2006. Replace any damaged bracket, support beam, or doorstop in accordance with the service bulletin, prior to further flight.

(i) If any support beam is damaged at only one spring location and the damage is within the limits defined in Bombardier Repair Drawing RD 8/4-52-202, Issue 1, dated December 2, 2005, do the actions specified in paragraphs (f)(1)(i)(A) and (f)(1)(i)(B) of this AD.

(A) Inspect each doorstop of the affected door for integrity in accordance with the service bulletin prior to further flight, and repeat the inspection thereafter at intervals not to exceed 400 flight hours, until the support beam is repaired as specified in paragraph (f)(1)(i)(B) of this AD or replaced in accordance with the service bulletin. If the doorstop does not meet integrity standards during any inspection required by this paragraph, before further flight, repair or replace the doorstop with a new or serviceable doorstop in accordance with the repair drawing.

(B) Within 5,000 flight hours after accomplishing the inspection described in paragraph (f)(1) of this AD, repair the support beam in accordance with the repair drawing or replace in accordance with the service bulletin. Doing the repair or replacement terminates the inspections required by paragraph (f)(1)(i)(A) of this AD.

(ii) If any support beam is damaged at one or two spring locations and any damage exceeds the limits defined in Bombardier Repair Drawing RD 8/4-52-202, Issue 1, dated December 2, 2005, prior to further flight, replace the damaged support beam with a new support beam in accordance with the service bulletin.

(iii) If any support beam is damaged at two spring locations and the damage is within the limits defined in Bombardier Repair Drawing RD 8/4-52-202, Issue 1, dated December 2, 2005, prior to further flight, repair the support beam in accordance with the repair drawing.

(2) Within 1,000 flight hours after the effective date of this AD, remove the nuts and washers at the bottom of the over-centering spring assemblies of the forward baggage door, aft service door, and aft passenger door by incorporating Modsum 4-155296, in accordance with Bombardier Service Bulletin 84-52-51, Revision A, dated September 8, 2006.

FAA AD Differences

Note:

This AD differs from the MCAI and/or service information as follows: No differences.

Other FAA AD Provisions

(g) The following provisions also apply to this AD:

(1) Alternative Methods of Compliance (AMOCs): The Manager, New York Aircraft Certification Office (ACO), FAA, has the authority to approve AMOCs for this AD, if requested using the procedures found in 14 CFR 39.19. Send information to ATTN: Pong K. Lee, Aerospace Engineer, New York ACO, FAA, 1600 Stewart Avenue, Suite 410, Westbury, New York 11590; telephone [phone]; fax [phone]. Before using any approved AMOC on any airplane to which the AMOC applies, notify your appropriate principal inspector (PI) in the FAA Flight Standards District Office (FSDO), or lacking a PI, your local FSDO.

(2) Airworthy Product: For any requirement in this AD to obtain corrective actions from a manufacturer or other source, use these actions if they are FAA-approved. Corrective actions are considered FAA-approved if they are approved by the State of Design Authority (or their delegated agent). You are required to assure the product is airworthy before it is returned to service.

(3) Reporting Requirements: For any reporting requirement in this AD, under the provisions of the Paperwork Reduction Act, the Office of Management and Budget (OMB) has approved the information collection requirements and has assigned OMB Control Number 2120-0056.

Related Information

(h) Refer to MCAI Canadian Airworthiness Directive CF-2007-05, effective April 24, 2007; Bombardier Service Bulletin 84-52-51, Revision A, dated September 8, 2006, including Service Bulletin 8-MHI0084, Revision C, dated September 6, 2006; and Bombardier Repair Drawing RD 8/4-52-202, Issue 1, dated December 2, 2005, for related information.

Issued in Renton, Washington, on November 5, 2007.

Ali Bahrami,

Manager, Transport Airplane Directorate, Aircraft Certification Service.