AD 2007-22-06

We are adopting a new airworthiness directive (AD) for the products listed above. This 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:

Over the years, several Fokker 100 (F28 Mark 0100) operators reported that a MLG (main landing gear) wheel fell off during regular operation of the aircraft. These incidents occurred due to a missing spacer, which had inadvertently not been installed during a previous wheel change. Omitting the installation of the wheel spacer allows the wheel to move sideways along the axle, which subsequently leads to bearing failure, followed by loss of the wheel. * * * This condition, if not corrected, * * * could conceivably result in loss of control of the aircraft during the take-off run, landing rollout or taxiing operations. * * *

We are issuing this AD to require actions to correct the unsafe condition on these products.

Final rule.

2007-22-06 Fokker Services B.V.: Amendment 39-15242. Docket No. FAA- 2007-28923; Directorate Identifier 2007-NM-133-AD.

Effective Date

(a) This airworthiness directive (AD) becomes effective November 28, 2007.

Affected ADs

(b) None.

Applicability

(c) This AD applies to Fokker Model F.28 Mark 0070 and 0100 airplanes; certificated in any category; all serial numbers, if equipped with Messier-Dowty main landing gear (MLG) units.

Subject

(d) Air Transport Association (ATA) of America Code 32: Landing gear.

Reason

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

Over the years, several Fokker 100 (F28 Mark 0100) operators reported that a MLG (main landing gear) wheel fell off during regular operation of the aircraft. These incidents occurred due to a missing spacer, which had inadvertently not been installed during a previous wheel change. Omitting the installation of the wheel spacer allows the wheel to move sidewaysalong the axle, which subsequently leads to bearing failure, followed by loss of the wheel. Investigation by Fokker and Messier-Dowty has shown that two separate items, the spacer and the axle nut, can be replaced by a single axle-nut/spacer assembly, to prevent the possibility of omitting the spacer. In 1995, Messier-Dowty issued Service Bulletin (SB) F100-32-72 to make sure that the operator does not assemble the axle nut without the spacer. Fokker subsequently issued SB F100-32- 096 to notify Fokker 100 operators of the (optional) Messier-Dowty SB's existence. At a later stage, Fokker revised the SB to the status of "recommended''. In spite of all this attention to the spacer problem, wheel losses are still being reported due to missing wheel nut spacers. This condition, if not corrected, may lead to further wheel loss incidents, each of which could conceivably result in loss of control of the aircraft during the take-off run, landing rollout or taxiing operations. Since a potentially unsafe condition has been identified that may exist or develop on aircraft of the same type design, this Airworthiness Directive requires the replacement of the axle-nut and spacer with an integrated axle-nut/ spacer assembly. In addition, the Aircraft Maintenance Manual (AMM) and Illustrated Parts Catalogue (IPC) must be amended to prevent reversal to a separate axle-nut and spacer installation during a subsequent wheel change.

Actions and Compliance

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

(1) Within 12 months after the effective date of this AD, replace each MLG wheel axle-nut and spacer with an integrated axle- nut/spacer assembly in accordance with the Accomplishment Instructions of Messier-Dowty Service Bulletin F100-32-72, Revision 1, dated March 5, 2007.

Note 1: Fokker 70/100 Service Letter 102, Revision 1, dated February 12, 1998; and Fokker Service Bulletin SBF100-32-096, Revision 2, dated April 29, 2005; also pertain to this subject.

(2)As of 12 months after the effective date of this AD, no person may install an axle nut having part number (P/N) 201072670 or alternate P/N 201072765, or any spacer having P/N 201072699, on any airplane. Only axle nut subassemblies having P/N 201251273 or P/N 201650216 may be installed.

(3) Actions accomplished before the effective date of this AD in accordance with Messier-Dowty Service Bulletin F100-32-72, dated January 25, 1995, are considered acceptable for compliance with the corresponding action specified in this AD.

FAA AD Differences

Note 2: This AD differs from the MCAI and/or service information as follows:

(1) The MCAI requires revising the AMM and IPC. As these documents are not FAA-approved, we do not require these revisions. Therefore, this AD requires compliance with paragraph (f)(2) of this AD, which accomplishes the intent of revising the AMM and IPC.

Other FAA AD Provisions

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

(1) Alternative Methods of Compliance (AMOCs): The Manager, International Branch, ANM-116, Transport Airplane Directorate, 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: Tom Rodriguez, Aerospace Engineer, International Branch, ANM-116, Transport Airplane Directorate, FAA, 1601 Lind Avenue, SW., Renton, Washington 98057-3356; telephone (425) 227-1137; fax (425) 227-1149. 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 isairworthy 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 Dutch Airworthiness Directive NL-2005-008, dated June 30, 2005, and the service information identified in Table 1 of this AD, for related information.

Table 1.--Related Service Information

Service Information
Revision Level
Date
Fokker 70/100 Service Letter 102
1
February 12, 1998
Fokker Service Bulletin SBF100-32-096
2
April 29, 2005
Messier-Dowty Service Bulletin F100-32-72
1
March 5, 2007

Material Incorporated by Reference

(i) You must use Messier-Dowty Service Bulletin F100-32-72, Revision 1, dated March 5, 2007, to do the actions required by this AD, unless the AD specifies otherwise.

(1) TheDirector of the Federal Register approved the incorporation by reference of this service information under 5 U.S.C. 552(a) and 1 CFR part 51.

(2) For service information identified in this AD, contact Fokker Services B.V., Technical Services Dept., P.O. Box 231, 2150 AE Nieuw-Vennep, the Netherlands.

(3) You may review copies at the FAA, Transport Airplane Directorate, 1601 Lind Avenue SW., Renton, Washington; or at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call (202) 741-6030, or go to: http://www.archives.gov/federal-register/cfr/ibr-locations.html .

Discussion

We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 to include an AD that would apply to the specified products. That NPRM was published in the Federal Register on August 16, 2007 (72 FR 45956). That NPRM proposed to correct an unsafe condition for the specified products. The MCAI states:

Over the years, several Fokker 100 (F28 Mark 0100) operators reported that a MLG (main landing gear) wheel fell off during regular operation of the aircraft. These incidents occurred due to a missing spacer, which had inadvertently not been installed during a previous wheel change. Omitting the installation of the wheel spacer allows the wheel to move sideways along the axle, which subsequently leads to bearing failure, followed by loss of the wheel. Investigation by Fokker and Messier-Dowty has shown that two separate items, the spacer and the axle nut, can be replaced by a single axle-nut/spacer assembly, to prevent the possibility of omitting the spacer. In 1995, Messier-Dowty issued Service Bulletin (SB) F100-32-72 to make sure that the operator does not assemble the axle nut without the spacer. Fokker subsequently issued SB F100-32- 096 to notify Fokker 100 operators of the (optional) Messier-Dowty SB's existence. At a later stage, Fokker revised the SB to the status of "recommended''. In spite of all this attention to the spacer problem, wheel losses are still being reported due to missing wheel nut spacers. This condition, if not corrected, may lead to further wheel loss incidents, each of which could conceivably result in loss of control of the aircraft during the take-off run, landing rollout or taxiing operations. Since a potentially unsafe condition has been identified that may exist or develop on aircraft of the same type design, this Airworthiness Directive requires the replacement of the axle-nut and spacer with an integrated axle-nut/ spacer assembly. In addition, the Aircraft Maintenance Manual(AMM) and Illustrated Parts Catalogue (IPC) must be amended to prevent reversal to a separate axle-nut and spacer installation during a subsequent wheel change.

You may obtain further information by examining the MCAI in the AD docket.

Comments

We gave the public the opportunity to participate in developing this AD. We received no comments on the NPRM or on the determination of the cost to the public.

Conclusion

We reviewed the available data and determined that air safety and the public interest require adopting the AD as proposed.

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 required different actions in this AD from those in the MCAI in order to follow our FAA policies. Any such differences are highlighted in a NOTE within the AD.

Costs of Compliance

We estimate that this AD will affect 13 products of U.S. registry. We also estimate that it will take about 4 work-hours per product to comply with the basic requirements of this AD. The average labor rate is $80 per work-hour. Required parts will cost about $3,750 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 parts. 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 this AD to the U.S. operators to be $52,910, or $4,070 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 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 this AD:
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 AD and placed it in the AD docket.

Examining the AD Docket

You may examine the AD docket on the Internet at http://dms.dot.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 the NPRM, the regulatory evaluation, any comments received, and other information. The street address for the Docket Operations office (telephone (800) 647-5527) is in the ADDRESSES section. Comments will be available in the AD docket shortly after receipt.

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.

Sec. 39.13 [Amended]

2. The FAA amends Sec. 39.13 by adding the following new AD: