Discussion
The Civil Aviation Authority--The Netherlands (CAA-NL), which is the airworthiness authority for the Netherlands, notified us that an unsafe condition might exist on certain Fokker Model F.27 Mark 050 airplanes. The CAA-NL advises that there has been a report that the sliding member of the main landing gear has been overextended after landing. During subsequent investigation, it was found that an end stop had unscrewed itself to a certain extent, and that there was no lockwiring present on the two lockbolts that hold the end stop. The unscrewed end stop caused the gear torque links of the main landing gear to come into an overextended position against the sliding member. This condition, if not corrected, could result in structural damage of the main gear and loss of control of the airplane during the landing roll, due to main landing gear overextension.
Relevant Service Information
Fokker has issued Service Bulletin SBF50-32-039,dated July 2, 2007, which describes procedures for measuring the length of the extended portion of the sliding member of the main landing gear, and performing an inspection for the presence of lockwiring on the lock bolts of the two end stops, and doing corrective actions if necessary. Corrective actions include applying lockwiring if not installed or installed incorrectly.
Accomplishing the actions specified in the service information is intended to adequately address the unsafe condition. The CAA-NL mandated the service information and issued Dutch airworthiness directive NL-2007-002, dated October 31, 2007 (referred to after this as "the MCAI"), to ensure the continued airworthiness of these airplanes in the Netherlands.
Fokker Service Bulletin SBF50-32-039, dated July 2, 2007, refers to Messier-Dowty Service Bulletin F50-32-62, dated January 17, 2007, as an additional source of service information for measuring the length of the extended portion of the sliding member of the main landing gear, performing an inspection for the presence of lockwiring on the lock bolts of the two end stops, and installing new lockwiring when lockwiring is missing or installed incorrectly.
FAA's Determination and Requirements of This 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.
Therefore, we are issuing this AD to detect and correct improper installation of the lockwire on the two lockbolts that hold the sliding member end stop, which could result in structural damage of the main gear and loss of control of the airplane during the landing roll, due to main landing gear overextension. This AD requires accomplishing the actions specified in the service information described previously, except as discussed under "Differences Between the AD and the MCAI."
Differences Between the AD and the MCAI
The MCAI specifies only to inspect for the presence of lockwiring if overextension is found. However, Messier-Dowty Service Bulletin F50- 32-62, dated January 17, 2007, also specifies to inspect if the measurement has increased between inspections. This AD requires inspection for the presence of lockwiring if overextension is found or the measurement of the repeat inspection has increased by 1.0 mm compared to a previous inspection. We have coordinated this difference with CAA-NL.
Costs of Compliance
None of the airplanes affected by this action are on the U.S. Register. All airplanes affected by this AD are currently operated by non-U.S. operators under foreign registry; therefore, they are not directly affected by this AD action. However, we consider this AD necessary to ensure that the unsafe condition is addressed if any affected airplane is imported and placed on the U.S. Register in the future.
If an affected airplane is imported and placed on the U.S. Register in the future, the required actions would take about 8 work hours per airplane, at an average labor rate of $80 per work hour. Required parts would cost about $1,082 per airplane. Based on these figures, the estimated cost of the AD would be $1,722 per airplane.
FAA's Determination of the Effective Date
No airplane affected by this AD is currently on the U.S. Register. Therefore, providing notice and opportunity for public comment is unnecessary before this AD is issued, and this AD may be made effective in less than 30 days after it is published in the Federal Register.
Comments Invited
This AD is a final rule that involves requirements affecting flight safety, and we did not provide you with notice and an opportunity to provide your comments before it becomes effective. However, we invite you to send any written data, views, or arguments about this AD. Send your comments to an address listed under the ADDRESSES section. Include "Docket No. FAA-2009-0214; Directorate Identifier 2007-NM-343-AD" at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of this AD. We will consider all comments received by the closing date and may amend this AD because of 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 AD.
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 amongthe various levels of government.
For the reasons discussed above, I certify that the 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 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.
Sec. 39.13 [Amended]
2. The Federal Aviation Administration (FAA) amends Sec. 39.13 by adding the following new airworthiness directive (AD):