AD 95-24-12

This amendment adopts a new airworthiness directive (AD) that applies to Jetstream Aircraft Limited (JAL) Model 3201 airplanes. This action requires repetitively inspecting the main landing gear (MLG) bay forward lower edge wing skin structure for cracks, replacing any cracked doubler with a joggled doubler of improved design to reinforce the area and prevent future cracking, and eventually incorporating these doublers on all affected airplanes. Cracking found at the MLG bay forward lower edge wing skin structure during fatigue testing of the JAL Model 3201 prompted this action. The actions specified by this AD are intended to prevent the MLG bay forward lower edge wing skin structure from cracking, which, if not detected and corrected, could cause failure of the wing structure and loss of control of the airplane.

Final rule

95-24-12 JETSTREAM AIRCRAFT LIMITED: Amendment 39-9442; Docket No. 95-CE-26-AD.
Applicability: Model 3201 Airplanes (all serial numbers), certificated in any category.

NOTE 1: This AD applies to each airplane identified in the preceding applicability provision, regardless of whether it has been modified, altered, or repaired in the area subject to the requirements of this AD. For airplanes that have been modified, altered, or repaired so that the performance of the requirements of this AD is affected, the owner/operator must request approval for an alternative method of compliance in accordance with paragraph (e) of this AD. The request should include an assessment of the effect of the modification, alteration, or repair on the unsafe condition addressed by this AD; and, if the unsafe condition has not been eliminated, the request should include specific proposed actions to address it.

Compliance: Required as indicated in the body of this AD, unless already accomplished.

To prevent the main landing gear (MLG) bay forward lower edge wing skin structure from cracking, which, if not detected and corrected, could cause failure of the wing structure and loss of control of the airplane, accomplish the following:

(a) Upon accumulating 4,000 hours time-in-service (TIS) or within the next 200 hours TIS after the effective date of this AD, whichever occurs later, inspect the MLG bay forward lower edge wing skin structure adjacent to the main spar for cracks in accordance with the ACCOMPLISHMENT INSTRUCTIONS section of Jetstream Service Bulletin (SB) 57-A-JA920540, Original Issue September 1, 1992.

(1) If cracks are found, prior to further flight, replace the existing doublers with joggled doublers of improved design in accordance with the ACCOMPLISHMENT INSTRUCTIONS section of Jetstream SB 57-A-JA920540, Original Issue September 1, 1992.

(2) If no cracks are found, re-inspect the MLG bay forward lower edge wing skin structure at intervals not to exceed 600 hours TIS until modified as specified in paragraph (b) of this AD.

(b) Upon accumulating 9,000 hours TIS or within the next 200 hours TIS after the effective date of this AD, whichever occurs later, unless already accomplished as specified in paragraph (a)(1) of this AD, replace the existing doublers with joggled doublers of improved design in accordance with the ACCOMPLISHMENT INSTRUCTIONS section of Jetstream SB 57-A-JA920540.

(c) Replacing the joggled doublers as required by paragraph (a)(1) or (b) of this AD eliminates the repetitive inspection requirements of this AD.

(d) Special flight permits may be issued in accordance with sections 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199) to operate the airplane to a location where the requirements of this AD can be accomplished.

(e) An alternative method of compliance or adjustment of the initial or repetitive compliance times that provides an equivalent levelof safety may be approved by the Manager, Brussels Aircraft Certification Office, FAA, Europe, Africa, and Middle East Office, c/o American Embassy, B-1000 Brussels, Belgium. The request shall be forwarded through an appropriate FAA Maintenance Inspector, who may add comments and then send it to the Manager, Brussels Aircraft Certification Office.

NOTE 2: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Brussels Aircraft Certification Office.

(f) The inspection and modification required by this AD shall be done in accordance with SB 57-A-JA920540, Original Issue September 1, 1992. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from Jetstream Aircraft Limited, Prestwick International Airport, Ayrshire, KA9 2RW, Scotland; or Jetstream Aircraft Inc., Librarian, P.O. Box 16029, Dulles International Airport, Washington, D.C. 20041-6029. Copies may be inspected at the FAA, Central Region, Office of the Assistant Chief Counsel, Room 1558, 601 E. 12th Street, Kansas City, Missouri, or at the Office of the Federal Register, 800 North Capitol Street, NW., 7th Floor, suite 700, Washington, DC.

(g) This amendment becomes effective on January 17, 1996.

A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to include an AD that would apply to Jetstream Aircraft Limited (JAL) Model 3201 airplanes was published in the Federal Register on August 14, 1995 (60 FR 41868). The action proposed to require repetitively inspecting the main landing gear (MLG) bay forward lower edge wing skin structure for cracks, replacing any cracked doubler with a joggled doubler of improved design to reinforce the area and prevent future cracking, and eventually incorporating these doublers on all affected airplanes. Accomplishment of the proposed action would be in accordance with Jetstream Service Bulletin (SB) 57-A-JA920540; Original Issue September 1, 1992.

Interested persons have been afforded an opportunity to participate in the making of this amendment. No comments were received on the proposed rule or the FAA's determination of the cost to the public.

After careful review of all available information related to the subject presented above, the FAA has determined that air safety and the public interest require the adoption of the rule as proposed except for minor editorial corrections. The FAA has determined that these minor corrections will not change the meaning of the AD and will not add any additional burden upon the public than was already proposed.

The FAA estimates that 134 airplanes in the U.S. registry will be affected by this AD, that it will take approximately 35 workhours per airplane to accomplish the required action, and that the average labor rate is approximately $60 an hour. Parts will be provided by the manufacturer at no cost to the owners/operators. Based on these figures, the total cost impact of this AD on U.S. operators is estimated to be $281,400. This figure is based on the assumption that all of the affected airplanes do not have the new joggled doublers installed and that none of the owners/operators of the affected airplanes have replaced the doublers. The FAA has no way of determining the number of repetitive inspections an owner/operator may incur.

The regulations adopted herein will not have substantial direct effects 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. Therefore, in accordance with Executive Order 12612, it is determined that this final rule does not have sufficient federalism implications to warrant the preparation of a Federalism Assessment.

For the reasons discussed above, I certify that this action (1) is not a "significant regulatory action" under Executive Order 12866; (2) is not a "significant rule" under 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. A copy of the final evaluation prepared for this action is contained in the Rules Docket. A copy of it may be obtained by contacting the Rules Docket at the location provided under the caption "ADDRESSES".

List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Incorporation by reference, Safety.

Adoption of the Amendment
Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration amends part 39 of the Federal Aviation Regulations (14 CFR part 39) as follows:

PART 39 - AIRWORTHINESS DIRECTIVES
1. The authority citation for part 39 continues to read as follows:
Authority: 49 USC 106(g), 40101, 40113, 44701.

Section 39.13 - [AMENDED]
2. Section 39.13 is amended by adding a new airworthiness directive (AD) to read as follows: