AD 98-17-07

This amendment adopts a new airworthiness directive (AD), applicable to all Fokker Model F28 Mark 0070 and Mark 0100 series airplanes, that requires inspection of the wing leading edge sections for the correct amount of bleed air exhaust holes, and corrective actions, if necessary. This amendment is prompted by issuance of mandatory continuing airworthiness information by a foreign civil airworthiness authority. The actions specified by this AD are intended to prevent malfunction of the wing leading edge thermal anti-ice system, which could result in reduced controllability of the airplane and/or reduced structural integrity of the wing due to overheating.

Final rule

98-17-07 FOKKER: Amendment 39-10709; Docket 97-NM-248-AD.

Applicability: All Model F28 Mark 0070 and Mark 0100 series airplanes, 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 (c) 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, unless accomplished previously.

To prevent malfunction of the wing leading edge thermal anti-ice system, which could result in reduced controllability of the airplane and/or reduced structural integrity of the wing due to overheating, accomplish the following:

(a) Within 60 days after the effective date of this AD, inspect all wing leading edge sections for the presence of the correct number of bleed air exhaust holes, in accordance with Part 1 of the Accomplishment Instructions of Fokker Service Bulletin SBF100-57-032, dated August 21, 1995. If any missing holes are detected, prior to further flight, accomplish paragraphs (a)(1) and (a)(2) of this AD, in accordance with Part 2 of the Accomplishment Instructions of the service bulletin:

(1) Rework the affected wing leading edge section(s) to add the correct number of holes, and

(2) Perform a visual inspection of the auxiliary spar or front spar, as applicable, to detect heat damage. If any heat damage is detected, prior to further flight, repair the affected structure in accordance with a method approved by the Manager, International Branch, ANM-116, FAA, Transport Airplane Directorate.

(b) As of the effective date of this AD, no person shall install on any airplane a wing leading edge section, unless it has been inspected for the presence of the correct number of bleed air exhaust holes, and reworked, if necessary, to add the correct number of holes, in accordance with Fokker Component Service Bulletin D14000-57-004, dated August 21, 1995.

(c) An alternative method of compliance or adjustment of the compliance time that provides an acceptable level of safety may be used if approved by the Manager, International Branch, ANM-116, FAA, Transport Airplane Directorate. Operators shall submit their requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, International Branch, ANM-116.

NOTE 2: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the International Branch, ANM-116.

(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) The actions shall be done in accordance with Fokker Service Bulletin SBF100-57-032, dated August 21, 1995; and Fokker Component Service Bulletin D14000-57-004, dated August 21, 1995. 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 Fokker Services B.V., Technical Support Department, P.O. Box 75047, 1117 ZN Schiphol Airport, the Netherlands. Copies may be inspected at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

NOTE 3: The subject of this AD is addressed in Dutch airworthiness directive BLA No. 1995-087 (A), dated August 31, 1995.

(f) This amendment becomes effective on September 18, 1998.

A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to include an airworthiness directive (AD) that is applicable to all Fokker Model F28 Mark 0070 and Mark 0100 series airplanes was published in the Federal Register on December 9, 1997 (62 FR 64775). That action proposed to require inspection of the wing leading edge sections for the correct amount of bleed air exhaust holes, and corrective actions, if necessary.

Comments
Interested persons have been afforded an opportunity to participate in the making of this amendment. Due consideration has been given to the comments received.

One commenter supports the proposed rule.

Request to Revise Compliance Time for Follow-On Actions
One commenter supports the requirement for conducting the initial inspection within 60 days, as specified in the proposed AD, but strongly opposes the requirement to further inspect and accomplish leading edge repairs prior to further flight. The commenter notes that Fokker Service Bulletin SBF100-57-032, dated August 21, 1995, was issued over two years ago, and provides a recommended compliance time for accomplishment of these follow-on actions. The commenter states that, since the time to detect the discrepancy is extended an additional 60 days by the proposed AD, it is very improbable that any degradation that may be found will warrant permanent repair prior to further flight. The commenter suggests that, based on the severity of the damage that could be expected, a time scale should be developed correlating the time allowed to accomplish the additional inspections and repair work with the number of holes found missing. The commenter requests that the proposed AD be revised to allow 1,200 flight hours, as a minimum, for accomplishment of the follow-on actions; such a revision would enable the work to be accomplished during a scheduled maintenance period.

The FAA does not concur with the commenter's request. The FAA has determined that, should any missing holes or heat damage be detected during the initial inspection required by this AD, an unsafe condition exists that necessitates repairs prior to further flight in order to adequately address that condition. As a matter of law, in order to be airworthy, an airplane must conform to its type design and be in a condition for safe operation. Apart from the requirements of this AD, if such missing holes or heat damage of the wing leading edge were found on an airplane at any time, the airplane would be rendered unairworthy and, as such, would require repair prior to further flight.

Further, the commenter has not provided any data to substantiate why continued flight should be allowed with missing bleed air holes in the wing leading edge section, or with heat damage to this area. However, under the provisions of paragraph (c) of the final rule, an operator may request an adjustment to the compliance time, if sufficient data are submitted to justify why such an extension would not compromise safety.

Conclusion
After careful review of the available data, including the comments noted above, the FAA has determined that air safety and the public interest require the adoption of the rule as proposed.

Cost Impact
The FAA estimates that 131 Fokker Model F28 Mark 0070 and 0100 series airplanes of U.S. registry will be affected by this AD, that it will take approximately 1 work hour per airplane to accomplish the required inspection, and that the average labor rate is $60 per work hour. Based on these figures, the cost impact of the required inspection on U.S. operators is estimated to be $7,860, or $60 per airplane.

The cost impact figure discussed above is based on assumptions that no operator has yet accomplished any of the requirements of this AD action, and that no operator would accomplish those actions in the future if this AD were not adopted.

Regulatory Impact
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 final evaluation has been prepared for this action and it is contained in the Rules Docket. A copy of it may be obtained from 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 U.S.C. 106(g), 40113, 44701.

39.13 [Amended]
2. Section 39.13 is amended by adding the following new airworthiness directive: