AD 96-25-09

This amendment adopts a new airworthiness directive (AD), applicable to certain Fokker Model F28 Mark 0100 series airplanes, that requires modification of the thrust reverser doors, and replacement of the Collins multifunction display units (MFDU) with new MFDU's. This amendment also requires installation of a placard if the replacement of the MFDU is accomplished prior to modification of the thrust reverser door. This amendment is prompted by a report that cracks were found in the flanges of the main hinge fittings of the horizontal stabilizer, which were caused by higher than anticipated loads induced during thrust reverser operation. The actions specified by this AD are intended to ensure the structural integrity of the horizontal stabilizer by reducing the thrust reverser loads on the horizontal stabilizer.

Final rule

96-25-09 FOKKER: Amendment 39-9852. Docket 95-NM-58-AD.
Applicability: Model F28 Mark 0100 series airplanes; serial numbers 11244 through 11460 inclusive, 11463 through 11469 inclusive, 11471, 11474, 11476, 11478, and 11479; 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 (d) 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.

(a) Prior to the accumulation of 15,000 total flight cycles, or within 1 year after the effective date of this AD, whichever occurs later, accomplish the requirements of paragraphs (a)(1) and (a)(2) of this AD concurrently, except as provided by paragraph (b) of this AD.

(1) Modify the thrust reverser doors in accordance with Fokker Service Bulletin SBF100-78-010, Revision 1, dated April 26, 1994; and

(2) Replace the Collins multifunction display units (MFDU) having part number (P/N) 622-8047-412 or 622-8047-422 with new MFDU's having P/N 622-8047-414 or 622-8047- 423, respectively; as applicable; in accordance with Fokker Service Bulletin SBF100-31-036, dated February 7, 1994.

(b) Paragraph (a)(2) of this AD may be accomplished prior to paragraph (a)(1) of this AD provided that a placard is installed on the main instrument panel in accordance with Fokker Service Bulletin SBF100-31-038, dated April 26, 1994, and removed, prior to further flight, after accomplishment of the requirements of paragraph (a)(1) of this AD.

(c) For airplanes that have been modified in accordance with paragraphs (a)(1) and (a)(2) of this AD: No person may install a Grumman Aerospace aft engine cowling having part number 1159P41440 on any airplane unless it has been previously modified in accordance with Fokker Component Service Bulletin P41440-78-02, dated December 17, 1993, as revised by Fokker Component Service Bulletin Change Notification P41440-78-02/001, dated February 25, 1995.

(d) 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, Standardization Branch, ANM-113, 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, Standardization Branch,ANM-113.

NOTE 2: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Standardization Branch, ANM-113.

(e) 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.

(f) The actions shall be done in accordance with Fokker Service Bulletin SBF100-31-036, dated February 7, 1994; Fokker Service Bulletin SBF100-31-038, dated April 26, 1994; and Fokker Service Bulletin SBF100-78-010, Revision 1, dated April 26, 1994, which contains the following list of effective pages:

Page Number
Revision Level
Shown on Page
Date
Shown on Page
1-6, 8, 10, 11
1
April 26, 1994
7, 9, 12-14
Original
February 7, 1994

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 Aircraft USA, Inc., 1199 North Fairfax Street, Alexandria, Virginia 22314. 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.

(g) This amendment becomes effective on January 31, 1997.

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 certain Fokker Model F28 Mark 0100 series airplanes was published in the Federal Register on December 4, 1995 (60 FR 62051). That action proposed to require modification of the thrust reverser doors. That action also proposed to require replacement of certain Collins multifunction display units (MFDU) with certain new MFDU's, and installation of a placard if the replacement of the MFDU is accomplished prior to modification of the thrust reverser door.

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

Support for the Proposal
One commenter supports the proposed AD.

Request to Revise Compliance Time
One commenter requests that the compliance time for accomplishing the modification be revisedfrom the proposed "prior to the accumulation of 15,000 total flight cycles or within 1 year after the effective date of the AD, whichever is later," to "prior to the accumulation of 16,000 total flight cycles or within 2 years after the effective date of the AD, whichever is later." This commenter states that the interval for its regular heavy maintenance ("Q" check) is expected to be escalated in the near future to 16,000 flight hours/cycles; if the compliance time of the AD is extended likewise, it will allow this commenter to modify its fleet of affected airplanes during this regularly scheduled heavy maintenance interval. The commenter notes that, since the modification takes approximately 300 work hours to complete, it would be more economical to accomplish the modification during regularly scheduled maintenance, rather than having to schedule special times for the modification to be done. The commenter also states that, if it were required to bring its airplanes in for modification at a time other than the "Q" check interval, the associated costs would be far more than what the FAA indicated in its "cost impact" information that appeared in the preamble to the notice. Further, this commenter states that 6 of its 40 affected airplanes already have gone through their "Q" checks without having the modification installed; and if those 6 airplanes were required to be modified within 1 year, this commenter would sustain significant economic and logistical burdens.

The FAA does not concur with the commenter s request. The compliance time specified in the notice was developed in consultation with both the Rijksluchtvaartdienst (RLD), which is the airworthiness authority for the Netherlands, and Fokker. Based on fatigue test results and analysis of the effects of the thrust reverser loads on adjacent structure, the FAA has determined that 15,000 flight cycles is the maximum number of cycles that these airplanes can be allowed to operate prior to modificationwithout compromising safety. The commenter has submitted no technical data to justify its request for an extension of this limit by 1,000 additional flight cycles. Although the FAA does consider the maintenance schedules of affected operators when developing appropriate compliance times for AD actions, it does not revise AD s merely to accommodate individual operators maintenance schedules.

Additionally, the FAA disagrees with the commenter s statement that the modification takes 300 work hours to complete. The cost impact information that appeared in the preamble to the notice (and in this final rule, below) indicated that only 127 work hours were necessary to complete the modification. That figure was based on information provided by the manufacturer, and was conservatively estimated based on performing options that take the longest time to accomplish. Further, the manufacturer estimates that the total elapsed time necessary to accomplish the modification is only 67 hours,since more than one person can perform the work.

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 102 Fokker Model F28 Mark 0100 series airplanes of U.S. registry will be affected by this AD, that it will take approximately 127 work hours per airplane to accomplish the required actions, and that the average labor rate is $60 per work hour. Required parts will cost approximately $19,000 per airplane. Based on these figures, the cost impact of the AD on U.S. operators is estimated to be $2,715,240, or $26,620 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: