AD 98-13-25

This amendment supersedes an existing airworthiness directive (AD), applicable to certain Fokker Model F.28 Mark 1000, 2000, 3000, and 4000 series airplanes, that currently requires an inspection to detect free movement of the actuator servo-valve sub-assembly of the horizontal stabilizer actuator, and replacement, if necessary. This amendment adds a one-time inspection to determine the residual strength of the servo-valve sub-assembly of the horizontal stabilizer actuator, and replacement of the actuator with a new or serviceable actuator, if necessary; and eventual replacement of the horizontal stabilizer actuator with an improved actuator. 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 uncommanded trimming or failure of the trim system of the horizontal stabilizer, and consequent reduced controllability of the airplane.

Final rule

98-13-25 FOKKER: Amendment 39-10616. Docket 98-NM-16-AD. Supersedes AD 92-18-04, Amendment 39-8348.

Applicability: Model F.28 Mark 1000, 2000, 3000, and 4000 series airplanes; equipped with Menasco horizontal stabilizer actuators having part number (P/N) 11100-( ); 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, unless accomplished previously.

To prevent uncommanded trimming or failure of the trim system of the horizontal stabilizer, and consequent reduced controllability of the airplane, accomplish the following:

(a) Within 20 days after September 9, 1992 (the effective date of AD 92-18-04, amendment 39-8348), perform an inspection of the servo-valve sub-assembly rod-end bearing and servo-valve sub-assembly for movement, in accordance with Fokker Service Bulletin F28/27-180, dated July 3, 1992.

(1) If the servo-valve sub-assembly rod-end bearing and servo-valve sub-assembly move freely within the load limits specified in the service bulletin, reassemble and conduct a functional test, in accordance with the service bulletin.

(2) If the servo-valve sub-assembly rod-end bearing or servo-valve sub-assembly require higher loads for movement than specified in the service bulletin, prior tofurther flight, remove and replace the horizontal stabilizer control unit with a serviceable control unit that has been inspected and found to be within the load limits of the service bulletin, or that has been inspected and repaired in accordance with Chapter 27-42-4 of the Menasco Overhaul Manual (OHM), as revised by Temporary Revision Number 3, dated July 10, 1992.

(b) Within 6 months after the effective date of this AD, perform a one-time inspection to determine the residual strength of the servo-valve sub-assembly of the horizontal stabilizer actuator, in accordance with Part 1 of the Accomplishment Instructions of Fokker Service Bulletin F28/27-183, dated November 21, 1994. If any discrepancy is found, prior to further flight, replace the actuator with a new or serviceable actuator in accordance with the service bulletin.

(c) Within 3 years after the effective date of this AD, replace the horizontal stabilizer actuator with an actuator that has been modified and re-marked in accordance with Part 2 of the Accomplishment Instructions of Fokker Service Bulletin F28/27-183, dated November 21, 1994.

(d) As of the effective date of this AD, no person shall install a horizontal stabilizer control unit on any airplane, unless the horizontal stabilizer actuator has been modified and re-marked in accordance with Part 2 of the Accomplishment Instructions of Fokker Service Bulletin F28/27-183, dated November 21, 1994.

(e) 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.

(f) 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.

(g) The actions shall be done in accordance with Fokker Service Bulletin F28/27-180, dated July 3, 1992, and Fokker Service Bulletin F28/27-183, dated November 21, 1994.

(1) The incorporation by reference of Fokker Service Bulletin F28/27-183, dated November 21, 1994, is approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51.

(2) The incorporation by reference of Fokker Service Bulletin F28/27-180, dated July 3, 1992, was approved previously by the Director of the Federal Register as of September 9, 1992 (57 FR 38432, August 25, 1992).

(3) 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 1992-007/2(A), dated January 31, 1995.

(h) This amendment becomes effective on July 30, 1998.

A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) by superseding AD 92-18-04, amendment 39-8348 (57 FR 38432, August 25, 1992), which is applicable to certain Fokker Model F.28 Mark 1000, 2000, 3000, and 4000 series airplanes, was published in the Federal Register on April 27, 1998 (63 FR 20554). The action proposed to continue to require an inspection to detect free movement of the actuator servo-valve sub-assembly of the horizontal stabilizer actuator, and replacement, if necessary. The action proposed to add a one-time inspection to determine the residual strength of the servo-valve sub-assembly of the horizontal stabilizer actuator, and replacement of the actuator with a new or serviceable actuator, if necessary; and eventual replacement of the horizontal stabilizer actuator with an improved actuator.

Comments
Interested persons have been afforded an opportunity to participate in the making of this amendment. Nocomments were submitted in response to the proposal or the FAA's determination of the cost to the public.

Conclusion
The FAA has determined that air safety and the public interest require the adoption of the rule as proposed.

Cost Impact
There are approximately 27 airplanes of U.S. registry that will be affected by this AD.

The inspection that is currently required by AD 92-18-04 takes approximately 1 work hour per airplane to accomplish, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of the previously required inspection on U.S. operators is estimated to be $1,620, or $60 per airplane.

The inspection that is required in this new AD action will take approximately 2 work hours per airplane to accomplish, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of the new inspection requirements of this AD on U.S. operators is estimated to be $3,240, or $120 per airplane.

The replacementrequired in this new AD action will take approximately 8 work hours per airplane to accomplish, at an average labor rate of $60 per work hour. Required parts will be provided by the manufacturer at no cost to the operator. Based on these figures, the cost impact of the replacement required by this AD on U.S. operators is estimated to be $12,960, or $480 per airplane.

The cost impact figures discussed above are 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 removing amendment 39-8348 (57 FR 38432, August 25, 1992), and by adding a new airworthiness directive (AD), amendment 39-10616 to read as follows: