AD 99-20-07

This amendment supersedes an existing airworthiness directive (AD), applicable to all Fokker Model F.28 Mark 0070 and Mark 0100 series airplanes, that currently requires revising the Airplane Flight Manual to provide the flightcrew with instructions not to arm the liftdumper system prior to commanding the landing gear to extend. This amendment requires modification of the grounds of the shielding of the wheelspeed sensor wiring of the main landing gear (MLG) and installation of new electrical grounds for the wheelspeed sensor channel of the anti-skid control box of the MLG. 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 electromagnetic interference generated by electrical wiring that runs parallel to the wheelspeed sensor wiring, which could result in inadvertent deployment of the liftdumpers during approach for landing or reduced brake pressure during low speed taxiing, and consequent reduced controllability and performance of the airplane.

Final rule

99-20-07 FOKKER SERVICES B.V.: Amendment 39-11337. Docket 98-NM-346-AD. Supersedes AD 98-11-02, Amendment 39-10529. Issued September 21, 1999.

Applicability: All Model F.28 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 (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.

To prevent electromagnetic interference generated by electrical wiring that runs parallel to the wheelspeed sensor wiring, which could result in inadvertent deployment of the liftdumpers during approach for landing or reduced brake pressure during low speed taxiing, and consequent reduced controllability and performance of the airplane, accomplish the following:

RESTATEMENT OF REQUIREMENTS OF AD 98-11-02, AMENDMENT 39-10529
(a) Within 5 days after June 2, 1998 (the effective date of AD 98-11-02), revise the Limitations and Normal Procedures sections of the FAA-approved Airplane Flight Manual (AFM) in accordance with paragraphs (a)(1) and (a)(2) of this AD. This may be accomplished by inserting a copy of this AD in the AFM.

(1) Add the following information to section 5 - NORMAL PROCEDURES, sub-Section APPROACH AND LANDING, after the subject APPROACH:

"BEFORE LANDING
WARNING: DO NOT ARM THE LIFTDUMPER SYSTEM BEFORE LANDING GEAR
DOWN SELECTION.

Selecting Landing Gear DOWN after arming the liftdumper system may result in inadvertent deployment of the liftdumpers, because the liftdumper arming test may be partially ineffective."

(2) Add the following information to the LIMITATIONS section:

"LIFTDUMPER SYSTEM
DO NOT ARM THE LIFTDUMPER SYSTEM BEFORE LANDING GEAR DOWN SELECTION."

NEW REQUIREMENTS OF THIS AD
Corrective Actions
(b) For Model F.28 Mark 0100 series airplanes having serial numbers as listed in Fokker Service Bulletin SBF100-32-067, Revision 1, dated July 6, 1998: Within 6 months after the effective date of this AD, modify the grounds of the shielding of the wheelspeed sensor wiring of the main landing gear (MLG) in accordance with Part 1, 2, 3, or 4 of the Accomplishment Instructions of the service bulletin, as applicable.

NOTE 2: Modifications accomplished prior to the effective date of this AD in accordance with Fokker Service Bulletin SBF100-32-067, dated March 12, 1993, are considered acceptable for compliance with the requirements of paragraph (b) of this AD.

(c) For Model F.28 Mark 0100 series airplanes having serial numbers as listed in Fokker Service Bulletin SBF100-32-037, Revision 2, dated December 4, 1998: Within 12 months after the effective date of this AD, install new electrical grounds for the wheelspeed sensor channel of the anti-skid control box of the MLG in accordance with Part 1, 2, or 3 of the Accomplishment Instructions of the service bulletin, as applicable.

NOTE 3: Installations accomplished prior to the effective date of this AD in accordance with Fokker Service Bulletin SBF100-32-037, dated November 12, 1990, or Revision 1, dated November 16, 1998, are considered acceptable for compliance with the requirements of paragraph (c) of this AD.

Alternative Methods of Compliance
(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, 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 4: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the International Branch, ANM-116.

Special Flight Permits
(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.

NOTE 5: The subject of this AD is addressed in Dutch airworthiness directives BLA 1998-100, dated August 31, 1998, and 1998-100/2, dated November 30, 1998.

Incorporation by Reference
(f) The actions shall be done inaccordance with the following Fokker service bulletins, as applicable, which contain the specified effective pages:

Service Bulletin
Referenced
Page Number
Revision Level
Shown on Page
Date Shown on
Page
SBF100-32-067
1-6
7-54
1
Original
July 6, 1998
March 12, 1993
SBF100-32-037 2
1-3
4-18
2
1
December 4, 1998
November 16, 1998

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., P.O. Box 231, 2150 AE Nieuw-Vennep, 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.

(g) This amendment becomes effective on November 2, 1999.

A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) by superseding AD 98-11-02, amendment 39-10529 (63 FR 27197, May 18, 1998), which is applicable to all Fokker Model F.28 Mark 0070 and Mark 0100 series airplanes, was published in the Federal Register on April 16, 1999 (64 FR 18840). The action proposed to require revising the Airplane Flight Manual (AFM) to provide the flightcrew with instructions not to arm the liftdumper system prior to commanding the landing gear to extend. The action also proposed to require modification of the grounds of the shielding of the wheelspeed sensor wiring of the main landing gear (MLG) and installation of new electrical grounds for the wheelspeed sensor channel of the anti-skid control box of the MLG.

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

Supportfor the Proposal
One commenter supports the proposed AD and another commenter generally supports the proposal.

Request to Extend the Compliance Time for the Modification
One commenter requests that the compliance time for accomplishment of the modification action specified by Fokker Service Bulletin SBF100-32-067, Revision 1, dated July 6, 1998 [as cited in paragraph (b) of the proposed AD], be extended from 6 to 12 months. The commenter contends that an extension of the compliance time is necessary to coincide with the 12-month compliance time specified in paragraph (c) of the proposed AD for accomplishment of the installation of new electrical grounds for the wheelspeed sensor channel of the anti-skid control box of the MLG. The commenter contends that failure to extend the compliance time to 12 months would force operators to take airplanes out of service specifically to accomplish the modification, and result in unnecessary operational costs.

The FAA does not concur with the commenter's request. The manufacturer has informed the FAA that its discussions with operators indicated that the modification could be accomplished prior to the compliance time recommended in Fokker Service Bulletin SBF100-32-067, which is March 1, 1999. Also, the related Dutch airworthiness directive specifies a parallel compliance time of 6 months. Therefore, the FAA finds a 6-month compliance time for accomplishing the modification to be warranted, in that it represents an appropriate interval of time allowable for affected airplanes to continue to operate without compromising safety. However, under the provisions of paragraph (d) of the final rule, the FAA may consider requests for adjustments to the compliance time if data are submitted to substantiate that such an adjustment would provide an acceptable level of safety.

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

Cost Impact
There are approximately 131 Model F.28 Mark 0070 and Mark 0100 series airplanes of U.S. registry that will be affected by this AD.

For all airplanes, the actions that are currently required by AD 98-11-02 take 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 actions on U.S. operators is estimated to be $7,860, or $60 per airplane.

There are approximately 127 airplanes of U.S. Registry that will require the modification and installation, and the new actions that are required by this new AD will take approximately 33 work hours per airplane to accomplish, at an average labor rate of $60 per work hour. Required parts will cost between $755 and $1,236 per airplane. Based on these figures, the cost impact of the new requirements of this AD on U.S. operators is estimated to be between$347,345 and $408,432, or between $2,735 and $3,216 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 39-10529 (63FR 27197, May 18, 1998), and by adding a new airworthiness directive (AD), amendment 39-11337, to read as follows: