[Federal Register Volume 64, Number 73 (Friday, April 16, 1999)]
[Proposed Rules]
[Pages 18840-18842]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-9512]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-NM-346-AD]
RIN 2120-AA64


Airworthiness Directives; Fokker Model F.28 Mark 0070 and Mark 
0100 Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes the supersedure of 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 action would 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. This proposal 
is prompted by issuance of mandatory continuing airworthiness 
information by a foreign civil airworthiness authority. The actions 
specified by the proposed 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.

DATES: Comments must be received by May 17, 1999.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 98-NM-346-AD, 1601 Lind Avenue, SW., 
Renton, Washington 98055-4056. Comments may be inspected at this 
location between 9:00 a.m. and 3:00 p.m., Monday through Friday, except 
Federal holidays.
    The service information referenced in the proposed rule may be 
obtained from Fokker Services B.V., Technical Support Department, P.O. 
Box 75047, 1117 ZN Schiphol Airport, the Netherlands. This information 
may be examined at the FAA, Transport Airplane Directorate, 1601 Lind 
Avenue, SW., Renton, Washington.

FOR FURTHER INFORMATION CONTACT: Norman B. Martenson, Manager, 
International Branch, ANM-116, FAA, Transport Airplane Directorate, 
1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 
227-2110; fax (425) 227-1149.

SUPPLEMENTARY INFORMATION:

Comments Invited

    Interested persons are invited to participate in the making of the 
proposed rule by submitting such written data, views, or arguments as 
they may desire. Communications shall identify the Rules Docket number 
and be submitted in triplicate to the address specified above. All 
communications received on or before the closing date for comments, 
specified above, will be considered before taking action on the 
proposed rule. The proposals contained in this notice may be changed in 
light of the comments received.
    Comments are specifically invited on the overall regulatory, 
economic, environmental, and energy aspects of the proposed rule. All 
comments submitted will be available, both before and after the closing 
date for comments, in the Rules Docket for examination by interested 
persons. A report summarizing each FAA-public contact concerned with 
the substance of this proposal will be filed in the Rules Docket.
    Commenters wishing the FAA to acknowledge receipt of their comments 
submitted in response to this notice must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to

[[Page 18841]]

Docket Number 98-NM-346-AD.'' The postcard will be date stamped and 
returned to the commenter.

Availability of NPRMs

    Any person may obtain a copy of this NPRM by submitting a request 
to the FAA, Transport Airplane Directorate, ANM-114, Attention: Rules 
Docket No. 98-NM-346-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    On May 11, 1998, the FAA issued AD 98-11-02, amendment 39-10529 (63 
FR 27197, May 18, 1998), applicable to all Fokker Model F.28 Mark 0070 
and Mark 0100 series airplanes, 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. That 
action was prompted by issuance of mandatory continuing airworthiness 
information by a foreign civil airworthiness authority. The 
requirements of that AD are intended to prevent inadvertent deployment 
of the liftdumpers during approach for landing, and consequent reduced 
controllability and performance of the airplane.

Actions Since Issuance of Previous Rule

    Since the issuance of that AD, the Rijksluchtvaartdienst (RLD), 
which is the airworthiness authority for the Netherlands, has 
determined that the design safety features that provide adequate 
electromagnetic interference (EMI) protection of the wheelspeed signal 
wiring, and verify erroneous ``high'' wheelspeed signals through the 
liftdumper arming test, may not be fully effective. Further analysis 
has determined that airplanes on which Fokker Service Bulletins SBF100-
32-067 and SBF100-32-037 have been accomplished are less susceptible to 
effects of EMI on the wheelspeed signals. Measurements have indicated 
that the EMI is being generated between the electrical wiring supply 
for the lights and the electrical wiring for the wheelspeed sensors of 
the main landing gear (MLG), which run parallel to each other. If the 
EMI reaches a certain level, an erroneous wheelspeed signal may occur, 
which could result in inadvertent deployment of the liftdumpers or 
reduced brake pressure during low speed taxiing. These conditions, if 
not corrected, could result in reduced controllability and performance 
of the airplane.

Explanation of Relevant Service Information

    Fokker has issued Service Bulletin SBF100-32-067, Revision 1, dated 
July 6, 1998, which describes procedures for modification of the ground 
wiring to the shielding of the wheelspeed sensor wiring of the MLG. The 
modification involves modifying the applicable avionics rack and 
installing additional ground wiring to the shielding of the wheelspeed 
sensor wiring.
    Fokker also has issued Service Bulletin SBF100-32-037, Revision 2, 
dated December 4, 1998, which describes procedures for installing new 
electrical grounds for the wheelspeed sensor channel of the anti-skid 
control box of the MLG. The installation involves re-routing existing 
electrical wiring and installing new terminal blocks and electrical 
wiring.
    These modifications would provide additional grounds to the 
shielding of the wheelspeed sensor wiring and to the power supplies of 
the anti-skid control box. These additional grounds reduce the effects 
of EMI generated by electrical wiring that runs parallel to the 
wheelspeed sensor wiring. The RLD classified these service bulletins as 
mandatory and issued Dutch airworthiness directives BLA 1998-100, dated 
August 31, 1998, and 1998-100/2, dated November 30, 1998, in order to 
assure the continued airworthiness of these airplanes in the 
Netherlands.

FAA's Conclusions

    These airplane models are manufactured in the Netherlands and are 
type certificated for operation in the United States under the 
provisions of Sec. 21.29 of the Federal Aviation Regulations (14 CFR 
21.29) and the applicable bilateral airworthiness agreement. Pursuant 
to this bilateral airworthiness agreement, the RLD has kept the FAA 
informed of the situation described above. The FAA has examined the 
findings of the RLD, reviewed all available information, and determined 
that AD action is necessary for products of this type design that are 
certificated for operation in the United States.

Explanation of Requirements of Proposed Rule

    Since an unsafe condition has been identified that is likely to 
exist or develop on other airplanes of the same type design registered 
in the United States, the proposed AD would supersede AD 98-11-02 to 
continue to require revision of the Limitations and Normal Procedures 
sections of the FAA-approved AFM to provide the flightcrew with 
instructions not to arm the liftdumper system prior to commanding the 
landing gear to extend. In addition, this proposed AD would add 
requirements for modification of the grounds of the shielding of the 
wheelspeed sensor wiring of the MLG and installation of new electrical 
grounds for the wheelspeed sensor channel of the anti-skid control box 
of the MLG. The actions would be required to be accomplished in 
accordance with the service bulletins described previously.

Interim Action

    This is considered to be interim action until final action is 
identified, at which time the FAA may consider further rulemaking.

Cost Impact

    There are approximately 131 airplanes of U.S. registry that would 
be affected by this proposed 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 currently 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 would 
be required to accomplish the modification and installation. It would 
take approximately 33 work hours per airplane to accomplish the 
modification and installation, at an average labor rate of $60 per work 
hour. Required parts would cost between $755 and $1,236 per airplane. 
Based on these figures, the cost impact of the proposed 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 proposed 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 proposed herein would 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 
proposal would not have sufficient

[[Page 18842]]

federalism implications to warrant the preparation of a Federalism 
Assessment.
    For the reasons discussed above, I certify that this proposed 
regulation (1) is not a ``significant regulatory action'' under 
Executive Order 12866; (2) is not a ``significant rule'' under the DOT 
Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); 
and (3) if promulgated, 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 draft 
regulatory 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, Safety.

The Proposed Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration proposes to amend 
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.


Sec. 39.13  [Amended]

    2. Section 39.13 is amended by removing amendment 39-10529 (63 FR 
27197, May 18, 1998), and by adding a new airworthiness directive (AD), 
to read as follows:

Fokker Services B.V.: Docket 98-NM-346-AD. Supersedes AD 98-11-02, 
Amendment 39-10529.

    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 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 
Secs.  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.

    Issued in Renton, Washington, on April 9, 1999.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 99-9512 Filed 4-15-99; 8:45 am]
BILLING CODE 4910-13-U