[Federal Register Volume 63, Number 50 (Monday, March 16, 1998)]
[Rules and Regulations]
[Pages 12611-12613]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-6502]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 95-NM-38-AD; Amendment 39-10393; AD 98-06-15]
RIN 2120-AA64


Airworthiness Directives; Fokker Model F28 Mark 0100 Series 
Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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SUMMARY: This amendment adopts a new airworthiness directive (AD), 
applicable to certain Fokker Model F28 Mark 0100 series airplanes, that 
requires replacement of the return filter diaphragm assemblies on 
hydraulic systems 1 and 2 with modified filter units having new 
diaphragms. This amendment is prompted by a report of insufficient 
running clearance of the brake units due to overpressure in the 
hydraulic return system; this condition could lead to brake 
overheating. The actions specified by this AD are intended to prevent 
too high pressure in the hydraulic return system during the selection 
of subsystem(s), which could result in inadvertent braking and/or blown 
tires.

DATES: Effective April 20, 1998.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of April 20, 1998.

ADDRESSES: The service information referenced in this AD 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 Federal Aviation Administration (FAA), Transport 
Airplane Directorate, Rules Docket, 1601 Lind Avenue, SW., Renton, 
Washington; or at the Office of the Federal Register, 800 North Capitol 
Street, NW., suite 700, Washington, DC.

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: 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 May 25, 1995 
(60 FR 27704). That action proposed to require replacement of the 
return filter diaphragm assemblies on hydraulic systems 1 and 2 with 
modified filter units having new diaphragms.
    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. Due consideration has been given to 
the comments received.

Request To Withdraw Proposed AD

    The Air Transport Association (ATA) of America, on behalf of one 
member, requests that the proposed AD be withdrawn because the 
corrective action specified in the referenced Fokker Service Bulletin 
SBF100-29-025, dated December 31, 1993, is ineffectual in preventing 
overpressure of the subject hydraulic return system.
    The FAA does not concur with the commenter's request to withdraw 
the proposal. The Rijksluchtvaartdienst (RLD), which is the 
airworthiness authority for the Netherlands, has advised the FAA that 
there have been no additional reports of discrepancies in the system 
since the service bulletin was issued. In addition, the commenter 
provides no justification to substantiate the claim that the corrective 
action is ineffectual. Based on this information, the FAA has 
determined that the modification specified in Fokker Service Bulletin 
SBF100-29-025, dated December 31, 1993, adequately addresses the unsafe 
condition.

Request To Extend Compliance Time

    One commenter requests an extension of the proposed compliance time 
of 6 months, but provides no specific extension time. The commenter's 
request is based on the number of airplanes in its fleet and the time 
required to accomplish the action. The commenter expresses concern that 
it may not be able to modify all airplanes in 6 months.
    The FAA does not concur with the request for an extension of the 
compliance time. In developing the compliance time, the FAA considered 
the safety implications, parts availability, and normal maintenance 
schedules. In consideration of all these factors, and the time since 
the Notice of Proposed Rulemaking (NPRM) was published, the FAA has 
determined that the compliance time, as proposed, represents an 
appropriate interval to complete the necessary replacement.

Request to Revise Unsafe Condition

    One commenter, the manufacturer, requests that the description of 
the cause of the addressed unsafe condition that appeared in the 
proposed AD be clarified. The unsafe condition that appears in the 
proposal reads as follows: ``* * * to prevent overpressure in the 
hydraulic return system which could result in reduced braking 
performance and/or blown tires due to brake overheating.'' The 
commenter suggests that a more accurate description would be ``* * * to 
prevent too high pressure in the hydraulic return system during the 
selection of the subsystem(s), which could result in inadvertent 
braking and/or blown tires.'' The manufacturer states that its service 
bulletin was issued following an incident in which all four tires blew 
on touchdown. During a taxi check, following the replacement of several 
components, inspections revealed a brake problem. It was found that the 
brakes locked as soon as the flaps moved to a new position and unlocked 
as soon as the flaps stopped moving.

[[Page 12612]]

    The FAA concurs. Based on the information provided by the 
manufacturer following further investigation into the incident, the FAA 
has revised the unsafe condition in this final rule to reflect the 
commenter's suggestion.

Request for Inclusion of Operator Modification as Alternative 
Method of Compliance

    One commenter requests that the FAA revise the proposed AD to 
include its own modification as an acceptable alternative method of 
compliance for replacing the diaphragms with filter element retaining 
spacers. The commenter, in collaboration with Fokker and PALL-APME, has 
developed a new modification, which it believes satisfactorily 
addresses the safety objective of the proposed AD. The commenter is of 
the opinion that if an AD is issued, it should include that 
modification as an acceptable means of compliance. The commenter also 
states that the applicability of the proposed AD should not include 
those aircraft on which units having modified part numbers designated 
by -1 are installed.
    The FAA does not concur that the modification suggested by the 
commenter should be incorporated in this final rule, or that airplanes 
on which the modified part numbers designated by ``-1'' are installed 
should be excluded from the applicability. The FAA does not consider it 
appropriate to include various provisions in an AD applicable to a 
single operator's unique modification. However, paragraph (c) of this 
AD contains a provision for requesting approval of an alternative 
method of compliance to address these types of individual 
circumstances.

Request To Revise Cost Impact Information

    One commenter, the manufacturer, requests that the cost impact 
information, below, be revised to reflect that only 79 airplanes of 
U.S. registry are affected by the proposed AD. The change is requested 
based on the most current information available to the manufacturer.
    The FAA concurs and has revised the cost impact information, below, 
accordingly.

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 with the changes previously 
described. The FAA has determined that these changes will neither 
increase the economic burden on any operator nor increase the scope of 
the AD.

Cost Impact

    The FAA estimates that 79 Model F28 Mark 0100 series airplanes of 
U.S. registry will be affected by this AD, that it will take 
approximately 2 work hours per airplane to accomplish the required 
actions, and that the average labor rate is $60 per work hour. Required 
parts will be provided by the parts manufacturer at no cost to 
operators. Based on these figures, the cost impact of the AD on U.S. 
operators is estimated to be $9,480, or $120 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.


Sec. 39.13  [Amended]

    2. Section 39.13 is amended by adding the following new 
airworthiness directive:
    98-06-15 Fokker: Amendment 39-10393. Docket 95-NM-38-AD.

    Applicability: Model F28 Mark 0100 series airplanes equipped 
with Aircraft Porous Media Europe (APME) Limited hydraulic return 
filter assemblies having part numbers (P/N) QA07236 and QA07237, all 
serial numbers; 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 too high pressure in the hydraulic return system 
during the selection of subsystem(s), which could result in 
inadvertent braking and/or blown tires, accomplish the following:
    (a) Within 6 months after the effective date of this AD, replace 
the return filters, P/N's QA07236 and QA07237, on hydraulic systems 
1 and 2, respectively, with modified return filter units, in 
accordance with Fokker Service Bulletin SBF100-29-025, dated 
December 31, 1993.
    (b) As of the effective date of this AD, no person shall install 
on any airplane a return filter unit, P/N QA07236 or QA07237, on 
hydraulic system 1 or 2, respectively, unless that unit has been 
modified in accordance with Fokker Service Bulletin SBF100-29-025, 
dated December 31, 1993.
    (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.

    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

[[Page 12613]]

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 replacement shall be done in accordance with Fokker 
Service Bulletin SBF100-29-025, dated December 31, 1993. 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 94-024 (A), dated January 28, 1994.

    (f) This amendment becomes effective on April 20, 1998.

    Issued in Renton, Washington, on March 9, 1998.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 98-6502 Filed 3-13-98; 8:45 am]
BILLING CODE 4910-13-U