[Federal Register Volume 60, Number 101 (Thursday, May 25, 1995)]
[Proposed Rules]
[Pages 27704-27705]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-12827]



========================================================================
Proposed Rules
                                                Federal Register
________________________________________________________________________

This section of the FEDERAL REGISTER contains notices to the public of 
the proposed issuance of rules and regulations. The purpose of these 
notices is to give interested persons an opportunity to participate in 
the rule making prior to the adoption of the final rules.

========================================================================


Federal Register / Vol. 60, No. 101 / Thursday, May 25, 1995 / 
Proposed Rules

[[Page 27704]]

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 95-NM-38-AD]


Airworthiness Directives; Fokker Model F28 Mark 0100 Series 
Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

-----------------------------------------------------------------------

SUMMARY: This document proposes the adoption of a new airworthiness 
directive (AD) that is applicable to certain Fokker Model F28 Mark 0100 
series airplanes. This proposal would require replacement of the return 
filter diaphragm assemblies on hydraulic systems 1 and 2 with modified 
filter units having new diaphragms. This proposal 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 the proposed AD are 
intended to prevent overpressure of the hydraulic return system, which 
could result in reduced braking performance and/or blown tires due to 
brake overheating.

DATES: Comments must be received by July 5, 1995.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 95-NM-38-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 Aircraft USA, Inc., 1199 North Fairfax Street, 
Alexandria, Virginia 22314. This information may be examined at the 
FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, 
Washington.

FOR FURTHER INFORMATION CONTACT: Tim Dulin, Aerospace Engineer, 
Standardization Branch, ANM-113, FAA, Transport Airplane Directorate, 
1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (206) 
227-2141; fax (206) 227-1320.

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 Docket Number 95-NM-38-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-103, Attention: Rules 
Docket No. 95-NM-38-AD, 1601 Lind Avenue SW., Renton, Washington 98055-
4056.

Discussion

    The Rijksluchtvaartdienst (RLD), which is the airworthiness 
authority for the Netherlands, recently notified the FAA that an unsafe 
condition may exist on certain Fokker Model F28 Mark 0100 series 
airplanes. The RLD advises that it received a report of insufficient 
running clearance of the brake units on a Fokker Model F28 Mark 0100 
series airplane due to overpressure in the hydraulic return system. 
Results of an investigation revealed that the outlet check valve of a 
return filter diaphragm assembly of the hydraulic system was blocked. 
The probable cause of this blockage was determined to be incorrect 
manufacturing tolerances, which resulted in extrusion of the lower seal 
at the inner diameter during installation. The RLD received additional 
reports concerning the possibility of a hydraulic lock between the 
diaphragm and the check valve of the filter inlet port. This hydraulic 
lock could lead to incorrect installation of the filter bowl and 
element.
    These conditions, if not corrected, could result in overpressure of 
the hydraulic return system, which may result in reduced braking 
performance and/or blown tires due to brake overheating.
    Fokker has issued Service Bulletin SBF100-29-025, dated December 
31, 1993, which describes procedures for replacement of the return 
filter diaphragm assemblies on hydraulic systems 1 and 2 with modified 
filter units having new diaphragms. Installation of these modified 
units will ensure that the outlet check valve of the return filter 
diaphragm assembly is not blocked, and will eliminate the possibility 
of a hydraulic lock between the diaphragm and the check valve of the 
filter inlet port. The RLD classified this service bulletin as 
mandatory and issued Netherlands airworthiness directive 94-024 (A), 
dated January 28, 1994, in order to assure the continued airworthiness 
of these airplanes in the Netherlands.
    This airplane model is manufactured in the Netherlands and is type 
certificated for operation in the United States under the provisions of 
section 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 
[[Page 27705]] certificated for operation in the United States.
    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 require replacement of the 
return filter diaphragm assemblies on hydraulic systems 1 and 2 with 
modified filter units having new diaphragms. The actions would be 
required to be accomplished in accordance with the service bulletin 
described previously.
    As a result of recent communications with the Air Transport 
Association (ATA) of America, the FAA has learned that, in general, 
some operators may misunderstand the legal effect of AD's on airplanes 
that are identified in the applicability provision of the AD, but that 
have been altered or repaired in the area addressed by the AD. The FAA 
points out that all airplanes identified in the applicability provision 
of an AD are legally subject to the AD. If an airplane has been altered 
or repaired in the affected area in such a way as to affect compliance 
with the AD, the owner or operator is required to obtain FAA approval 
for an alternative method of compliance with the AD, in accordance with 
the paragraph of each AD that provides for such approvals. A note has 
been included in this notice to clarify this long-standing requirement.
    The FAA estimates that 119 airplanes of U.S. registry would be 
affected by this proposed AD, that it would take approximately 2 work 
hours per airplane to accomplish the proposed actions, and that the 
average labor rate is $60 per work hour. Required parts would be 
provided by the parts manufacturer at no cost to operators. Based on 
these figures, the total cost impact of the proposed AD on U.S. 
operators is estimated to be $14,280, or $120 per airplane.
    The total cost impact figure discussed above is 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.
    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 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. App. 1354(a), 1421 and 1423; 49 U.S.C. 
106(g); and 14 CFR 11.89.


Sec. 39.13  [Amended]

    2. Section 39.13 is amended by adding the following new 
airworthiness directive:

Fokker: 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 use the authority 
provided in paragraph (c) to request approval from the FAA. This 
approval may address either no action, if the current configuration 
eliminates the unsafe condition; or different actions necessary to 
address the unsafe condition described in this AD. Such a request 
should include an assessment of the effect of the changed 
configuration on the unsafe condition addressed by this AD. In no 
case does the presence of any modification, alteration, or repair 
remove any airplane from the applicability of this AD.

    Compliance: Required as indicated, unless accomplished 
previously.
    To prevent overpressure in the hydraulic return system, which 
could result in reduced braking performance and/or blown tires due 
to brake overheating, 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, 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.

    (d) 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.

    Issued in Renton, Washington, on May 19, 1995.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 95-12827 Filed 5-24-95; 8:45 am]
BILLING CODE 4910-13-U