[Federal Register Volume 60, Number 243 (Tuesday, December 19, 1995)]
[Proposed Rules]
[Pages 65256-65258]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-30746]



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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 95-NM-172-AD]


Airworthiness Directives; Fokker Model F28 Mark 0100 Series 
Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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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 a one-time measurement 
during refueling to determine the pressure in each collector tank; for 
certain airplanes, non-destructive test (NDT) inspections to detect 
cracking or deformations of the collector tank ribs on each wing, and 
repair, if necessary; and modification of top-hat stringers in each 
outer wing tank. This proposal is prompted by a report of damage to the 
ribs of the wing collector tank caused by over-pressure in the 
collector tank during refueling. The actions specified by the proposed 
AD are intended to prevent cracking and deformation of the wing 
collector tanks due to over-pressure, which could result in reduced 
structural integrity of the wing.

DATES: Comments must be received by January 30, 1996.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 95-NM-172-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: Ruth E. Harder, Aerospace Engineer, 
Standardization Branch, ANM-113, FAA, Transport Airplane Directorate, 

[[Page 65257]]
1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (206) 
227-1721; fax (206) 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 Docket Number 95-NM-172-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-172-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 during scheduled maintenance on a 
Model F28 Mark 0100 series airplane, the ribs in the right-hand wing 
collector tank were found to be damaged. Investigation revealed that 
the damage was caused by over-pressure in the collector tank during 
refueling.
    The top-hat stringers between the wing collector tank and the outer 
wing tank contain restriction blocks that are intended to close off, 
but still ventilate the collector tank. The four forward most top-hat 
stringers (2.32, 2.33, 2.34, and 2.35) should not contain these 
restriction blocks, which would enable fuel to flow from the wing 
collector tank to the outer wing tank. Subsequent investigation 
revealed that the over-pressure was due to the installation of 
restriction blocks in these four top-hat stringers, which adversely 
affected the fuel transfer capacity of these airplanes. This condition, 
if not corrected, could result in cracking and deformation of the ribs 
in the wing collector tank, which could lead to reduced structural 
integrity of the wing.
    Fokker has issued Service Bulletin SBF 100-57-030, dated December 
17, 1994, which describes procedures for conducting a one-time 
measurement during refueling to determine the pressure in each 
collector tank. The service bulletin also describes procedures for 
conducting non-destructive test (NDT) inspections of certain airplanes 
to detect cracking and deformations of the collector tank ribs at wing 
stations 1825, 2230, and 2635.
    Fokker has also issued Service Bulletin SBF 100-57-029, Revision 1, 
dated March 23, 1995, which describes procedures for modification of 
the four top-hat stringers (2.32, 2.33, 2.34, and 2.35) in the outer 
wing tank area. This modification entails removal of the restriction 
blocks in the top-hat stringers.
    The RLD classified both of these service bulletins as mandatory and 
issued the Netherlands airworthiness directive BLA 1994-172 (A), dated 
December 23, 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 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, the 
proposed AD would require a one-time measurement during refueling to 
determine the pressure in each collector tank; and modification of the 
four top-hat stringers in the outboard wing tank area. For certain 
airplanes, this proposed AD would require non-destructive test (NDT) 
inspections of the collector tank ribs to detect cracking or 
deformations. The actions would be required to be accomplished in 
accordance with the service bulletins described previously.
    This AD also proposes to require repair of any cracking or 
deformations in accordance with a method approved by the FAA.
    The FAA estimates that 58 airplanes of U.S. registry would be 
affected by this proposed AD, that it would take approximately 85 work 
hours per airplane to accomplish the proposed actions, and that the 
average labor rate is $60 per work hour. Based on these figures, the 
cost impact of the proposed AD on U.S. operators is estimated to be 
$295,800, or $5,100 per airplane.
    The 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 

[[Page 65258]]
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), 40101, 40113, 44701.


Sec. 39.13  [Amended]

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

Fokker: Docket 95-NM-172-AD.

    Applicability: Model F28 Mark 0100 airplanes, serial numbers 
11244 through 11277 inclusive, 11279, 11281 through 11287 inclusive, 
and 11289 through 11400 inclusive, 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 (g) of this AD 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 over-pressurization and/or damage to the wing 
collector tanks, which could result in reduced structural integrity 
of the wings, accomplish the following:
    (a) Within 45 days after the effective date of this AD, perform 
a one-time measurement during refueling to determine the pressure in 
each collector tank in accordance with Part 1 of the Accomplishment 
Instructions of Fokker Service Bulletin SBF100-57-030, dated 
December 17, 1994.

    Note 2: Pressure Limits Categories are defined in Table 2 of 
Fokker Service Bulletin SBF100-57-030, dated December 17, 1994.

    (b) For Pressure Limits Category 1: Within 2 years after the 
effective date of this AD, modify the four affected top-hat 
stringers (2.32, 2.33, 2.34, and 2.35) in each outer wing tank area 
by removing the restriction blocks, in accordance with the 
Accomplishment Instructions of Fokker Service Bulletin SBF100-57-
029, Revision 1, dated March 23, 1995.
    (c) For Pressure Limits Categories 2 through 5: Except as 
provided by paragraph (d) of this AD, prior to the number of 
accumulated total flight cycles or within the time specified in 
Table 1 of Fokker Service Bulletin SBF100-57-030, dated December 17, 
1994, whichever occurs earlier, accomplish the requirements of 
paragraphs (c)(1) and (c)(2) of this AD.
    (1) Perform the Non-Destructive Test (NDT) inspections specified 
in Part 2 of the Accomplishment Instructions of Fokker Service 
Bulletin SBF100-57-030, dated December 17, 1994, to detect cracking 
or deformations of the collector tank ribs on each wing at wing 
stations 1825, 2230, and 2635. These inspections are to be performed 
in accordance with Fokker Service Bulletin SBF100-57-030, dated 
December 17, 1994.
    (2) Modify the four affected top-hat stringers (2.32, 2.33, 
2.34, and 2.35) in each outer wing tank area by removing the 
restriction blocks, in accordance with the Accomplishment 
Instructions of Fokker Service Bulletin SBF100-57-029, Revision 1, 
dated March 23, 1995.
    (d) For Pressure Limits Category 6, and for airplanes having 
pressure limits within the limits specified in Categories 3 through 
5 and that have exceeded the number of accumulated total flight 
cycles specified in Table 1: Within 100 flight cycles, accomplish 
the requirements of paragraphs (d)(1) and (d)(2) of this AD.
    (1) Perform the NDT inspections in accordance with the 
procedures of Part 2 of the Accomplishment Instructions of Fokker 
Service Bulletin SBF100-57-030, dated December 17, 1994. The fueling 
pressure must not exceed 25 pounds per square inch (PSI) during 
refueling.
    (2) Modify the four affected top-hat stringers (2.32, 2.33, 
2.34, and 2.35) in each outer wing tank area by removing the 
restriction blocks, in accordance with the Accomplishment 
Instructions of Fokker Service Bulletin SBF100-57-029, Revision 1, 
dated March 23, 1995.
    (e) For Pressure Limits Category 7: Prior to further flight 
following the measurement required by paragraph (a) of this AD, 
accomplish the requirements of paragraphs (e)(1) and (e)(2) of this 
AD.
    (1) Perform the NDT inspections in accordance with the 
procedures of Part 2 of the Accomplishment Instructions of Fokker 
Service Bulletin SBF100-57-030, dated December 17, 1994.
    (2) Modify the four affected top-hat stringers (2.32, 2.33, 
2.34, and 2.35) in each outer wing tank area by removing the 
restriction blocks, in accordance with the Accomplishment 
Instructions of Fokker Service Bulletin SBF100-57-029, Revision 1, 
dated March 23, 1995.
    (f) If any cracking or deformation is detected during any 
inspection required by this AD, prior to further flight, repair in 
accordance with a method approved by the Manager, Standardization 
Branch, ANM-113, FAA, Transport Airplane Directorate.
    (g) 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 3: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Standardization Branch, ANM-113.

    (h) 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 December 13, 1995.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 95-30746 Filed 12-18-95; 8:45 am]
BILLING CODE 4910-13-U