[Federal Register Volume 61, Number 183 (Thursday, September 19, 1996)]
[Rules and Regulations]
[Pages 49248-49250]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-23712]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 95-NM-59-AD; Amendment 39-9762; AD 96-19-16]
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 inspections to detect cracking of the Hi-lok bolt holes in the 
main hinge fittings of the horizontal stabilizer, and repair, if 
necessary. The amendment also requires modification of the main hinge 
fitting, modification or replacement of rib connecting angles, and 
modification of ribs. This amendment is prompted by a report indicating 
that cracking was found in the main hinge fittings of the horizontal 
stabilizer during fatigue testing. The cracking was a result of higher-
than-anticipated loads induced during operation of the thrust reverser. 
The actions specified by this AD are intended to prevent deterioration 
of the fatigue life of the main hinge fittings of the horizontal 
stabilizer and reduced structural integrity of the horizontal 
stabilizer due to higher induced loads.

DATES: Effective October 24, 1996.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of October 24, 1996.

ADDRESSES: The service information referenced in this AD may be 
obtained from Fokker Aircraft USA, Inc., 1199 North Fairfax Street, 
Alexandria, Virginia 22314. 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: 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) 227-1149.

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 February 13, 
1996 (61 FR 5524). That action proposed to require a rotor probe 
inspection and a pencil probe inspection to detect cracks of the Hi-lok 
bolt holes in the main hinge fittings of the horizontal stabilizer. For 
certain airplanes, that action also proposed to require modification of 
the Hi-lok bolt holes by cold expansion and stiffening of the ribs at 
Station 215.
    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. Due consideration has been given to 
the comments received.

Support for the Proposal

    One commenter supports the proposed rule.

Request To Extend the Compliance Time

    One commenter requests that the compliance time for the initial 
inspection be extended from the proposed 15,000 total flight cycles to 
16,000 flight cycles. The commenter considers that extending the 
compliance time to 16,000 flight cycles would allow an operator to 
accomplish the inspection during regularly scheduled maintenance, and 
would prevent any disruption of service. The commenter states that the 
adoption of the proposed compliance time would require scheduling of 
special times for the accomplishment of this inspection at considerable 
expense beyond what was estimated in the cost impact of the proposed 
rule.
    The FAA does not concur. In developing the compliance time for this 
rulemaking action, the FAA took into consideration not only the safety 
implications associated with the addressed unsafe condition and the 
normal maintenance schedules for the majority of affected operators, 
but also the results of fatigue tests and analysis performed by the 
manufacturer, the manufacturer's recommended compliance time specified 
in the

[[Page 49249]]

applicable service bulletin, and the foreign airworthiness authority's 
recommended compliance time of 15,000 total flight cycles. In 
consideration of these factors, the FAA finds that a compliance time of 
15,000 total flight cycles (or within 1 year after the effective date 
of this date) is appropriate and should fall during a time of scheduled 
maintenance for the majority of affected operators. However, paragraph 
(d) of the final rule does provide affected operators the opportunity 
to apply for an adjustment of the compliance time if data are presented 
to justify such an adjustment.

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 as proposed.

Cost Impact

    The FAA estimates that 90 airplanes of U.S. registry will be 
affected by this AD, that it will take approximately 136 work hours per 
airplane to accomplish the required actions, and that the average labor 
rate is $60 per work hour. Required parts will cost approximately 
$1,800 per airplane. Based on these figures, the cost impact of the AD 
on U.S. operators is estimated to be $896,400, or $9,960 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:

96-19-16  Fokker: Amendment 39-9762. Docket 95-NM-59-AD.

    Applicability: Model F28 Mark 0100 airplanes; having serial 
numbers 11244 through 11420 inclusive, 11422, 11424 through 11428 
inclusive, 11432 through 11439 inclusive, and 11443 through 11445 
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 
otherwise 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 reduced structural integrity of the horizontal 
stabilizer, accomplish the following:

    Note 2: Inspections and modifications accomplished prior to the 
effective date of this amendment in accordance with Fokker Service 
Bulletin SBF100-55-021, Revision 1, dated September 6, 1993, are 
considered acceptable for compliance with the inspections and 
modifications required by this amendment.

    (a) Prior to the accumulation of 15,000 total flight cycles, or 
within 1 year after the effective date of this AD, whichever occurs 
later: Perform a rotor probe inspection and a pencil probe 
inspection to detect cracking of the Hi-lok bolt holes in the main 
hinge fittings of the horizontal stabilizer, in accordance with Part 
5 of the Accomplishment Instructions of Fokker Service Bulletin 
SBF100-55-021, Revision 2, dated December 27, 1993. This inspection 
is not required for airplanes that have been modified as specified 
in paragraph (b) of this AD, provided that the modification is 
accomplished prior to the accumulation of 1,000 total flight cycles.
    (b) Either prior to the accumulation of 1,000 total flight 
cycles; or prior to further flight after the inspection required by 
paragraph (a) of this AD if, as a result of that inspection, no 
cracking is found, or all cracks that are found are less than or 
equal to the values specified in the Decision Diagram (Figure 2) of 
Fokker Service Bulletin SBF100-55-021, Revision 2, dated December 
27, 1993: Accomplish the modification requirements specified in 
paragraph (b)(1) and (b)(2) of this AD.
    (1) Modify the main hinge fittings of the horizontal stabilizer; 
and replace or modify the connecting angles at Rib 215, as 
applicable; in accordance with Fokker Service Bulletin SBF100-55-
021, Revision 2, dated December 27, 1993, and as specified in either 
paragraph (b)(1)(i) or (b)(1)(ii) of this AD, as applicable.
    (i) For airplanes that have accumulated less than 1,000 total 
flight cycles at the time of modification: Accomplish the 
modification in accordance with either Part 3 or Part 4 of the 
Accomplishment Instructions of the service bulletin, as applicable.
    (ii) For airplanes that have accumulated 1,000 or more total 
flight cycles at the time of modification: Accomplish the 
modification in accordance with either Part 6 or Part 7 of the 
Accomplishment Instructions of the service bulletin, as applicable.
    (2) Modify Rib 215 of the horizontal stabilizer to close the 
lightening holes in accordance with Part 8 of the Accomplishment 
Instructions of Fokker Service Bulletin SBF100-55-021, Revision 2, 
dated December 27, 1993.
    (c) If any cracking is found as a result of the inspection 
required by paragraph (a) of this AD, and the cracking exceeds the 
values specified in the Decision Diagram (Figure 2) of Fokker 
Service Bulletin SBF100-55-021, Revision 2, dated December 27, 1993: 
Prior to further flight, repair in accordance with a method approved 
by the Manager, Standardization Branch, ANM-113, FAA, Transport 
Airplane Directorate.
    (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, Standardization Branch, ANM-113. 
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.


[[Page 49250]]


    (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.
    (f) The actions shall be done in accordance with Fokker Service 
Bulletin SBF100-55-021, Revision 2, dated December 27, 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 Aircraft USA, Inc., 1199 
North Fairfax Street, Alexandria, Virginia 22314. 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 October 24, 1996.

    Issued in Renton, Washington, on September 10, 1996.
James V. Devany,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 96-23712 Filed 9-18-96; 8:45 am]
BILLING CODE 4910-13-U