[Federal Register Volume 62, Number 229 (Friday, November 28, 1997)]
[Rules and Regulations]
[Pages 63262-63264]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-31029]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 96-NM-185-AD; Amendment 39-10218; AD 97-24-11]
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 repetitive inspections of certain flanges and finger strips at
rib 5.0 of the vertical stabilizer to detect fatigue cracking, and
repairs, if necessary. This amendment also requires modifications that
would strengthen the torsion box at rib 5.0 and prevent fatigue
cracking; one of these modifications constitutes terminating action for
the repetitive inspections. This amendment is prompted by reports
indicating that, during full-scale fatigue testing, cracking has been
found on the vertical stabilizer of the test article. The actions
specified by this AD are intended to detect and prevent fatigue
cracking in the subject area, which, if not corrected, could reduce the
structural integrity of the vertical stabilizer.
DATES: Effective January 2, 1998.
The incorporation by reference of certain publications listed in
the regulations is approved by the Director of the Federal Register as
of January 2, 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: 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 January 14,
1997 (62 FR 1866). That action proposed to require repetitive eddy
current inspections to detect fatigue cracking of the left-hand and
right-hand flanges and finger strips at rib 5.0 of the vertical
stabilizer, and repair, if necessary. That action also proposed to
require modification of rib 5.0 by the installation of a stiffener to
the torsion box; this modification would be preceded by an eddy current
inspection to detect fatigue cracking, and repair, if necessary.
Accomplishment of this modification constitutes terminating action for
the repetitive inspection requirements. In addition, that action
proposed to require another modification of rib 5.0 by cold-expanding
certain bolt holes on the torsion box.
Comments
Interested persons have been afforded an opportunity to participate
in the making of this amendment. Due consideration has been given to
the comments received.
One commenter supports the proposed rule.
Requests To Extend the Compliance Time
Two commenters request that the compliance time for accomplishing
the proposed eddy current inspection and modification of rib 5.0 of the
vertical stabilizer [required by paragraphs (b)(1) and (b)(2) of the
proposed AD, respectively] be extended from ``prior to the accumulation
of 13,500 total landings, or within 6 months * * * '' to ``prior to the
accumulation of 16,000 total landings or within 12 months.'' One of
these commenters states that it is currently performing the subject
inspection and modification during its F100 ``Q'' check visit, which is
currently scheduled at 16,000 flight hours or 16,000 landings,
whichever occurs first. The commenter also states that ten of its
airplanes, which have accumulated between 10,972 and 14,976 flight
cycles, have been inspected and modified. This commenter points out
that no cracks have been detected on these airplanes. This commenter
contends that accomplishment of the repetitive inspections required by
paragraph (a) of the proposed AD at 2,000 flight cycle intervals will
assure that the required level of safety is maintained.
The FAA does not concur with the commenters' request to extend the
compliance time. The FAA points out that the proposed compliance time
of paragraphs (b)(1) and (b)(2) of the AD was developed in
consideration of not only the degree of urgency associated with
addressing the unsafe condition, but such factors as the manufacturer's
and the foreign airworthiness authority's [i.e., Rijksluchtvaartdienst
(RLD)] recommendations, the availability of required parts, and the
practical aspect of installing the required modification within an
interval of time that parallels normal scheduled maintenance for the
majority of affected operators. The FAA also has consulted with the
manufacturer and RLD and determined that 13,500 flight cycles
represents the maximum number of flight cycles allowable for the
affected airplanes to continue to operate prior to accomplishing the
required inspections and modification without compromising safety. The
proposed compliance times are based on results of fatigue tests and
analysis of the effects of the thrust reverser loads on adjacent
structure.
In addition, the FAA finds that the commenters have not submitted
any data to substantiate why a 2,500 flight-cycle extension of the
compliance time would not compromise safety, nor have the commenters
addressed whether further inspections would be necessary to ensure the
long term operational safety. However, under the provisions of
paragraph (e) of the final rule, the FAA may approve requests for
adjustments to the compliance time if sufficient data are submitted to
substantiate that such an adjustment would provide an acceptable level
of safety.
Conclusion
After careful review of the available data, including the comments
noted
[[Page 63263]]
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 122 Fokker Model F28 Mark 0100 series
airplanes of U.S. registry will be affected by this proposed AD.
Approximately 77 airplanes will be required to conduct repetitive
inspections of the left-hand and right-hand flanges and finger strips
at rib 5.0 of the vertical stabilizer. It will take approximately 10
work hours per airplane to accomplish each required inspection. The
average labor rate is $60 per work hour. Based on these figures, the
cost impact of these inspections required by this AD on U.S. operators
of these airplanes is estimated to be $46,200, or $600 per airplane,
per inspection.
Approximately 77 airplanes also will be required to accomplish the
installation of steel reinforcement in the torsion box at rib 5.0 of
the vertical stabilizer. It will take approximately 170 work hours per
airplane to accomplish this modification (including a pre-modification
inspection). The average labor rate is $60 per work hour. Required
parts will cost approximately $27,000. Based on these figures, the cost
impact of this modification required by this AD on U.S. operators of
these airplanes is estimated to be $2,864,400, or $37,200 per airplane.
Approximately 122 airplanes will be required to accomplish the cold
expansion of holes in the torsion box at rib 5.0 of the vertical
stabilizer. It will take approximately 17 work hours per airplane to
accomplish this modification, or approximately 8 work hours per
airplane if this modification is done at the same time as the
installation of steel reinforcement. The average labor rate is $60 per
work hour. Required parts will cost approximately $206. Based on these
figures, the cost impact of this modification required by this AD on
U.S. operators of these airplanes is estimated to be between $83,692
and $149,572, or between $686 and $1,226 per airplane.
The cost impact figures discussed above are 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:
97-24-11 Fokker: Amendment 39-10218. Docket 96-NM-185-AD.
Applicability: Model F28 Mark 0100 series airplanes having the
serial numbers specified in Table 1 of this AD; certificated in any
category.
Table 1.--Serial Numbers of Airplanes Subject to This AD
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11244 through 11460, inclusive
11463 through 11469, inclusive
11471
11474 through 11483, inclusive
11489 through 11491, inclusive
11497 through 11499, inclusive
11501
11502
11504
11506
11507
11512 through 11515, inclusive
11517
11520
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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 (e) 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 detect and prevent fatigue cracking in the vertical
stabilizer, which consequently could reduce its structural
integrity, accomplish the following
(a) For airplanes having serial numbers 11244 through 11419,
inclusive, and 11421: Except as provided by paragraph (c) of this
AD, prior to the accumulation of 8,500 total landings or within 30
days after the effective date of this AD, whichever occurs later,
perform an eddy current inspection to detect fatigue cracking in the
left-hand and right-hand flanges and finger strips at rib 5.0 of the
vertical stabilizer, in accordance with Fokker Service Bulletin
SBF100-55-019, Revision 1, dated May 19, 1993.
(1) If no cracking is detected, repeat this inspection
thereafter at intervals not to exceed 2,000 landings until the
requirements of paragraph (b) of this AD are accomplished.
(2) If any cracking is detected, prior to further flight, repair
in accordance with a method approved by the Manager, International
Branch, ANM-116, FAA, Transport Airplane Directorate.
(b) For airplanes with serial numbers 11244 through 11419
inclusive, and 11421, accomplish the requirements of both paragraphs
(b)(1) and (b)(2) of this AD:
(1) Except as provided by paragraph (c) of this AD, prior to the
accumulation of 13,500 total landings, or within 6 months after the
effective date of this AD, whichever occurs later, perform an eddy
current inspection to detect fatigue cracking in the left-hand and
right-hand flanges and finger strips at rib 5.0 of the vertical
stabilizer, in accordance with Part 1 of the Accomplishment
Instructions of Fokker Service Bulletin SBF100-55-018, Revision 1,
dated December 27, 1993.
(i) If no cracking is detected, prior to further flight,
accomplish the requirements of paragraph (b)(2) of this AD.
(ii) If any cracking is detected, prior to further flight,
repair in accordance with a method approved by the Manager,
International Branch, ANM-116, and
[[Page 63264]]
accomplish the requirements of paragraph (b)(2) of this AD.
(2) After accomplishing the requirements of paragraph (b)(1) of
this AD, modify rib 5.0 of the vertical stabilizer by installing new
stiffening, in accordance with Part 2 of the Accomplishment
Instructions of Fokker Service Bulletin SBF100-55-018, Revision 1,
dated December 27, 1993. Accomplishment of this modification
constitutes terminating action for the repetitive inspections
required by paragraph (a) of this AD.
(c) The following exceptions apply with regard to the
requirements of paragraphs (a) and (b) of this AD:
(1) Accomplishment of the inspection specified in paragraph (a)
and (b)(1) of this AD is not required if the modification specified
in paragraph (b)(2) is accomplished prior to the accumulation of
7,300 total landings on the airplane.
(2) Compliance with AD 91-18-15, amendment 39-8018, is not
required if the requirements of paragraph (b)(2) of this AD are
accomplished prior to the accumulation of 6,000 total landings on
the airplane.
(d) For all airplanes: At the applicable times specified in
paragraph (d)(1) or (d)(2), modify the Hi-lok bolt holes at rib 5.0
of the vertical stabilizer by cold expansion, in accordance with
Fokker Service Bulletin SBF100-55-023, dated January 3, 1995.
(1) For airplanes that have been modified in accordance with the
requirements of paragraph (b) of this AD prior to the effective date
of this AD: Modify prior to the accumulation of either 10,000
landings after in-service modification, or 10,000 landings after
delivery with factory modification, as applicable; or within 30 days
after the effective date of this AD, whichever occurs later.
(2) For all other airplanes: Modify concurrent with
accomplishing the requirements of paragraph (b) of this AD.
(e) 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.
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 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.
(f) 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.
(g) The actions shall be done in accordance with the following
Fokker service bulletins, which contain the following list of
effective pages:
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Referenced service bulletin Revision level shown on
and date Page No. page Date shown on page
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SBF100-55-018, Revision 1, 1-4, 8-16, 18, 19, 21- 1.......................... December 27, 1993.
December 27, 1993. 23, 25-28.
5-7, 17, 20, 24, 29-31 Original................... May 19, 1993.
SBF100-55-019, Revision 1, May 1-3, 5, 9,............ 1.......................... May 19, 1993.
19, 1993.
4, 6-8, 10-12......... Original................... August 11, 1992.
SBF100-55-023, January 3, 1995 1-17.................. Original................... January 3, 1995.
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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 (BLA) 93-069 (A), dated June 1, 1993.
(h) This amendment becomes effective on January 2, 1998.
Issued in Renton, Washington, on November 19, 1997.
James V. Devany,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 97-31029 Filed 11-26-97; 8:45 am]
BILLING CODE 4910-13-P
