[Federal Register Volume 64, Number 32 (Thursday, February 18, 1999)]
[Proposed Rules]
[Pages 8029-8031]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-4013]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 98-NM-220-AD]
RIN 2120-AA64
Airworthiness Directives; Saab Model SAAB SF340A and SAAB 340B
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 Saab Model SAAB SF340A and
SAAB 340B series airplanes. This proposal would require repetitive
inspections to detect cracking around certain fastener holes and
adjacent areas of the front spar of the horizontal stabilizers; and
corrective actions, if necessary. This proposal also would require cold
working of certain fastener holes of the front spar of the horizontal
stabilizers, and follow-on actions; and installation of new fasteners,
which would constitute terminating action for the repetitive
inspections proposed by this AD. This proposal is prompted by issuance
of mandatory continuing airworthiness information by a foreign civil
airworthiness authority. The actions specified by the proposed AD are
intended to prevent failure of the front spar due to fatigue cracking
around certain fastener holes of the front spar of the horizontal
stabilizers, which could result in reduced structural integrity of the
airplane.
DATES: Comments must be received by March 22, 1999.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Transport Airplane Directorate, ANM-114,
Attention: Rules Docket No. 98-NM-220-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 Saab Aircraft AB, SAAB Aircraft Product Support, S-
581.88, Linkoping, Sweden. This information may be examined at the FAA,
Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton,
Washington.
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:
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 98-NM-220-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-114, Attention: Rules
Docket No.
[[Page 8030]]
98-NM-220-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.
Discussion
The Luftfartsverket (LFV), which is the airworthiness authority for
Sweden, notified the FAA that an unsafe condition may exist on certain
Saab Model SAAB SF340A and SAAB 340B series airplanes. The LFV advises
that, during full-scale fatigue testing on a test article, cracking was
found in the front spar of the horizontal stabilizer at the
intersection between the rear fuselage and the front upper spar cap.
Further investigation revealed that the fatigue cracking may have
originated at one of the fastener holes in the upper part of the web of
the front spar. Such fatigue cracking, if not detected and corrected,
could result in reduced structural integrity of the airplane.
Explanation of Relevant Service Information
The manufacturer has issued SAAB Service Bulletin 340-55-033,
Revision 04, dated December 1, 1998, which describes procedures for
repetitive detailed visual and eddy current inspections to detect
cracking around certain fastener holes and adjacent areas of the front
spar of the horizontal stabilizers.
The manufacturer also has issued SAAB Service Bulletin 340-55-034,
dated October 16, 1998, which describes procedures for cold working of
certain fastener holes of the front spar of the horizontal stabilizers,
and follow-on actions. The follow-on actions involve performing eddy
current inspections of specified areas to detect cracking of certain
fastener holes before and after cold working and after oversizing any
hole. The service bulletin also describes procedures for installation
of new fasteners into certain holes of the front spar of the horizontal
stabilizers. Accomplishment of these actions would eliminate the need
for the repetitive inspections described in Saab Service Bulletin 340-
55-033.
Accomplishment of the actions specified in the Saab service
bulletins is intended to adequately address the identified unsafe
condition. The LFV classified these service bulletins as mandatory and
issued Swedish airworthiness directives 1-110R2, dated December 7,
1998, and 1-133, dated October 20, 1998, in order to assure the
continued airworthiness of these airplanes in Sweden.
FAA's Conclusions
These airplane models are manufactured in Sweden and are 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 LFV has kept the FAA informed of
the situation described above. The FAA has examined the findings of the
LFV, 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.
Explanation of Requirements of Proposed Rule
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 accomplishment of
the actions specified in the service bulletins described previously,
except as discussed below.
Differences Between Proposed Rule and Service Information
Operators should note that, although the service bulletins specify
that the manufacturer may be contacted for the disposition of certain
cracking conditions around certain fastener holes of the front spar of
the horizontal stabilizers, this AD would require repair of any fatigue
cracking to be accomplished in accordance with a method approved by
either the FAA, or the LFV (or its delegated agent). In light of the
type of repair that would be required to address the identified unsafe
condition, and in consonance with existing bilateral airworthiness
agreements, the FAA has determined that, for this AD, a repair approved
by either the FAA or the LFV is acceptable for compliance with this AD.
Cost Impact
The FAA estimates that 279 airplanes of U.S. registry would be
affected by this proposed AD.
It would take approximately 4 work hours per airplane to perform
the detailed visual inspection, at an average labor rate of $60 per
work hour. Based on these figures, the cost impact of the inspection
proposed by this AD on U.S. operators is estimated to be $66,960, or
$240 per airplane, per inspection cycle.
It would take approximately 6 work hours per airplane to accomplish
the proposed eddy current inspection, at an average labor rate of $60
per work hour. Based on these figures, the cost impact of the
inspection proposed by this AD on U.S. operators is estimated to be
$100,440, or $360 per airplane, per inspection cycle.
It would take approximately 42 work hours to accomplish the cold
working of the fastener holes, at an average labor rate of $60 per work
hour. Required parts would cost approximately $400 per airplane. Based
on these figures, the cost impact of the cold work proposed by this AD
on U.S. operators is estimated to be $814,680, or $2,920 per airplane.
The cost impact figures discussed above are 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.
Regulatory Impact
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. 106(g), 40113, 44701.
[[Page 8031]]
Sec. 39.13 [Amended]
2. Section 39.13 is amended by adding the following new
airworthiness directive:
Saab Aircraft AB: Docket 98-NM-220-AD.
Applicability: Model SAAB SF340A series airplanes,
manufacturer's serial numbers -004 through -159 inclusive; and SAAB
340B series airplanes, manufacturer's serial numbers -160 through -
439 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 request approval for an
alternative method of compliance in accordance with paragraph (f) 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 failure of the front spar due to fatigue cracking
around certain fastener holes of the front spar of the horizontal
stabilizers, which could result in reduced structural integrity of
the airplane, accomplish the following:
(a) For SAAB SF340A series airplanes with manufacturer's serial
numbers -004 through -159 inclusive: Perform inspections to detect
cracking around certain fastener holes and adjacent areas of the
front spar of the horizontal stabilizer, in accordance with Saab
Service Bulletin 340-55-033, Revision 04, dated December 1, 1998, at
the time specified in paragraph (a)(1), (a)(2), or (a)(3) of this
AD, as applicable. Thereafter, repeat the eddy current inspection at
intervals not to exceed 12,000 flight cycles until the requirements
of paragraph (d) of this AD are accomplished.
(1) For airplanes that have accumulated less than 22,000 total
flight cycles as of the effective date of this AD: Perform an eddy
current inspection prior to the accumulation of 22,000 total flight
cycles, or within 2,000 flight cycles after the effective date of
this AD, whichever occurs later.
(2) For airplanes that have accumulated 22,000 or more total
flight cycles and less than 30,000 total flight cycles as of the
effective date of this AD: Accomplish the requirements of paragraphs
(a)(2)(i) and (a)(2)(ii) of this AD.
(i) Perform a detailed visual inspection within 800 flight
cycles after the effective date of this AD; and
(ii) Perform an eddy current inspection within 2,000 flight
cycles after the effective date of this AD.
(3) For airplanes that have accumulated 30,000 or more total
flight cycles as of the effective date of this AD: Accomplish the
requirements of paragraphs (a)(3)(i) and (a)(3)(ii) of this AD.
(i) Perform a detailed visual inspection within 400 flight
cycles after the effective date of this AD; and
(ii) Perform an eddy current inspection within 1,200 flight
cycles after the effective date of this AD.
(b) For SAAB 340B series airplanes with manufacturer's serial
numbers -160 through -439 inclusive: Perform inspections to detect
cracking around certain fastener holes and adjacent areas of the
front spar of the horizontal stabilizer, in accordance with Saab
Service Bulletin 340-55-033, Revision 04, dated December 1, 1998, at
the time specified in paragraph (b)(1), (b)(2), or (b)(3) of this
AD, as applicable. Thereafter, repeat the eddy current inspection at
intervals not to exceed 6,000 flight cycles until the requirements
of paragraph (d) of this AD are accomplished.
(1) For airplanes that have accumulated less than 12,000 total
flight cycles as of the effective date of this AD: Perform an eddy
current inspection prior to the accumulation of 12,000 total flight
cycles, or within 2,000 flight cycles after the effective date of
this AD, whichever occurs later.
(2) For airplanes that have accumulated 12,000 or more total
flight cycles and less than 16,000 total flight cycles as of the
effective date of this AD: Accomplish the requirements of paragraphs
(b)(2)(i) and (b)(2)(ii) of this AD.
(i) Perform a detailed visual inspection within 800 flight
cycles after the effective date of this AD; and
(ii) Perform an eddy current inspection within 2,000 flight
cycles after the effective date of this AD.
(3) For airplanes that have accumulated 16,000 or more total
flight cycles as of the effective date of this AD: Accomplish the
requirements of paragraphs (b)(3)(i) and (b)(3)(ii) of this AD.
(i) Perform a detailed visual inspection within 400 flight
cycles after the effective date of this AD; and
(ii) Perform an eddy current inspection within 1,200 flight
cycles after the effective date of this AD.
(c) If any cracking is detected during any inspection required
by paragraph (a) or (b) of this AD, prior to further flight, either
repair in accordance with a method approved by the Manager,
International Branch, ANM-116, FAA, Transport Airplane Directorate,
or the Luftfartsverket (LFV) (or its delegated agent); or accomplish
the requirements of paragraph (d) of this AD.
Note 2: Inspections to detect cracking around certain fastener
holes and adjacent areas of the front spar of the horizontal
stabilizers that have been accomplished prior to the effective date
of this AD in accordance with Saab Service Bulletin 340-55-033,
Revision 03, dated January 22, 1998, are considered acceptable for
compliance with the applicable action specified by this AD.
(d) For all airplanes: Except as provided by paragraph (e) of
this AD, accomplish cold working of certain fastener holes of the
front spar of the horizontal stabilizers, and follow-on actions; and
install new fasteners; in accordance with Saab Service Bulletin 340-
55-034, dated October 16, 1998; at the time specified in paragraph
(d)(1), (d)(2), or (d)(3) of this AD, as applicable. Accomplishment
of this action constitutes terminating action for this AD.
(1) For all airplanes that have accumulated less than 26,000
total flight cycles as of the effective date of this AD: Within
10,000 flight cycles after the effective date of this AD.
(2) For all airplanes that have accumulated 26,000 or more total
flight cycles and less than 30,000 total flight cycles as of the
effective date of this AD: Within 6,000 flight cycles after the
effective date of this AD.
(3) For all airplanes that have accumulated 30,000 or more total
flight cycles as of the effective date of this AD: Within 3,000
flight cycles after the effective date of this AD.
(e) If any crack is detected during the accomplishment of
paragraph (d) of this AD, and if the service bulletin listed in
paragraph (d) of this AD specifies to contact the manufacturer for
an appropriate corrective action: Prior to further flight, repair in
accordance with a method approved by the Manager, International
Branch, ANM-116, or the LFV (or its delegated agent).
(f) 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 3: Information concerning the existence of approved
alternative methods of compliance with this AD, if any, may be
obtained from the International Branch, ANM-116.
(g) 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.
Note 4: The subject of this AD is addressed in Swedish
airworthiness directives 1-110R2, dated December 7, 1998, and 1-133,
dated October 20, 1998.
Issued in Renton, Washington, on February 11, 1999.
John J. Hickey,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 99-4013 Filed 2-17-99; 8:45 am]
BILLING CODE 4910-13-U
