[Federal Register Volume 62, Number 216 (Friday, November 7, 1997)]
[Proposed Rules]
[Pages 60191-60193]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-29421]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 97-NM-236-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 inspections to 
detect discrepancies of the support straps of the flaps and adjacent 
areas, and corrective action, if necessary; it would also require 
replacement of the support straps with new straps made of steel. This 
proposal is prompted by the issuance of mandatory continuing 
airworthiness information by a foreign civil airworthiness authority. 
The actions specified by the proposed AD are intended to prevent 
fatigue cracking of the support straps of the flaps, which could result 
in further damage to the flap structure, and consequently lead to 
reduced controllability of the airplane.

DATES: Comments must be received by December 8, 1997.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 97-NM-236-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: International Branch, ANM-116, 
FAA,Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, 
Washington 98055-4056; telephone (425) 227-2110; fax (425) 227-1149.

[[Page 60192]]

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 97-NM-236-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.97-NM-236-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 it received a report indicating that, during a scheduled 
inspection, fatigue cracks were found in flap support straps. Such 
fatigue cracking, if not detected and corrected in a timely manner, 
could result in damage to the flap structure, and consequently lead to 
reduced controllability of the airplane.

Explanation of Relevant Service Information

    Saab has issued Service Bulletin 340-57-033, dated May 29, 1997, 
Revision 1, dated August 18, 1997, which describes procedures for 
visual and detailed inspections to detect discrepancies of the flap 
support straps and adjacent areas, and corrective action, if necessary. 
The service bulletin also describes procedures for replacement of the 
support straps of the flaps with new straps made of steel. 
Accomplishment of the actions specified in the service bulletin is 
intended to adequately address the identified unsafe condition. The LFV 
classified this service bulletin as mandatory and issued Swedish 
airworthiness directive SAD No. 1-117, dated June 9, 1997, 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 Revision 1 of the service bulletin described 
previously, except as specified below.

Differences Between the Proposed AD and the Related Service 
Information

    This proposed AD would differ from Saab Service Bulletin 340-57-
033, Revision 1, dated August 18, 1997, in that the service bulletin 
recommends that any crack detected during an inspection be repaired in 
accordance with instructions that would be provided by the 
manufacturer. However, the FAA has determined that the repair of any 
crack would be required to be accomplished in accordance with a method 
approved by the FAA.

Cost Impact

    The FAA estimates that 252 Saab Model SAAB SF340A and SAAB 340B 
series airplanes of U.S. registry would be affected by this proposed 
AD.
    It would take approximately 30 work hours per airplane to 
accomplish the proposed visual inspection, at an average labor rate of 
$60 per work hour. Based on these figures, the cost impact of the 
visual inspection proposed by this AD on U.S. operators is estimated to 
be a total of $1,800 per airplane.
    It would take approximately 180 work hours per airplane to 
accomplish the proposed detailed visual inspection and concurrent 
replacement, at an average labor rate of $60 per work hour. Required 
parts would cost approximately $4,580 per airplane. Based on these 
figures, the cost impact of the detailed visual inspection and 
replacement proposed by this AD on U.S. operators is estimated to be 
$3,875,760, or $15,380 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

[[Page 60193]]

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:

Saab Aircraft AB: Docket 97-NM-236-AD.

    Applicability: Model SAAB SF340A and SAAB 340B series airplanes, 
as listed in Saab Service Bulletin 340-57-033, Revision 1, dated 
August 18, 1997; 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 fatigue cracking of the flap support straps, which 
could result in further damage to the flap structure and reduced 
controllability of the airplane, accomplish the following:
    (a) Except as provided by paragraph (b) of this AD: Prior to the 
accumulation of 16,000 total flight cycles, or within 1,500 flight 
cycles after the effective date of this AD, whichever occurs later, 
perform a visual inspection to detect discrepancies (i.e., cracking 
and/or damage) of the support straps of the left-and right-hand 
flaps and adjacent areas, in accordance with Saab Service Bulletin 
340-57-033, Revision 1, dated August 18, 1997. If any discrepancy is 
detected, prior to further flight, repair it in accordance with a 
method approved by the Manager, International Branch, ANM-116, FAA, 
Transport Airplane Directorate.
    (b) At the next scheduled structural inspection of the flaps, 
but not later than the accumulation of 3,000 flight cycles after the 
effective date of this AD, accomplish paragraphs (b)(1) and (b)(2) 
of this AD, in accordance with Saab Service Bulletin 340-57-033, 
Revision 1, dated August 18, 1997. Accomplishment of the inspection 
and replacement specified in paragraphs (b)(1) and (b)(2) of this AD 
constitutes terminating action for the requirements of paragraph (a) 
of this AD.
    (1) Perform a detailed inspection to detect discrepancies (i.e., 
cracking and/or damage) of the support straps of the left-and right-
hand flaps and adjacent areas, in accordance with the service 
bulletin. If any discrepancy is detected, prior to further flight, 
repair it in accordance with a method approved by the Manager, 
International Branch, ANM-116. And,
    (2) Replace the support straps of the left-and right-hand flaps 
with new straps made of steel, in accordance with the service 
bulletin.
    (c) As of the effective date of this AD, no person shall install 
a flap assembly having part number 7257800-501 through -508 
inclusive, -571, -572, or -851 through -858 inclusive, on any 
airplane, unless that flap assembly has been modified in accordance 
with Saab Service Bulletin 340-57-033, Revision 1, dated August 18, 
1997.
    (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, International Branch, ANM-116, 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, 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.

    (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.

    Note 3: The subject of this AD is addressed in Swedish 
airworthiness directive SAD No. 1-117, dated June 9, 1997.

    Issued in Renton, Washington, on October 31, 1997.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 97-29421 Filed 11-6-97; 8:45 am]
BILLING CODE 4910-13-U