AD 2000-12-07

[Federal Register Volume 65, Number 116 (Thursday, June 15, 2000)]
[Rules and Regulations]
[Pages 37478-37480]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 00-14951]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 99-NM-51-AD; Amendment 39-11785; AD 2000-12-07]
RIN 2120-AA64


Airworthiness Directives; Saab Model SAAB SF340A and SAAB 340B 
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 Saab Model SAAB SF340A and SAAB 340B series 
airplanes, that requires a one-time inspection to detect corrosion and 
scratches on the bearing housing surfaces of the support assembly on 
the main landing gear (MLG), and corrective actions, if necessary. This 
amendment is prompted by issuance of mandatory continuing airworthiness 
information by a foreign civil airworthiness authority. The actions 
specified by this AD are intended to prevent corrosion in the inboard 
and outboard bearing housings of the MLG support assembly, which could 
result in fatigue cracks in the support assembly and lead to failure of 
the MLG.

DATES: Effective July 20, 2000.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of July 20, 2000.

ADDRESSES: The service information referenced in this AD may be 
obtained from Saab Aircraft AB, SAAB Aircraft Product Support, S-
581.88, Linkoping, Sweden. 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: 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: 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 Saab Model SAAB SF340A and 
SAAB 340B series airplanes was published in the Federal Register on 
January 5, 2000 (65 FR 395). That action proposed to require a one-time 
inspection to detect corrosion and scratches on the bearing housing 
surfaces of the support assembly on the main landing gear, and 
corrective actions, if necessary.

Consideration of Comments Received

    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. Due consideration has been given to 
the two comments received.

Request To Include Optional Repair Procedure to This AD

    One commenter, an operator, requests that the optional repair 
procedure, included in a note in step 2.C.(1)(b)10 of the 
Accomplishment Instructions of Saab Service Bulletin 340-57-036, dated 
October 20, 1999, be added to the proposed AD. That procedure specifies 
certain options for follow-on repair based on the depth and extent of 
damage after rework. One option would require repair of the main 
landing gear (MLG) support assembly within 4,000 flight cycles after 
the inspection. Another option would require reinstalling the bearings 
for the MLG assembly and continuing to operate the airplane an 
additional 4,000 flight cycles before the final repair is accomplished. 
The commenter adds that [without having these options] ``we foresee a 
serious maintenance-scheduling issue'' due to the large number of Saab 
Model SAAB 340 series airplanes in its fleet (presently 115).
    The FAA concurs with the commenter's request to include in this AD 
the two options specified in the service bulletin. Although those 
options were inadvertently omitted in the proposed AD, both options are 
included in this AD. The FAA has determined that, for damage within 
certain limits after rework, deferral of the final repair of the MLG 
support assembly for 4,000 flight cycles will adequately address the 
identified unsafe condition and is acceptable for the requirements of 
this AD.

Request To Revise Cost Estimate

    One commenter states that ``unless there is a policy to address 
inspections only and not include preparation, corrective action, and 
close up costs, the costs are underestimated in the NPRM.'' The service 
bulletin includes detailed costs for the actions specified, which 
include access, inspection, corrective actions, close up, and test. The 
commenter adds that, if operators

[[Page 37479]]

accomplish those actions when the MLG's are removed for overhaul or 
repair, no extra costs are necessary for the removal/reinstallation of 
shock struts and drag braces. However, if such actions are not 
accomplished during overhaul or repair of the MLG's, removal/
installation will require an additional 8 hours. In addition, the costs 
will vary according to the damage found.
    The FAA does not concur with the commenter's request to revise the 
cost impact information presented in the proposed AD, which describes 
only the ``direct'' costs of the specific actions required by this AD. 
The number of work hours necessary to accomplish the required actions, 
specified as 2 work hours in the cost impact information, below, was 
provided to the FAA by the manufacturer based on the best data 
available to date. That number represents the time necessary to perform 
only the actions actually required by this AD. The FAA recognizes that, 
in accomplishing the requirements of any AD, operators may incur 
``incidental'' costs in addition to the ``direct'' costs. However, the 
cost analysis in AD rulemaking actions typically does not include 
incidental costs, such as the time required to gain access and close 
up, planning time, or time necessitated by other administrative 
actions. The FAA points out that because incidental costs may vary 
significantly from operator to operator, they are almost impossible to 
calculate. For these reasons, no change to the final rule is necessary 
in this regard.

Explanation of Changes Made to This Final Rule

    The FAA has made the following changes:
    <bullet> Revised paragraph (b) and added paragraphs (b)(1) and 
(b)(2) in the final rule.
    <bullet> Added a reference to ``paragraph (b)'' in paragraph (c) of 
the final rule.

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 with the changes described 
previously. The FAA has determined that these changes will neither 
increase the economic burden on any operator nor increase the scope of 
the AD.

Cost Impact

    The FAA estimates that 291 Model SAAB SF340A and SAAB 340B series 
airplanes of U.S. registry will be affected by this AD, that it will 
take approximately 2 work hours per airplane to accomplish the required 
actions, and that the average labor rate is $60 per work hour. Based on 
these figures, the cost impact of the AD on U.S. operators is estimated 
to be $34,920, or $120 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 a substantial direct 
effect 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, it 
is determined that this final rule does not have federalism 
implications under Executive Order 13132.
    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:

2000-12-07  SAAB Aircraft AB: Amendment 39-11785. Docket 99-NM-51-
AD.

    Applicability: Model SAAB SF340A, serial numbers -004 through -
159 inclusive; and SAAB 340B series airplanes, serial numbers -160 
through -444 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 (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 corrosion in the inboard and outboard bearing 
housings of the support assembly of the main landing gear (MLG), 
which could result in fatigue cracks in the support assembly and 
lead to failure of the MLG, accomplish the following:

Initial Inspection

    (a) At the applicable time specified in paragraph (a)(1), 
(a)(2), (a)(3), or (a)(4) of this AD: Perform a one-time general 
visual inspection of the eight bearing housing surfaces of the MLG 
to detect corrosion or scratches, in accordance with Saab Service 
Bulletin 340-57-036, dated October 20, 1999.
    (1) For airplanes with 32,000 or more total flight cycles as of 
the effective date of this AD, the inspection is to be performed 
within 4,000 flight cycles after the effective date of this AD.
    (2) For airplanes with 24,000 or more and fewer than 32,000 
total flight cycles as of the effective date of this AD, the 
inspection is to be performed within 6,000 flight cycles after the 
effective date of this AD.
    (3) For airplanes with 12,000 or more and fewer than 24,000 
total flight cycles as of the effective date of this AD, the 
inspection is to be performed prior to the accumulation of 24,000 
total flight cycles, or within 6,000 flight cycles after the 
effective date of this AD, whichever occurs later.
    (4) For airplanes with fewer than 12,000 total flight cycles as 
of the effective date of this AD, the inspection is to be performed 
prior to the accumulation of 12,000 total flight cycles, or within 
6,000 flight cycles after the effective date of this AD, whichever 
occurs later.

    Note 2: For the purposes of this AD, a general visual inspection 
is defined as: ``A visual examination of an interior or exterior 
area, installation, or assembly to detect obvious damage, failure, 
or irregularity. This level of inspection is made under normally 
available lighting conditions such as daylight, hangar lighting, 
flashlight, or drop-light, and may require removal or opening of 
access panels or doors. Stands, ladders, or

[[Page 37480]]

platforms may be required to gain proximity to the area being 
checked.''

Corrective Actions

    (b) Except as provided by paragraph (c) of this AD: If, during 
the inspection required by paragraph (a) of this AD, any corrosion 
or scratch is detected that is within the limits specified in Saab 
Service Bulletin 340-57-036, dated October 20, 1999, prior to 
further flight, perform corrective actions (including rework, an 
eddy current inspection, and repair) in accordance with Steps 2.B. 
and 2.C. of the Accomplishment Instructions of the service bulletin.
    (1) If, after rework, the depth of the damage is less than or 
equal to 0.15 mm (0.006 inches) AND the damage does not exceed 15 
percent of the area, no further action is required by this AD.
    (2) If, after rework, the depth of the damage exceeds 0.15 mm 
(0.006 inches) but is less than or equal to 1.1 mm (0.043 inches), 
AND the damage does not exceed 30 percent of the area: Within 4,000 
flight cycles after accomplishment of the inspection required by 
paragraph (a), repair the MLG support assembly in accordance with 
the service bulletin. Following the repair, no further action is 
required by this AD.
    (c) If, during any inspection required by this AD, a discrepancy 
is detected for which the service bulletin specifies to contact Saab 
for appropriate action [including any crack or any corrosion or 
scratch that exceeds 1.1 mm (0.043 in) after applicable rework has 
been performed as required by paragraph (b) of this AD]: Prior to 
further flight, repair in accordance with a method approved by the 
Manager, International Branch, ANM-116, Transport Airplane 
Directorate; or the Luftfartsverket (LFV) (or its delegated agent). 
For a repair method to be approved by the Manager, International 
Branch, ANM-116, as required by this paragraph, the Manager's 
approval letter must specifically reference this AD.

Alternative Methods of Compliance

    (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 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.

Special Flight Permits

    (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.

Incorporation by Reference

    (f) Except as specified by paragraph (c) of this AD, the 
inspections and corrective actions shall be done in accordance with 
Saab Service Bulletin 340-57-036, dated October 20, 1999. 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 Saab Aircraft AB, SAAB Aircraft 
Product Support, S-581.88, Linkoping, Sweden. 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 4: The subject of this AD is addressed in Swedish 
airworthiness directive 1-146, dated October 20, 1999.

    (g) This amendment becomes effective on July 20, 2000.

    Issued in Renton, Washington, on June 7, 2000.
Donald L. Riggin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 00-14951 Filed 6-14-00; 8:45 am]
BILLING CODE 4910-13-U