[Federal Register Volume 63, Number 122 (Thursday, June 25, 1998)]
[Rules and Regulations]
[Pages 34587-34589]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-16697]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 96-NM-212-AD; Amendment 39-10627; AD 98-13-36]
RIN 2120-AA64


Airworthiness Directives; Saab Model SAAB SF340A, SAAB 340B, and 
SAAB 2000 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, SAAB 340B, and SAAB 2000 
series airplanes, that requires repetitive operational tests of the 
pitch trim system of the elevator trim-tab of the flight control unit 
to ensure that the system operates correctly, and repair if necessary. 
This amendment is prompted by a report of uncommanded movement of the 
right-hand elevator trim-tab to a maximum deflection position, which 
was apparently due to a failure in the aircraft harness and a fault in 
the pitch trim synchronizer. The actions specified by this AD are 
intended to prevent such uncommanded movement of the elevator trim-tab, 
which could lead to structural overload of the horizontal stabilizers 
at speeds above 180 knots, and consequent reduced controllability of 
the airplane.

DATES: Effective July 30, 1998.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of July 30, 1998.

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

[[Page 34588]]

include an airworthiness directive (AD) that is applicable to certain 
Saab Model SAAB SF340A, SAAB 340B, and SAAB 2000 series airplanes was 
published in the Federal Register on May 9, 1997 (62 FR 25566). That 
action proposed to require repetitive operational tests of the pitch 
trim system of the elevator trim-tab of the flight control unit to 
ensure that the system operates correctly, and repair, 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 comments received.
    Two commenters support the proposed AD.

Requests to Withdraw the AD

    Two commenters suggest that the proposed AD is no longer required 
because the proposed action already is being performed by the operators 
in accordance with their usual maintenance procedures. One commenter 
states that it is redundant to issue an AD that would require the 
operational tests to be performed when those checks are already a 
mandatory task in its maintenance program. The manufacturer states that 
procedures for these tests have been included in the Saab Maintenance 
Review Board (MRB) Document (task 27-3210), which specifies repetitive 
checks every 150 flight hours. In addition, commenters state that Saab 
Service Bulletin 340-27-079, dated December 22, 1995, which describes 
procedures for the tests required by the proposed AD, has been 
canceled.
    The FAA acknowledges that the operator's maintenance program and 
manufacturer's MRB document may include the same information as the 
proposed AD and service bulletin. However, the FAA has determined that 
such programs and documents are not the appropriate means to address 
the unsafe condition; an airworthiness directive is issued to address 
an unsafe condition. In addition, the FAA has determined that allowing 
each operator to determine whether and how often operational tests 
should be conducted will not ensure an acceptable level of safety, and 
that allowing this degree of operator discretion is not appropriate in 
this case. Therefore, this AD is necessary to ensure that operators 
accomplish operational tests in a common manner and at common intervals 
to ensure compliance and public safety.

Request to Limit the Applicability of the AD

    The manufacturer states that, on all Saab Model SAAB 2000 series 
airplanes, the mechanical elevator control system (MECS) has been 
replaced by the powered elevator control system (PECS). For this 
reason, the manufacturer maintains that operational tests for the pitch 
trim system on these airplanes are no longer required.
    The FAA infers that the manufacturer requests that the FAA limit 
the applicability of the proposed AD to exclude Model SAAB 2000 series 
airplanes equipped with PECS. The FAA concurs with this request and 
agrees that, for Model SAAB SF340A, SAAB 340B, and SAAB 2000 series 
airplanes equipped with PECS, the actions required by the proposed AD 
are no longer required. Therefore, the FAA has removed such airplanes 
from the applicability of the final rule.

Requests to Incorporate the Manufacturer's Repair Instructions Into 
the Final Rule

    Two commenters request that the proposed AD be revised to 
incorporate the manufacturer's repair instructions into the final rule. 
In support of these requests, the manufacturer has provided repair 
instructions in its comments. The commenters state that, if a problem 
is encountered during an inspection, the requirement to contact the FAA 
for repair instructions could cause operators to incur long down times 
while waiting for such instructions.
    Although the FAA does not concur with the requests to incorporate 
the manufacturer's repair instructions into the final rule, it has 
taken into account the commenters' concerns about potential delays in 
receiving repair instructions. The FAA has been advised by the 
manufacturer that it has developed a repair procedure to isolate the 
fault and has developed a repair for the elevator trim synchronizer 
system in the event that the operational test fails. The FAA also has 
been advised that this repair procedure now has been included in the 
Saab 340 Aircraft Maintenance Manual (AMM) 27-32-30, dated January 1, 
1998. The FAA has reviewed this procedure and finds that it may be used 
as an acceptable means of compliance for the repair required by 
paragraph (a)(2) of this AD. Accordingly, the FAA has revised this 
final rule to include a new NOTE specifying that the repair may be 
accomplished in accordance with the Saab 340 AMM.
    In addition, the FAA has revised paragraph (a)(2) of the final rule 
to specify that repairs may be accomplished in accordance with a method 
approved by either the Manager, International Branch, ANM-116, FAA, 
Transport Airplane Directorate, or the Luftfartsverket (LFV), which is 
the airworthiness authority for Sweden. In light of the type of repair 
required to ensure that the pitch trim system operates correctly, and 
in consonance with existing bilateral airworthiness agreements, the FAA 
has determined that, for this AD, such a repair approved by either the 
FAA or the LFV (or its delegated agent) would be acceptable for 
compliance with this AD.

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

Interim Action

    This is considered to be interim action until final action is 
identified, at which time the FAA may consider further rulemaking.

Cost Impact

    The FAA estimates that 235 Model SAAB SF340A and SAAB 340B series 
airplanes of U.S. registry will be affected by this AD. Currently, 
there are no Model SAAB 2000 series airplanes of U.S. registry that 
would be affected by this AD. The FAA estimates that it will take 
approximately 1 work hour 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 $14,100, or $60 per airplane, per operational test.
    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

[[Page 34589]]

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:

98-13-36  SAAB Aircraft AB: Amendment 39-10627. Docket 96-NM-212-AD.

    Applicability: Model SAAB SF340A series airplanes, serial 
numbers -004 through -159, inclusive; Model SAAB 340B series 
airplanes, serial numbers -160 and subsequent; and SAAB 2000 series 
airplanes, serial numbers -005 and -007 through -009, inclusive; 
equipped with a mechanical elevator control system (MECS); 
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 (b) 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 uncommanded movement of the right-hand elevator trim-
tab to a maximum deflection position, which could lead to structural 
overload of the horizontal stabilizers at speeds above 180 knots, 
and consequent reduced controllability of the airplane, accomplish 
the following:
    (a) Within 150 hours time-in-service after the effective date of 
this AD, perform an operational test of the pitch trim system that 
moves the elevator trim-tab of the flight control unit to ensure 
that the system operates correctly, in accordance with Saab Service 
Bulletins 340-27-079 (for Model SAAB SF340A and SF340B series 
airplanes); or 2000-27-018 (for Model SAAB 2000 series airplanes); 
both dated December 22, 1995; as applicable.
    (1) If no discrepancy is found, repeat the operational test of 
the pitch trim system thereafter at intervals not to exceed 150 
hours time-in-service.
    (2) If any discrepancy is found, prior to further flight, 
accomplish repairs in accordance with a method approved by either 
the Manager, International Branch, ANM-116, FAA, Transport Airplane 
Directorate, or the Luftfartsverket (LFV), or its delegated agent.

    Note 2: Accomplishment of the repair required by paragraph 
(a)(2) of this AD, in accordance with Saab 340 Aircraft Maintenance 
Manual 27-32-30, dated January 1, 1998, is considered acceptable for 
compliance with the applicable action specified in this AD.

    (b) 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.

    (c) 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.
    (d) The operational test shall be done in accordance with Saab 
Service Bulletin 340-27-079, dated December 22, 1995, or Saab 
Service Bulletin 2000-27-018, dated December 22, 1995, as 
applicable. This incorporation by reference was previously 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 SAD No. 1-083, Revision 1, dated January 2, 
1996.

    (e) This amendment becomes effective on July 30, 1998.

    Issued in Renton, Washington, on June 17, 1998.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 98-16697 Filed 6-24-98; 8:45 am]
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