[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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