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, 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 SAABSF340A, 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 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.
39.13 [Amended]
2. Section 39.13 is amended by adding the following new airworthiness directive: