Airworthiness directives: Saab,

[Federal Register: February 19, 1999 (Volume 64, Number 33)]

[Rules and Regulations]

[Page 8227-8229]

From the Federal Register Online via GPO Access [wais.access.gpo.gov]

[DOCID:fr19fe99-2]

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 97-NM-236-AD; Amendment 39-11042; AD 99-04-17]

RIN 2120-AA64

Airworthiness Directives; Saab Model SAAB SF340A and SAAB 340B Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

SUMMARY: This amendment adopts a new airworthiness directive (AD), applicable to certain Saab Model SAAB SF340A and SAAB 340B series airplanes, that requires inspections to detect discrepancies of the support straps of the flaps and adjacent areas, and corrective action, if necessary. This amendment also requires replacement of the support straps with new straps made of steel. 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 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: Effective March 26, 1999.

The incorporation by reference of certain publications listed in the regulations is approved by the Director of the Federal Register as of March 26, 1999.

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, 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 November 7, 1997 (62 FR 60191). That action proposed to require inspections to detect discrepancies of the support straps of the flaps and adjacent areas; corrective action, if necessary; and replacement of the support straps with new straps made of steel.

Actions Since Issuance of Proposal

Since the issuance of the proposal, Saab issued Service Bulletin 340-57-033, Revision 02, dated January 29, 1998. The inspection and modification procedures described in Revision 02 are substantially equivalent to those described in Revision 01 (which was cited in the proposal as the appropriate source of service information for accomplishment of the actions). The only change effected by Revision 02 is to clarify certain procedures. The final rule has been revised to require accomplishment of the actions in accordance with either Revision 01 or Revision 02 of the service bulletin.

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Comments

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

Support for the Proposal

One commenter supports the proposal.

Requests To Accept or Include Manufacturer's Approved Repairs in Final Rule

One commenter, the manufacturer, requests that the proposal be revised to accept repairs based on approval by Saab, in lieu of approval by the FAA, in the event cracking is detected. The commenter notes that the LFV has authorized Saab to approve such repairs. Another commenter requests that the final rule be revised to specifically reference or incorporate repair instructions provided by the manufacturer. That commenter states that operators that are required to accomplish repairs will likely incur a sizable delay or cancellation while awaiting repair approval by the FAA.

The FAA does not concur. Specific repair instructions were not included in the referenced service bulletin, and have not been provided to the FAA by the manufacturer, so cannot be included in this AD. Additionally, despite the LFV's current authorization of repair approval by Saab, the FAA cannot delegate authority for general approval of repairs on the FAA's behalf to Saab, because the status of Saab's delegation by the LFV could change without notice. However, in light of the type of repair that would be required to address the identified unsafe condition, and in consonance with existing bilateral airworthiness agreement with Sweden, the FAA has determined that, for this AD, a repair approved by either the FAA or the LFV (or its delegated agent) is acceptable for compliance with this AD. Paragraphs (a) and (b) of the final rule have been revised accordingly.

Request To Cite Earlier Version of Service Bulletin

One commenter requests that the proposed AD be revised to refer to the original version of Saab Service Bulletin 340-57-033, dated May 29, 1997. (Revision 01 of the service bulletin, dated August 18, 1997, was referred to in the proposed AD as the appropriate source of service information for accomplishment of the actions.) The commenter states that it already has accomplished certain actions in accordance with the original version of the service bulletin, and requests credit for this work.

The FAA concurs. The FAA has determined that the actions described in the original version and Revision 01 of the service bulletin are substantially equivalent. Therefore, a NOTE has been added to the final rule to refer to the original issue of the service bulletin as an acceptable means of compliance with this AD. (Operators should note that, as discussed previously, the final rule has been revised to additionally cite Revision 02 as an appropriate source of service information for compliance with this AD.)

Request To Revise Compliance Language

One commenter (the manufacturer) requests that the compliance language of the proposal be revised to be consistent with the intent of the service bulletin. The commenter requests that paragraph (a) of the proposal be revised to identify compliance in terms of flight cycles on each flap, rather than flight cycles on the airplane. In addition, the commenter requests that paragraph (b) of the proposal be revised to require accomplishment, for flaps that have accumulated 16,000 flight cycles, at a time ``not later than either at the next scheduled structural inspection of the flaps or within 3,000 flight cycles, whichever occurs later.'' By contrast, the proposal specified compliance in terms of ``the next scheduled structural inspection of the flaps, but not later than the accumulation of 3,000 flight cycles.''

The FAA partially concurs with the commenter's request to revise the compliance language of the proposed AD.

The FAA does not agree that the compliance should be specified in terms of flight cycles on the flaps. Because the FAA requires operators to document flight cycles on each airplane, but not on individual flap assemblies, operators may be unable to ascertain the exact number of flight cycles on an individual flap. The final rule will retain compliance in terms of flight cycles on the airplane.

The FAA agrees that the detailed visual inspection and replacement should be performed at the next scheduled flap inspection or within 3,000 flight cycles, whichever occurs later. However, the FAA finds it necessary to more precisely define the ``next scheduled flap inspection'' interval because some U.S. operators may follow different inspection schedules. Therefore, the FAA finds that this compliance time should be defined as ``Prior to the accumulation of 6,000 flight cycles after the last scheduled detailed visual inspection (if any) of the flaps accomplished prior to the effective date of this AD'' (which may have been accomplished in accordance with the Saab 340 Maintenance Review Board document). Additionally, the FAA concurs that the inspection specified by paragraph (b) of this AD is not required until the airplane has accumulated 16,000 total flight cycles. Paragraph (b) of the final rule has been reformatted and revised accordingly. A new paragraph (c) has been added to the final rule to specify the terminating action for paragraph (a) of this AD [which was specified previously in paragraph (b) of the original NPRM].

Additional Change to Proposal

The FAA has become aware that the inspection requirement in paragraph (b) of the proposed rule could be misinterpreted contrary to the FAA's intent. Paragraph (b) of the final rule has further been revised to clarify that the required inspection is a ``detailed visual inspection'' rather than simply a ``detailed inspection.''

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 252 Saab Model SAAB SF340A and SAAB 340B series airplanes of U.S. registry will be affected by this AD.

It will take approximately 30 work hours per airplane to accomplish the required visual inspection, at an average labor rate of $60 per work hour. Based on these figures, the cost impact on U.S. operators of the visual inspection required by this AD is estimated to be $1,800 per airplane.

It will take approximately 180 work hours per airplane to accomplish the required detailed visual inspection and concurrent replacement, at an average labor rate of $60 per work hour. Required parts will cost approximately $4,580 per airplane. Based on these figures, the cost impact on U.S. operators of the detailed visual inspection and replacement required by this AD is estimated to be $3,875,760, or $15,380 per airplane.

The cost impact figures discussed above are based on assumptions that no

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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.

   Sec. 39.13 [Amended]

2. Section 39.13 is amended by adding the following new airworthiness directive:

   99-04-17 Saab Aircraft AB: Amendment 39-11042. Docket 97-NM-236-AD.

   Applicability: Model SAAB SF340A and SAAB 340B series airplanes, as listed in Saab Service Bulletin 340-57-033, Revision 01, 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 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 (e) 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 support straps of the flaps, which could result in further damage to the flap structure and reduced controllability of the airplane, accomplish the following:

   Note 2: Accomplishment of the inspections and replacement specified by paragraphs (a) and (b) of this AD, in accordance with Saab Service Bulletin 340-57-033, dated May 29, 1997, is also considered acceptable for compliance with the requirements of those paragraphs.

   (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 01, dated August 18, 1997; or Revision 02, dated January 29, 1998. If any discrepancy is detected, prior to further flight, repair it 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).

   (b) Perform a detailed visual inspection to detect discrepancies (i.e., cracking and/or damage) of the left- and right-hand flaps in the area adjacent to the support straps, and replace the support straps of the left- and right-hand flaps with new straps made of steel; at the latest of the times specified by paragraphs (b)(1), (b)(2), and (b)(3) of this AD; in accordance with Saab Service Bulletin 340-57-033, Revision 01, dated August 18, 1997, or Revision 02, dated January 29, 1998. If any discrepancy is detected during the detailed visual inspection, prior to further flight, repair it in accordance with a method approved by either the Manager, International Branch, ANM-116, or the LFV (or its delegated agent).

   (1) Prior to the accumulation of 6,000 flight cycles after the last scheduled detailed visual inspection (if any) of the flaps accomplished prior to the effective date of this AD; or

   (2) Within 3,000 flight cycles after the effective date of this AD; or

   (3) Prior to the accumulation of 16,000 total flight cycles.

   (c) Accomplishment of the inspection and replacement specified in paragraph (b) of this AD constitutes terminating action for the requirements of paragraph (a) of this AD.

   (d) 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 01, dated August 18, 1997, or Revision 02, dated January 29, 1998.

   (e) 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.

   (f) 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.

   (g) Except as provided by paragraphs (a) and (b) of this AD, the actions shall be done in accordance with Saab Service Bulletin 340- 57-033, Revision 01, dated August 18, 1997, or Saab Service Bulletin 340-57-033, Revision 02, dated January 29, 1998. 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 SAD No. 1-117, dated June 9, 1997.

   (h) This amendment becomes effective on March 26, 1999.

   Issued in Renton, Washington, on February 9, 1999. John J. Hickey, Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.

   [FR Doc. 99-3728Filed2-18-99; 8:45 am]

   BILLING CODE 4910-13-U