AD 2000-23-19

This amendment supersedes an existing airworthiness directive (AD), applicable to certain Saab Model SAAB SF340A and SAAB 340B series airplanes, that currently requires inspections to detect damage or cracking of the forward and aft attachment lugs of the flap fittings at wing station (WS) 123.38; an inspection to verify that the sizes of the holes of the flap fittings are within specified limits and to ensure that the swaged bushings are not loose; and modification of the flap fittings. This amendment requires repetitive accomplishment of the inspections using improved inspection methods; a one-time visual and repetitive general visual and detailed visual inspections; new repetitive non-destructive test (NDT) inspections; and corrective and follow-on actions, as necessary. This amendment also provides for terminating action for all repetitive inspections and revises the applicability of the existing AD. The actions specified by this AD are intended to prevent high bearingstress on the bushings of the flap fittings, which could result in wear on the bushings, cracking of the flap fittings, and breakage of the lugs; these conditions could result in jamming of the flaps and consequent reduced controllability of the airplane.

Final rule

2000-23-19 SAAB AIRCRAFT AB: Amendment 39-11992. Docket 2000-NM-76-AD. Supersedes AD 96-25-06 R1, Amendment 39-9891.
Applicability: Model SAAB SF340A series airplanes, manufacturer's serial numbers -004 through -159 inclusive; and SAAB 340B series airplanes, manufacturer's serial numbers -160 through -459 inclusive; certificated in any category; on which any flap assembly having part number (P/N) 7257800-501 through 508 inclusive, or 7257800-851 through 7257800-856 inclusive, is installed.

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 high bearing stress on the bushings in the flap fittings, which could result in jamming of the flaps and consequent reduced controllability of the airplane, accomplish the following:

Visual Inspection for Serial Numbers
(a) Within 800 flight hours after the effective date of this AD, perform a one-time visual inspection of the flap assemblies of the flap fittings at wing station (WS) 123.38 to determine the flap assembly serial numbers, in accordance with Saab Service Bulletin 340-57-035, dated January 18, 2000.

(1) If none of the serial numbers of the flap assemblies are listed in the service bulletin, no further action is required by this paragraph.

(2) If the serial number of any flap assembly is listed in the service bulletin, prior to further flight, accomplish the requirements of paragraph (a)(2)(i) and, at the time specified, accomplish the requirements of paragraph (a)(2)(ii) of this AD.

General Visual Inspection, Non-Destructive Test (NDT) Inspection, and Replacement of Bolts and Bushings
(i) Perform a general visual inspection of the affected flap fittings at WS 123.38 to detect cracking, in accordance with the service bulletin. If no cracking is detected, repeat the visual inspection thereafter at intervals not to exceed 800 flight hours, until the requirements of paragraph (a)(2)(ii) are accomplished. If any cracking is detected, prior to further flight, accomplish the terminating action specified by paragraph (c) of this AD.

(ii) Within 4,800 flight hours after the effective date of this AD, perform a one-time detailed visual inspection of the flap fittings to determine the size of theinboard and outboard holes (swaged bushing) and to detect loose swaged bushings; and perform an NDT inspection of the aft attachment lugs of the flap assemblies at WS 123.38 to detect cracking, in accordance with the service bulletin. Accomplishment of the NDT inspection terminates the general visual inspection required by paragraph (a)(2)(i) of this AD.

NOTE 2: For the purpose 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 platforms may be required to gain proximity to the area being checked."

NOTE 3: For the purposes of this AD, a detailed visual inspection is defined as: "An intensive visual examination of a specific structural area, system, installation, or assembly to detect damage, failure, or irregularity. Available lighting is normally supplemented with a direct source of good lighting at intensity deemed appropriate by the inspector. Inspection aids such as mirrors, magnifying lenses, etc., may be used. Surface cleaning and elaborate access procedures may be required."

(A) If all the hole sizes are within the limits specified by the service bulletin, no loose swaged bushings are found, and no cracking of the aft attachment lugs is detected: Prior to further flight, install new fasteners that attach to the flap hinges (nuts, bolts, bushing, and washers), in accordance with the service bulletin.

(B) If any hole size is outside the limits specified by the service bulletin, or any loose swaged bushing is found, or any cracking is detected on the aft attachment lugs: Prior to further flight, accomplish the terminating action specified in paragraph (c) of this AD.Visual Inspection for Modification Status
(b) Within 800 flight hours after the effective date of this AD, perform a one-time visual inspection of the aft attachment lugs (flap assemblies) of the flap fittings at wing station (WS) 123.38 to determine the flap assembly modification status, in accordance with Saab Service Bulletin 340-57-037, dated January 18, 2000.

(1) If the modification status is such that all flap assemblies installed have thicker lugs, as specified by Figure 1 of the service bulletin, no further action is required by this paragraph.

(2) If the modification status is such that any flap assembly installed has a thinner lug, as specified by Figure 1 of the service bulletin, prior to further flight, accomplish the requirements of paragraph (b)(2)(i) and, at the time specified, accomplish the requirements of paragraph (b)(2)(ii) of this AD.

Visual Inspection and NDT Inspection
(i) Perform a general visual inspection of the aft attachment lugsof the flap fittings at WS 123.38 to detect cracking or damage, in accordance with the service bulletin. If no cracking or damage is detected during the visual inspection, repeat the inspection thereafter at intervals not to exceed 800 flight hours, until the requirements of paragraph (b)(2)(ii) of this AD are accomplished. If any cracking or damage is detected during any general visual inspection required by this paragraph, prior to further flight, accomplish the terminating action specified by paragraph (c) of this AD.

(ii) Within 6,000 flight cycles after the effective date of this AD, perform an NDT inspection of the aft attachment lug of the flap fittings at WS 123.38 to detect cracking, in accordance with the service bulletin. Accomplishment of the NDT inspection terminates the repetitive visual inspections required by paragraph (b)(2)(i) of this AD. If no cracking is detected, repeat the NDT inspection thereafter at intervals not to exceed 6,000 flight cycles, until the actions specified by paragraph (c) are accomplished. If any cracking is detected during any NDT inspection required by this paragraph, prior to further flight, accomplish the terminating action specified by paragraph (c) of this AD.

Terminating Action
(c) Replacement of all flap fittings at WS 123.38 with new, improved flap fittings in accordance with Saab Service Bulletin 340-57-038, dated January 18, 2000, terminates all inspections required by 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 4: 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) The actions shall be done in accordance with Saab Service Bulletin 340-57-035, dated January 18, 2000; Saab Service Bulletin 340-57-037, dated January 18, 2000; and Saab Service Bulletin 340-57-038, dated January 18, 2000; as applicable. 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 5: The subject of this AD is addressed in Swedish airworthiness directives No. 1-152 and No. 1-153, each dated January 19, 2000.

Effective Date
(g) This amendment becomes effective on January 2, 2001.

A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) by superseding AD 96-25-06 R1, amendment 39-9891 (62 FR 3209, January 22, 1997), which is applicable to certain Saab Model SAAB SF340A and SAAB 340B series airplanes, was published in the Federal Register on July 31, 2000 (65 FR 46667). The action proposed to continue to require inspections to detect damage or cracking of the forward and aft attachment lugs of the flap fittings at wing station (WS) 123.38; an inspection to verify that the sizes of the holes of the flap fittings are within specified limits and to ensure that the swaged bushings are not loose; and modification of the flap fittings. The action also proposed to require repetitive accomplishment of the inspections using improved inspection methods; a one-time visual and repetitive general visual and detailed visual inspections; new repetitive non-destructive test (NDT) inspections; and corrective and follow-on actions, as necessary. Additionally, the action also proposed to provide for terminating action for all repetitive inspections and to revise the applicability of the existing AD.

Comments
Interested persons have been afforded an opportunity to participate in the making of this amendment. No comments were submitted in response to the proposal or the FAA's determination of the cost to the public.

Conclusion
The FAA has determined that air safety and the public interest require the adoption of the rule as proposed.

Cost Impact
The FAA estimates that 303 airplanes of U.S. registry will be affected by this AD.

It will take approximately 1 work hour per airplane to accomplish the required repetitive general visual inspections, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of the required general visual inspections on U.S. operators is estimated to be $18,180, or $60 per airplane, per inspection cycle.

It will take approximately 1 work hour per airplane to accomplish the required one-time general visual inspection, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of the required general visual inspection on U.S. operators is estimated to be $18,180, or $60 per airplane.

It will take approximately 1 work hour per airplane to accomplish the required repetitive detailed visual inspections, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of the required detailed visual inspections on U.S. operators is estimated to be $18,180, or $60 per airplane, per inspection cycle.

It will take approximately 2 work hours per airplane to accomplish the required repetitive NDT inspections, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of the required NDT inspections on U.S. operators is estimated to be $36,360, or $120 per airplane, per inspection cycle.

Should an operator be required or elect to accomplish the terminating modification, it will take approximately 92 work hours per airplane (46 work hours per flap), at an average labor rate of $60 per hour. Required parts will cost $7,362 per airplane ($3,681 per flap). Based on these figures, the cost impact of the terminating modification on U.S. operators is estimated to be $12,882 per airplane.

The cost impact figures discussed above are 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. The cost impact figures discussed in AD rulemaking actions represent only the time necessary to perform the specific actions actually required by the AD. These figures typically do not include incidental costs, such as the time required to gain access and close up, planning time, or time necessitated by other administrative actions.

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 Part39
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 removing amendment 39-9891 (62 FR 3209, January 22, 1997), and by adding a new airworthiness directive (AD), amendment 39-11992, to read as follows: