AD 2001-23-12 R1

This document revises an existing airworthiness directive (AD) that applies to certain Saab Model SAAB SF340A and SAAB 340B series airplanes. That AD currently requires a one-time review of records to determine whether an airplane has been repainted since its delivery from the factory; and a one-time inspection to detect damage associated with improper preparation for the repainting, and corrective action if necessary. The actions specified in that AD are intended to detect and correct damage to the aluminum skin of the airplane, which could result in a weakening of the structure of the airplane. This document corrects certain conditional requirements of the existing AD.

The incorporation by reference of certain publications listed in the regulations was approved previously by the Director of the Federal Register as of December 31, 2001 (66 FR 58927, November 26, 2001).

Final rule; correction

2001-23-12 R1 Saab Aircraft AB: Amendment 39-12576. Docket 2001-NM-91-AD. Revises AD 2001-23-12, Amendment 39-12511.

Applicability: Model SAAB SF340A series airplanes having serial numbers -004 through -159 inclusive, and SAAB 340B series airplanes having serial numbers -160 through -459 inclusive; 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 (c) 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 detect and correct damage to the aluminum skin of the airplane, which could result in a weakening of the structure of the airplane, accomplish the following:

Review of Records

(a) Within 2,000 flight hours or 1 year after December 31, 2001(the effective date of AD 2001-23-12, amendment 39-12511), whichever occurs first: Perform a review of records to determine whether an airplane subject to this AD has been repainted since its delivery from the factory. If the airplane has not been repainted, no further action is needed.

Inspection and Corrective Action

(b) If an airplane has been repainted since its delivery from the factory: Within 2,000 flight hours or 1 year after December 31, 2001, whichever occurs first, perform chemical stripping of local areas of the skin and inspection to detect damage to (or removal of) the protective coat of bonding primer, in accordance with Saab Service Bulletin 340-51-020, Revision 01, dated May 16, 2001.

(1) If no damage to the protective coat of bonding primer is detected: Prior to further flight, repaint the stripped areas, in accordance with the service bulletin.

(2) If damage to (or removal of) the protective coat of bonding primer is detected: Prior to further flight, perform additional chemical stripping and inspection of the skin for pitting corrosion, in accordance with the service bulletin.

(i) If pitting corrosion is detected: Perform corrective action in a manner and within a compliance time approved by the Manager, International Branch, ANM-116, Transport Airplane Directorate, FAA, or the Luftfartsverket (or its designated agent).

(ii) If no pitting corrosion is detected: Prior to further flight, measure the thickness of the skin of the airplane, in accordance with the service bulletin.

(A) If a reduction in skin thickness is detected: Perform corrective action in a manner and within a compliance time approved by the Manager, International Branch, ANM-116, or the Luftfartsverket (or its designated agent).

(B) If no reduction in skin thickness is detected: Prior to further flight, check records to determine whether the airplane was repainted using an approved paint system. For purposes of this AD, criteria for an "approved" paint system are found in section 51-20-43 of the Saab 340 Structural Repair Manual.

(1) If the airplane was repainted using an approved paint system: Prior to further flight, repaint the stripped areas of the airplane, in accordance with the service bulletin.

(2) If the airplane was repainted using an unapproved paint system: Prior to further flight, repaint the stripped areas in accordance with the service bulletin; and within 4,000 flight hours or 2 years after detection of the damage or removed protective coating, whichever occurs first, chemically strip and repaint the airplane as specified by and in accordance with the service bulletin.

Alternative Methods of Compliance

(c) 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 2: 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

(d) 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

(e) Except as required by paragraphs (a), (b)(2)(i), and (b)(2)(ii)(A) of this AD: The actions shall be done in accordance with Saab Service Bulletin 340-51-020, Revision 01, dated May 16, 2001. This incorporation by reference was approved previously by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51 as of December 31, 2001 (66 FR 58927, November 26, 2001). 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 3: The subject of this AD is addressed in Swedish airworthiness directive SAD 1-161R2, dated March 13, 2001.

Effective Date

(f) The effective date of this amendment remains December 31, 2001.

On November 15, 2001, the FAA issued AD 2001-23-12, amendment 39-12511 (66 FR 58927, November 26, 2001), applicable to certain Saab Model SAAB SF340A and SAAB 340B series
airplanes, to require a one-time review of records to determine whether an airplane has been repainted since its delivery from the factory; and a one-time inspection to detect damage associated with improper preparation for the repainting, and corrective action if necessary. That action was prompted by mandatory continuing airworthiness
information from a foreign civil airworthiness authority. The requirements of that AD are intended to detect and correct damage to the aluminum skin of the airplane, which could result in a weakening of the structure of the airplane.

Need for the Correction

Information obtained recently by the FAA indicates that the final rule of this AD conveyed an inaccurate interpretation of a comment submitted on the proposed AD. The commenter had requested that paragraph "(B)(2)" of the proposed AD be revised to include a corrective action to immediately repaint the stripped areas, and to extend the compliance time to strip and repaint the airplane. As discussed in the response to the comments in AD 2001-23-12, the FAA concurred with the request and incorporated that instruction. However, the instruction was added to subparagraph (b)(2) when it appears the commenter intended the instruction to be inserted into subparagraph (b)(2)(ii)(B)(2).

The FAA has determined that a correction to AD 2001-23-12 is necessary. Under the current requirements of subparagraph (b)(2) of the AD, affected airplanes are allowed to operate for an additional 4,000 flight hours or 2 years with inadequate protective coating, which could subject the airplanes to damage (or further damage). This correction
removes the requested language from subparagraph (b)(2) of the AD and incorporates the instruction into subparagraph (b)(2)(ii)(B)(2) to specify immediate repair of damage and delay the requirement to strip and repaint the airplane.

To clarify the 4,000-flight-hour/2-year compliance time for this conditional requirement, the FAA has added the phrase, "whichever occurs first."

In addition, the FAA has been advised that subparagraph (b)(2)(ii)(B)(2) of the proposed AD inaccurately specifies that the entire airplane must be repainted if damage is detected during the inspection and if an unapproved paint system had been used. The service bulletin specifies that the entire airplane must not be stripped and repainted if damage is found in only a certain section of the airplane--except for the forward and rear fuselage, stabilizer, and wing, which must always be stripped and repainted in total if any damage is found within the respective inspection area. The FAA did not intend that this AD differ from the service bulletin in that regard. This correction revises subparagraph (b)(2)(ii)(B)(2) to clarify the conditional requirement by referring to the service bulletin.

Correction of Publication

This document corrects these errors and correctly adds the AD as an amendment to section 39.13 of the Federal Aviation Regulations (14 CFR 39.13). The AD is reprinted in its entirety for the convenience of affected operators. The effective date of the AD remains December 31, 2001.

Since this action only corrects current requirements, it has no adverse economic impact and imposes no additional burden on any person. Therefore, the FAA has determined that notice and public procedures are
unnecessary.

List of Subjects in 14 CFR Part 39

Air transportation, Aircraft, Aviation safety, Incorporation by reference, Safety.

Adoption of the Correction

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 removing amendment 39-12511 (66 FR 58927, November 26, 2001), and by adding a new airworthiness directive (AD), amendment 39-12576, to read as follows: