AD 97-16-07

This amendment adopts a new airworthiness directive (AD), applicable to certain Saab Model SAAB 2000 series airplanes, that requires replacement of the existing fire, tailpipe, and bleed-air overheat detector control units with new, improved units. This amendment is prompted by reports indicating that false engine and auxiliary power unit (APU) fire warnings were issued from the fire detector control units due to moisture or induced voltages of the detector control unit. The actions specified by this AD are intended to prevent such false fire warnings, which could result in unnecessary diversion of the airplane, and resultant increased risks to the airplane, passengers, and crew, and the potential for an overweight landing.

Final rule

97-16-07 SAAB AIRCRAFT AB: Amendment 39-10099. Docket 96-NM-167-AD.
Applicability: Model SAAB 2000 series airplanes having serial numbers 005 through 029 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 otherwise 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 prevent false fire warning inputs of the engines and auxiliary power unit (APU), which could result in unnecessary diversion of the airplane, resultant increased risks to the airplane, passengers, and crew, and the potential for an overweight landing; accomplish the following:

(a) Within 4 months after the effective date of this AD, replace the existing fire (engine/APU), tailpipe, and bleed-air overheat detector control units with new, improved control units, in accordance with Saab Service Bulletin 2000-26-002, dated May 9, 1995, including Attachments 1 and 2.

(b) As of the effective date of this AD, no person shall install a fire, tailpipe, or bleed-air detector control unit having part number 25000020-21, 25000021-31, or 25000020-11 on any airplane.

(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, Standardization Branch, ANM-113,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, Standardization Branch, ANM-113.

NOTE 2: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Standardization Branch, ANM-113.

(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.

(e) The replacement shall be done in accordance with Saab Service Bulletin 2000-26-002, dated May 9, 1995, including Attachments 1 and 2, which includes the following list of effective pages:

Page Number
Revision Level
Shown on Page
Date
Shown on Page
1-6
Original
May 9, 1995

Attachment 1

1-3
Original
Not Dated

Attachment 2

1-3
Original
Not Dated

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, Link ping, 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.

(f) This amendment becomes effective on September 24, 1997.

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 2000 series airplanes was published in the Federal Register on May 1, 1997 (62 FR 23695). That action proposed to require replacement of the existing fire, tailpipe, and bleed leak detector control units with new, improved units.

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.

Revised Service Bulletin Citation
The final rule has been revised to clarify that Saab Service Bulletin 2000-26-002, which was cited in the proposal as the appropriate source of service information, includes Attachments 1 and 2. These attachments specify procedures from the Aircraft Maintenance Manual for removal and installation of the bleed-airoverheat detection system control unit.

Conclusion
After careful review of the available data, the FAA has determined that air safety and the public interest require the adoption of the rule with the change previously described. The FAA has determined that this change will neither increase the economic burden on any operator nor increase the scope of the AD.

Cost Impact
The FAA estimates that 2 Saab Model SAAB 2000 series airplanes of U.S. registry will be affected by this AD, that it will take approximately 3 work hours per airplane to accomplish the required actions, and that the average labor rate is $60 per work hour. Required parts will be provided by the manufacturer at no cost to the operators. Based on these figures, the cost impact of the AD on U.S. operators is estimated to be $360, or $180 per airplane.

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: