AD 96-03-08

This amendment adopts a new airworthiness directive (AD), applicable to certain Saab Model SAAB SF340A and SAAB 340B series airplanes, that requires repetitive operational tests of the valve limit switch of the propeller brake. This amendment also provides for an optional terminating action for the repetitive tests. This amendment is prompted by a report that when the propeller brake was not properly engaged the crew did not receive a "PROP BRAKE" warning due to a faulty valve limit switch. The actions specified by this AD are intended to prevent a valve limit switch from failing to send input to the warning system; absence of a "PROP BRAKE" warning could result in the crew being unaware that the propeller brake is not properly engaged and the propeller may turn without warning.

Final rule

96-03-08 SAAB AIRCRAFT AB: Amendment 39-9505. Docket 95-NM-79-AD.
Applicability: Model SAAB SF340A series airplanes, having serial numbers 004 through 159 inclusive; and Model SAAB 340B series airplanes, having serial numbers 160 through 369 inclusive; on which the propeller brake system is connected; 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 use the authority provided in paragraph (d) of this AD to request approval from the FAA. This approval may address either no action, if the current configuration eliminates the unsafe condition; or different actions necessary to address the unsafe condition described in this AD. Such arequest should include an assessment of the effect of the changed configuration on the unsafe condition addressed by this AD. In no case does the presence of any modification, alteration, or repair remove any airplane from the applicability of this AD.

Compliance: Required as indicated, unless accomplished previously.

To prevent a valve limit switch from failing to send input to the "PROP BRAKE" warning system, which could result in the crew being unaware that the propeller brake is not properly engaged and the propeller may turn without warning, accomplish the following:

(a) Within 100 flight hours after the effective date of this AD, perform an operational test of the valve limit switch of the propeller brake in accordance with Saab Service Bulletin SAAB 340-61-032, Revision 1, dated June 30, 1995. Repeat the test thereafter at intervals not to exceed 100 flight hours.

(b) Replacement of a propeller brake control unit having part number (P/N) HP1410100-3, -5,or -7 with a new propeller brake control unit having P/N HP1410100-10, and performance of an operational test, in accordance with Saab Service Bulletin SAAB 340-61-033, dated March 6, 1995, constitutes terminating action for the repetitive inspections required by paragraph (a) of this AD.

(c) As of the effective date of this AD, no person shall install on any airplane a propeller brake control unit having P/N HP1410100-3; or any unit having P/N HP1410100-5 or -7 unless that unit has been modified in accordance with Saab Service Bulletin SAAB 340-61-033, dated March 6, 1995.

(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, 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.

(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.

(f) The tests shall be done in accordance with Saab Service Bulletin SAAB 340-61-033, dated March 6, 1995. The replacement shall be done in accordance with Saab Service Bulletin SAAB 340-61-032, Revision 1, dated June 30, 1995. 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.

(g) This amendment becomes effective on March 13, 1996.

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 8, 1995 (60 FR 56274). That action proposed to require repetitive operational tests of the valve limit switch of the propeller brake. That action also proposed to provide for the optional replacement of certain propeller brake control units with a new unit, which would constitute terminating action for the repetitive test requirements.

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

The FAA estimates that 23 airplanes of U.S. registry will be affected by this AD, that it will take approximately 1 work hour per airplane to accomplish the required operational tests, at an 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 $1,380, or $60 per airplane, per test cycle.

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.

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 USC 106(g), 40113, 44701.

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