AD 98-06-34 ACTIVE

This amendment adopts a new airworthiness directive (AD), applicable to all Aerospatiale Model ATR-42 and ATR-72 series airplanes, that requires revising the Airplane Flight Manual (AFM) to modify the limitation that prohibits positioning the power levers below the flight idle stop during flight, and to provide a statement of the consequences of positioning the power levers below the flight idle stop during flight. This amendment is prompted by incidents and accidents involving airplanes equipped with turboprop engines in which the ground propeller beta range was used improperly during flight. The actions specified by this AD are intended to prevent loss of airplane controllability, or engine overspeed and consequent loss of engine power caused by the power levers being positioned below the flight idle stop while the airplane is in flight.

Final rule.

98-06-34 AEROSPATIALE: Amendment 39-10413. Docket 97-NM-228-AD.

Applicability: All Model ATR-42 and ATR-72 series airplanes, 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 (b) 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 loss of airplane controllability, or engine overspeed and consequent loss of engine power caused by the power levers being positioned below the flight idle stop while the airplane is in flight, accomplish the following:

(a) Within 30 days after the effective date of this AD, revise the Limitations Section of the FAA-approved Airplane Flight Manual (AFM) to include the following statements. This action may be accomplished by inserting a copy of this AD into the AFM.

"Limitation under Flight Operation: ATR airplanes are protected against a positioning of power levers below the flight idle stop in flight by an IDLE GATE device. It is reminded that any attempt to override this protection is prohibited. Such positioning may lead to loss of airplane control or may result in an engine overspeed condition and consequent loss of engine power."

(b) 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.

(c) 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.

(d) This amendment becomes effective on May 5, 1998.

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 all Aerospatiale Model ATR-42 and ATR-72 series airplanes was published in the Federal Register on December 9, 1997 (62 FR 64787). That action proposed to require revision of the Limitations Section of the AFM to modify the limitation that prohibits the positioning of the power levers below the flight idle stop while the airplane is in flight, and to add a statement of the consequences of positioning the power levers below the flight idle stop while the airplane is in flight.

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

One commenter, the manufacturer, requests that the proposed rule not be issued specifically against Model ATR airplanes. The commenter states that ATR models already have a "warning" regarding failure of the electro-mechanical gate device. The manufacturer points out that the "warning" contains specific wording that was presented to the FAA during the public meeting held on June 11-12, 1996, in Seattle, Washington. The commenter also states that the proposal appears to indicate that ATR models are particularly affected by the identified unsafe condition. The commenter disagrees, and adds that the in-service experience of these models does not warrant an AD.

The FAA does not concur. The FAA finds that the AFM limitation required by this AD is necessary to prohibit positioning the power levers below the flight idle stop during flight, regardless of the protective features and warnings provided in the design of the affected airplanes. Additionally, although none of the accidents and incidents referenced in the preamble of the proposal involved Model ATR airplanes, the FAA has determined that AD action must be taken against all turbopropeller-powered airplanes (regardless of the design features of the airplane) that are not approved for operation in the beta range during flight. The FAA finds that revising the AFM to prohibit operation below the flight idle stop in flight is necessary in order to correct the identified unsafe condition. The appropriate vehicle for mandating such a requirement is an AD.

This same commenter requests that the wording of the AFM revision that was specified in the proposed rule be revised to reflect the wording of the current AFM revision. The commenter points out that the wording of the proposed AFM change and the wording of the current AFM revision are similar, and that the technical contents are equivalent.

The FAA concurs with the commenter that the wording specified in the proposal is similar to the wording of the current AFM change, and that the technical contents are equivalent. Therefore, the FAA has revised paragraph (a) of the final rule to remove the proposed AFM wording and has inserted the current AFM change.

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 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 144 Aerospatiale Model ATR-42 and ATR-72 series 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 actions, and that the 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 to be $8,640, or $60 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:

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.

Mark Quam, Aerospace Engineer, Standardization Branch, ANM-113, FAA, Transport Airplane Directorate, 1601 Lind Avenue SW., Renton, Washington 98055-4056; telephone (425) 227-2145; fax (425) 227-1149.