AD 99-09-19

This amendment adopts a new airworthiness directive (AD) that is applicable to all Aerospatiale Model ATR42 and ATR72 series airplanes. This action requires revising the Airplane Flight Manual to provide the flightcrew with modified procedures and limitations for operating in severe icing conditions. This amendment is prompted by issuance of mandatory continuing airworthiness information by a foreign civil airworthiness authority. The actions specified in this AD are intended to prevent the airplane from stalling due to prolonged exposure to severe icing conditions, which could result in reduced performance and controllability of the airplane.

Final rule; request for comments

99-09-19 AEROSPATIALE: Amendment 39-11152. Docket 99-NM-50-AD.

Applicability: All Model ATR42 and ATR72 series airplanes, certificated in any category.

Compliance: Required as indicated, unless accomplished previously.

To prevent the airplane from stalling due to prolonged exposure to severe icing conditions, which could result in reduced performance and controllability of the airplane, accomplish the following:

(a) For Model ATR42-200, -300, and -320 series airplanes: Within 10 days after the effective date of this AD, revise the Limitations section of the FAA-approved Airplane Flight Manual (AFM) by inserting a copy of Chapter 2.06.01, page 2, of ATR 42 AFM Temporary Revision (TR), dated February 1999; and revise the Emergency Procedures section of the AFM by inserting a copy of Chapter 4.05.05, pages 5 and 6, of the TR.

(b) For Model ATR42-500 series airplanes: Within 10 days after the effective date of this AD, revise the Limitations section of theFAA-approved Airplane Flight Manual (AFM) by inserting into the AFM a copy of Chapter 2.06.01, page 2, of ATR AFM Temporary Revision, dated February 1999; and revise the Emergency Procedures section of the AFM by inserting a copy of Chapter 4.05.05, pages 5 and 6, of the TR.

(c) For Model ATR72 series airplanes: Within 10 days after the effective date of this AD, revise the Limitations section of the FAA-approved Airplane Flight Manual (AFM) by inserting into the AFM a copy of Chapter 2.06.01, page 2, of ATR 72 AFM Temporary Revision, dated February 1999; and revise the Emergency Procedures section of the AFM by inserting a copy of Chapter 4.05.05, pages 5 and 6, of the TR.

(d) For Model ATR72-212A series airplanes: Within 10 days after the effective date of this AD, revise the Limitations section of the FAA-approved Airplane Flight Manual (AFM) by inserting into the AFM a copy of Chapter 2.06.01, page 2, of ATR 72 A AFM Temporary Revision, dated February 1999; and revise the Emergency Procedures section of the AFM by inserting a copy of Chapter 4.05.05, pages 5 and 6, of the TR.

NOTE 1: The AFM revisions required by paragraphs (a), (b), (c), and (d) of this AD may be accomplished by inserting a copy of the TR's into the applicable AFM. When these TR's have been incorporated into the general revisions of the AFM, the general revisions may be inserted into the AFM, provided that the information contained in the general revisions is identical to that specified in the TR's. Alternative Methods of Compliance

(e) 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 Operations 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

(f) 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

(g) The AFM revisions shall be done in accordance with the following, as applicable:

ATR 42 Airplane Flight Manual Temporary Revision, dated February 1999, Chapter 2.06.01, page 2
ATR 42 Airplane Flight Manual Temporary Revision, dated February 1999, Chapter 4.05.05, pages 5 and 6
ATR Airplane Flight Manual Temporary Revision, dated February 1999, Chapter 2.06.01, page 2
ATR Airplane Flight Manual Temporary Revision, dated February 1999, Chapter 4.05.05, pages 5 and 6
ATR 72 Airplane Flight Manual Temporary Revision, dated February 1999, Chapter 2.06.01, page 2
ATR 72 Airplane Flight Manual Temporary Revision, dated February 1999, Chapter 4.05.05, pages 5 and 6
ATR 72 A Airplane Flight Manual Temporary Revision, dated February 1999, Chapter 2.06.01, page 2
ATR 72 A Airplane Flight Manual Temporary Revision, dated February 1999, Chapter 4.05.05, pages 5 and 6

(Note: The AFM temporary revisions for Chapter 4.05.05 contain only pages 5 and 6 of the Emergency Procedures Section; no other page of that section has been revised. The AFM temporary revisions for Chapter 2.06.01 contain only page 2 of the Limitations Section; no other page of that section has been revised that pertains to this AD.)

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 Aerospatiale, 316 Route de Bayonne, 31060 Toulouse, Cedex 03, France. 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 French airworthiness directives 1999-014-076(B) and 1999-015-040(B), both dated January 13, 1999.

(h) This amendment becomes effective on May 19, 1999.

The Direction G n rale de l'Aviation Civile (DGAC), which is the airworthiness authority for France, notified the FAA that an unsafe condition may exist on all Aerospatiale Model ATR42 and ATR72 series airplanes. The DGAC advises that during an in-flight incident an ATR airplane stalled in severe icing conditions and lost 4,000 feet of altitude before recovery.

Experience has shown that the currently recommended airspeeds in icing conditions provide adequate stall margins when flying in normal icing conditions, but provide little margin to stall speeds when the airplane has accreted a large amount of ice following prolonged flight in severe icing conditions. The current procedures in the FAA-approved Airplane Flight Manual (AFM) require immediate exit when severe icing conditions are detected. However, even if the exit maneuver is initiated immediately, a few minutes may elapse before the airplane is out of the severe icing conditions. Late detection of severe icing conditions and nonapplication or late application of appropriate AFM procedures can contribute to prolonged exposure to severe icing conditions that may be outside the certification envelope (as required by Appendix C of part 25 of the Federal Aviation Regulations). Such prolonged exposure can cause the airplane to stall, resulting in reduced performance and controllability of the airplane.

Explanation of Relevant Service Information
Aerospatiale has issued AFM Temporary Revisions (TR) for the affected airplanes (Model ATR42-200, -300, and -320; Model ATR72-212A, Model ATR72-100, -200, and -210; and Model ATR42-500) to provide the flightcrew with modified limitations and procedures for operating in severe icing conditions. The TR for Chapter 2.06.01, dated February 1999, revises the AFM to aid in the early detection of severe icing by adding criteria related to unusual performance degradation. The TR for Chapter 4.05.05, dated February 1999, revises the AFM toincrease the speed during the exit maneuver in order to provide improved margin to stall.

The Direction G n rale de l'Aviation Civile (DGAC), which is the airworthiness authority for France, issued French airworthiness directives 1999-014-076(B) and 1999-015-040(B), both dated January 13, 1999, in order to ensure the continued airworthiness of these airplanes in France. (Errata to those French airworthiness directives were issued January 27, 1999, to correct typographical errors that referred to compliance times.)

U.S. Type Certification of the Airplane
These airplane models are manufactured in France and are type certificated for operation in the United States under the provisions of section 21.29 of the Federal Aviation Regulations (14 CFR 21.29) and the applicable bilateral airworthiness agreement. Pursuant to this bilateral airworthiness agreement, the DGAC has kept the FAA informed of the situation described above. The FAA has examined the findings of the DGAC, reviewedall available information, and determined that AD action is necessary for products of this type design that are certificated for operation in the United States.

FAA s Determinations
The FAA has examined the circumstances and reviewed all available information related to the incident described previously. The FAA finds that the Limitations and Emergency Procedures sections of the FAA-approved AFM s for ATR42 and ATR72 series airplanes must be revised to prevent prolonged exposure to severe icing conditions that may be outside the certification envelope, which could result in reduced performance and controllability of the airplane. In light of this, the FAA considers that revision of the AFM s is necessary to ensure early detection of severe icing conditions and to provide improved margin to a stall.

Explanation of Requirements of Rule
Since an unsafe condition has been identified that is likely to exist or develop on other airplanes of the same type design registered in the United States, this AD is being issued to prevent prolonged exposure to severe icing conditions that may be outside the certification envelope (as defined previously), which could result in reduced performance and controllability of the airplane. This AD requires revising the Limitations and Emergency Procedures sections of the AFM s to provide the flightcrew with modified procedures and limitations for operating in severe icing conditions.

Differences Between Rule and Foreign AD
Although the compliance time for the French airworthiness directives is 3 days, this rule requires accomplishment within 10 days. In determining an appropriate compliance interval for timely accomplishment of the AFM revisions for this AD, the FAA considered the safety implications and operators maintenance schedules. In consideration of these factors, the FAA has determined that 10 days represents an appropriate interval in which the AFM revisions can be accomplished in a timely manner within the fleetand still maintain an adequate level of safety.

Determination of Rule's Effective Date
Since a situation exists that requires the immediate adoption of this regulation, it is found that notice and opportunity for prior public comment hereon are impracticable, and that good cause exists for making this amendment effective in less than 30 days.

Comments Invited
Although this action is in the form of a final rule that involves requirements affecting flight safety and, thus, was not preceded by notice and an opportunity for public comment, comments are invited on this rule. Interested persons are invited to comment on this rule by submitting such written data, views, or arguments as they may desire. Communications shall identify the Rules Docket number and be submitted in triplicate to the address specified under the caption "ADDRESSES." All communications received on or before the closing date for comments will be considered, and this rule may be amended in light of the comments received. Factual information that supports the commenter's ideas and suggestions is extremely helpful in evaluating the effectiveness of the AD action and determining whether additional rulemaking action would be needed.

Comments are specifically invited on the overall regulatory, economic, environmental, and energy aspects of the rule that might suggest a need to modify the rule. All comments submitted will be available, both before and after the closing date for comments, in the Rules Docket for examination by interested persons. A report that summarizes each FAA-public contact concerned with the substance of this AD will be filed in the Rules Docket.

Commenters wishing the FAA to acknowledge receipt of their comments submitted in response to this rule must submit a self-addressed, stamped postcard on which the following statement is made: "Comments to Docket Number 99-NM-50-AD." The postcard will be date stamped and returned to the commenter.

Regulatory Impact
Theregulations 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.

The FAA has determined that this regulation is an emergency regulation that must be issued immediately to correct an unsafe condition in aircraft, and that it is not a "significant regulatory action" under Executive Order 12866. It has been determined further that this action involves an emergency regulation under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979). If it is determined that this emergency regulation otherwise would be significant under DOT Regulatory Policies and Procedures, a final regulatory evaluation will beprepared and placed in the Rules Docket. A copy of it, if filed, 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: