Airworthiness Directives; British Aerospace Model BAe 146 and Avro 146-RJ Series Airplanes

Comments Invited

Interested persons are invited to participate in the making of the proposed 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 above. All communications received on or before the closing date for comments, specified above, will be considered before taking action on the proposed rule. The proposals contained in this notice may be changed in light of the comments received. Comments are specifically invited on the overall regulatory, economic, environmental, and energy aspects of the proposed 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 summarizing each FAA-public contact concerned with the substance of this proposal will be filed in the Rules Docket. Commenters wishing the FAA to acknowledge receipt of their comments submitted in response to this notice must submit a self-addressed, stamped postcard on which the following statement is made: ``Comments to Docket Number 96-NM-51-AD.'' The postcard will be date stamped and returned to the commenter.

Availability of NPRMs

Any person may obtain a copy of this NPRM by submitting a request to the FAA, Transport Airplane Directorate, ANM-103, Attention: Rules Docket No. 96-NM-51-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.

Discussion

The Civil Aviation Authority (CAA), which is the airworthiness authority for the United Kingdom, recently notified the FAA that an unsafe condition may exist on all British Aerospace Model BAe 146 and Avro 146-RJ series airplanes. The CAA advises that it has received reports indicating that water and ice have accumulated at the trailing edge of the left and right elevators; this accumulation can cause the elevators to become unbalanced, and to oscillate or flutter. Reduced controllability is a consequence of steady elevator oscillation which could cause uncommanded pitch (rising and falling movements) of the airplane. Reduced structural integrity of the airplane can occur if divergent elevator flutter is coupled with natural vibrations of the airplane.

Explanation of Relevant Service Information

British Aerospace has issued Service Bulletin SB.55-014-01510A, dated December 15, 1995, which describes procedures for modification of the left and right elevators by installing mass balance weights at the leading edge of the horn, forward of the hinge line, to counteract the effect of accumulated water and ice on the trailing edge of the elevator. The manufacturer also has issued British Aerospace Service Bulletin SB.27-150-01510B, dated December 15, 1995, which describes additional procedures for modification of the left and right elevators by replacing the elevator spring with a stiffer spring. With the addition of mass balance weights to the elevators, a stiffer spring holds down the increased weight, and makes it easier for the pilot to conduct full movement and free movement checks of the elevators when the airplane is on the ground. The CAA classified both service bulletins as mandatory and issued British airworthiness directive 002-12-95, dated January 31, 1996, in order to assure the continued airworthiness of these airplanes in the United Kingdom. These airplane models are manufactured in the United Kingdom 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 CAA has

kept the FAA informed of the situation described above. The FAA has examined the findings of the CAA, reviewed all available information, and determined that AD action is necessary for products of this type design that are certificated for operation in the United States.

Explanation of Requirements of Proposed 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, the proposed AD would require modification of the left and right elevators by installation of mass balance weights at the leading edge of the horn, forward of the hinge line; and replacement of the elevator spring with a stiffer spring. The actions would be required to be accomplished in accordance with the service bulletins described previously. On August 15, 1995, the FAA issued AD 95-17-13, amendment 39-9343 (60 FR 44417, August 28, 1995). [A correction of the rule was published in the Federal Register on October 26, 1995 (60 FR 54800).] That AD requires operators of British Aerospace Model BAe 146 and Avro 146-RJ airplanes to modify the left and right elevators to improve water drainage, and thereby help maintain the balance of the elevators. That modification involves, among other actions, drilling new drain holes, applying sealant, and plugging drain holes on certain airplanes. The FAA determined that action to be interim action until further action is identified. Accomplishment of the actions required by this proposed AD would be the next step in eliminating the accumulation of ice and water in the left and right elevators. This action also would be interim action until final action is identified, at which time the FAA may consider further rulemaking.

Difference Between the Proposed Rule and CAA Airworthiness Directive

The proposed AD and the parallel CAA airworthiness directive differ on compliance times: the proposed AD would require the actions to be completed within 12 months after the effective date of the AD; the CAA mandates an 18-month period. In developing a compliance time, the FAA considered the safety implications, parts availability, and normal maintenance schedules for timely accomplishment of the modification and part replacement. After evaluating these factors, the FAA determined that a 12-month compliance time is appropriate.

Cost Impact

The FAA estimates that 52 British Aerospace Model BAe 146 and Avro 146-RJ series airplanes of U.S. registry would be affected by this proposed AD, that it would take approximately 12 work hours per airplane to accomplish the proposed actions, and that the average labor rate is $60 per work hour. Required parts would cost approximately $700 per airplane. Based on these figures, the cost impact of the proposed AD on U.S. operators is estimated to be $73,840, or $1,420 per airplane. The cost impact figure discussed above is based on assumptions that no operator has yet accomplished any of the proposed 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 proposed herein would 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 proposal would not have sufficient federalism implications to warrant the preparation of a Federalism Assessment. For the reasons discussed above, I certify that this proposed regulation (1) is not a ``significant regulatory action'' under Executive Order 12866; (2) is not a ``significant rule'' under the DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and (3) if promulgated, 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 copy of the draft regulatory evaluation prepared for this action is contained in the Rules Docket. A copy of it may be obtained by contacting the Rules Docket at the location provided under the caption ADDRESSES.

List of Subjects in 14 CFR Part 39

Air transportation, Aircraft, Aviation safety, Safety.

The Proposed Amendment

Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration proposes to amend 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 adding the following new airworthiness directive:

British Aerospace Regional Aircraft Limited, Avro International Aerospace Division (Formerly British Aerospace, plc; British Aerospace Commercial Aircraft Limited): Docket 96-NM-51-AD.

Applicability: All Model BAe 146 and Avro 146-RJ 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 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 the left and right elevators from oscillating or fluttering, which could result in either reduced controllability of the airplane, or loss of the airplane's structural integrity, accomplish the following: (a) Within 12 months after the effective date of this AD, accomplish the requirements of paragraphs (a)(1) and (a)(2) of this AD. (1) Modify the left and right elevators by installing mass balance weights at the leading edge of the horn, forward of the elevator hinge line, in accordance with British Aerospace Service Bulletin SB.55-014-01510A, dated December 15, 1995. And (2) Replace the left and right elevator spring with a stiffer spring, in accordance with British Aerospace Service Bulletin SB.27- 150-01510B, dated December 15, 1995. (b) As of 12 months after the effective date of this AD, no person shall install on any airplane an elevator that has not been modified in accordance with paragraph (a) of this AD. (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.

Issued in Renton, Washington, on October 9, 1996. S.R. Miller, Acting Manager, Transport Airplane Directorate, Aircraft Certification Service. [FR Doc. 96-26708 Filed 10-17-96; 8:45 am] BILLING CODE 4910-13-U