Airworthiness directives: Bombardier,

[Federal Register: June 22, 1999 (Volume 64, Number 119)]

[Proposed Rules]

[Page 33232-33234]

From the Federal Register Online via GPO Access [wais.access.gpo.gov]

[DOCID:fr22jn99-29]

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 99-NM-55-AD]

RIN 2120-AA64

Airworthiness Directives; Bombardier Model DHC-8 Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

SUMMARY: This document proposes the adoption of a new airworthiness directive (AD) that is applicable to certain Bombardier Model DHC-8 series airplanes. This proposal would require a one-time inspection of the spring assemblies located in the rudder control feel unit to verify that dual rate configuration springs are installed; and revising the Airplane Flight Manual to prohibit airplane operation from runways less than 75 feet wide, if necessary. This proposal also would require eventual replacement of any single rate configuration springs with dual rate configuration springs, which would terminate the requirement for the AFM revision. This proposal is prompted by issuance of mandatory continuing airworthiness information by a foreign civil airworthiness authority. The actions specified by the proposed AD are intended to prevent an asymmetric rudder force condition, which could result in reduced controllability of the airplane and consequent potential for center line deviation.

DATES: Comments must be received by July 22, 1999.

ADDRESSES: Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 99-NM-55-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056. Comments may be inspected at this location between 9:00 a.m. and 3:00 p.m., Monday through Friday, except Federal holidays.

The service information referenced in the proposed rule may be obtained from Bombardier, Inc., Bombardier Regional Aircraft Division, Garratt Boulevard, Downsview, Ontario M3K 1Y5, Canada. This information may be examined at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the FAA, Engine and Propeller Directorate, New York Aircraft Certification Office, 10 Fifth Street, Third Floor, Valley Stream, New York.

FOR FURTHER INFORMATION CONTACT: James E. Delisio, Aerospace Engineer, Airframe and Propulsion Branch, ANE-171, FAA, Engine and Propeller Directorate, New York Aircraft Certification Office, 10 Fifth Street, Third Floor, Valley Stream, New York 11581; telephone (516) 256-7521; fax (516) 568-2716.

SUPPLEMENTARY INFORMATION:

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 filedin 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 99-NM-55-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-114, Attention: Rules Docket No. 99-NM-55-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.

[[Page 33233]]

Discussion

Transport Canada Aviation (TCA), which is the airworthiness authority for Canada, notified the FAA that an unsafe condition may exist on certain Bombardier Model DHC-8 series airplanes. TCA indicated that during production of these airplanes, single rate configuration springs were inadvertently installed in the rudder control feel units. The installation of single rate configuration springs in lieu of the correct dual rate configuration springs could require heavier than normal rudder pedal forces, causing the pilot to exert extreme pressure on the rudder pedal during takeoff or landing resulting in an asymmetric rudder force condition. Such conditions could result in reduced controllability of the airplane and consequent potential for center line deviation.

Explanation of Relevant Service Information

The manufacturer has issued Bombardier Alert Service Bulletin S.B. A8-27-82, dated July 10, 1998, which describes procedures for a one- time inspection of the spring assemblies located in the rudder control feel unit to verify that dual rate configuration springs are installed, and replacement of any single rate configuration springs with dual rate configuration springs. Accomplishment of the actions specified in the alert service bulletin is intended to adequately address the identified unsafe condition. TCA classified this alert service bulletin as mandatory and issued Canadian airworthiness directives CF-98-39, dated October 23, 1998, and CF-98-39R1, dated December 31, 1998; in order to assure the continued airworthiness of these airplanes in Canada.

FAA's Conclusions

This airplane model is manufactured in Canada and is 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, TCA has kept the FAA informed of the situation described above. The FAA has examined the findings of TCA, 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 accomplishment of the actions specified in the alert service bulletin described previously.

Differences Between Proposed Rule and Foreign AD

The proposed AD would differ from the parallel Canadian airworthiness directive in that it would require a revision to the operator's Airplane Flight Manual (AFM). The AFM revision would specify that operation from runways less than 75 feet wide is prohibited for airplanes operating with single rate configuration springs. Operators currently follow the procedures specified in deHavilland Supplement No. 54, ``Operation from Narrow Runways,'' which has not been FAA-approved for U.S.-registered airplanes. This supplement allows a minimum runway width of 59 feet for airplanes operating with single rate configuration springs. The FAA has examined the charts included in the supplement, crew training issues, and feedback from U.S. operators, and has determined that accomplishment of the AFM revision described previously is necessary in order to address the unsafe condition. This is based on the FAA's determination that this would not impose an unnecessary burden on U.S. operators, and would allow affected airplanes to continue to operate without compromising safety.

Cost Impact

The FAA estimates that 235 airplanes of U.S. registry would be affected by this proposed AD.

It would take approximately 1 work hour per airplane to accomplish the proposed inspection, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of the inspection proposed by this AD on U.S. operators is estimated to be $14,100, or $60 per airplane.

It would take approximately 10 work hours per airplane to accomplish the proposed replacement, at an average labor rate of $60 per work hour. Required parts would be provided by the manufacturer at no cost to the operators. Based on these figures, the cost impact of the replacement proposed by this AD on U.S. operators is estimated to be $141,000, or $600 per airplane.

If accomplished, it would take approximately 1 work hour per airplane to accomplish the AFM revision, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of the AFM revision on U.S. operators, if accomplished, is estimated to be $14,100, or $60 per airplane.

The cost impact figures discussed above are 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:

   Bombardier, Inc. (Formerly de Havilland, Inc.): Docket 99-NM-55-AD.

   Applicability: Model DHC-8 series airplanes, as listed in Bombardier Alert

   [[Page 33234]]

   Service Bulletin S.B. A8-27-82, dated July 10, 1998; 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 (d) 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 an asymmetric rudder force condition, which could result in reduced controllability of the airplane and consequent potential for center line deviation, accomplish the following:

   General Visual Inspection

   (a) Within 100 flight hours or 14 days after the effective date of this AD, whichever occurs later: Perform a one-time visual inspection of the spring assemblies located in the rudder control feel unit to verify that dual rate configuration springs are installed, in accordance with Bombardier Alert Service Bulletin S.B. A8-27-82, dated July 10, 1998.

   (1) If dual rate configuration springs are installed, no further action is required by this AD.

   AFM Revision

   (2) If any single rate configuration springs are installed, prior to further flight: Revise the Limitations Section of the de Havilland Dash 8 Airplane Flight Manual (AFM) to include the following statement. This action may be accomplished by inserting a copy of this AD into the AFM. ``OPERATION FROM RUNWAYS LESS THAN 75 FEET WIDE IS PROHIBITED.''

   Terminating Action

   (b) At the next scheduled maintenance visit, but no later than 36 months after the effective date of this AD: Replace any single rate configuration springs located in the rudder control feel unit with dual rate configuration springs, in accordance with Part C through Part H inclusive, of the Accomplishment Instructions of Bombardier Alert Service Bulletin S.B. A8-27-82, dated July 10, 1998. Such replacement constitutes terminating action for the requirements of this AD. After the replacement has been accomplished, the AFM limitation required by paragraph (a)(2) of this AD may be removed from the AFM.

   Spares Paragraph

   (c) As of the effective date of this AD, no person shall install any spring assembly having part number 82760050-003 on any airplane.

   Alternative Methods of Compliance

   (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, New York Aircraft Certification Office (ACO), FAA, Engine and Propeller Directorate. Operators shall submit their requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, New York ACO.

   Note 2: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the New York ACO.

   Special Flight Permits

   (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.

   Note 3: The subject of this AD is addressed in Canadian airworthiness directives CF-98-39, dated October 23, 1998, and CF- 98-39R1, dated December 31, 1998.

   Issued in Renton, Washington, on June 15, 1999. Dorenda D. Baker, Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.

   [FR Doc. 99-15773Filed6-21-99; 8:45 am]

   BILLING CODE 4910-13-P