AD 97-28874

[Federal Register Volume 62, Number 211 (Friday, October 31, 1997)] [Proposed Rules] [Pages 58925-58927] From the Federal Register Online via the Government Publishing Office [www.gpo.gov] [FR Doc No: 97-28874]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 97-CE-69-AD] RIN 2120-AA64

Airworthiness Directives; Twin Commander Aircraft Corporation 500, 520, 560, 680, 681, 685, 690, 695, and 720 Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes to supersede Airworthiness Directive (AD) 94-04-17, which currently requires the following on Twin Commander Aircraft Corporation (Twin Commander) 500, 520, 560, 680, 681, 685, 690, 695, and 720 series airplanes: inspecting (one-time) the flap system for cables with broken wires or pulleys with worn cable clips, replacing any damaged parts, and replacing the master pulley and cable with new parts of improved design. The proposed AD would require inspecting all flap system cable grooves for the correct width, inspecting all flap system pulleys for rubbing on the support brackets, inspecting all flap pulley cable assemblies for frayed wires, and reworking or replacing any parts with discrepancies. The proposed AD results from several reports of worn and frayed flap system cables attributed to flap pulley grooves that are too narrow. The actions specified by the proposed AD are intended to prevent failure of a flap system cable caused by fatigue, which could result in loss of control of the airplane.

DATES: Comments must be received on or before January 6, 1998.

ADDRESSES: Submit comments in triplicate to the Federal Aviation Administration (FAA), Central Region, Office of the Regional Counsel, Attention: Rules Docket No. 97-CE-69-AD, Room 1558, 601 E. 12th Street, Kansas City, Missouri 64106. Comments may be inspected at this location between 8 a.m. and 4 p.m., Monday through Friday, holidays excepted. Service information that applies to the proposed AD may be obtained from the Twin Commander Aircraft Corporation, 19003 59th Drive, NE, Arlington, Washington 98223-7832; telephone (360) 435-9797. This information also may be examined at the Rules Docket at the address above.

FOR FURTHER INFORMATION CONTACT: Mr. Jeffrey Morfitt, Aerospace Engineer, FAA, Northwest Mountain Region, 1601 Lind Avenue S.W., Renton, Washington 98055-4056; telephone (425) 227-2595; facsimile (425) 227-1181.

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 should 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 that summarizes 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

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statement is made: ``Comments to Docket No. 97-CE-69-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, Central Region, Office of the Regional Counsel, Attention: Rules Docket No. 97-CE-69-AD, Room 1558, 601 E. 12th Street, Kansas City, Missouri 64106.

Discussion

AD 94-04-17, Amendment 39-8837 (59 FR 8845, February 24, 1995), currently requires the following on Twin Commander Aircraft Corporation (Twin Commander) 500, 520, 560, 680, 681, 685, 690, 695, and 720 series airplanes: inspecting (one-time) the flap system for certain cables with broken wires or pulleys with worn cable clips, replacing any damaged parts, and replacing the master pulley and cable with new parts of improved design. Accomplishment of the actions specified in AD 94- 04-17 is in accordance with Twin Commander Service Bulletin 210, dated February 1, 1991.

Actions Since Issuance of Previous Rule

Since issuing AD 94-04-17, the FAA has received two reports of flap pulley assemblies with cable grooves that were too narrow. The two pulleys were the right inboard (slave pulley) and the right outboard assemblies. In addition, the FAA has received reports of discrepancies on flap system cables and pulleys. A number of pulleys were incorrectly manufactured with cable groove radii that are too narrow. These incorrect pulleys were produced from several manufacturers because the type certificate of the affected airplanes has been sold and transferred several times. These incorrectly manufactured parts include all six flap system pulleys. The incidents referenced in the reports affect airplanes covered by AD 94- 04-17 and airplanes not covered by AD 94-04-17. Previous compliance with AD 94-04-17 does not address the unsafe condition proposed in this NPRM because incorrectly manufactured pulleys may have been installed on the affected airplanes at any time before and after the issuance of AD 94-04-17.

Relevant Service Information

Twin Commander has issued Service Bulletin No. 226, dated April 14, 1997 (Revision No. 1 Release Date: July 15, 1997), which applies to all models of Twin Commander 500, 520, 560, 680, 681, 685, 690, 695, and 720 series airplanes. This service bulletin specifies procedures for the following:

-Inspecting all flap system pulleys and cable assemblies; -Replacing or reworking any pulley assemblies with discrepancies found during the inspection; -Replacing cables, support brackets, or clips with discrepancies found during the inspection; and -Identifying pulleys where the actions specified in the service bulletin have been accomplished

Revision No. 1 Release Date: July 15, 1997, of Twin Commander Mandatory Service Bulletin No. 226, specifies changes in the workhours necessary to accomplish this action and makes reference to a gauge that is available from the manufacturer for use in accomplishing the inspection.

The FAA's Determination

After examining the circumstances and reviewing all available information related to the incidents described above, the FAA has determined that AD action should be taken to prevent failure of a flap system cable caused by fatigue, which could result in loss of control of the airplane.

Explanation of the Provisions of the Proposed AD

Since an unsafe condition has been identified that is likely to exist or develop in other 500, 520, 560, 680, 681, 685, 690, 695, and 720 series airplanes of the same type design, the FAA is proposing an AD to supersede AD 94-04-17. The proposed AD would require inspecting all flap system cable grooves for the correct width, inspecting all flap system pulleys for rubbing on the support brackets, inspecting all flap pulley cable assemblies for frayed wires, and reworking or replacing any parts with discrepancies. Accomplishment of the proposed actions would be in accordance with Twin Commander Mandatory Service Bulletin No. 226, dated April 14, 1997, (Revision No. 1 Release Date: July 15, 1997).

Cost Impact

The FAA estimates that 1,230 airplanes in the U.S. registry would be affected by the proposed AD, that it would take approximately 22 workhours per airplane to accomplish the proposed inspection, and that the average labor rate is approximately $60 an hour. Based on these figures, the total cost impact of the proposed AD on U.S. operators is estimated to be $1,623,600, or $1,320 per airplane. These figures only take into account the inspection costs of the proposed AD and do not reflect the costs of any repairs or replacements that may be required if discrepancies are found during the proposed inspection. The FAA has no way of determining how many parts would need to be repaired or replaced after accomplishing the inspection proposed in this action.

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 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) 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 has been placed 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 14 CFR part 39 of the Federal Aviation Regulations 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 removing Airworthiness Directive (AD) 94-04-17, Amendment 39-8837 (59 FR

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8845, February 24, 1995), and by adding a new AD to read as follows:

Twin Commander Aircraft Corporation: Docket No. 97-CE-69-AD; Supersedes AD 94-04-17, Amendment 39-8837.

Applicability: The following airplane models (all serial numbers), certificated in any category: 500, 500-A, 500-B, 500-S, 500-U, 520, 560, 560-A, 560-E, 560-F, 680, 680-E, 680-F, 680FL, 680FL(P), 680FP, 680T, 680V, 680W, 681, 685, 690, 690A, 690B, 690C, 690D, 695, 695A, 695B, 720.

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 (e) 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 in the body of this AD, unless already accomplished. To prevent failure of a flap system cable caused by fatigue, which could result in loss of control of the airplane, accomplish the following: (a) Within the next 100 hours time-in-service (TIS) after the effective date of this AD, accomplish the following in accordance with the accomplishment instructions section of Twin Commander Aircraft Corporation (Twin Commander) Mandatory Service Bulletin No. 226, dated April 14, 1997 (Revision No. 1 Release Date: July 15, 1997): (1) Inspect all flap system cable grooves for the correct width; (2) Inspect all flap system pulleys for rubbing on the support brackets; (3) Inspect all flap pulley cable assemblies for frayed wires; and (4) Mark pulleys that have been inspected and have the correct groove radius with two parallel lines as specified in the service bulletin.

Note 2: Revision No. 1 Release Date: July 15, 1997, of Twin Commander Mandatory Service Bulletin No. 226, specifies changes in the workhours necessary to accomplish this action and makes reference to a gauge that is available from the manufacturer for use in accomplishing the inspection.

(b) If any of the above discrepancies are found, prior to further flight, rework or replace the affected part in accordance with Twin Commander Mandatory Service Bulletin No. 226, dated April 14, 1997 (Revision No. 1 Release Date: July 15, 1997). (c) As of the effective date of this AD, no person may install a pulley that does not have the criteria presented in either paragraph (c)(1), (c)(2), or (c)(3) of this AD: (1) A pulley that has been inspected, found acceptable, and marked with two parallel lines in accordance with paragraph (a), including all subparagraphs, of this AD; (2) A pulley that has been reworked in accordance with an FAA- approved procedure and is marked ``SB 226''; or (3) A new pulley that is marked ``SB 226-NEW''. (d) Special flight permits may be issued in accordance with 14 CFR 21.197 and 21.199 to operate the airplane to a location where the requirements of this AD can be accomplished. (e) An alternative method of compliance or adjustment of the compliance time that provides an equivalent level of safety may be approved by the Manager, Seattle Aircraft Certification Office (ACO), Northwest Mountain Region, FAA, 1601 Lind Avenue S.W., Renton, Washington 98055-4056. (1) The request shall be forwarded through an appropriate FAA Maintenance Inspector, who may add comments and then send it to the Manager, Seattle ACO. (2) Alternative methods of compliance approved in accordance with AD 94-04-17 (superseded by this AD) are not considered approved as alternative methods of compliance for this AD.

Note 3: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Seattle ACO.

(f) All persons affected by this directive may obtain copies of the document referred to herein upon request to the Twin Commander Aircraft Corporation, 19003 59th Drive, NE., Arlington, Washington 98223-7832; or may examine this document at the FAA, Central Region, Office of the Regional Counsel, Room 1558, 601 E. 12th Street, Kansas City, Missouri 64106. (g) This amendment supersedes AD 94-04-17, Amendment 39-8837.

Issued in Kansas City, Missouri, on October 24, 1997. Michael Gallagher, Manager, Small Airplane Directorate, Aircraft Certification Service. [FR Doc. 97-28874 Filed 10-30-97; 8:45 am] BILLING CODE 4910-13-U