Airworthiness Directives; deHavilland Inc. Model Otter DHC-3 Airplanes

[Federal Register Volume 63, Number 70 (Monday, April 13, 1998)] [Proposed Rules] [Pages 17970-17972] From the Federal Register Online via the Government Publishing Office [www.gpo.gov] [FR Doc No: 98-9583]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 97-CE-120-AD] RIN 2120-AA64

Airworthiness Directives; deHavilland Inc. Model Otter DHC-3 Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes to adopt a new airworthiness directive (AD) that would apply to certain deHavilland Inc. (deHavilland) Model Otter DHC-3 airplanes modified by supplemental type certificate (STC) No. SA3777NM. The proposed action would require modifying the airplane's electrical system. The actions specified by the proposed AD are intended to prevent electrical system failure, which, if not corrected, could result in the loss of the engine instruments or a possible electrical fire in the airplane's cockpit.

DATES: Comments must be received on or before May 13, 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-120-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 A.M. Luton, 3025 Eldridge Avenue, Bellingham, Washington 98225; telephone: (360) 671-7817, facsimile: (360) 671-7820. This information also may be examined at the Rules Docket at the address above.

FOR FURTHER INFORMATION CONTACT: Mr. Mike Pasion, Aerospace Engineer, Seattle Aircraft Certification Office, FAA, 1601 Lind Avenue, SW, Renton, Washington 98055-4056; telephone: (425) 227-2594; 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

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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 No. 97-CE-120-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-120-AD, Room 1558, 601 E. 12th Street, Kansas City, Missouri 64106.

Discussion

Transport Canada, which is the airworthiness authority for Canada, recently notified the FAA that an unsafe condition may exist on certain deHavilland Model Otter DHC-3 airplanes that are modified by A.M. Luton STC No. SA3777NM. Transport Canada reports that that the modification of the electrical system in accordance with STC No. SA3777NM is in non- compliance with part 23 of the Federal Aviation Regulations (14 CFR part 23), Electrical Systems requirements. The deficiencies that exist with the current installations of this STC are: that the voltage regulator for the starter/generator does not have ``over-voltage'' protection, the ammeter does not indicate the actual electrical system loads after the new engine installation, and the electrical distribution bus for the new engine instrumentation and operational loads are improperly protected. These conditions, if not corrected, could result in the loss of the engine instruments or a possible electrical fire in the airplane's cockpit.

Relevant Service Information

A.M. Luton has issued Service Information Letter SA-SIL-98-11-03, ``Electrical Systems'', Revision I/R, undated, which references the A.M. Luton Electrical System Schematic Drawing 20075, Rev. F and D, Sheets 1, 2, and 3, dated August 15, 1997. This drawing includes procedures for replacing the voltage regulator and voltage-ammeter gauge, and modifying the auxiliary bus systems.

The FAA's Determination

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. The FAA has reviewed all available information related to this subject; including the service information referenced above, and determined that AD action is necessary for products of this type design that are certificated for operation in the United States.

Explanation of the Provisions of the Proposed AD

Since an unsafe condition has been identified that is likely to exist or develop in other deHavilland Model Otter DHC-3 airplanes of the same type design registered in the United States that are modified by STC No. SA3777NM, the proposed AD would require modifying the airplane's electrical system. Accomplishment of the proposed installation would be in accordance with A.M. Luton Service Information Letter SA-SIL-98-11-03, ``Electrical Systems'', Revision I/R, undated, which references the A.M. Luton Electrical System Schematic Drawing 20075, Rev. D and F, Sheets 1, 2, and 3, dated August 15, 1997.

Cost Impact

The FAA estimates that 17 airplanes in the U.S. registry would be affected by the proposed AD, that it would take approximately 20 workhours per airplane to accomplish the proposed action, and that the average labor rate is approximately $60 an hour. Parts cost approximately $2,000 per airplane. Based on these figures, the total cost impact of the proposed AD on U.S. operators is estimated to be $54,400 or $3,200 per airplane.

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 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 a new airworthiness directive (AD) to read as follows:

Dehavilland, Inc.: Docket No. 97-CE-120-AD.

Applicability: Model Otter DHC-3 airplanes (all serial numbers), certificated in any category, that are modified by A.M. Luton Supplemental Type Certificate (STC) No. SA3777NM.

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 (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 within the next 100 hours time-in-service (TIS) after the effective date of this AD, unless already accomplished. To prevent electrical system failure, which, if not corrected, could result in the loss of the engine instruments or a possible electrical fire in the airplane's cockpit, accomplish the following: (a) Replace the voltage regulator and the voltage-ammeter gauge, and modify the auxiliary bus systems in accordance with A.M. Luton Service Information Letter No. SA-SIL-98-11-03, ``Electrical Systems'', Revision I/R, undated, which specifies following the procedures found in A.M. Luton Electrical System Schematic, Drawing

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20075, Rev. D and F, Sheets 1, 2, and 3, dated August 15, 1997. (b) 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. (c) 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, FAA, 1601 Lind Avenue, SW, Renton, Washington 98055-4056. The request shall be forwarded through an appropriate FAA Maintenance Inspector, who may add comments and then send it to the Manager, Seattle Aircraft Certification Office.

Note 2: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from Seattle Aircraft Certification Office.

(d) Questions or technical information related to A.M. Luton Service Information Letter SA-SIL-98-11-03, Electrical Systems, Revision I/R, undated, and A.M. Luton Electrical System Schematic, Drawing 20075, Rev. D and F, Sheets 1, 2, and 3, dated August 15, 1997, should be directed to A.M. Luton, 3025 Eldridge Ave., Bellingham, WA 98226; telephone: (360) 671-7817, facsimile: (360) 671-7820. This service information may be examined at the FAA, Central Region, Office of the Regional Counsel, Room 1558, 601 E. 12th Street, Kansas City, Missouri 64106.

Issued in Kansas City, Missouri, on April 3, 1998. Michael Gallagher, Manager, Small Airplane Directorate, Aircraft Certification Service. [FR Doc. 98-9583 Filed 4-10-98; 8:45 am] BILLING CODE 4910-13-P