[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

[[Page 17971]]

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

[[Page 17972]]

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