[Federal Register Volume 59, Number 65 (Tuesday, April 5, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-8054]


[[Page Unknown]]

[Federal Register: April 5, 1994]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 93-NM-206-AD]

 

Airworthiness Directives; de Havilland Model DHC-8-100 and DHC-8-
300 Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes the adoption of a new airworthiness 
directive (AD) that is applicable to certain de Havilland Model DHC-8-
100 and DHC-8-300 series airplanes. This proposal would require a 
revision to the Airplane Flight Manual (AFM) to advise flight crew 
members that certain cockpit indications may reveal faulty anti-
collision strobe light units, and to provide procedures for subsequent 
flight crew action. This proposal would also require a modification 
that eliminates the need for the AFM revision. This proposal is 
prompted by reports that the function of the proximity switch 
electronics unit (PSEU) may be adversely effected during operation of 
the white anti-collision lights. The actions specified by the proposed 
AD are intended to ensure correct operation of the PSEU and its 
associated systems.

DATES: Comments must be received by May 31, 1994.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 93-NM-206-AD, 1601 Lind Avenue, SW., 
Renton, Washington 98055-4056. Comments may be inspected at this 
location between 9 a.m. and 3 p.m., Monday through Friday, except 
Federal holidays.
    The service information referenced in the proposed rule may be 
obtained from de Havilland, Inc., 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, 181 South Franklin Avenue, room 202, Valley 
Stream, New York.

FOR FURTHER INFORMATION CONTACT: Michele Maurer, Aerospace Engineer, 
Systems and Equipment Branch, ANE-173, New York Aircraft Certification 
Office, FAA, Engine and Propeller Directorate, 181 South Franklin 
Avenue, room 202, Valley Stream, New York 11581; telephone (516) 791-
6427; fax (516) 791-9024.

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 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 93-NM-206-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. 93-NM-206-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    Transport Canada Aviation, which is the airworthiness authority for 
Canada, recently notified the FAA that an unsafe condition may exist on 
certain de Havilland Model DHC-8-100 and DHC-8-300 series airplanes. 
Transport Canada Aviation advises that three field reports indicate 
that the electrical power supplies of the white anti-collision lights 
may develop a fault which produces greater than normal electrical 
emissions. The cause of this fault has been attributed to a capacitor 
failure in some ``Grimes'' strobe light systems. This electromagnetic 
interference can adversely affect the operation of the proximity switch 
electronics unit (PSEU) and its associated systems. The following 
occurrences have resulted:

    1. Flashing of the landing gear green locked down advisory 
lights during cruise;
    2. Fluctuation of the cabin pressurization rate needle during 
cruise;
    3. Retraction and extension of roll and ground spoilers during 
ground operation;
    4. Inoperative nose gear steering subsequent to landing; and
    5. Unavailable normal wheel brakes below 35-40 knots.

    Incorrect operation of the PSEU and its associated systems may 
interfere with or distract the flight crew in carrying out its regular 
duties during flight or on the ground, and thus serve to compromise the 
safe operation of the airplane.
    De Havilland, Inc., has issued Alert Service Bulletin S.B. A8-33-
33, dated May 31, 1993, that describes flight crew and maintenance 
procedures to detect faulty power supply units. The alert service 
bulletin also describes procedures for replacement of any faulty 
``Grimes'' unit with a new or serviceable ``Grimes'' unit, or 
installation of a new ``Whelan'' system (Modification 8/1273).
    De Havilland, Inc., has also issued Service Bulletin S/B 8-33-19, 
`Revision A', dated May 31, 1993, that describes procedures for 
installation of Modification 8/1273, which entails replacing the 
existing anti-collision strobe light system (consisting of anti- 
collision strobe lights, brackets, and power supplies) at all three 
locations with the new, improved ``Whelen'' anti-collision strobe light 
system. (The ``Whelen'' system includes new dual strobes, new brackets, 
and new power supplies.) This new system is considered more durable 
than the currently installed anti-collision strobe light system. The 
``Whelan'' system also has a back-up strobe light at each position.
    Transport Canada Aviation classified these service bulletins as 
mandatory and issued Canadian Airworthiness Directive CF-93-20, dated 
August 3, 1993, in order to assure the continued airworthiness of these 
airplanes in Canada.
    This airplane model is manufactured in Canada and is type 
certificated for operation in the United States under the provisions of 
Sec. 21.29 of the Federal Aviation Regulations and the applicable 
bilateral airworthiness agreement. Pursuant to this bilateral 
airworthiness agreement, Transport Canada Aviation has kept the FAA 
informed of the situation described above. The FAA has examined the 
findings of Transport Canada Aviation, 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.
    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 revising the 
Limitations section of the FAA-approved Airplane Flight Manual (AFM) to 
advise flight crew members that certain cockpit indications during in-
flight or ground operations may reveal faulty anti-collision strobe 
light units, and to provide procedures for subsequent flight crew 
action. This proposal would also require replacement of faulty 
``Grimes'' units with new or serviceable ``Grimes'' units or 
installation of the new ``Whelan'' system (Modification 8/1273). The 
proposed AD would also require eventual replacement of the existing 
anti-collision strobe light system with the ``Whelen'' anti-collision 
strobe light system (Modification 8/1273) at all three locations. When 
accomplished, incorporation of this modification would constitute 
terminating action for the requirements of this proposal. Following 
incorporation of Modification 8/1273, operators would be permitted to 
remove the proposed changes to the AFM. The actions would be required 
to be accomplished in accordance with the service bulletins described 
previously.
    Additionally, applicability of the proposed rule would exclude 
those airplanes on which Modification 8/1273 has been accomplished 
previously, since airplanes so modified are not subject to the unsafe 
condition addressed by this proposed AD. The manufacturer has installed 
Modification 8/1273 on airplanes having serial numbers 215 and 
subsequent.
    The FAA estimates that 74 airplanes of U.S. registry would be 
affected by this proposed AD, that it would take approximately 16 work 
hours per airplane to accomplish the proposed actions, and that the 
average labor rate is $55 per work hour. Required parts for 
installation of Modification 8/1273 at all three locations would cost 
approximately $1,397 per airplane. Based on these figures, the total 
cost impact of the proposed AD on U.S. operators is estimated to be 
$168,498, or $2,277 per airplane.
    The total 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.
    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 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. App. 1354(a), 1421 and 1423; 49 U.S.C. 
106(g); and 14 CFR 11.89.


Sec. 39.13  [Amended]

    2. Section 39.13 is amended by adding the following new 
airworthiness directive:

De Havilland, Inc.: Docket 93-NM-206-AD.

    Applicability: Model DHC-8-102, -103, -302, and -311 series 
airplanes, serial numbers 003 through 214 inclusive; on which 
Modification 8/1273 (as described in de Havilland Service Bulletin 
S/B No. 8-33-19, Revision `A', dated May 31, 1993) has not been 
accomplished; certificated in any category.
    Compliance: Required as indicated, unless accomplished 
previously.
    To ensure correct operation of the proximity switch electronics 
unit (PSEU) and its associated systems, accomplish the following:
    (a) Within 30 days after the effective date of this AD, revise 
the Limitations Section of the FAA-approved Airplane Flight Manual 
(AFM) to include the following statement. This may be accomplished 
by inserting a copy of this AD into the AFM.
    ``The electrical power supplies for the white anti-collision 
lights may fail and cause the following abnormalities:

--Flashing of the landing gear green locked down advisory lights 
during cruise;
--Fluctuation of cabin pressurization rate needle during cruise; and
--Retraction and extension of roll and ground spoilers during ground 
operation.

    The failure may also result in loss of nose landing gear 
steering subsequent to landing, and loss of wheel brakes below 35-40 
knots.
    If any of these abnormal indications are observed, select A/COL 
light switch--RED. Leave the switch in this position for the 
remainder of the flight.''
    (b) If the flight crew reports the occurrence of any of the 
cockpit indications stated in paragraph (a) of this AD: Prior to the 
next flight, perform the maintenance procedures to confirm and 
isolate the faulty power supply unit, in accordance with paragraph 
III., part B, Accomplishment Instructions of de Havilland Alert 
Service Bulletin S.B. A8-33-33, dated May 31, 1993.
    (1) If any power supply unit is determined to be faulty, prior 
to further flight, replace the unit with a new or serviceable 
``Grimes'' unit or a new ``Whelen'' system in accordance with the 
alert service bulletin.
    (2) If the specific unit causing the faults cannot be 
determined, prior to further flight, replace all three units with 
new or serviceable ``Grimes'' units or a new ``Whelen'' system in 
accordance with the alert service bulletin. Installation of a new 
``Whelen'' system at all three locations constitutes terminating 
action for the requirements of this AD, and after installation, the 
AFM revision required by paragraph (a) of this AD may be removed.
    (c) Within 6 months after the effective date of this AD, install 
Modification 8/1273 (which entails replacement of the existing anti-
collision strobe lights, brackets, and power supplies with the 
```Whelen' Anti-Collision Strobe Light System'') at all three 
locations, in accordance with de Havilland Service Bulletin S/B No. 
8-33-19, `Revision A', dated May 31, 1993. Following installation, 
the AFM revision required by paragraph (a) of this AD may be 
removed.
    (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), ANE-170, 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: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the New York ACO.

    (e) Special flight permits may be issued in accordance with FAR 
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 March 30, 1994.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 94-8054 Filed 4-4-94; 8:45 am]
BILLING CODE 4910-13-U