[Federal Register Volume 59, Number 247 (Tuesday, December 27, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-30940]


[[Page Unknown]]

[Federal Register: December 27, 1994]


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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 93-NM-46-AD; Amendment 39-9098; AD 94-26-02]

 

Airworthiness Directives; de Havilland Model DHC-8 Series 
Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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SUMMARY: This amendment adopts a new airworthiness directive (AD), 
applicable to certain de Havilland Model DHC-8 series airplanes, that 
requires repetitive inspections of the passenger service unit (PSU) 
printed circuit boards and power supply connectors to detect corrosion 
and evidence of overheating; repair or replacement of the circuit 
boards or replacement of connectors, if necessary; and eventual 
installation of a terminating modification. This amendment is prompted 
by reports that certain PSU printed circuit boards and power supply 
connectors have overheated in service. The actions specified by this AD 
are intended to prevent overheating of the PSU printed circuit board 
and power supply connectors, which could lead to a fire in the PSU.

DATES: Effective January 26, 1995. -
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of January 26, 1995.

ADDRESSES: The service information referenced in this AD may be 
obtained from de Havilland, Inc., Garratt Boulevard, Downsview, Ontario 
M3K 1Y5, Canada. This information may be examined at the Federal 
Aviation Administration (FAA), Transport Airplane Directorate, Rules 
Docket, 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; 
or at the Office of the Federal Register, 800 North Capitol Street, 
NW., suite 700, Washington, DC.

FOR FURTHER INFORMATION CONTACT: Michele Maurer, Aerospace Engineer, 
Systems and Equipment Branch, ANE-173, FAA, Engine and Propeller 
Directorate, New York Aircraft Certification Office, 181 South Franklin 
Avenue, Room 202, Valley Stream, New York 11581; telephone (516) 791-
6428; fax (516) 791-9024.

SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal 
Aviation Regulations (14 CFR part 39) to include an airworthiness 
directive (AD) that is applicable to certain de Havilland Model DHC-8 
series airplanes was published as a supplemental notice of proposed 
rulemaking (NPRM) in the Federal Register on April 29, 1994 (59 FR 
22138). That action proposed to require repetitive inspections of the 
passenger service unit (PSU) printed circuit boards and power supply 
connectors to detect corrosion and evidence of overheating; repair or 
replacement of the circuit boards or replacement of connectors, if 
necessary; and eventual installation of a modification that would 
terminate the required inspections. -
    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. Due consideration has been given to 
the comments received. -
    One commenter supports the proposal. -
    Another commenter requests that the proposed requirement to submit 
inspection results to de Havilland be deleted. The commenter states 
that, since the proposed rule would require that a terminating action 
be accomplished, and since de Havilland has been aware of the addressed 
problem for several years, any data supplied to de Havilland through 
inspection reports would not shed any new light on the problem. The FAA 
concurs. Upon reconsideration of this proposed requirement, the FAA 
considers the submission of reports to be unnecessary. Additionally, de 
Havilland has advised the FAA that it foresees no future need to 
receive such reports. Accordingly, the FAA has revised the final rule 
by deleting the reporting requirement. -
    This same commenter requests that the compliance time for the 
proposed initial inspection be revised to account for new airplanes. 
The commenter suggests that new airplanes should not be required to be 
inspected for at least 12 months since new. In considering this 
comment, the FAA has determined that the applicability of the final 
rule must be revised to limit it only to airplanes having serial 
numbers 3 through 369, inclusive. Airplanes having serial numbers 
higher that 369 were delivered with the equivalent of Modification 8/
1950 (the terminating modification required by this AD) installed. In 
light of this, a revision to the final rule to address ``new'' 
airplanes, as suggested by the commenter, is unnecessary since all of 
the affected airplanes have accumulated more than 12 months since new. 
-
    The FAA has revised the applicability of the final rule to clarify 
the specific part numbers of the subject PSU's installed on the 
affected airplanes. -
    As a result of recent communications with the Air Transport 
Association (ATA) of America, the FAA has learned that, in general, 
some operators may misunderstand the legal effect of AD's on airplanes 
that are identified in the applicability provision of the AD, but that 
have been altered or repaired in the area addressed by the AD. The FAA 
points out that all airplanes identified in the applicability provision 
of an AD are legally subject to the AD. If an airplane has been altered 
or repaired in the affected area in such a way as to affect compliance 
with the AD, the owner or operator is required to obtain FAA approval 
for an alternative method of compliance with the AD, in accordance with 
the paragraph of each AD that provides for such approvals. A note has 
been added to this final rule to clarify this requirement. -
    The FAA has recently reviewed the figures it has used over the past 
several years in calculating the economic impact of AD activity. In 
order to account for various inflationary costs in the airline 
industry, the FAA has determined that it is necessary to increase the 
labor rate used in these calculations from $55 per work hour to $60 per 
work hour. The economic impact information, below, has been revised to 
reflect this increase in the specified hourly labor rate. -
    After careful review of the available data, including the comments 
noted above, the FAA has determined that air safety and the public 
interest require the adoption of the rule with the changes previously 
described. The FAA has determined that these changes will neither 
increase the economic burden on any operator nor increase the scope of 
the AD. -
    The FAA estimates that 133 airplanes of U.S. registry will be 
affected by this AD. -
    The required inspections will take approximately 2 work hours per 
airplane to accomplish, at an average labor rate of $60 per work hour. 
Based on these figures, the total cost impact of the proposed 
inspections on U.S. operators is estimated to be $15,960, or $120 per 
airplane, per inspection. -
    The required terminating modification will require approximately 3 
work hours per PSU to accomplish, at an average labor cost of $60 per 
work hour. Required parts would cost approximately $62 per PSU. Each 
airplane is equipped with between 18 and 26 PSU's. Based on these 
figures, the total cost impact of the proposed modification on U.S. 
operators is estimated to be $242 per PSU, or between $4,356 and $6,292 
per airplane. -
    The total 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. However, the 
FAA has been advised that the initial inspection has already been 
accomplished on approximately 22 airplanes; therefore the future 
economic impact of this rule is reduced by at least $2,640.
    The regulations adopted herein will 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 final 
rule does 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) 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 final evaluation has been prepared for this action 
and it is contained in the Rules Docket. A copy of it may be obtained 
from the Rules Docket at the location provided under the caption 
ADDRESSES.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by 
reference, Safety.

Adoption of the Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration amends 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. 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:

94-26-02 de Havilland, Inc.: Amendment 39-9098. Docket 93-NM-46-AD.

    Applicability: Model DHC-8 series airplanes, serial numbers 003 
through 369, inclusive; equipped with passenger service units (PSU) 
have part numbers 10-1418-1 or -2, or 10-1081-1 through -8; 
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 use the authority 
provided in paragraph (c) to request approval from the FAA. This 
approval may address either no action, if the current configuration 
eliminates the unsafe condition; or different actions necessary to 
address the unsafe condition described in this AD. Such a request 
should include an assessment of the effect of the changed 
configuration on the unsafe condition addressed by this AD. In no 
case does the presence of any modification, alteration, or repair 
remove any airplane from the applicability of this AD.

    Compliance: Required as indicated, unless accomplished 
previously.
    To prevent overheating of the passenger service unit (PSU) 
printed circuit board and power supply connectors, which could lead 
to a fire in the PSU, accomplish the following:
    (a) Within 300 hours time-in-service after the effective date of 
this AD, or within 30 days after the effective date of this AD, or 
within 12 months after any previous inspection conducted prior to 
the effective date in accordance with this paragraph, whichever 
occurs later: Conduct a visual inspection of all PSU printed circuit 
boards and power supply connectors to detect corrosion and evidence 
of overheating, in accordance with paragraph III. of de Havilland 
Alert Service Bulletin S.B. A8-33-30, Revision `A', dated December 
18, 1992.

    Note 2: The overheat condition referred to in this paragraph is 
the discoloration of the printed circuit board around the connector 
interfaces, and not the light conformal coating discoloration 
resulting from the normal operation of high current devices mounted 
on the printed circuit board.

    (1) If no corrosion or evidence of overheating is detected, 
repeat the inspection at intervals not to exceed 12 months.
    (2) If any corrosion or evidence of overheating of the PSU 
printed circuit board is detected as a result of any inspection, 
prior to further flight, either repair or replace the PSU printed 
circuit board in accordance with the service bulletin. Thereafter, 
repeat the inspection at intervals not to exceed 12 months.
    (3) If any corrosion or evidence of overheating of the power 
supply connectors is detected as a result of any inspection, prior 
to further flight, replace the affected power supply connector in 
accordance with the service bulletin. Thereafter, repeat the 
inspection at intervals not to exceed 12 months.
    (b) Within 24 months after the effective date of this AD, 
install Modification 8/1950 in accordance with de Havilland Service 
Bulletin S.B. 8-33-34, dated August 10, 1993. Installation of this 
modification constitutes terminating action for the inspections 
required by paragraph (a) of this AD.
    (c) 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 3: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the New York ACO.

    (d) Special flight permits may be issued in accordance with 
Secs. 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.
    (e) The inspections shall be done in accordance with de 
Havilland Alert Service Bulletin S.B. A8-33-30, Revision `A', dated 
December 18, 1992. The modification shall be done in accordance with 
de Havilland Service Bulletin S.B. 8-33-34, dated August 10, 1993. 
This incorporation by reference was approved by the Director of the 
Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 
51. Copies may be obtained from de Havilland, Inc., Garratt 
Boulevard, Downsview, Ontario M3K 1Y5, Canada. Copies may be 
inspected 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; or at the Office 
of the Federal Register, 800 North Capitol Street, NW., suite 700, 
Washington, DC.
    (f) This amendment becomes effective on January 26, 1995.

    Issued in Renton, Washington, on December 12, 1994.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 94-30940 Filed 12-23-94; 8:45 am]
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