[Federal Register Volume 60, Number 82 (Friday, April 28, 1995)]
[Rules and Regulations]
[Pages 20889-20891]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-10203]
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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39
[Docket No. 94-NM-127-AD; Amendment 39-9207; AD 95-09-04]
Airworthiness Directives; de Havilland Model DHC-8-100 and -300
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-8-100 and -300 series
airplanes, that requires an inspection to verify the integrity of the
shield grounds for the cable harness of the electronic engine control
(EEC), and correction of any discrepancy. This amendment also requires
measurement of the electrical resistance of certain shield grounds, and
repair, if necessary. This amendment is prompted by a report of an
engine flameout after a lightning strike, due to several shields for
the cable harness of the EEC not being properly grounded to the
airframe. The actions specified by this AD are intended to prevent
engine flameout due to insufficient protection of the EEC.
DATES: Effective May 30, 1995.
The incorporation by reference of certain publications listed in
the regulations is approved by the Director of the Federal Register as
of May 30, 1995.
ADDRESSES: The service information referenced in this AD may be
obtained from Bombardier Inc., Bombardier Regional Aircraft Division,
Garratt Boulevard, Downsview, Ontario, Canada M3K 1Y5. 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, 10 Fifth Street, Third Floor, 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: Richard Fiesel, Aerospace Engineer,
Propulsion Branch, ANE-174, FAA, Engine and Propeller Directorate, New
York Aircraft Certification Office, 10 Fifth Street, Third Floor,
Valley Stream, New York 11581; telephone (516) 256-7504; fax (516) 568-
2716.
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-
100 and -300 series airplanes, was published in the Federal Register on
September 21, 1994 (59 FR 48408). That action proposed to require a
visual inspection to verify the integrity of the shield grounds for the
cable harness of the EEC, and correction of any discrepancy. That
action also proposed to require measurement of the electrical
resistance of certain shield grounds, and repair, if necessary.
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 requests that the proposed 45-day compliance time in
paragraph (b) of the proposed AD be extended to permit operators to
schedule the proposed actions according to the size of their individual
fleets and, specifically, to allow up to 165 days for a fleet-wide
inspection. The commenter bases this request on the following factors:
1. The commenter states that, to accomplish the proposed
measurement requirement, the use of a low resistance ohm meter (micro-
ohm) is necessary. The commenter has only one low resistance ohm meter
to perform the measurement of all the airplanes in its fleet. With only
one micro-ohm meter available, the commenter could inspect only a
limited number of its fleet of airplanes during its regularly scheduled
maintenance visits, and would not be able to accomplish the proposed
inspections within the proposed 45-day compliance time. Further, the
commenter does not believe it should have to purchase or otherwise
obtain additional units to satisfy the requirements of the proposed AD.
2. The commenter states that the actions specified in the service
bulletin could not be accomplished in less than 25 hours and, that
based on the amount of time available for a scheduled maintenance
visit, up to 4 visits may be required to complete the inspection. The
commenter is concerned about these additional expenses that would be
associated with this action.
The FAA does not concur with the commenter's request to extend the
compliance time. In developing an appropriate compliance time for this
action, the FAA considered not only the degree of urgency associated
with addressing the subject unsafe condition, but the normal
maintenance schedules for timely accomplishment of the actions required
by the final rule for all affected airplanes to continue to operate
without compromising safety. In consideration of these items, the FAA
has determined that the 45-day compliance time represents an average
maintenance interval for the affected fleet, during which time the
required inspections, measurement, repair, and restoration can
reasonably be accomplished and an acceptable level of safety can be
maintained. However, under the provisions of paragraph (e) of the final
rule, the FAA may approve requests for adjustments to the compliance
time if data are submitted to substantiate that such an adjustment
would provide an acceptable level of safety.
As for the commenter's concern regarding the expenses associated
with accomplishing the requirements of this AD, the FAA recognizes that
the obligation to maintain aircraft in an airworthy condition is vital,
but sometimes expensive. Because AD's require specific actions (such as
testing with special equipment) to address specific unsafe conditions
as required in this rule, they appear to impose costs that would not
otherwise be borne by operators. Attributing those costs solely to the
issuance of this AD is unrealistic because, in the interest of
maintaining safe aircraft, prudent operators would accomplish the
required actions in a timely manner even if they were not required to
do so by the AD.
One commenter requests that a certain procedure for repairing
frayed or broken harnesses be referenced in the proposed rule as an
acceptable means of repair. The commenter states that
[[Page 20890]] accomplishment of this repair procedure may be necessary
in the course of performing the required inspections. The commenter
notes that this repair procedure is not included in any service
bulletin or manual.
The FAA does not concur. The FAA does not consider it appropriate
to include various provisions in an AD applicable to a single operator.
Paragraph (e) of this AD provides for the approval of alternative
methods of compliance to address these types of unique circumstances.
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 included in this notice to clarify this long-standing 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 as proposed.
The FAA estimates that 141 airplanes of U.S. registry will be
affected by this AD, that it will take approximately 16 work hours per
airplane to accomplish the required actions, and that the average labor
rate is $60 per work hour. Based on these figures, the total cost
impact of the AD on U.S. operators is estimated to be $135,360, or $960
per airplane.
The total cost impact figure discussed above is based on
assumptions that no operator has yet accomplished any of the
requirements of this AD action, and that no operator would accomplish
those actions in the future if this AD were not adopted.
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:
95-09-04 De Havilland, Inc.: Amendment 39-9207. Docket 94-NM-127-
AD.
Applicability: Model DHC-8-102, -103, and -106 series airplanes,
serial numbers 3 through 369 inclusive; and Model DHC-8-301, -311,
and -314 series airplanes, serial numbers 100 through 370 inclusive;
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 (e) 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 engine flameout following a lightning strike,
accomplish the following:
(a) Within 45 days after the effective date of this AD, perform
a visual inspection of the mounting clamps and ``breakout
junctions'' in the metal overbraid to verify the integrity of the
shield grounds for the cable harness of the electronic engine
control (EEC), in accordance with de Havilland Service Bulletin S.B.
8-73-18 (for Model DHC-8-100 series airplanes), or S.B. 8-73-19 (for
Model DHC-8-300 series airplanes), both dated April 29, 1994, as
applicable. If any discrepancy is found, prior to further flight,
correct the discrepancy in accordance with the applicable service
bulletin.
(b) Within 45 days after the effective date of this AD, perform
an electrical resistance measurement of Class A and Class B shield
grounds in accordance with de Havilland Service Bulletin S.B. 8-73-
18 (for Model DHC-8-100 series airplanes), or S.B. 8-73-19 (for
Model DHC-8-300 series airplanes), both dated April 29, 1994, as
applicable.
(1) For Class A shield grounds: If the electrical resistance
exceeds the value specified in the service bulletin, within 50
flight hours after performing the resistance measurement, repair in
accordance with the applicable service bulletin.
(2) For Class B shield grounds: If the electrical resistance
exceeds the value specified in the service bulletin, within 180 days
after performing the resistance measurement, repair in accordance
with the applicable service bulletin.
(c) For Model DHC-8-102, -103, and -106 series airplanes on
which an interim shield ground is installed in accordance with
paragraphs 19 and 93 of the Accomplishment Instructions of de
Havilland Service Bulletin S.B. 8-73-18, dated April 29, 1994:
Within one year after the effective date of this AD, restore the
airplane to the Post-Modification 8/0772 configuration in accordance
with paragraph 161 of the Accomplishment Instructions of that
service bulletin.
(d) For Model DHC-8-301, -311, and -314 series airplanes on
which an interim shield ground is installed in accordance with
paragraphs 19 and 112 of the Accomplishment Instructions of de
Havilland Service Bulletin S.B. 8-73-19, dated April 29, 1994:
Within one year after the effective date of this AD, restore the
airplane to the Post-Modification 8/0772 configuration in accordance
with paragraph [[Page 20891]] 200 of the Accomplishment Instructions
of that service bulletin.
(e) 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 2: Information concerning the existence of approved
alternative methods of compliance with this AD, if any, may be
obtained from the New York ACO.
(f) 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.
(g) The inspections, measurement, repair, and restoration shall
be done in accordance with de Havilland Service Bulletin S.B. 8-73-
18 (for Model DHC-8-100 series airplanes), or de Havilland S.B. 8-
73-19 (for Model DHC-8-300 series airplanes), both dated April 29,
1994. 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 Bombardier Inc., Bombardier
Regional Aircraft Division, Garratt Boulevard, Downsview, Ontario,
Canada M3K 1Y5. Copies may be inspected at the FAA, Transport
Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or
at FAA, Engine and Propeller Directorate, New York Aircraft
Certification Office, 10 Fifth Street, Third Floor, Valley Stream,
New York; or at the Office of the Federal Register, 800 North
Capitol Street, NW., suite 700, Washington, DC.
(h) This amendment becomes effective on May 30, 1995.
Issued in Renton, Washington, on April 20, 1995.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 95-10203 Filed 4-27-95; 8:45 am]
BILLING CODE 4910-13-U
