[Federal Register Volume 59, Number 35 (Tuesday, February 22, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-3752]
[[Page Unknown]]
[Federal Register: February 22, 1994]
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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39
[Docket No. 93-NM-149-AD; Amendment 39-8829; AD 94-04-09]
Airworthiness Directives; de Havilland, Inc., Model DHC-8-100 and
DHC-8-300 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 DHC-8-300 series
airplanes, that requires inspections to detect breakage in the engine
rear mount strut assemblies, and replacement of broken struts. This
amendment also requires eventual replacement of all currently installed
struts with new and/or reworked struts, as terminating action for the
inspections. This amendment is prompted by several reports of failure
of the engine rear mount struts, due to fracture at one of the rosette
welds on the shank of the strut where full weld depth was not achieved
during manufacture. The actions specified by this AD are intended to
prevent fracture of the engine rear mount struts, which could reduce
the structural integrity of the nacelle and engine support structure.
DATES: Effective March 24, 1994.
The incorporation by reference of certain publications listed in
the regulations is approved by the Director of the Federal Register as
of March 24, 1994.
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: Jon Hjelm, Aerospace Engineer,
Airframe Branch, ANE-172, FAA, Engine and Propeller Directorate, New
York Aircraft Certification Office, 181 South Franklin Avenue, room
202, Valley Stream, New York 11581; telephone (516) 791-6220; fax (516)
791-9024.
SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal
Aviation Regulations to include an airworthiness directive (AD) that is
applicable to certain de Havilland Model DHC-8-100 and DHC-8-300 series
airplanes was published in the Federal Register on October 25, 1993 (58
FR 55031). That action proposed to require repetitive detailed visual
inspections to detect breakage in the engine strut assemblies, and
replacement of broken struts with new and/or reworked struts. That
action also proposed to require eventual replacement of the currently
installed struts with new and/or reworked struts; when accomplished,
this replacement would terminate the need for the repetitive
inspections.
Interested persons have been afforded an opportunity to participate
in the making of this amendment. Due consideration has been given to
the single comment received.
The commenter supports the proposed rule.
After careful review of the available data, including the comment
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 125 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 $55 per work hour. Required parts will be provided by the
manufacturer at no cost to the operators. Based on these figures, the
total cost impact of the AD on U.S. operators is estimated to be
$110,000, or $880 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 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:
94-04-09 De Havilland, Inc.: Amendment 39-8829. Docket 93-NM-149-AD.
-Applicability: Model DHC-8-102 and -103 series airplanes,
serial numbers 003 through 310 inclusive; and Model DHC-8-301, -311,
and -314 series airplanes, serial numbers 100 through 311 inclusive,
certificated in any category. -
Compliance: Required as indicated, unless accomplished
previously.
To prevent fracture of the engine rear mount struts, and
subsequent reduced structural integrity of the nacelle and engine
support structure, accomplish the following: -
(a) Within 50 hours time-in-service after the effective date of
this AD, perform a detailed visual inspection to detect breakage in
the engine strut assemblies, part number 8711016-001, -003, -005, or
-007, in accordance with De Havilland, Inc., Service Bulletin S.B.
8-71-17, dated April 3, 1992. -
(1) If any broken strut is detected, prior to further flight,
replace the broken strut with a new strut, part number 87110016-009,
or a reworked strut, part number 8DK1763-001; Post-Modification 8/
1763; in accordance with the service bulletin.
-Note 1: The Post-Modification 8/1763 struts are either new
struts, part number 87110016-009, or reworked struts, part number
8DK1763-001.
-(2) If no broken strut is detected, repeat the inspection
thereafter at intervals not to exceed 50 flight hours.
(b) Within 24 months after the effective date of this AD,
replace all of the currently installed engine rear mount struts with
new struts, part number 87110016-009, and/or reworked struts, part
number 8DK1763-001; Post-Modification 8/1763; in accordance with de
Havilland, Inc., Service Bulletin S.B. 8-71-17, dated April 3, 1992.
This replacement constitutes terminating action for the repetitive
inspection requirements of this AD.
(c) As of the effective date of this AD, no person shall install
an engine rear mount strut, part number 8711016-001, -003, -005, or
-007, on any airplane.
(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), 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.
(e) Special flight permits may be issued in accordance with
Federal Aviation Regulations (FAR) 21.197 and 21.199 to operate the
airplane to a location where the requirements of this AD can be
accomplished.
(f) The inspections and replacements shall be done in accordance
with de Havilland, Inc., Service Bulletin S.B. 8-71-17, dated April
3, 1992. 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.
(g) This amendment becomes effective on March 24, 1994.
Issued in Renton, Washington, on Feburary 14, 1994.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 94-3752 Filed 2-18-94; 8:45 am]
BILLING CODE 4910-13-U
