[Federal Register Volume 59, Number 174 (Friday, September 9, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-22230]
[[Page Unknown]]
[Federal Register: September 9, 1994]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 94-NM-108-AD]
Airworthiness Directives; British Aerospace Model Viscount 744,
745D, and 810 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 all British Aerospace Model
Viscount 744, 745D, and 810 series airplanes. This proposal would
require inspections to detect cracks in the chassis side bracing
structure and in the chassis top strut support intercostals inside the
wings, and replacement of discrepant parts with new parts. This
proposal would also require inspection of the intercostals to determine
the specification of the material, if necessary, and replacement of
discrepant parts with new parts. This proposal is prompted by a report
of cracking in the chassis top strut support intercostal in the side
bracing structure inside the wing due to the effects of metal fatigue.
The actions specified by the proposed AD are intended to prevent such
fatigue-related cracking, which could lead to the failure of the
chassis side bracing structure inside the wings and consequent reduced
structural integrity of the chassis support structure.
DATES: Comments must be received by November 4, 1994.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Transport Airplane Directorate, ANM-103,
Attention: Rules Docket No. 94-NM-108-AD, 1601 Lind Avenue, SW.,
Renton, Washington 98055-4056. Comments may be inspected at this
location between 9:00 a.m. and 3:00 p.m., Monday through Friday, except
Federal holidays.
The service information referenced in the proposed rule may be
obtained from British Aerospace Regional Aircraft Ltd., Engineering
Support Manager, Military Business Unit, Chadderton Works, Greengate,
Middleton, Manchester M24 1SA, England. This information may be
examined at the FAA, Transport Airplane Directorate, 1601 Lind Avenue,
SW., Renton, Washington.
FOR FURTHER INFORMATION CONTACT: William Schroeder, Aerospace Engineer,
ANM-113, Standardization Branch, ANM-113, FAA, Transport Airplane
Directorate, 1601 Lind Avenue, SW., Renton, Washington 98055-4056;
telephone (206) 227-2148; fax (206) 227-1320.
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 94-NM-108-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. 94-NM-108-AD, 1601 Lind Avenue, SW., Renton, Washington
98055-4056.
Discussion
The Civil Aviation Authority (CAA), which is the airworthiness
authority for the United Kingdom, recently notified the FAA that an
unsafe condition may exist on all British Aerospace Model Viscount 744,
745D, and 810 series airplanes. The CAA advises that it has received a
report of cracking in the chassis top strut support intercostals of the
side bracing structure inside the wings between stations 81 and 96.
Investigation revealed that such cracking was caused by metal fatigue.
The effects of such fatigue-related cracking could lead to failure of
the chassis top strut support intercostals of the side bracing
structure inside the wings. This condition, if not detected and
corrected in a timely manner, could result in reduced structural
integrity of the chassis support structure.
British Aerospace has issued Viscount Preliminary Technical Leaflet
(PTL) 332, Issue 1, Disc 11 Doc. 4, dated December 2, 1991 (for Model
Viscount 744 and 745D series airplanes), and Viscount PTL 203, Issue 1,
Disc 11 Doc. 2, dated December 2, 1991 (for Model Viscount 810 series
airplanes), which describe procedures for repetitive detailed visual
inspections to detect cracks in the chassis side bracing structure
inside the wings and in the chassis top strut support intercostals
inside the wings, and replacement of discrepant parts with new parts.
These PTL's also describe procedures for an eddy current inspection to
determine the specification of the material of the intercostals, if
necessary; and discarding and replacing discrepant parts with new
parts. The CAA classified these PTL's as mandatory.
This airplane model is manufactured in the United Kingdom 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. Pursuant
to this bilateral airworthiness agreement, the CAA has kept the FAA
informed of the situation described above. The FAA has examined the
findings of the CAA, 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 repetitive detailed
visual inspections to detect cracks in the chassis side bracing
structure and in the chassis top strut support intercostals of the
inner wings, and replacement of discrepant parts with new parts. This
proposed AD would also require an eddy current inspection to determine
the specification of the material of the intercostals, if necessary;
and replacement of discrepant parts with new parts. The actions would
be required to be accomplished in accordance with the PTL's described
previously.
The FAA estimates that 25 Model Viscount 744 and 745D series
airplanes of U.S. registry would be affected by this proposed AD, that
it would take approximately 15 work hours per airplane to accomplish
the proposed actions, and that the average labor rate is $55 per work
hour. Based on these figures, the total cost impact of the proposed AD
on U.S. operators is estimated to be $20,625, or $825 per airplane, per
inspection cycle.
The FAA estimates that 4 Model Viscount 810 series airplanes of
U.S. registry would be affected by this proposed AD, that it would take
approximately 15 work hours per airplane to accomplish the proposed
actions, and that the average labor rate is $55 per work hour. Based on
these figures, the total cost impact of the proposed AD on U.S.
operators is estimated to be $3,300, or $825 per airplane, per
inspection cycle.
Based on the above figures, the total cost impact of the actions
proposed by this AD on U.S. operators is estimated to be $23,925, or
$825 per airplane, per inspection cycle.
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
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:
British Aerospace Regional Aircraft Limited (Formerly British
Aerospace Commercial Aircraft Limited, Vickers-Armstrongs Aircraft
Limited): Docket 94-NM-108-AD.
Applicability: All Model Viscount 744, 745D, and 810 series
airplanes, certificated in any category.
Compliance: Required as indicated, unless accomplished
previously.
To prevent reduced structural integrity of the chassis,
accomplish the following:
(a) Within 6 months after the effective date of this AD, perform
a detailed visual inspection to detect cracks in the chassis side
bracing structure and in the chassis top strut support intercostals
inside the wings between stations 81 and 96, in accordance with
British Aerospace Viscount Preliminary Technical Leaflet (PTL) 332,
Issue 1, Disc 11 Doc.4, dated December 2, 1991 (for Model Viscount
744 and 745D series airplanes); or British Aerospace Viscount PTL
203, Issue 1, Disc 11 Doc.2, dated December 2, 1991 (for Model
Viscount 810 series airplanes); as applicable.
(1) If no cracking is detected in the chassis side bracing
structure, repeat the inspection thereafter at intervals not to
exceed 1,500 flight hours or 14 months, whichever occurs first.
(2) If any cracking is detected in the chassis side bracing
structure, prior to further flight, replace the cracked side of the
bracing structure with a new structure, in accordance with the
applicable PTL.
(3) If no cracking is detected in the chassis top strut support
intercostal, prior to further flight, perform an eddy current
inspection to determine the specification of the material (either
L72 or L73) of the intercostals, in accordance with the applicable
PTL.
(i) If the material is manufactured from L72, prior to further
flight, replace the chassis top strut support intercostal with and a
new chassis top strut support intercostal, in accordance with the
applicable PTL.
(ii) If the material is manufactured from L73, no further action
is required by paragraph (a)(3) of this AD.
(4) If cracking is detected in the chassis top strut support
intercostal, prior to further flight, replace it with a new chassis
top strut support intercostal, in accordance with the applicable
PTL.
(b) 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, Standardization Branch, ANM-113,
FAA, Transport Airplane Directorate. Operators shall submit their
requests through an appropriate FAA Principal Maintenance Inspector,
who may add comments and then send it to the Manager,
Standardization Branch, ANM-113.
Note: Information concerning the existence of approved
alternative methods of compliance with this AD, if any, may be
obtained from the Standardization Branch, ANM-113.
(c) 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.
Issued in Renton, Washington, on September 2, 1994.
S.R. Miller,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 94-22230 Filed 9-8-94; 8:45 am]
BILLING CODE 4910-13-U