[Federal Register Volume 60, Number 75 (Wednesday, April 19, 1995)]
[Proposed Rules]
[Pages 19551-19553]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-9625]
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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39
[Docket No. 94-NM-112-AD]
Airworthiness Directives; British Aerospace Model Viscount 744,
745D, and 810 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 airplanes. This proposal would require an
inspection of certain fittings of the engine mount structure to
determine whether fasteners have been installed in inspection holes and
to determine whether those holes are oversized. It would also require
various follow-on actions, depending upon the results of the
inspection. This proposal is prompted by reports indicating that
fasteners were installed in the inspection hole of the engine ``W''
frame socket fittings and the inspection hole was oversized due to
fatigue cracking. The actions specified by the proposed AD are intended
to prevent such fatigue cracking, which could lead to failure of the
fasteners and consequent separation of the engine from the airframe.
DATES: Comments must be received by May 30, 1995.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Transport Airplane Directorate, ANM-103,
Attention: Rules Docket No. 94-NM-112-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,
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-112-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-112-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 certain British Aerospace
[[Page 19552]] Model Viscount 744, 745D, and 810 airplanes. The CAA
advises that it has received a report indicating that drive screws were
installed in the inspection hole of engine ``W'' frame socket fittings.
Investigation revealed that these drive screws were installed in
accordance with Gulfstream Customer Bulletin No. 241C. However, the
fitting of the drive screws into the inspection holes has caused
fatigue cracking. In another report, the inspection hole was oversized
in excess of the original 0.125-inch diameter; with such oversizing of
the inspection hole, the fitting is susceptible to the problems
associated with premature fatigue cracking. These conditions, if not
detected and corrected in a timely manner, could lead to failure of the
fitting and consequent separation of the engine from the airframe.
British Aerospace has issued Preliminary Technical Leaflet (PTL)
501, dated May 1, 1994, which describes procedures for performing a
detailed visual inspection of ``W'' frame socket fittings of the engine
mount structure to determine whether drive screws or blind rivets have
been installed in inspection holes, and to determine whether those
holes are oversized. The PTL also describes various follow-on actions,
including a nondestructive test (NDT) to detect discontinuity (i.e.,
cracks, corrosion, and mechanical damage) of holes, rework of the hole,
and replacement of the ``W'' frame fitting with a new or serviceable
part. The CAA classified this PTL as mandatory.
These airplane models are manufactured in the United Kingdom and
are 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 performing a
detailed visual inspection of ``W'' frame socket fittings of the engine
mount structure to determine whether drive screws or blind rivets have
been installed in inspection holes and to determine whether those holes
are oversized. It would also require various follow-on actions,
depending upon the results of the inspection. The actions would be
required to be accomplished in accordance with the PTL described
previously.
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 estimates that 29 airplanes of U.S. registry would be
affected by this proposed AD, that it would take approximately 25 work
hours per airplane to accomplish the proposed actions, and that the
average labor rate is $60 per work hour. Based on these figures, the
total cost impact of the proposed AD on U.S. operators is estimated to
be $43,500, or $1,500 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
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-112-AD.
Applicability: All Model Viscount 744, 745D, and 810 airplanes,
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 fatigue cracking, which could lead to the possible
separation of the engine from the airframe, accomplish the
following:
(a) Within 12 months after the effective date of this AD,
perform a detailed visual inspection of ``W'' frame socket fittings
of the engine mount structure to determine whether drive screws or
blind rivets have been installed in inspection holes and to
determine whether those holes are oversized, [[Page 19553]] in
accordance with the Accomplishment Instructions, section 2.1 PART
ONE, paragraphs A., B., C., D., E. and F., of British Aerospace
Preliminary Technical Leaflet (PTL) 501, dated May 1, 1994.
(b) If drive screws or blind rivets are found installed, or if
the inspection holes are found to be oversized, during the
inspection required by paragraph (a) of this AD, at the next
scheduled engine removal, but no later than 12 months after the
effective date of this AD, perform a nondestructive test (NDT) to
detect discontinuities (i.e., cracks, corrosion, and mechanical
damage) at inspection holes; rework the hole or replace the ``W''
frame fitting with a new or serviceable part; and perform the
specified follow-on actions; in accordance with the Accomplishment
Instructions, section 2.2 PART TWO, paragraphs A., B., C., D., E.,
and F., of British Aerospace Preliminary Technical Leaflet (PTL)
501, dated May 1, 1994.
(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, 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 2: Information concerning the existence of approved
alternative methods of compliance with this AD, if any, may be
obtained from the Standardization Branch, ANM-113.
(d) 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 April 13, 1995.
John J. Hickey,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 95-9625 Filed 4-18-95; 8:45 am]
BILLING CODE 4910-13-U
