[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