[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