[Federal Register Volume 60, Number 89 (Tuesday, May 9, 1995)]
[Proposed Rules]
[Pages 24587-24589]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-11357]



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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 94-NM-135-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 supersedure of an existing 
airworthiness directive (AD), applicable to certain British Aerospace 
Model Viscount 744, 745D, and 810 airplanes, that currently establishes 
time-in-service limits for components of the fuselage pressure vessel, 
and requires modifications and inspections of various fuselage 
components to assure the continued structural integrity of these 
airplanes through the manufacturer's design life goal. This action 
would require additional modifications and inspections of the fuselage 
pressure vessel to extend the fuselage pressure vessel life from 30 to 
45 years since new. This proposal is prompted by results of a review of 
fatigue test findings, stress analysis, and in-service history 
associated with pressure vessel components. The actions specified by 
the proposed AD are intended to prevent reduced structural capability 
of the fuselage pressure vessel.

DATES: Comments must be received by June 20, 1995.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 94-NM-135-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 [[Page 24588]] 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-135-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-135-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    On January 30, 1978, the FAA issued AD 65-20-04, amendment 39-3138 
(23 FR 5506, February 9, 1978), applicable to certain British Aerospace 
Model Viscount 744, 745D, and 810 airplanes. That AD establishes time-
in-service limits of 30 years since new or 75,000 landings (whichever 
occurs first) for components of the fuselage pressure vessel. That AD 
also requires modifications and repetitive inspections of various 
fuselage components to assure the continued structural integrity of 
these airplanes to 30 years since new or 75,000 landings (whichever 
occurs first). That action was prompted by results of the 
manufacturer's fatigue tests, stress analysis, and in-service history 
associated with life-limited fuselage parts. The requirements of that 
AD are intended to prevent reduced structural capability of the 
fuselage pressure vessel.
    Since the issuance of that AD, the airplane manufacturer has 
conducted an additional review of fatigue test results, stress 
analysis, and in-service experience. Results of that review have 
revealed that additional new modifications and repetitive inspections 
are necessary to ensure that the fuselage pressure vessel can maintain 
the continued structural integrity necessary to attain the initial 
time-in-service limit of 30 years since new or 75,000 landings 
(whichever occurs first) specified in the existing AD.
    In addition, the manufacturer has developed a program for Model 
Viscount 744, 745D, and 810 airplanes, which involves performing new 
inspections and modifications, and revising the implementation times 
for existing requirements. Once accomplished, these actions will allow 
an extension of the initial time-in-service limit of 30 years or 75,000 
landings (whichever occurs first) of the fuselage pressure vessel to 45 
years or 75,000 landings (whichever occurs first).
    British Aerospace has issued Preliminary Technical Leaflet (PTL) 
No. 221, Issue 10, dated May 1, 1994 (for Model Viscount 744 and 745D 
airplanes), and PTL No. 94, Issue 10, dated September 1, 1993 (for 
Model Viscount 810 airplanes). These PTL's describe procedures for 
additional visual inspections, non-destructive testing (NDT) 
inspections, and modifications of the fuselage necessary to assure the 
continued structural integrity of the pressure vessel to the initial 
time-in-service limit of 30 years or 75,000 landings (whichever occurs 
first). These PTL's also specify compliance with two other PTL's, 
described below, for operation of affected airplanes beyond 30 years, 
but not to exceed 75,000 landings. The Civil Aviation Authority (CAA), 
which is the airworthiness authority for the United Kingdom, classified 
PTL No. 221 and PTL No. 94 as mandatory in order to assure the 
continued airworthiness of these airplanes in the United Kingdom.
    British Aerospace also has issued PTL No. 320, Issue 3, dated 
October 1, 1993 (for Model Viscount 744 and 745D airplanes), and PTL 
No. 189, Issue 5, dated May 1, 1994 (for Model Viscount 810 airplanes). 
These PTL's specify inspections and modifications of the fuselage 
pressure vessel assembly, and revise the implementation times for 
certain existing requirements for continued operation of specific 
airplanes (listed in the PTL's) beyond 30 years since new. 
Accomplishment of the actions specified in these PTL's will allow 
extension of the initial time-in-service limit of the fuselage pressure 
vessel to 45 years or 75,000 landings (whichever occurs first).
    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 supersede AD 65-20-04 to 
require additional modifications and inspections of the fuselage 
pressure vessel. The actions would be required to be accomplished in 
accordance with the PTL's 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 requirement.
    The FAA estimates that 29 airplanes of U.S. registry would be 
affected by this proposed AD, that it would take approximately 400 work 
hours per airplane to accomplish the proposed actions, and that the 
average labor rate is $60 per work hour. Required parts would cost 
approximately $37,400 per airplane. Based on these figures, the total 
cost impact of the proposed AD on U.S. operators is estimated to be 
$1,780,600, or $61,400 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 
[[Page 24589]] 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 removing amendment 39-3138 (23 FR 
5506, February 9, 1978), and by adding a new airworthiness directive 
(AD), to read as follows:

British Aerospace Regional Aircraft Limited (Formerly British 
Aerospace Commercial Aircraft Limited, Vickers-Armstrongs Aircraft 
Limited): Docket 94-NM-135-AD. Supersedes AD 65-20-04, Amendment 39-
3138.

    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 (d) 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 reduced structural capability of the fuselage 
pressure vessel, accomplish the following:
    (a) To operate the airplane for a maximum of 30 years since the 
date of manufacture or 75,000 total landings, whichever occurs 
first, accomplish the following:
    (1) Perform visual, eddy current, dye penetrant, and x-ray 
inspections in accordance with Sections 2 through 10 of British 
Aerospace Preliminary Technical Leaflet (PTL) No. 221, Issue 10, 
dated May 1, 1994 (for Model Viscount 744 and 745D airplanes); or 
PTL No. 94, Issue 10, dated September 1, 1993 (for Model Viscount 
810 airplanes); as applicable. Perform the initial inspection at the 
later of the times specified in paragraphs (a)(1)(i) and (a)(2)(ii) 
of this AD. Thereafter, repeat these inspections at the repetitive 
intervals specified in the applicable PTL.
    (i) Prior to the threshold specified in Sections 2 through 10 of 
the applicable PTL; or within the next repetitive inspection 
specified in Sections 2 through 10 of the applicable PTL following 
the immediately preceding inspection accomplished in accordance with 
PTL No. 221, Issue 4 (for Model Viscount 744 and 745D airplanes), or 
PTL No. 94, Issue 4 (for Model Viscount 810 airplanes); whichever 
occurs first. Or
    (ii) Within 60 days after the effective date of this AD.
    (2) Install the modifications specified in Sections 2 through 10 
of British Aerospace PTL No. 221, Issue 10, dated May 1, 1994 (for 
Model Viscount 744 and 745D airplanes); or PTL No. 94, Issue 10, 
dated September 1, 1993 (for Model Viscount 810 airplanes); as 
applicable. Accomplish this installation at the later of the times 
specified in paragraphs (a)(2)(i) and (a)(2)(ii) of this AD.
    (i) Prior to the accumulation of the number of equivalent 
flights at 6.5 pounds per square inch (psi) specified in the initial 
compliance columns of Sections 2 through 10 of the applicable PTL. 
Or
    (ii) Within 60 days after the effective date of this AD.

    Note 2: The number of equivalent flights at 6.5 psi is 
determined by using the procedure specified in Section 1, Part 6, 
Paragraph 6.6, of PTL No. 221 or PTL No. 94, as applicable.

    (3) Modify the components of the pressurization system to reduce 
the cabin pressure maximum pressure setting to 3.5 psi, in 
accordance with Section 1, Part 7, Paragraph 7.5.2 of British 
Aerospace PTL No. 221, Issue 10, dated May 1, 1994 (for Model 
Viscount 744 and 745D airplanes); or PTL No. 94, Issue 10, dated 
September 1, 1993 (for Model Viscount 810 airplanes); as applicable. 
Accomplish this modification at the later of the times specified in 
paragraphs (a)(3)(i) and (a)(3)(ii) of this AD.
    (i) Prior to the accumulation of 25 years since date of 
manufacture, or prior to the accumulation of the number of flights 
equivalent to 17,000 flights at 6.5 psi; whichever occurs first. Or
    (ii) Within 30 days after the effective date of this AD.
    (b) This paragraph is applicable only to airplanes listed in 
British Aerospace PTL No. 320, Issue 3, dated October 1, 1993 (for 
Model Viscount 744 and 745D airplanes); and PTL No. 189, Issue 5, 
dated May 1, 1994 (for Model Viscount 810 airplanes). To operate the 
airplane for a maximum of 45 years since date of manufacture or 
75,000 total landings, whichever occurs first: Prior to the 
accumulation of 30 years since date of manufacture, or within 2 
months after the effective date of this AD, whichever occurs later, 
perform the inspections, change the inspection times, install the 
modifications, and perform all other actions specified in the 
applicable PTL.
    (c) If any crack(s) or corrosion is found during any inspection 
required by this AD, prior to further flight, repair in accordance 
with British Aerospace PTL No. 221, Issue 10, dated May 1, 1994 (for 
Model 744 and 745D airplanes), or PTL No. 94, Issue 10, dated 
September 1, 1993 (for Model 810 airplanes).
    (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, 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 3: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Standardization Branch, ANM-113.

    (e) 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 May 3, 1995.
James V. Devany,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 95-11357 Filed 5-8-95; 8:45 am]
BILLING CODE 4910-13-U