[Federal Register Volume 63, Number 103 (Friday, May 29, 1998)]
[Proposed Rules]
[Pages 29362-29364]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-14189]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-CE-03-AD]
RIN 2120-AA64


Airworthiness Directives; British Aerospace Model B.121 Series 1, 
2, and 3 Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Supplemental notice of proposed rulemaking (NPRM); Reopening of 
the comment period.

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SUMMARY: This document proposes to revise an earlier proposed 
airworthiness directive (AD) that would have required the following on 
certain British Aerospace Model B.121 Series 1, 2, and 3 airplanes: 
installing an inspection opening in the area of the main spar web, 
repetitively inspecting the area at the main spar web for cracks and 
the area of the wing to fuselage attach bolt holes for corrosion, and 
repairing or replacing any cracked or corroded part. The proposed AD 
was the result of mandatory continuing airworthiness information (MCAI) 
issued by the airworthiness authority for the United Kingdom. Since 
issuing the NPRM, British Aerospace has developed additional service 
information to that referenced in the previous proposal to include the 
installation of nuts of improved design at the wing to fuselage main-
spar attachment fittings and the deletion of the inspection of the area 
of the wing to fuselage attach bolt holes for corrosion. The improved 
design nuts provide better torque retention than the nuts originally 
installed. The Federal Aviation Administration (FAA) has determined 
that the above-referenced changes in the revised service information 
should be incorporated into the NPRM, and that the comment period for 
the proposal should be reopened and the public should have additional 
time to comment. The actions specified by the proposed AD are intended 
to prevent structural failure of the main spar web area caused by 
fatigue cracking or separation of the wing caused by loose nuts at the 
wing to fuselage main-spar attachment fittings, which could result in 
loss of control of the airplane.

DATES: Comments must be received on or before July 3, 1998.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Central Region, Office of the Regional Counsel, 
Attention: Rules Docket No. 98-CE-03-AD, Room 1558, 601 E. 12th Street, 
Kansas City, Missouri 64106. Comments may be inspected at this location 
between 8 a.m. and 4 p.m., Monday through Friday, holidays excepted.
    Service information that applies to the proposed AD may be obtained 
from British Aerospace (Operations) Limited, British Aerospace Regional 
Aircraft, Prestwick International Airport, Ayrshire, KA9 2RW, Scotland; 
telephone: (01292) 479888; facsimile: (01292) 479703. This information 
also may be examined at the Rules Docket at the address above.

FOR FURTHER INFORMATION CONTACT: Mr. Roger Chudy, Aerospace Engineer, 
Small Airplane Directorate, Aircraft Certification Service, 1201 
Walnut, suite 900, Kansas City, Missouri 64106; telephone: (816) 426-
6932; facsimile: (816) 426-2169

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 should 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 that summarizes each FAA-public contact concerned 
with the substance of this

[[Page 29363]]

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 No. 98-CE-03-AD.'' The postcard will be date stamped and 
returned to the commenter.

Availability of Supplemental NPRM's

    Any person may obtain a copy of this NPRM by submitting a request 
to the FAA, Central Region, Office of the Regional Counsel, Attention: 
Rules Docket No. 98-CE-03-AD, Room 1558, 601 E. 12th Street, Kansas 
City, Missouri 64106.

Discussion

    A proposal to amend part 39 of the Federal Aviation Regulations (14 
CFR part 39) to include an AD that would apply to certain British 
Aerospace Model B.121 Series 1, 2, and 3 airplanes was published in the 
Federal Register as a notice of proposed rulemaking (NPRM) on March 16, 
1998 (63 FR 12708). The NPRM proposed to require installing an 
inspection opening in the area of the main spar web, repetitively 
inspecting the area at the main spar web for cracks and the area of the 
wing to fuselage attach bolt holes for corrosion, and repairing or 
replacing any cracked or corroded part. Accomplishment of the proposed 
inspections would be required in accordance with British Aerospace PUP 
Mandatory Service Bulletin No. B121/102, Revision No. 1, Issued April 
16, 1997. If necessary, the proposed repair or replacement would be 
required in accordance with a scheme obtained from the manufacturer 
through the FAA, Small Airplane Directorate.
    The NPRM was the result of mandatory continuing airworthiness 
information (MCAI) issued by the airworthiness authority for the United 
Kingdom.
    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. No comments were received on the 
proposed rule or the FAA's determination of the cost to the public.

Events Since Issuance of the NPRM

    Since issuance of the NPRM, British Aerospace has developed 
additional service information to that referenced in the previous 
proposal to include the installation of nuts of improved design at the 
wing to fuselage main-spar attachment fittings and the deletion of the 
inspection at the area of the wing to fuselage attach bolt holes for 
corrosion. The improved design nuts provide better torque retention 
than the ones originally installed.
    In addition, British Aerospace has re-examined the service history 
and evaluated reports from the field and has changed the compliance 
time (that is referenced in the service information) for the inspection 
opening installation and the initial eddy current inspection to upon 
the accumulation of 2,000 flying hours.
    To incorporate the above changes, British Aerospace has issued the 
following service bulletins, which supersede British Aerospace PUP 
Mandatory Service Bulletin No. B121/102, Revision No. 1, Issued April 
16, 1997:

--British Aerospace PUP Mandatory Service Bulletin No. B121/106, dated 
January 12, 1998, which specifies procedures for replacing the nuts 
(with improved design nuts) at the wing to fuselage main-spar 
attachment fittings; and
--British Aerospace PUP Mandatory Service Bulletin No. B121/105, dated 
January 12, 1998, which specifies procedures for installing an 
inspection opening in the area of the main spar web, and inspecting the 
area at the main spar web for cracks. These procedures are basically 
the same as contained in British Aerospace PUP Mandatory Service 
Bulletin No. B121/102, Revision No. 1, Issued April 16, 1997.

The FAA's Determination

    After examining all information related to the subject described in 
this document, the FAA has determined that:

--Improved design nuts should be installed at the wing to fuselage 
main-spar attachment fittings;
--The improved service information should be incorporated into the 
proposed AD;
--The compliance time of the proposed inspection opening installation 
and initial eddy current inspection should be changed to coincide with 
the service information referenced above; and
--AD action should be taken to incorporate these changes to prevent 
structural failure of the main spar web area caused by fatigue cracking 
or separation of the wing caused by loose nuts at the wing to fuselage 
main-spar attachment fittings, which could result in loss of control of 
the airplane.

The Supplemental NPRM

    Since installing improved design nuts at the wing to fuselage main-
spar attachment fittings proposes actions that go beyond the scope of 
what was already proposed, the FAA is reopening the comment period to 
allow the public additional time to comment on this proposed action.

Cost Impact

    The FAA estimates that 2 airplanes in the U.S. registry would be 
affected by the proposed AD; that it would take approximately 37 
workhours per airplane to accomplish the proposed initial inspection, 
inspection opening installation, and improved design nut installations; 
that the average labor rate is approximately $60 an hour. There is no 
cost for the parts to accomplish the proposed replacements. Based on 
these figures, the total cost impact of the proposed AD on U.S. 
operators is estimated to be $4,440, or $2,220 per airplane. These 
figures only take into account the cost of the proposed initial 
inspections, inspection opening installation, and improved design nut 
installations; and do not take into account the cost of repetitive 
inspections. The FAA has no way of determining the number of repetitive 
inspections each owner/operator of the affected airplanes will incur.

Regulatory Impact

    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 action (1) is 
not a ``significant regulatory action'' under Executive Order 12866; 
(2) is not a ``significant rule'' under 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 has been placed in the Rules Docket. A copy of 
it may be obtained by contacting the Rules Docket at the location 
provided under the caption ADDRESSES.

[[Page 29364]]

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. 106(g), 40113, 44701.

Sec. 39.13  [Amended]

    2. Section 39.13 is amended by adding a new airworthiness directive 
(AD) to read as follows:

British Aerospace (Operations) Limited: Docket No. 98-CE-03-AD.

    Applicability: Model B.121 Series 1, 2, and 3 airplanes, all 
serial numbers, 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 request approval for an 
alternative method of compliance in accordance with paragraph (f) of 
this AD. The request should include an assessment of the effect of 
the modification, alteration, or repair on the unsafe condition 
addressed by this AD; and, if the unsafe condition has not been 
eliminated, the request should include specific proposed actions to 
address it.

    Compliance: Required as indicated in the body of this AD, unless 
already accomplished.
    To prevent structural failure of the main spar web area caused 
by fatigue cracking or separation of the wing caused by loose nuts 
at the wing to fuselage main-spar attachment fittings, which could 
result in loss of control of the airplane, accomplish the following:
    (a) Within the next 100 hours time-in-service (TIS) after the 
effective date of this AD, replace the nuts (with improved design 
nuts) at the wing to fuselage main-spar attachment fittings in 
accordance with British Aerospace PUP Mandatory Service Bulletin No. 
B121/106, dated January 12, 1998.
    (b) Upon accumulating 2,000 hours TIS on the main spar or within 
the next 50 hours TIS, whichever occurs later, install an inspection 
opening and inspect, using eddy current methods, the area at the 
main spar web for cracks in accordance with the ACCOMPLISHMENT 
INSTRUCTIONS section of British Aerospace PUP Mandatory Service 
Bulletin No. B121/105, dated January 12, 1998.

    Note 2: Accomplishing the installation inspection opening and 
initial eddy current inspection required by this AD in accordance 
with British Aerospace PUP Mandatory Service Bulletin No. B121/102, 
Revision No. 1, Issued April 16, 1997, is considered ``already 
accomplished'' for the requirements of paragraph (b) of this AD.

    (c) Within 800 hours TIS after the initial inspection required 
by paragraph (b) of this AD, and thereafter at intervals not to 
exceed 800 hours TIS, reinspect the area of the main spar web as 
specified in paragraph (b) of this AD.
    (d) If any cracks are found during any inspection required by 
this AD, prior to further flight, accomplish the following:
    (1) Obtain a repair or replacement scheme from the manufacturer 
through the FAA, Small Airplane Directorate, at the address 
specified in paragraph (e) of this AD; and
    (2) Incorporate this scheme and continue to repetitively inspect 
as required by paragraph (c) of this AD, unless specified 
differently in the instructions to the repair or replacement scheme.
    (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.
    (f) An alternative method of compliance or adjustment of the 
initial or repetitive compliance times that provides an equivalent 
level of safety may be approved by the Manager, Small Airplane 
Directorate, Aircraft Certification Service, 1201 Walnut, suite 900, 
Kansas City, Missouri 64106. The request shall be forwarded through 
an appropriate FAA Maintenance Inspector, who may add comments and 
then send it to the Manager, Small Airplane Directorate.

    Note 3: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Small Airplane Directorate.

    (g) Questions or technical information related to the service 
information referenced in this document should be directed to 
British Aerospace (Operations) Limited, British Aerospace Regional 
Aircraft, Prestwick International Airport, Ayrshire, KA9 2RW, 
Scotland; telephone: (01292) 479888; facsimile: (01292) 479703. This 
service information may be examined at the FAA, Central Region, 
Office of the Regional Counsel, Room 1558, 601 E. 12th Street, 
Kansas City, Missouri 64106.

    Note 4: The subject of this AD is addressed in British AD 005-
01-98, not dated.

    Issued in Kansas City, Missouri, on May 21, 1998.
Michael Gallagher,
Manager, Small Airplane Directorate, Aircraft Certification Service.
[FR Doc. 98-14189 Filed 5-28-98; 8:45 am]
BILLING CODE 4910-13-P