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

[Federal Register Volume 63, Number 152 (Friday, August 7, 1998)]
[Rules and Regulations]
[Pages 42201-42203]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-20840]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-CE-03-AD; Amendment 39-10691; AD 98-16-15]
RIN 2120-AA64


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

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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SUMMARY: This amendment adopts a new airworthiness directive (AD) that 
applies to certain British Aerospace Model B.121 Series 1, 2, and 3 
airplanes. This AD requires installing an

[[Page 42202]]

inspection opening in the area of the main spar web, repetitively 
inspecting the area at the main spar web for cracks, and repairing or 
replacing any cracked part. This AD also requires installing nuts of 
improved design at the wing to fuselage main-spar attachment fittings. 
This AD is the result of mandatory continuing airworthiness information 
(MCAI) issued by the airworthiness authority for the United Kingdom. 
The actions specified by this 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: Effective September 21, 1998.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of September 21, 1998.

ADDRESSES: Service information that applies to this 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 
may also be examined at 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; or at the Office of the Federal Register, 800 North Capitol 
Street, NW, suite 700, Washington, DC.

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:

Events Leading to the Issuance of This AD

    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 as specified in the NPRM 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.
    After issuance of the NPRM, British Aerospace 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 re-examined the service history and 
evaluated reports from the field and 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 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.

    This prompted the FAA to issue 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. This proposal was published in the Federal Register as a 
supplemental NPRM on May 29, 1998 (63 FR 29362). The supplemental NPRM 
proposed to also require installing nuts of improved design at the wing 
to fuselage main-spar attachment fittings and deleting the inspection 
at the area of the wing to fuselage attach bolt holes for corrosion. 
Accomplishment of the proposed action as specified in the supplemental 
NPRM would be in accordance with the service information previously 
referenced.
    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.

The FAA's Determination

    After careful review of all available information related to the 
subject presented above, the FAA has determined that air safety and the 
public interest require the adoption of the rule as proposed except for 
minor editorial corrections. The FAA has determined that these minor 
corrections will not change the meaning of the AD and will not add any 
additional burden upon the public than was already proposed.

Cost Impact

    The FAA estimates that 2 airplanes in the U.S. registry will be 
affected by this AD; that it will take approximately 37 workhours per 
airplane to accomplish the 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 replacements. Based on these figures, the total cost 
impact of this 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 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 adopted herein will 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 final 
rule does

[[Page 42203]]

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) 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 final 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, Incorporation by 
reference, Safety.

Adoption of the Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration amends 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:

98-16-15  British Aerospace (Operations) Limited: Amendment 39-
10691; 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 after the effective date of this AD, 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 (f) 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 British 
Aerospace PUP Mandatory Service Bulletin No. B121/106, dated January 
12, 1998, and British Aerospace PUP Mandatory Service Bulletin No. 
B121/105, dated January 12, 1998, 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.
    (h) The replacements, installation, and inspections required by 
this AD shall be done in accordance with British Aerospace PUP 
Mandatory Service Bulletin No. B121/106, dated January 12, 1998, and 
British Aerospace PUP Mandatory Service Bulletin No. B121/105, dated 
January 12, 1998. This incorporation by reference was approved by 
the Director of the Federal Register in accordance with 5 U.S.C. 
552(a) and 1 CFR part 51. Copies may be obtained from British 
Aerospace (Operations) Limited, British Aerospace Regional Aircraft, 
Prestwick International Airport, Ayrshire, KA9 2RW, Scotland. Copies 
may be inspected at the FAA, Central Region, Office of the Regional 
Counsel, Room 1558, 601 E. 12th Street, Kansas City, Missouri, or at 
the Office of the Federal Register, 800 North Capitol Street, NW, 
suite 700, Washington, DC.

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

    (i) This amendment becomes effective on September 21, 1998.

    Issued in Kansas City, Missouri, on July 28, 1998.
Michael Gallagher,
Manager, Small Airplane Directorate, Aircraft Certification Service.
[FR Doc. 98-20840 Filed 8-6-98; 8:45 am]
BILLING CODE 4910-13-U

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