[Federal Register Volume 63, Number 84 (Friday, May 1, 1998)]
[Proposed Rules]
[Pages 24136-24138]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-11561]
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Proposed Rules
Federal Register
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This section of the FEDERAL REGISTER contains notices to the public of
the proposed issuance of rules and regulations. The purpose of these
notices is to give interested persons an opportunity to participate in
the rule making prior to the adoption of the final rules.
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Federal Register / Vol. 63, No. 84 / Friday, May 1, 1998 / Proposed
Rules
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 98-NM-113-AD]
RIN 2120-AA64
Airworthiness Directives; British Aerospace BAe Model ATP
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 certain British Aerospace BAe
Model ATP airplanes. This proposal would require repetitive inspections
for discrepancies of the spring strut assembly of the forward door of
the main landing gear (MLG), and replacement of the existing spring
strut assembly with a new or serviceable part, if necessary. This
proposal also would require eventual replacement of the existing spring
strut assembly with an improved part, which, when accomplished, would
terminate the repetitive inspections. This proposal is prompted by
issuance of mandatory continuing airworthiness information by a foreign
civil airworthiness authority. The actions specified by the proposed AD
are intended to prevent failure of the spring strut assembly of the
forward door of the MLG, which, if not corrected, could result in
inability to extend the MLG.
DATES: Comments must be received by June 1, 1998.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Transport Airplane Directorate, ANM-114,
Attention: Rules Docket No. 98-NM-113-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 AI(R) American Support, Inc., 13850 Mclearen Road,
Herndon, Virginia 20171. This information may be examined at the FAA,
Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton,
Washington.
FOR FURTHER INFORMATION CONTACT: Norman B. Martenson, Manager,
International Branch, ANM-116, FAA, Transport Airplane Directorate,
1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425)
227-2110; fax (425) 227-1149.
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 98-NM-113-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-114, Attention: Rules
Docket No. 98-NM-113-AD, 1601 Lind Avenue, SW., Renton, Washington
98055-4056.
Discussion
The Civil Aviation Authority (CAA), which is the airworthiness
authority for the United Kingdom, notified the FAA that an unsafe
condition may exist on certain British Aerospace BAe Model ATP
airplanes. The CAA advises that a BAe Model ATP airplane made an
emergency landing because the left main landing gear (MLG) failed to
extend. Investigation of the incident revealed a number of possible
causes, including corrosion, wear, or damage to the operating
mechanism. On March 31, 1998, the FAA issued a notice of proposed
rulemaking (NPRM) to address these possible causes (reference Docket
No. 97-NM-312-AD; 63 FR 16713, April 6, 1998).
Further investigation of the incident revealed that the spring
strut assembly of the forward door of the MLG on the airplane was
loose. (The spring strut assembly is part of the mechanism which opens
the MLG door and allows extension and retraction of the MLG.) Similar
loose attachment also was observed on one other in-service airplane,
and has been attributed to damage of the rivets that connect the fork
end of the spring strut assembly to the tube of the assembly. Failure
of these rivets, if not corrected, could cause failure of the spring
strut assembly of the forward door of the MLG, which could result in
inability to extend the MLG.
Explanation of Relevant Service Information
The manufacturer has issued British Aerospace Alert Service
Bulletin ATP-32-85, Revision 1, dated March 20, 1998, which describes
procedures for repetitive visual inspections for discrepancies of the
fork end of the spring strut assembly of the forward door of the left
and right MLG on the airplane. The actions involve inspecting for
looseness or damage of the rivets that connect the fork end fitting to
the tube of the spring strut assembly, and inspecting for movement
between the fork end fitting and the tube of the spring strut assembly.
This alert service bulletin also describes procedures for replacing the
spring strut assembly with a new or serviceable part, if any rivet is
found to be damaged, if any rivet hole is found to be elongated, or if
the
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attachment of the fork end fitting to the tube is found to be loose.
The CAA classified this alert service bulletin as mandatory in order to
assure the continued airworthiness of these airplanes in the United
Kingdom.
The manufacturer also has issued British Aerospace Service Bulletin
ATP-32-87, dated January 29, 1998, which describes procedures for
replacing the existing spring strut assembly of the forward door of the
MLG with an improved spring strut assembly. Such replacement eliminates
the need for the repetitive inspections described previously.
Accomplishment of the actions specified in the service bulletins is
intended to adequately address the identified unsafe condition.
FAA's Conclusions
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.
Explanation of Requirements of Proposed Rule
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 accomplishment of
actions specified in the service bulletins described previously, except
as discussed below.
Differences Between Proposed Rule and Service Bulletin
Operators should note that this AD proposes to mandate the
replacement of the existing spring strut assembly of the forward door
of the MLG with an improved spring strut assembly, as described in
British Aerospace Service Bulletin ATP-32-87, dated January 29, 1998,
as terminating action for the repetitive inspections specified in
British Aerospace Alert Service Bulletin ATP-32-85, Revision 1, dated
March 20, 1998. Accomplishment of the modification specified in this
service bulletin has not been classified as mandatory by the CAA.
The FAA has determined that, in certain cases, long-term continued
operational safety will be better assured by design changes to remove
the source of the problem, rather than by repetitive inspections. Long-
term inspections may not be providing the degree of safety assurance
necessary for the transport airplane fleet. This, coupled with a better
understanding of the human factors associated with numerous continual
inspections, has led the FAA to consider placing less emphasis on
inspections and more emphasis on design improvements. The proposed
requirement to replace the existing spring strut assembly with an
improved spring strut assembly is in consonance with these conditions.
Cost Impact
The FAA estimates that 10 airplanes of U.S. registry would be
affected by this proposed AD.
It would take approximately 4 work hours (2 work hours per MLG) to
accomplish the proposed inspection, at an average labor rate of $60 per
work hour. Based on this figure, the cost impact of the inspection
proposed by this AD on U.S. operators is estimated to be $2,400, or
$240 per airplane, per inspection cycle.
It would take approximately 12 work hours (6 work hours per MLG) to
accomplish the proposed modification, at an average labor rate of $60
per work hour. Required parts would cost approximately $2,200 per
airplane ($1,100 per MLG). Based on this figure, the cost impact of the
modification proposed by this AD on U.S. operators is estimated to be
$29,200, or $2,920 per airplane.
The cost impact figures discussed above are 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.
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 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. 106(g), 40113, 44701.
Sec. 39.13 [Amended]
2. Section 39.13 is amended by adding the following new
airworthiness directive:
British Aerospace Regional Aircraft (Formerly Jetstream Aircraft
Limited; British Aerospace (Commercial Aircraft) Limited): Docket
98-NM-113-AD.
Applicability: BAe Model ATP airplanes, as listed in British
Aerospace Alert Service Bulletin ATP-32-85, Revision 1, dated March
20, 1998, 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 (c) 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, unless accomplished
previously.
To prevent failure of the spring strut assembly of the forward
door of the main landing gear (MLG), which, if not corrected, could
result in the inability to extend the MLG, accomplish the following:
(a) Within 600 flight hours after the effective date of this AD,
perform a visual
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inspection for discrepancies of the fork end of the spring strut
assembly of the forward door of the MLG, on the left and right side
of the airplane; in accordance with British Aerospace Alert Service
Bulletin ATP-32-85, Revision 1, dated March 20, 1998.
(1) If no discrepancy is detected, repeat the visual inspection
thereafter at intervals not to exceed 1,500 flight hours until the
actions specified by paragraph (b) of this AD are accomplished.
(2) If any discrepancy is detected, prior to further flight,
replace the existing spring strut assembly with a new or serviceable
part, in accordance with the alert service bulletin. Repeat the
visual inspection thereafter at intervals not to exceed 1,500 flight
hours until the actions specified by paragraph (b) of this AD are
accomplished.
(b) Within 18 months after the effective date of this AD,
replace the spring strut assembly of the forward door of the MLG
with an improved spring strut assembly, on the left and right side
of the airplane; in accordance with British Aerospace Service
Bulletin ATP-32-87, dated January 29, 1998. This replacement
constitutes terminating action for the requirements of this AD.
(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, International Branch, ANM-116, FAA,
Transport Airplane Directorate. Operators shall submit their request
through an appropriate FAA Principal Maintenance Inspector, who may
add comments and then send it to the Manager, International Branch,
ANM-116.
Note 2: Information concerning the existence of approved
alternative methods of compliance with this AD, if any, may be
obtained from the International Branch, ANM-116.
(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 24, 1998.
Gary L. Killion,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 98-11561 Filed 4-30-98; 8:45 am]
BILLING CODE 4910-13-P