[Federal Register Volume 59, Number 223 (Monday, November 21, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-27849]
[[Page Unknown]]
[Federal Register: November 21, 1994]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 93-NM-210-AD; Amendment 39-9068; AD 94-23-06]
Airworthiness Directives; Airbus Model A320-111, -211, and -231
Airplanes
AGENCY: Federal Aviation Administration, DOT.
ACTION: Final rule.
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SUMMARY: This amendment adopts a new airworthiness directive (AD),
applicable to certain Airbus Model A320-111, -211, and -231 airplanes,
that requires modification of the currently installed one-stage shock
absorbers on the main landing gear to two-stage shock absorbers. This
amendment is prompted by the results of an evaluation of the air-to-
ground sensing logic relative to the operation of other airplane
systems during landing in adverse weather conditions. The actions
specified by this AD are intended to prevent a delay in sensing by the
air-to-ground logic system that the airplane is on the ground, which
could prevent the airplane from achieving the landing distances
specified in the FAA-approved Airplane Flight Manual (AFM).
DATES: Effective December 21, 1994.
The incorporation by reference of certain publications listed in
the regulations is approved by the Director of the Federal Register as
of December 21, 1994.
ADDRESSES: The service information referenced in this AD may be
obtained from Airbus Industrie, 1 Rond Point Maurice Bellonte, 31707
Blagnac Cedex, France. This information may be examined at the Federal
Aviation Administration (FAA), Transport Airplane Directorate, Rules
Docket, 1601 Lind Avenue, SW., Renton, Washington; or at the Office of
the Federal Register, 800 North Capitol Street, NW., suite 700,
Washington, DC.
FOR FURTHER INFORMATION CONTACT:
Stephen Slotte, Aerospace Engineer, Standardization Branch, ANM-113,
FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton,
Washington 98055-4056; telephone (206) 227-2797; fax (206) 227-1320.
SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal
Aviation Regulations (14 CFR part 39) to include an airworthiness
directive (AD) that is applicable to certain Airbus Model A320-111, -
211, and -231 airplanes was published in the Federal Register on
December 29, 1993 (58 FR 68786). That action proposed to require
modification of the currently installed one-stage shock absorbers on
the main landing gear (MLG) to two-stage shock absorbers.
Interested persons have been afforded an opportunity to participate
in the making of this amendment. Due consideration has been given to
the comments received.
One commenter supports the proposed rule.
One commenter opposes the proposed requirement to modify the
currently installed one-stage shock absorber on the MLG to two-stage
shock absorbers. This commenter states that the requirement is
unnecessary due to the fact that the one-stage absorbers currently
installed on Model A320 series airplanes, when operated within the
certification standards of the airplane, do not adversely affect the
airworthiness of these airplanes. This commenter contends that the
purpose of the two-stage shock absorber is solely to improve passenger
comfort. The FAA does not concur that this rulemaking action is
unnecessary. The FAA has determined that the installation of the two-
stage shock absorber will improve the airplane's ability to achieve the
landing distances specified in the FAA-approved Airplane Flight Manual
(AFM). Earlier activation of supplemental braking devices, which would
be available by installing two-stage shock absorbers, will enhance
deceleration of the airplane when necessary to meet the required
landing distances. The FAA has re-evaluated the air-to-ground sensing
logic, has reviewed all other available data, and has determined that
an unsafe condition exists with regard to the airplane failing to
achieve the landing distances specified in the FAA-approved AFM.
Further, the FAA has determined that this AD action is necessary for
airplanes of this type design that are certificated for operation in
the United States.
One commenter asserts that the FAA is taking action contrary to the
normal course of action by proposing to issue the AD, when the French
Direction Generale de l'Aviation Civile (DGAC), which is the
airworthiness authority for France, has not issued a parallel AD. From
this comment, the FAA infers that the commenter is requesting that the
rule be withdrawn or delayed until the DGAC issues a similar mandatory
action. The FAA does not concur. While the United States and France
observe the provisions of the bilateral airworthiness agreement, it
remains the responsibility of the FAA to monitor and maintain the
continuing airworthiness of U.S.-type certificated and registered
airplanes. The bilateral airworthiness agreements do not restrict the
FAA from issuing AD's based upon its own finding of an unsafe
condition, regardless of the decision made by another airworthiness
authority relative to the same subject. In that the FAA has determined
that an unsafe condition exists, and that action is necessary to
correct that condition in the fleet, the issuance of this AD is not
only appropriate, but warranted.
One commenter suggests that the issuance of this rule be delayed
until such time that a lower cost alternative can be developed by the
manufacturer. In the interim, this commenter suggests that the proposal
be revised to require a periodic inspection to be performed at 15-month
intervals. The FAA does not concur. To delay this action would be
inappropriate, since the FAA has determined that an unsafe condition
exists, a corrective modification is currently available, and the
modification must be accomplished to ensure continued safety. However,
paragraph (b) of the final rule does provide affected operators the
opportunity to obtain approval from the FAA for alternative methods of
compliance by presenting justification for those alternatives.
Two commenters request that the proposed compliance time of 12
months be extended to accomplish the proposed modification of the shock
absorbers. One of these commenters requests that the compliance time be
extended to 24 months. The other commenter requests that the compliance
time be extended to 60 months, in light of the low probability of
duplicating the combination of factors that may result in an accident.
This commenter notes that, due to the unavailability of manpower and
tooling, the proposed modification would result in a minimum of three
days of downtime per airplane. Both commenters state that the
manufacturer may be unable to provide an adequate number of MLG pistons
to accomplish the modification within the proposed 12-month compliance
time.
The FAA concurs that the compliance time may be extended somewhat.
The FAA acknowledges the low probability of duplicating all of the
factors that may result in an accident. However, in the unlikely event
that all of the factors should be duplicated, airplanes equipped with
dual stage shock absorbers would be able to activate, at an earlier
stage of the landing roll, all available braking devices, including the
deployment of ground spoilers, application of wheel brakes, and
deployment of thrust reversers. Proper activation of braking devices
would permit the airplane to land within the distances specified in the
FAA-approved AFM. In light of the potential for these airplanes to
overrun the end of the runway due to delayed onset of braking, the FAA
cannot concur with the one commenter's request to extend the compliance
time to 60 months; the FAA considers that such an extension (five times
the amount of time proposed) would adversely affect safety. However, it
was not the FAA's intent to impose an undue economic burden on
operators by requiring them to take airplanes out of service for an
extended period of time due to the problem posed by a lack of available
parts to accomplish the modification required by this AD. Although the
airframe manufacturer has indicated that ample modification parts are
currently available, the supplier of those parts has indicated that
shipping to operators may take an extended period of time. In light of
this, the FAA has determined that an extension of the compliance time
to 18 months is appropriate; it will allow sufficient time for
operators to obtain the parts necessary to accomplish the modification,
while minimizing the economic burden on operators. The FAA finds that
this extension of the compliance time will not adversely affect the
safety of the fleet. Accordingly, paragraph (a) of the final rule has
been revised to extend the compliance time to accomplish the
modification of the shock absorber to 18 months.
After careful review of the available data, including the comments
noted above, the FAA has determined that air safety and the public
interest require the adoption of the rule with the change previously
described. The FAA has determined that this change will neither
increase the economic burden on any operator nor increase the scope of
the AD.
The FAA estimates that 35 airplanes of U.S. registry will be
affected by this AD, that it will take approximately 58 work hours per
airplane to accomplish the required actions, and that the average labor
rate is $55 per work hour. Required parts will cost approximately
$16,000 per airplane. Based on these figures, the total cost impact of
the AD on U.S. operators is estimated to be $671,650, or $19,190 per
airplane.
The total cost impact figure discussed above is based on
assumptions that no operator has yet accomplished any of the
requirements of this AD action, and that no operator would accomplish
those actions in the future if this AD were not adopted.
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 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 final evaluation has been prepared for this action
and it is contained in the Rules Docket. A copy of it may be obtained
from 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. 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:
94-23-06 Airbus Industrie: Amendment 39-9068. Docket 93-NM-210-AD.
Applicability: Model A320-111, -211, and -231 airplanes, as
listed in Airbus Industrie Service Bulletin A320-32-1058, Revision
2, dated June 16, 1993, certificated in any category.
Compliance: Required as indicated, unless accomplished
previously.
To prevent a delay in sensing by the air-to-ground logic system
that the airplane is on the ground, which could prevent the airplane
from achieving the landing distances specified in the FAA-approved
Airplane Flight Manual (AFM), accomplish the following:
(a) Within 18 months after the effective date of this AD, modify
the currently installed one-stage shock absorbers to two-stage shock
absorbers, in accordance with Airbus Industrie Service Bulletin
A320-32-1058, Revision 2, dated June 16, 1993.
(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
Secs. 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.
(d) The modification shall be done in accordance with Airbus
Industrie Service Bulletin A320-32-1058, Revision 2, dated June 16,
1993. 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 Airbus Industrie, 1 Rond Point
Maurice Bellonte, 31707 Blagnac Cedex, France. Copies may be
inspected at the FAA, Transport Airplane Directorate, 1601 Lind
Avenue, SW., Renton, Washington; or at the Office of the Federal
Register, 800 North Capitol Street, NW., suite 700, Washington, DC.
(e) This amendment becomes effective on December 21, 1994.
Issued in Renton, Washington, on November 4, 1994.
S. R. Miller,
Acting Management, Transport Airplane Directorate Aircraft
Certification Service.
[FR Doc. 94-27849 Filed 11-18-94; 8:45 am]
BILLING CODE 4910-13-U