[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