[Federal Register Volume 63, Number 182 (Monday, September 21, 1998)]
[Rules and Regulations]
[Pages 50135-50137]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-24906]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 97-NM-310-AD; Amendment 39-10771; AD 98-20-05]
RIN 2120-AA64


Airworthiness Directives; Airbus Model A310 and A300-600 Series 
Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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SUMMARY: This amendment supersedes an existing airworthiness directive 
(AD), applicable to certain Airbus Model A310 and A300-600 series 
airplanes, that currently requires, among other things, repetitive 
inspections to ensure correct synchronization of the hydraulic control 
valves of the trimmable horizontal stabilizer (THS) actuator; 
replacement of the horizontal stabilizer actuator motors with new or 
serviceable motors and resynchronization of the valves, or adjustment 
of the synchronization, if necessary; and a functional test of the THS. 
This amendment adds a requirement to replace the hydraulic motor of the 
THS with an improved motor, which constitutes terminating action for 
the repetitive inspections. This amendment also expands the 
applicability to include additional airplanes. This amendment is 
prompted by issuance of mandatory continuing airworthiness information 
by a foreign civil airworthiness authority. The actions specified by 
this AD are intended to prevent desynchronization of the hydraulic 
control valves, which could result in runaway of the horizontal 
stabilizer to its full up or down position, subsequent reduced 
maneuvering capability, and potential pitch upset.

DATES: Effective October 26, 1998.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of October 26, 1998.
    The incorporation by reference of Airbus All Operators Telex (AOT) 
27-21, Revision 1, dated January 5, 1996, as listed in the regulations, 
was approved previously by the Director of the Federal

[[Page 50136]]

Register as of February 5, 1996 (61 FR 2697, January 29, 1996).

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: 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: A proposal to amend part 39 of the Federal 
Aviation Regulations (14 CFR part 39) by superseding AD 96-01-52, 
amendment 39-9491 (61 FR 2697, January 29, 1996), which is applicable 
to certain Airbus Model A310 and A300-600 series airplanes, was 
published in the Federal Register on April 30, 1998 (63 FR 23690). The 
action proposed to continue to require, among other things, repetitive 
inspections to ensure correct synchronization of the hydraulic control 
valves of the trimmable horizontal stabilizer (THS) actuator; 
replacement of the horizontal stabilizer actuator motors with new or 
serviceable motors and resynchronization of the valves, or adjustment 
of the synchronization, if necessary; and a functional test of the THS. 
The action also proposed to add a requirement to replace the hydraulic 
motor of the THS with an improved motor, which would constitute 
terminating action for the repetitive inspections.
    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. Due consideration has been given to 
the comments received.
    The Air Transport Association (ATA) of America, on behalf of one of 
its members, requests that the proposed compliance time for the 
replacement of the hydraulic motor of the trimmable horizontal 
stabilizer actuator be extended from 1 year to 18 months. The commenter 
bases its request on the limitations of the overhaul vendor, the 
equivalent level of safety provided by the frequent inspections, and 
the lack of findings during those inspections.
    The commenter has established an aggressive motor replacement 
program, but has been limited by the ability of the overhaul vendor to 
modify and return the units. Due to the limited number of spares 
available and a turnaround time of 20 days, the commenter is only able 
to accomplish the replacement on one or two airplanes per month. At 
that rate of accomplishment, this commenter believes 18 months to be 
the minimum amount of time in which it can accomplish the replacement 
on its entire fleet.
    The commenter also states that, for the past two years, it has been 
performing the inspection required by AD 96-01-52 at intervals of 500 
hours time-in-service on unmodified units, and has yet to find any 
desynchronized motors. Further, the commenter notes that, since the 
issuance of AD 96-01-52, the Direction Generale de l'Aviation Civile, 
(DGAC), which is the airworthiness authority for France, revised the 
inspection interval to 1,200 flight hours; however, AD 96-01-52 was not 
revised to reflect this relaxation of the inspection interval.
    The FAA concurs with the commenter's request. The FAA has confirmed 
that the DGAC is in the process of revising its related airworthiness 
directive to extend the compliance time for accomplishment of the 
replacement. In light of this, and in consideration of the fact that a 
more stringent inspection interval of 500 hours time-in-service is 
retained in this AD, the FAA finds that the compliance time for motor 
replacement can be extended to 18 months without compromising the 
safety of the affected fleet. The final rule has been revised 
accordingly.

Conclusion

    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.

Cost Impact

    There are approximately 88 airplanes of U.S. registry that will be 
affected by this AD.
    The actions that are currently required by AD 96-01-52, and 
retained in this AD, take approximately 1 work hour per airplane to 
accomplish, at an average labor rate of $60 per work hour. Based on 
these figures, the cost impact of the requirements of the existing AD 
on U.S. operators is estimated to be $5,280, or $60 per airplane.
    The new actions that are required by this new AD will take 
approximately 4 work hours per airplane to accomplish, at an average 
labor rate of $60 per work hour. Required parts will be provided by the 
manufacturer at no cost to operators. Based on these figures, the cost 
impact of the new requirements of this AD on U.S. operators is 
estimated to be $21,120, or $240 per airplane.
    The cost impact figures discussed above are 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.

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 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. 106(g), 40113, 44701.

[[Page 50137]]

Sec. 39.13  [Amended]

    2. Section 39.13 is amended by removing amendment 39-9491 (61 FR 
2697, January 29, 1996), and by adding a new airworthiness directive 
(AD), amendment 39-10771, to read as follows:

98-20-05  Airbus: Amendment 39-10771. Docket 97-NM-310-AD. 
Supersedes AD 96-01-52, Amendment 39-9491.

    Applicability: Model A310 and A300-600 series airplanes on which 
Airbus Modification 11607 has not been installed, certificated in 
any category.

    Note 1: This AD applies to each airplane identified in the 
preceding applicability provision, regardless of whether it has been 
otherwise 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 (e) 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 desynchronization of the hydraulic control valves, 
which could result in runaway of the horizontal stabilizer to its 
full up or down position, subsequent reduced maneuvering capability, 
and potential pitch upset, accomplish the following:

Restatement of Requirements of AD 96-01-52

    (a) Within 12 days after February 5, 1996 (the effective date of 
AD 96-01-52, amendment 39-9491), perform an inspection to ensure 
correct synchronization of the hydraulic control valves of the 
trimmable horizontal stabilizer (THS) actuator, in accordance with 
paragraph 4.2.2.1 of Airbus All Operators Telex (AOT) 27-21, 
Revision 1, dated January 5, 1996.
    (1) If the actuator is synchronized correctly, prior to further 
flight, perform a functional test of the THS in accordance with 
paragraph 4.2.2.1 of the AOT. Thereafter, repeat the inspection 
required by paragraph (a) of this AD at intervals not to exceed 500 
hours time-in-service.
    (2) If the actuator is desynchronized slightly, as specified in 
the AOT, prior to further flight, adjust the synchronization, and 
perform a functional test of the THS, in accordance with paragraph 
4.2.2.2 of the AOT. Thereafter, repeat the inspection required by 
paragraph (a) of this AD at intervals not to exceed 500 hours time-
in-service.
    (3) If the actuator is desynchronized significantly, as 
specified in the AOT, prior to further flight, accomplish either 
paragraph (a)(3)(i) or (a)(3)(ii) of this AD. Prior to further 
flight following the accomplishment of either of those paragraphs, 
adjust the synchronization, and perform a functional test of the 
THS, in accordance with paragraph 4.2.2.3 of the AOT. Thereafter, 
repeat the inspection required by paragraph (a) of this AD at 
intervals not to exceed 500 hours time-in-service.
    (i) Remove and replace the hydraulic motors of the horizontal 
stabilizer actuator (HSA) with new or serviceable motors in 
accordance with procedures specified in the Airplane Maintenance 
Manual. Or
    (ii) Remove the hydraulic motors of the HSA and perform the 
various follow-on actions specified in paragraph 4.2.2.4 of the AOT, 
in accordance with that paragraph. (The follow-on actions include 
checking the motors and the cam seats, assembling the motors, and 
metal stamping the modification plate of the motors.) If any 
discrepancy is found during the check, prior to further flight, 
repair in accordance with paragraph 4.2.2.4 of the AOT.
    (b) For airplanes on which any maintenance action relating to a 
hydraulic motor or a hydraulic valve block of the HSA has occurred 
since the airplane was new: Within 12 days after February 5, 1996, 
accomplish either paragraph (b)(1) or (b)(2) of this AD.
    (1) Replace both hydraulic motors of the HSA with new or 
serviceable motors in accordance with the procedures specified in 
the Airplane Maintenance Manual. Adjust the synchronization, and 
perform a functional test of the THS in accordance with paragraph 
4.2.2.3 of Airbus AOT 27-21, Revision 1, dated January 5, 1996. 
Thereafter, perform the repetitive inspections required by paragraph 
(a) of this AD at intervals not to exceed 500 hours time-in-service. 
Or
    (2) Remove the hydraulic motors of the HSA and perform the 
various follow-on actions specified in paragraph 4.2.2.4 of the AOT, 
in accordance with that paragraph of the AOT. Adjust the 
synchronization, and perform a functional test of the THS in 
accordance with paragraph 4.2.2.3 of the AOT. (The follow-on actions 
include checking the motors and the cam seats, assembling the 
motors, and metal stamping the modification plate of the motors.) If 
any discrepancy is found during the check, prior to further flight, 
repair in accordance with paragraph 4.2.2.4 of the AOT. Thereafter, 
perform the repetitive inspections required by paragraph (a) of this 
AD at intervals not to exceed 500 hours time-in-service.

New Requirements of This AD

    (c) Within 18 months after the effective date of this AD, 
replace the hydraulic motors of the THS actuator with improved 
motors, in accordance with Airbus Service Bulletin A310-27-2081 (for 
Model A310 series airplanes) or A300-27-6035 (for Model A300-600 
series airplanes), both dated November 26, 1996, as applicable. 
Accomplishment of this action constitutes terminating action for the 
repetitive inspection requirements of this AD.
    (d) As of the effective date of this AD, no person shall install 
on any airplane a THS actuator having part number 47142-201/-203.
    (e)(1) 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 
requests through an appropriate FAA Principal Maintenance Inspector, 
who may add comments and then send it to the Manager, International 
Branch, ANM-116.
    (e)(2) Alternative methods of compliance, approved previously in 
accordance with AD 96-01-52, amendment 39-9491, are approved as 
alternative methods of compliance with paragraphs (a) and (b) of 
this AD.

    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.

    (f) 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.
    (g) Except as provided by paragraphs (a)(3)(i) and (b)(1) of 
this AD, the actions shall be done in accordance with Airbus All 
Operators Telex (AOT) 27-21, Revision 1, dated January 5, 1996; 
Airbus Service Bulletin A310-27-2081, dated November 26, 1996; or 
Airbus Service Bulletin A300-27-6035, dated November 26, 1996; as 
applicable.
    (1) The incorporation by reference of Airbus Service Bulletin 
A310-27-2081, dated November 26, 1996, and Airbus Service Bulletin 
A300-27-6035, dated November 26, 1996, is approved by the Director 
of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR 
part 51.
    (2) The incorporation by reference of Airbus All Operators Telex 
(AOT) 27-21, Revision 1, dated January 5, 1996, was approved 
previously by the Director of the Federal Register as of February 5, 
1996 (61 FR 2697, January 29, 1996).
    (3) 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.

    Note 3: The subject of this AD is addressed in French 
airworthiness directive 97-081-217(B), dated March 12, 1997.

    (h) This amendment becomes effective on October 26, 1998.

    Issued in Renton, Washington, on September 11, 1998.
Dorenda D. Baker,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 98-24906 Filed 9-18-98; 8:45 am]
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