[Federal Register Volume 61, Number 238 (Tuesday, December 10, 1996)]
[Proposed Rules]
[Pages 65004-65006]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-31268]


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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 96-CE-57-AD]
RIN 2120-AA64


Airworthiness Directives; Aerospace Technologies of Australia Pty 
Ltd. (Formerly Government Aircraft Factory) Models N22B, N22S, and N24A 
Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes to adopt a new airworthiness directive 
(AD) that would apply to Aerospace Technologies of Australia Pty Ltd. 
(ASTA) Models N22B, N22S, and N24A airplanes. The proposed action would 
require repetitively inspecting the horizontal stabilizer upper and 
lower skin, intercostal angles, and the horizontal stabilizer trailing 
edge channel for cracks; and repairing any cracks or replacing any 
cracked parts, as applicable. The proposed AD results from numerous 
reports of cracking in these horizontal stabilizer areas on the 
affected airplanes. The actions specified by the proposed AD are 
intended to prevent structural failure of the horizontal stabilizer 
caused by fatigue cracks, which could result in loss of control of the 
airplane.

DATES: Comments must be received on or before February 21, 1997.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Central Region, Office of the Assistant Chief 
Counsel, Attention: Rules Docket No. 96-CE-57-AD, Room 1558, 601 E. 
12th Street, Kansas City, Missouri 64106. Comments may be inspected at 
this location between 8 a.m. and 4 p.m., Monday through Friday, 
holidays excepted.
    Service information that applies to the proposed AD may be obtained 
from Aerospace Technologies of Australia Pty Ltd., ASTA DEFENCE, 
Private Bag No. 4, Beach Road Lara 3212, Victoria, Australia. This 
information also may be examined at the Rules Docket at the address 
above.

FOR FURTHER INFORMATION CONTACT: Mr. Ron Atmur, Aerospace Engineer, 
FAA, Los Angeles Aircraft Certification Office, 3960 Paramount 
Boulevard., Lakewood, California 90712; telephone (310) 627-5224; 
facsimile (310) 627-5210.

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 should 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 that summarizes 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 No. 96-CE-57-AD.'' The

[[Page 65005]]

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, Central Region, Office of the Assistant Chief Counsel, 
Attention: Rules Docket No. 96-CE-57-AD, Room 1558, 601 E. 12th Street, 
Kansas City, Missouri 64106.

Discussion

    The Civil Aviation Safety Authority (CASA), which is the 
airworthiness authority for Australia, recently notified the FAA that 
an unsafe condition may exist on certain ASTA Models N22B, N22S, and 
N24A airplanes. The CASA reports a number of incidents of fatigue 
cracking in the areas of the horizontal stabilizer upper and lower 
skin, intercostal angles, and the horizontal stabilizer trailing edge 
channel. These conditions, if not detected and corrected, could lead to 
structural failure of the horizontal stabilizer, which could result in 
loss of control of the airplane.

Applicable Service Information

    ASTA has issued Nomad Service Bulletin (SB) NMD-55-34, dated April 
22, 1996, which includes procedures for inspecting the horizontal 
stabilizer upper and lower skin, intercostal angles, and the horizontal 
stabilizer trailing edge channel.
    The CASA of Australia classified this service bulletin as mandatory 
and issued FCAA AD/GAF-N22/72, dated August 1996, in order to assure 
the continued airworthiness of these airplanes in Australia.

The FAA's Determination

    This airplane model is manufactured in Australia 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 CASA of Australia has kept the 
FAA informed of the situation described above. The FAA has examined the 
findings of the CASA of Australia; reviewed all available information, 
including the service information referenced above; and determined that 
AD action is necessary for products of this type design that are 
certificated for operation in the United States.

Explanation of the Provisions of the Proposed AD

    Since an unsafe condition has been identified that is likely to 
exist or develop in other ASTA Models N22B, N22S, and N24A airplanes of 
the same type design that are registered in the United States, the 
proposed AD would require repetitively inspecting the horizontal 
stabilizer upper and lower skin, intercostal angles, and the horizontal 
stabilizer trailing edge channel for cracks; and repairing any cracks 
or replacing any cracked parts, as applicable.
    Accomplishment of the proposed inspections would be in accordance 
with Nomad SB NMD-55-34, dated April 22, 1996. Accomplishment of any 
proposed repair or replacement, as necessary and as applicable, would 
be in accordance with the Nomad Structural Repair Manual, Chapter 55-
10-11.

Cost Impact

    The FAA estimates that 15 airplanes in the U.S. registry would be 
affected by the proposed AD, that it would take approximately 2 
workhours per airplane to accomplish the proposed initial inspections, 
and that the average labor rate is approximately $60 an hour. Based on 
these figures, the total cost impact of the proposed AD on U.S. 
operators is estimated to be $1,800 or $120 per airplane. This figure 
does not take into account the cost of repetitive inspections or the 
cost to repair or replace any horizontal stabilizer upper and lower 
skin, intercostal angles, or horizontal stabilizer trailing edge 
channel. The FAA has no way of determining the number of repetitive 
inspections each operator would incur over the life of each affected 
airplane or the number of horizontal stabilizer upper and lower skins, 
intercostal angles, or horizontal stabilizer trailing edge channels 
that may be found cracked during the inspections proposed by this 
action.

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 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) 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 has been placed 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 a new airworthiness directive 
(AD) to read as follows:

Aerospace Technologies of Australia Pty Ltd: Docket No. 96-CE-57-AD.

    Applicability: Models N22B, N22S, and N24A 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 (d) 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 within the next 100 hours time-in-
service (TIS) after the effective date of this AD, unless already 
accomplished, and thereafter at intervals not to exceed 100 hours 
TIS.

    To prevent structural failure of the horizontal stabilizer 
caused by fatigue cracks, which could result in loss of control of 
the airplane, accomplish the following:
    (a) Inspect the horizontal stabilizer upper and lower skin, 
intercostal angles, and the horizontal stabilizer trailing edge 
channel for cracks in accordance with the ACCOMPLISHMENT 
INSTRUCTIONS section of Nomad Service Bulletin (SB) NMD-55-34, dated 
April 22, 1996.

[[Page 65006]]

    (b) If any crack is found during any inspection required by this 
AD, prior to further flight, repair or replace the cracked part or 
area, as applicable, in accordance with the Nomad Structural Repair 
Manual, Chapter 55-10-11. Those cracked areas that can be repaired 
and those cracked areas that must be replaced are defined in Nomad 
SB NMD-55-34, dated April 22, 1996, and the Nomad Structural Repair 
Manual, Chapter 55-10-11.
    (c) 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.
    (d) An alternative method of compliance or adjustment of the 
compliance time that provides an equivalent level of safety may be 
approved by the Manager, FAA, Los Angeles ACO, 3960 Paramount 
Boulevard., Lakewood, California 90712. The request shall be 
forwarded through an appropriate FAA Maintenance Inspector, who may 
add comments and then send it to the Manager, Los Angeles ACO.

    Note 2: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Los Angeles ACO.

    (e) All persons affected by this directive may obtain copies of 
the document referred to herein upon request to Aerospace 
Technologies of Australia Pty Ltd., ASTA DEFENCE, Private Bag No. 4, 
Beach Road Lara 3212, Victoria, Australia; or may examine this 
document at the FAA, Central Region, Office of the Assistant Chief 
Counsel, Room 1558, 601 E. 12th Street, Kansas City, Missouri 64106.

    Issued in Kansas City, Missouri, on December 2, 1996.
Michael Gallagher,
Manager, Small Airplane Directorate, Aircraft Certification Service.
[FR Doc. 96-31268 Filed 12-9-96; 8:45 am]
BILLING CODE 4910-13-U