[Federal Register Volume 62, Number 44 (Thursday, March 6, 1997)]
[Proposed Rules]
[Pages 10236-10237]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-5470]


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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 96-CE-23-AD]
RIN 2120-AA64


Airworthiness Directives; Aviat Aircraft, Inc. Models S-1S, S-1T, 
S-2, S-2A, S-2S, and S-2B Airplanes (formerly known as Pitts Models S-
1S, S-1T, S-2, S-2A, S-2S, and S-2B Airplanes)

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes to revise AD 96-12-03, which applies to 
Aviat Aircraft, Inc. (Aviat) Models S-1S, S-1T, S-2, S-2A, S-2S, and S-
2B airplanes that are equipped with aft lower fuselage wing attach 
fittings incorporating either part number (P/N) 76090, 2-2107-1, or 1-
210-102. That AD currently requires repetitively inspecting the aft 
lower fuselage wing attach fitting on both wings for cracks, and 
modifying any cracked aft lower fuselage wing attach fitting. Modifying 
both aft lower fuselage wing attach fittings eliminates the repetitive 
inspection requirement of AD 96-12-03. Aviat recently started 
incorporating modified aft lower fuselage wing attach fittings on newly 
manufactured airplanes. The proposed AD would retain the requirements 
of AD 96-12-03, but would exempt airplanes that had the modified aft 
lower fuselage wing attach fittings incorporated at manufacture. The 
actions specified by the proposed AD are intended to prevent possible 
in-flight separation of the wing from the airplane caused by a cracked 
fuselage wing attach fitting.

DATES: Comments must be received on or before June 4, 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-23-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 Aviat Aircraft, Inc., P.O. Box 1240 (postal service delivery), 672 
South Washington Street (express mail), Afton, Wyoming 83110. This 
information also may be examined at the Rules Docket at the address 
above.

FOR FURTHER INFORMATION CONTACT: Mr. Roger Caldwell, Aerospace 
Engineer, FAA, Denver Aircraft Certification Office, 26805 E. 68th 
Avenue, Room 214, Denver, Colorado 80249; telephone (303) 342-1086; 
facsimile (303) 342-1088.

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-23-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, Central Region, Office of the Assistant Chief Counsel, 
Attention: Rules Docket No. 96-CE-23-AD, Room 1558, 601 E. 12th Street, 
Kansas City, Missouri 64106.

Events Leading to the Proposed AD

    AD 96-12-03, Amendment 39-9645 (61 FR 28730, June 6, 1996), applies 
to Aviat Models S-1S, S-1T, S-2, S-2A, S-2S, and S-2B airplanes that 
are equipped with aft lower fuselage wing attach fittings incorporating 
either part number (P/N) 76090, 2-2107-1, or 1-210-102. The AD 
currently requires repetitively inspecting the aft lower fuselage wing 
attach fitting on both wings for cracks, and modifying any cracked aft 
lower fuselage wing attach fitting. Modifying both aft lower fuselage 
wing attach fittings eliminates the repetitive inspection requirement 
of AD 96-12-03. Accomplishment of the actions required by AD 96-12-03 
is in accordance with Aviat Service Bulletin (SB) No. 25, dated April 
3, 1996.
    Aviat recently started incorporating modified aft lower fuselage 
wing attach fittings on newly manufactured Models S-1S, S-1T, S-2, S-
2A, S-2S, and S-2B airplanes. In addition, Aviat revised SB No. 25 
(Revised November 12, 1996) to include this airplane serial number 
effectivity change.

The FAA's Determination

    After examining the circumstances and reviewing all available 
information related to the incidents described above, the FAA has 
determined that (1) those airplanes with modified aft lower fuselage 
wing attach fittings incorporated at manufacture should be exempt from 
AD 96-12-03; and (2) AD action should be taken to prevent possible in-
flight separation of the wing from the airplane caused by a cracked 
fuselage wing attach fitting.

Explanation of the Provisions of the Proposed AD

    Since an unsafe condition has been identified that is likely to 
exist or develop in other Aviat Models S-1S, S-1T, S-2, S-2A, S-2S, and 
S-2B airplanes of the same type design that are equipped with aft lower 
fuselage wing attach fittings incorporating either P/N 76090, 2-2107-1, 
or 1-210-102, the FAA is proposing to revise AD 96-12-03. The proposed 
AD would retain the requirements of AD 96-12-03, but would exempt 
airplanes that had the modified aft lower fuselage wing attach fittings 
incorporated at manufacture. Accomplishment of the proposed AD would be 
in accordance with Aviat SB No. 25, dated April 3, 1996, Revised 
November 12, 1996.

Cost Impact

    The FAA estimates that 500 airplanes in the U.S. registry would be 
affected by the proposed AD, that it would take approximately 2 
workhours per airplane

[[Page 10237]]

to accomplish the proposed initial inspection, and that the average 
labor rate is approximately $60 an hour. Parts to accomplish the 
repetitive inspections cost approximately $100 per airplane. Based on 
these figures, the total cost impact of the proposed AD on U.S. 
operators is estimated to be $110,000. These figures do not take into 
account the cost of repetitive inspections. The FAA has no way of 
determining how many repetitive inspections each owner/operator may 
incur over the life of the airplane.
    In addition, AD 96-12-03 currently requires the same inspections as 
the proposed AD for all 500 of the affected airplanes. The only 
difference is that newly manufactured airplanes would be exempt from 
the actions because they have modified aft lower fuselage wing attach 
fittings incorporated at manufacture. Therefore, the cost impact of the 
proposed AD for operators of all affected airplanes is the same as AD 
96-12-03.

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 USC 106(g), 40113, 44701.


Sec. 39.13  [Amended]

    2. Section 39.13, is amended by removing Airworthiness Directive 
(AD) 96-12-03, Amendment 39-9645, and by adding a new AD to read as 
follows:

Aviat Aircraft, Inc.: Docket No. 96-CE-23-AD. Revises AD 96-12-03, 
Amendment 39-9645.

    Applicability: The following airplane models and serial numbers, 
certificated in any category, that are equipped with aft lower 
fuselage wing attach fittings incorporating part number (P/N) 76090, 
2-2107-1, or 1-210-102, and where these aft lower fuselage wing 
attach fittings on both wings have not been modified in accordance 
with the ACCOMPLISHMENT INSTRUCTIONS section of Aviat Service 
Bulletin (SB) No. 25, dated April 3, 1996, Revised November 12, 
1996; or Aviat SB No. 25, dated April 3, 1996:
    --Models S-1S, S-1T, S-2, S-2A, and S-2S airplanes, all serial 
numbers.
    --Model S-2B airplanes, serial numbers 5000 through 5348.

    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 (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 initially within the next 50 hours time-in-
service (TIS) after the effective date of this AD, unless already 
accomplished (compliance with AD 96-12-03), and thereafter at 
intervals not to exceed 50 hours TIS.
    To prevent possible in-flight separation of the wing from the 
airplane caused by a cracked aft lower fuselage wing attach fitting, 
accomplish the following:
    (a) Inspect the aft lower fuselage wing attach fitting on both 
wings for cracks in accordance with the ACCOMPLISHMENT INSTRUCTIONS 
section of Aviat SB No. 25, dated April 3, 1996, Revised November 
12, 1996; or Aviat SB No. 25, dated April 3, 1996.
    (b) If any cracked aft lower fuselage wing attach fitting is 
found during any inspection required by this AD, prior to further 
flight, modify the cracked aft lower fuselage wing attach fitting in 
accordance with the ACCOMPLISHMENT INSTRUCTIONS section of Aviat SB 
No. 25, dated April 3, 1996, Revised November 12, 1996; or Aviat SB 
No. 25, dated April 3, 1996. Repetitive inspections are no longer 
necessary on an aft lower fuselage wing attachment fitting that was 
found cracked and has the referenced modification incorporated.
    (c) Modifying the aft lower fuselage wing attach fitting on both 
wings in accordance with the ACCOMPLISHMENT INSTRUCTIONS section of 
Aviat SB No. 25, dated April 3, 1996, Revised November 12, 1996; or 
Aviat SB No. 25, dated April 3, 1996, is considered terminating 
action for the repetitive inspection requirement of this AD.
    (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.
    (e) An alternative method of compliance or adjustment of the 
initial or repetitive compliance times that provides an equivalent 
level of safety may be approved by the Manager, Denver Aircraft 
Certification Office, 26805 E. 68th Avenue, Room 214, Denver, 
Colorado 80249. The request shall be forwarded through an 
appropriate FAA Maintenance Inspector, who may add comments and then 
send it to the Manager, Denver ACO. Alternative methods of 
compliance approved in accordance with AD 96-12-03 are considered 
approved for this AD.

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

    (f) All persons affected by this directive may obtain copies of 
the service bulletin referred to herein upon request to Aviat 
Aircraft, Inc., P.O. Box 1240 (postal service delivery), 672 South 
Washington Street (express mail), Afton, Wyoming 83110; or may 
examine this service bulletin at the FAA, Central Region, Office of 
the Assistant Chief Counsel, Room 1558, 601 E. 12th Street, Kansas 
City, Missouri 64106.
    (g) This amendment revises AD 96-12-03, Amendment 39-9645. 
Issued in Kansas City, Missouri, on February 24, 1997.
Michael Gallagher,
Manager, Small Airplane Directorate, Aircraft Certification Service.
[FR Doc. 97-5470 Filed 3-5-97; 8:45 am]
BILLING CODE 4910-13-U