[Federal Register Volume 62, Number 138 (Friday, July 18, 1997)]
[Rules and Regulations]
[Pages 38445-38447]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-17533]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 96-CE-47-AD; Amendment 39-10063; AD 97-14-05]
RIN 2120-AA64


Airworthiness Directives; Air Tractor Incorporated Models AT-301, 
AT-302, AT-400, AT-400A, AT-401, AT-402, AT-501, and AT-502 Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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SUMMARY: This amendment supersedes Airworthiness Directive AD 95-20-06, 
which applies to certain Air Tractor Incorporated (Air Tractor) Models 
AT-301, AT-302, AT-400, AT-400A, AT-401, AT-402, AT-501, and AT-502 
airplanes and currently requires repetitively inspecting the front spar 
attachment lugs and the rear spar for fatigue cracks, and modifying the 
vertical fin if cracks are found. The modification terminates the 
repetitive inspection requirement of AD 95-20-06 and may be 
incorporated at any time, if cracks are not found. The FAA has 
determined that the Air Tractor Models mentioned above with a \1/4\-
inch fin front spar fitting installed should be exempt from the AD. The 
AD will retain the requirements of AD 95-20-06 for all Air Tractor 
airplanes that have a \3/16\-inch fin front spar fitting. The actions 
specified by this AD are intended to prevent in-flight vertical fin 
cracking, which, if not detected and corrected, could result in 
structural failure of the front spar attachments and eventually the 
rear spar attachment and cause loss of directional control of the 
airplane.

DATES: Effective August 25, 1997.

    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of August 25, 1997.

ADDRESSES: Service information that applies to this AD may be obtained 
from Air Tractor Incorporated, P. O. Box 485, Olney, Texas 76374. This 
information may also be examined at the Federal Aviation Administration 
(FAA), Central Region, Office of the Assistant Chief Counsel, 
Attention: Rules Docket 96-CE-47-AD, Room 1558, 601 E. 12th Street, 
Kansas City, Missouri 64106; or at the Office of the Federal Register, 
800 North Capitol Street, NW., suite 700, Washington, DC.

FOR FURTHER INFORMATION CONTACT: Bob May, Aerospace Engineer, FAA, Fort 
Worth Airplane Certification Office, 2601 Meacham Boulevard, Fort 
Worth, Texas 76193-0150; telephone (817) 222-5156; facsimile (817) 222-
5960.

SUPPLEMENTARY INFORMATION:

Events Leading to the Issuance of This AD

    A proposal to amend part 39 of the Federal Aviation Regulations (14 
CFR part 39) to include an AD that would apply to Air Tractor airplanes 
fitted with \3/16\-inch thick front spar attachment fittings that do 
not have the modification in Snow Engineering Company Report No. 138, 
dated July 29, 1995, Revised August 7, 1996, included the following 
Models and serial numbers:

------------------------------------------------------------------------
                 Models                           Serial numbers        
------------------------------------------------------------------------
AT-301 and AT-401......................  301-0261 through 301-0736, and 
                                          401-0662 through 401-0736 that
                                          have been converted to turbine
                                          powerplants and equipped with 
                                          the all metal rudder, part    
                                          number (P/N) 30456-1.         
AT-302.................................  All aircraft equipped with the 
                                          all metal rudder, P/N 30456-1.
AT-400 and AT-400A.....................  All aircraft equipped with the 
                                          all metal rudder, P/N 30456-1.
AT-402.................................  402-0694, and 402-0695 through 
                                          402-0736.                     
AT-501.................................  501-0002 through 501-0030 that 
                                          have been converted to turbine
                                          powerplants and equipped with 
                                          the all metal rudder, P/N     
                                          30456-1.                      
AT-502.................................  502-0002 through 502-0030.     
------------------------------------------------------------------------

The notice of proposed rulemaking (NPRM) for this action was published 
in the Federal Register on February 19, 1997 (62 FR 7377). The proposed 
AD would supersede AD 95-20-06 with a new AD that would require 
inspecting the fin front spar attachment fittings of Models that have 
\3/16\-inch thick fin front spar attachment fittings for cracks, and if 
cracks are found, prior to further flight, modifying the front spar 
attachment fittings. If no cracks are

[[Page 38446]]

found, the proposed AD would require repetitively inspecting the front 
spar attachment fittings until cracks are found. Accomplishing the 
modification upon finding cracks or at any time prior to finding cracks 
would terminate the repetitive inspections.
    Accomplishment of the proposed action would be in accordance with 
Snow Engineering Report (SER) number (No.) 138, dated July 29, 1995, 
Revised August 7, 1996.
    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. No comments were received on the 
proposed rule or the FAA's determination of the cost to the public.

The FAA's Determination

    After careful review of all available information related to the 
subject presented above, the FAA has determined that air safety and the 
public interest require the adoption of the rule as proposed except for 
minor editorial corrections. The FAA has determined that these minor 
corrections will not change the meaning of the AD and will not add any 
additional burden upon the public than was already proposed.

Cost Impact

    The FAA estimates that 24 airplanes in the U.S. registry will be 
affected by this AD, that it will take approximately 16 workhours per 
airplane to accomplish this action, and that the average labor rate is 
approximately $60 an hour. Parts cost approximately $10 per airplane. 
Based on these figures, the total cost impact of this AD on U.S. 
operators is estimated to be $23,280 or $970 per airplane. This figure 
is based on the presumption that no owner/operator of the affected 
airplanes has accomplished the required actions.

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 copy of the final evaluation prepared for this 
action is contained 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, 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 USC 106(g), 40113, 44701.


Sec. 39.13  [Amended]

    2. Section 39.13 is amended by removing airworthiness directive 
(AD) 95-20-06, Amendment No. 39-9384 (60 FR 52620) and by adding a new 
AD to read as follows:

97-14-05. Air Tractor Incorporated: Amendment No. 39-10063; Docket 
No. 96-CE-47-AD; Supersedes AD 95-20-06, Amendment 39-9384. 
Applicability: The following airplane Models and serial numbers 
fitted with a \3/16\-inch fin front spar fitting that do not have 
the modification in Snow Engineering Company Report No. 138, dated 
July 29, 1995, revised August 7, 1996, incorporated, certificated in 
any category:

    Note 1: The modification in Snow Engineering Company Report No. 
138, dated July 29, 1995, revised August 7, 1996, and AD 95-20-06 
required the airplanes to replace 3/16-inch thick fin front spar 
attach fittings with \1/4\-inch thick fin front spar attach 
fittings.

------------------------------------------------------------------------
                 Models                           Serial numbers        
------------------------------------------------------------------------
AT-301 and AT-401......................  301-0261 through 301-0736, and 
                                          401-0662 through 401-0736 that
                                          have been converted to turbine
                                          powerplants and equipped with 
                                          the all metal rudder, part    
                                          number (P/N) 30456-1.         
AT-302.................................  All aircraft equipped with the 
                                          all metal rudder, P/N 30456-1.
AT-400 and AT-400A.....................  All aircraft equipped with the 
                                          all metal rudder, P/N 30456-1.
AT-402.................................  402-0694 and 402-0695 through  
                                          402-0736.                     
AT-501.................................  501-0002 through 501-0030 that 
                                          have been converted to turbine
                                          powerplants and equipped with 
                                          the all metal rudder, P/N     
                                          30456-1.                      
AT-502.................................  AT-502 502-0002 through 502-   
                                          0030.                         
------------------------------------------------------------------------

    Note 2: 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 (f) 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 25 hours time-in-
service (TIS) after the effective date of this AD, unless already 
accomplished, and thereafter as indicated in the body of this AD.
    To prevent in-flight vertical fin cracking, which, if not 
detected and corrected, could result in structural failure of the 
front spar attachments and eventually the rear spar attachment and 
cause loss of directional control of the airplane, accomplish the 
following:
    (a) Inspect the fin front spar attachment fittings for fatigue 
cracks in accordance with the INSTRUCTIONS section of the Snow 
Engineering Report (SER) number (No.) 138, dated July 29, 1995, 
Revised August 7, 1996.
    (b) If no cracks are found during the initial inspection, repeat 
the inspection required by paragraph (a) of this AD at intervals not 
to exceed 25 hours TIS thereafter in accordance with the 
INSTRUCTIONS section of the SER No. 138, Revised August 7, 1996.
    (c) If cracks are found during any inspections required by this 
AD, prior to further flight, modify the fin front spar attachment 
fittings in accordance with the

[[Page 38447]]

INSTRUCTIONS section of the SER No. 138, dated July 29, 1995, 
Revised August 7, 1996.
    (d) Incorporating the modification specified in paragraph (c) of 
this AD is considered terminating action for the repetitive 
inspection requirements of this AD.
    (e) 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.
    (f) An alternative method of compliance or adjustment of the 
compliance times that provides an equivalent level of safety may be 
approved by the Manager, Fort Worth Airplane Certification Office, 
2601 Meacham Boulevard, Fort Worth, Texas 76193-0150. The request 
shall be forwarded through an appropriate FAA Maintenance Inspector, 
who may add comments and then send it to the Manager, Fort Worth 
Airplane Certification Office.

    Note 3: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from Fort Worth Airplane Certification Office.

    (g) The inspection and modification required by this AD shall be 
done in accordance with Snow Engineering Report No. 138, dated July 
29, 1995, Revised August 7, 1996. 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 
Air Tractor Incorporated, P.O. Box 485, Olney, Texas 76374. Copies 
may be inspected at the FAA, Central Region, Office of the Assistant 
Chief Counsel, Room 1558, 601 E. 12th Street, Kansas City, Missouri, 
or at the Office of the Federal Register, 800 North Capitol Street, 
NW., suite 700, Washington, DC.
    (h) This amendment supersedes AD 95-20-06, Amendment 39-9384.
    (i) This amendment (39-10063) becomes effective on August 25, 
1997.

    Issued in Kansas City, Missouri, on June 26, 1997.
James E. Jackson,
Acting Manager, Small Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 97-17533 Filed 7-17-97; 8:45 am]
BILLING CODE 4910-13-U