[Federal Register Volume 66, Number 107 (Monday, June 4, 2001)]
[Rules and Regulations]
[Pages 29900-29904]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 01-13737]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2000-CE-72-AD; Amendment 39-12247; AD 2001-10-04 R1]
RIN 2120-AA64


Airworthiness Directives; Air Tractor, Inc. AT-400, AT-500, and 
AT-800 Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule; request for comments.

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SUMMARY: This amendment revises AD 2001-10-04, which concerns certain 
Air Tractor, Inc. (Air Tractor) AT-400, AT-500, and AT-800 series 
airplanes. AD 2001-10-04 superseded AD 2000-14-51 and lowers the safe 
life for the wing lower spar cap on these airplanes. The AD was the 
result of numerous reports of cracks in the 3/8-inch bolthole of the 
wing lower spar cap on the affected airplanes. We inadvertently 
included certain AT-800 series airplanes in the Applicability of this 
AD. Those AT-800 series airplanes that are equipped with the factory-
supplied part number 80540 computerized fire gate should not be 
affected by AD 2001-10-04. This action revises the AD to reflect this 
change and to provide information for applying for an alternative 
method of compliance with this AD. The actions specified by this AD are 
intended to prevent fatigue cracks from occurring in the wing lower 
spar cap before the originally established safe life is reached. 
Fatigue cracks in the wing lower spar cap, if not detected and 
corrected, could result in the wing separating from the airplane during 
flight.

DATES: This AD becomes effective on June 8, 2001.
    The Director of the Federal Register previously approved the 
incorporation by reference of certain publications listed in the 
regulation as of June 8, 2001 (66 FR 27014, May 16, 2001).
    The Federal Aviation Administration (FAA) must receive any comments 
on this rule on or before July 13, 2001.

ADDRESSES: Submit comments in triplicate to FAA, Central Region, Office

[[Page 29901]]

of the Regional Counsel, Attention: Rules Docket No. 2000-CE-72-AD, 901 
Locust, Room 506, Kansas City, Missouri 64106.
    You may get the service information referenced in this AD from Air 
Tractor, Incorporated, P.O. Box 485, Olney, Texas 76374. You may look 
at this information at FAA, Central Region, Office of the Regional 
Counsel, Attention: Rules Docket No. 2000-CE-72-AD, 901 Locust, Room 
506, 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: Rob Romero, Aerospace Engineer, FAA, 
Fort Worth Airplane Certification Office, 2601 Meacham Boulevard, Fort 
Worth, Texas 76193-0150; telephone: (817) 222-5102; facsimile: (817) 
222-5960.

SUPPLEMENTARY INFORMATION:

Discussion

    What events have caused this AD? Several reports of cracked wing 
lower spar caps on Air Tractor AT-400, AT-500, and AT-800 series 
airplanes have caused the manufacturer (Air Tractor) to recalculate the 
fatigue life of the wing lower spar cap on these airplanes. One report 
was an accident where the wing separated from the airplane during 
flight. The cracks are originating in the outboard \3/8\-inch bolthole 
of the wing lower spar cap.
    What are the consequences if the condition is not corrected? This 
condition could result in fatigue cracks in the wing lower spar cap 
before the originally established safe life is reached. Fatigue cracks 
in the wing lower spar cap, if not detected and corrected, could result 
in the wing separating from the airplane during flight.
    Is there service information that applies to this subject? Air 
Tractor has issued the following:

--Snow Engineering Company Service Letter #197, Revised March 26, 2001, 
which applies to certain Models AT-501, AT-502, and AT-502A airplanes;
--Snow Engineering Company Service Letter #202, Revised March 26, 2001, 
which applies to certain Models AT-400, AT-401, AT-401B, AT-402, AT-
402A, and AT-402B airplanes;
--Snow Engineering Company Service Letter #203, Revised March 26, 2001, 
which applies to certain Models AT-802 and AT-802A airplanes; and
--Snow Engineering Company Service Letter #205, Revised March 26, 2001, 
which applies to certain Models AT-501, AT-502, AT-502B, and AT-503A 
airplanes.

    These service letters include procedures for inspecting and 
replacing/modifying the wing lower spar cap on the affected airplanes.
    Has FAA taken any action to this point? To address this condition, 
FAA issued AD 2001-10-04, Amendment 39-12230 (66 FR 27014, May 16, 
2001). This AD lowers the safe life for the wing lower spar cap on Air 
Tractor AT-400, AT-500, and AT-800 series airplanes. This AD also 
allows for inspection, using eddy current methods, of the wing lower 
spar cap for airplanes that are at or over the lower safe life and 
parts are not available. Operation of the airplane is not allowed if 
cracks are found and inspections must be terminated when parts become 
available or after performing three repetitive inspections.
    This AD supersedes AD 2000-14-51, Amendment 39-11837 (65 FR 46567, 
July 31, 2000), which currently requires inspection of the wing lower 
spar cap for cracks on Air Tractor Models AT-501, AT-502, and AT-502A 
airplanes, and modification or replacement of any cracked wing lower 
spar cap.
    What has happened since AD 2001-10-04 to initiate this action? We 
inadvertently included certain AT-800 series airplanes in the 
Applicability of this AD. Those AT-800 series airplanes that are 
equipped with the factory-supplied part number 80540 computerized fire 
gate should not be affected by AD 2001-10-04.
    In addition, we will consider inspection of the wing lower spar cap 
as an alternative method of compliance provided certain criteria are 
followed.

The FAA's Determination and an Explanation of the Provisions of 
This AD

    What has FAA decided? After examining the circumstances and 
reviewing all available information related to the incidents described 
above, we have determined that:

--The unsafe condition referenced in this document continues to exist 
and could still develop on other Air Tractor AT-400, AT-500, and AT-800 
series airplanes of the same type design;
--Those AT-800 series airplanes equipped with the factory-supplied part 
number 80540 computerized fire gate should not be affected by AD 2001-
10-04;
--Information about the above-referenced alternative method of 
compliance should be incorporated into the AD; and
--AD 2001-10-04 should be revised to reflect this change and addition.

    Will I have the opportunity to comment prior to the issuance of the 
rule? This action only clarifies the intent of AD 2001-10-04 and makes 
a change to not affect certain airplanes. It has no adverse economic 
impact and imposes no additional burden on any person than would have 
been necessary to accomplish AD 2001-10-04. Therefore, FAA has 
determined that prior notice and opportunity for public comment are 
unnecessary.

Comments Invited

    How do I comment on this AD? Although this action is in the form of 
a final rule and was not preceded by notice and opportunity for public 
comment, we invite your comments on the rule. You may submit whatever 
written data, views, or arguments you choose. You need to include the 
rule's docket number and submit your comments in triplicate to the 
address specified under the caption ADDRESSES. We will consider all 
comments received on or before the closing date specified above. We may 
amend this rule in light of comments received. Factual information that 
supports your ideas and suggestions is extremely helpful in evaluating 
the effectiveness of the AD action and determining whether we need to 
take additional rulemaking action.
    Are there any specific portions of the AD I should pay attention 
to? The FAA specifically invites comments on the overall regulatory, 
economic, environmental, and energy aspects of the rule that might 
suggest a need to modify the rule. You may examine all comments we 
receive before and after the closing date of the rule in the Rules 
Docket. We will file a report in the Rules Docket that summarizes each 
FAA contact with the public that concerns the substantive parts of this 
AD.
    We are reviewing the writing style we currently use in regulatory 
documents, in response to the Presidential memorandum of June 1, 1998. 
That memorandum requires federal agencies to communicate more clearly 
with the public. We are interested in your comments on whether the 
style of this document is clear, and any other suggestions you might 
have to improve the clarity of FAA communications that affect you. You 
can get more information about the Presidential memorandum and the 
plain language initiative at http://www.plainlanguage.gov.
    How can I be sure FAA receives my comment? If you want us to 
acknowledge the receipt of your comments, you must include a self-
addressed, stamped postcard. On the postcard, write ``Comments to 
Docket No. 2000-CE-72-AD.'' We will date

[[Page 29902]]

stamp and mail the postcard back to you.

Regulatory Impact

    Does this AD impact various entities? These regulations will not 
have a substantial direct effect 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, FAA has determined that this final rule does not have 
federalism implications under Executive Order 13132.
    Does this AD involve a significant rule or regulatory action? The 
FAA has determined that this regulation is an emergency regulation that 
must be issued immediately to correct an unsafe condition in aircraft, 
and is not a significant regulatory action under Executive Order 12866. 
It has been determined further that this action involves an emergency 
regulation under DOT Regulatory Policies and Procedures (44 FR 11034, 
February 26, 1979). If it is determined that this emergency regulation 
otherwise would be significant under DOT Regulatory Policies and 
Procedures, a final regulatory evaluation will be prepared and placed 
in the Rules Docket (otherwise, an evaluation is not required). A copy 
of it, if filed, may be obtained from the Rules Docket.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by 
Reference, Safety.

Adoption of the Amendment

    Accordingly, under 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.


Sec. 39.13  [Amended]

    2. FAA amends Sec. 39.13 by removing AD 2001-10-04, Amendment 39-
12230 (66 FR 27014, May 16, 2001), and by adding a new airworthiness 
directive (AD) to read as follows:

2001-10-04  R1 Air Tractor, Inc.: Amendment 39-12247; Docket No. 
2000-CE-72-AD; Revises AD 2001-10-04, Amendment 39-12230, which 
superseded AD 2000-14-51, Amendment 39-11837.

    (a) What airplanes are affected by this AD? The following 
presents the airplanes (certificated in any category) that are 
affected by this AD, along with the new safe life (presented in 
hours time-in-service (TIS)) of the wing lower spar cap for all 
airplane models and serial numbers:

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                Model                               Serial Nos.                            Safe life
----------------------------------------------------------------------------------------------------------------
AT-400..............................  All serial numbers beginning with 0416  13,300 hours TIS.
AT-401..............................  0662 through 0951.....................  10,757 hours TIS.
AT-401B.............................  0952 through 1014 and 1016 though 1020  6,948 hours TIS.
AT-401B.............................  1015 and 1021 through 1124............  7,777 hours TIS.
AT-402..............................  0694 through 0951.....................  7,440 hours TIS.
AT-402A.............................  0738 through 0951.....................  7,440 hours TIS.
AT-402A.............................  0952 through 1020.....................  4,589 hours TIS.
AT-402B.............................  0966 through 1020.....................  4,589 hours TIS.
AT-402A.............................  1021 through 1124.....................  5,268 hours TIS.
AT-402B.............................  1021 through 1124.....................  5,268 hours TIS.
AT-501..............................  0002 through 0061.....................  4,531 hours TIS.
AT-501..............................  All serial numbers beginning with 0062  7,693 hours TIS.
AT-502..............................  0003 through 0236.....................  4,000 hours TIS.
AT-502A.............................  0158 through 0618.....................  3,000 hours TIS.
AT-502B.............................  0187 through 0618.....................  4,000 hours TIS.
AT-503A.............................  All serial numbers beginning with 0067  4,000 hours TIS.
AT-802..............................  0001 through 0059 except those          4,132 hours TIS.
                                       equipped with the factory-supplied
                                       part number 80540 computerized fire
                                       gate.
AT-802A.............................  0003 through 00590059 except those      4,969 hours TIS.
                                       equipped with the factory-supplied
                                       part number 80540 computerized fire
                                       gate.
AT-802..............................  0060 through 0091 0059 except those     4,188 hours TIS.
                                       equipped with the factory-supplied
                                       part number 80540 computerized fire
                                       gate.
AT-802..............................  0092 through 0101 except those          8,163 hours TIS.
                                       equipped with the factory-supplied
                                       part number 80540 computerized fire
                                       gate.
AT-802A.............................  0060 through 0091 except those          4,531 hours TIS.
                                       equipped with the factory-supplied
                                       part number 80540 computerized fire
                                       gate.
AT-802A.............................  0092 through 0101 except those          8,648 hours TIS.
                                       equipped with the factory-supplied
                                       part number 80540 computerized fire
                                       gate.
----------------------------------------------------------------------------------------------------------------


    Note 1: Piston powered aircraft that have been converted to 
turbine power should use the limits for corresponding serial number 
turbine-powered aircraft.

    (b) Who must comply with this AD? Anyone who wishes to operate 
any of the above airplanes must comply with this AD.
    (c) What problem does this AD address? The actions specified by 
this AD are intended to prevent fatigue cracks from occurring in the 
wing lower spar cap before the originally established safe life is 
reached. Fatigue cracks in the wing lower spar cap, if not detected 
and corrected, could result in the wing separating from the airplane 
during flight.
    (d) What must I do to address this problem? To address this 
problem, you must accomplish the following actions:

[[Page 29903]]



----------------------------------------------------------------------------------------------------------------
                    Action                            Compliance time                    Procedures
----------------------------------------------------------------------------------------------------------------
(1) Modify the applicable aircraft records as   Accomplish the logbook      The owner/operator holding at least
 follows to show the reduced safe life for the   entry within the next 10    a private pilot certificate as
 wing lower spar cap (that is specified in the   hours TIS after June 8,     authorized by section 43.7 of the
 table in paragraph (a) of this AD):             2001 (the effective date    Federal Aviation Regulations (14
                                                 of this AD). An             CFR 43.7) may modify the aircraft
                                                 additional 10 hours TIS     records as specified in paragraphs
                                                 to accomplish the           (d)(1)(i) and (d)(1)(ii) of this
                                                 modification/replacement    AD. Make an entry into the aircraft
                                                 is allowed if you are       records showing compliance with
                                                 already over the safe       this portion of the AD in
                                                 life limit.                 accordance with section 43.9 of
                                                                             Federal Aviation Regulations (14
                                                                             CFR 43.9). Accomplish the actual
                                                                             replacements/modifications in
                                                                             accordance with Snow Engineering
                                                                             Service Letter #197, #202, #203, or
                                                                             #205, all Revised March 26, 2001,
                                                                             as applicable.
    (i) For the affected Models AT-802 and AT-                              ....................................
     802A airplanes: update the Owners Manual,
     Section 6--Airworthiness Limitations,
     Life Limited Parts.
    (ii) For all affected airplanes other than                              ....................................
     the Models AT-802 and AT-802A airplanes:
     incorporate the following into the
     Aircraft Logbook ``In accordance with AD
     2001-10-04 R1, the wing lower spar cap is
     life limited to------(insert the
     applicable safe life number from the
     chart in paragraph (a) of this AD).
    (iii) If, as of the time of the logbook                                 ....................................
     entry requirement of paragraph (d)(1) of
     this AD, your airplane is over or within
     10 hours of the safe life limit, an
     additional 10 hours TIS is allowed to
     accomplish the replacement/modification.
(2) If you have ordered parts from the factory  Prior to further flight     In accordance with the procedures in
 when it is time to replace the wing lower       after ordering the parts    Snow Engineering Service Letter
 spar cap (as required per the logbook safe      and thereafter at           #197, #202, #203, or #205, all
 life reduction in paragraph (d)(1) of this      intervals not to exceed     Revised March 26, 2001, as
 AD), but the parts are not available,           400 hours TIS until one     applicable.
 inspect, using eddy current methods, the wing   of the criteria in
 lower spar cap. These inspections are allowed   paragraphs (d)(2)(i),
 until one of the following occurs, at which     (d)(2)(ii), and
 time the replacement/modification (required     (d)(2)(iii) of this AD is
 when the lower spar cap has reached its safe    met.
 life) must be accomplished:
    (i) Crack(s) is/are found;                                              ....................................
    (ii) Parts become available from the                                    ....................................
     manufacturer; or
    (iii) Not more than three inspections or                                ....................................
     1,200 hours TIS go by: the first
     inspection would have to be accomplished
     upon accumulating the safe life; the
     second inspection would have to be
     accomplished within 400 hours TIS after
     accumulating the safe life; the third
     inspection would have to be accomplished
     400 hours TIS after the second
     inspection; and the replacement/
     modification would have to be
     accomplished within 400 hours TIS after
     the third inspection (maximum elapsed
     time would be 1,200 hours TIS).
----------------------------------------------------------------------------------------------------------------

    (e) Can I comply with this AD in any other way? You may use an 
alternative method of compliance or adjust the compliance time if:
    (1) Your alternative method of compliance provides an equivalent 
level of safety; and
    (2) The Manager, Fort Worth Airplane Certification Office (ACO), 
approves your alternative. Submit your request through an FAA 
Principal Maintenance Inspector. The inspector may add comments 
before sending it to the Manager, Fort Worth ACO.
    (3) Alternative methods of compliance approved for AD 2001-10-04 
or AD 2000-14-51 are not considered approved for this AD.

    Note 2: This AD applies to each airplane identified in paragraph 
(a) of this AD, 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 you have not eliminated the unsafe condition, specific 
actions you propose to address it.

    (f) Are there any alternative methods of compliance already 
approved or being considered for this AD? The FAA may approve, as an 
as an alternative method of compliance, inspection of the wing lower 
spar cap. You must submit the request in accordance with the 
procedures in paragraph (e) of this AD and adhere to the following:
    (1) If you are over or within 10 hours TIS of the safe life for 
the wing lower spar cap and you have ordered parts and scheduled a 
date for the replacement/modification, but having the replacement/
modification done on this date grounds the airplane, accomplish the 
following:
    (i) inspect the wing lower spar cap within 10 hours TIS after 
approval of the alternative method of compliance;
    (ii) reinspect thereafter at intervals not to exceed 400 hours 
TIS until either cracks are found, the date of the scheduled 
replacement/modification occurs, or 1,200 hours TIS after the 
initial inspection are accumulated, whichever occurs first;
    (iii) accomplish the inspections in accordance with the 
procedures in Snow Engineering Service Letter #197, #202, #203, or 
#205, all Revised March 26, 2001, as applicable.
    (2) Submit the following to the Fort Worth Airplane 
Certification Office using the procedures described in paragraph (e) 
of this AD:
    (i) The airplane model and serial number designation;
    (ii) The number of hours TIS on the airplane;

[[Page 29904]]

    (iii) The scheduled date for the replacement/modification; and
    (iv) The name and location of the authorized repair shop.
    (3) For more information about this issue: contact Rob Romero, 
Aerospace Engineer, FAA, Fort Worth ACO, 2601 Meacham Boulevard, 
Fort Worth, Texas 76193-0150; telephone: (817) 222-5102; facsimile: 
(817) 222-5960; e:mail: [email protected].
    (g) What if I need to fly the airplane to another location to 
comply with this AD? The FAA can issue a special flight permit under 
sections 21.197 and 21.199 of the Federal Aviation Regulations (14 
CFR 21.197 and 21.199) to operate your airplane to a location where 
you can accomplish the requirements of this AD provided that the 
following is adhered to:
    (1) Only operate in day visual flight rules (VFR) only.
    (2) Ensure that the hopper is empty.
    (3) Limit airspeed to 135 miles per hour (mph) indicated 
airspeed (IAS).
    (4) Avoid any unnecessary g-forces.
    (5) Avoid areas of turbulence.
    (6) Plan the flight to follow the most direct route.
    (h) Are any service bulletins incorporated into this AD by 
reference? Replacement actions required by this AD must be done in 
accordance with Snow Engineering Service Letter #197, #202, #203, or 
#205, all Revised March 26, 2001, as applicable. The Director of the 
Federal Register previously approved this incorporation by reference 
under 5 U.S.C. 552(a) and 1 CFR part 51, as of June 8, 2001 (66 FR 
27014, May 16, 2001). You may get copies of this document from Air 
Tractor, Incorporated, P.O. Box 485, Olney, Texas 76374. You can 
look at copies at FAA, Central Region, Office of the Regional 
Counsel, 901 Locust, Room 506, Kansas City, Missouri, or at the 
Office of the Federal Register, 800 North Capitol Street, NW., suite 
700, Washington, DC.
    (i) When does this amendment become effective? This amendment 
becomes effective on June 8, 2001.

    Issued in Kansas City, Missouri, on May 25, 2001.
James E. Jackson,
Acting Manager, Small Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 01-13737 Filed 6-1-01; 8:45 am]
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