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

[Federal Register Volume 66, Number 95 (Wednesday, May 16, 2001)]
[Rules and Regulations]
[Pages 27014-27017]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 01-11968]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2000-CE-72-AD; Amendment 39-12230; AD 2001-10-04]
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 supersedes Airworthiness Directive (AD) 2000-
14-51, which requires inspection of the wing lower spar cap for cracks 
on Air Tractor, Inc. (Air Tractor) Models AT-501, AT-502, and AT-502A 
airplanes, and modification or replacement of any cracked wing lower 
spar cap. 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 is the 
result of numerous reports of cracks in the \3/8\-inch bolthole of the 
wing lower spar cap on the affected airplanes. 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 approved the incorporation by 
reference of certain publications listed in the regulation as of June 
8, 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 
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.
    Air Tractor fatigue tested 24 wings and all had cracks in the area 
of the \3/8\-inch bolthole. Follow-on field inspections revealed more 
cracks in this area.

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

[[Page 27015]]

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.

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

What Has FAA Decided?

    The FAA has reviewed all available information, including the 
service information referenced above; and determined that:

--The unsafe condition referenced in this document exists or could 
develop on other Air Tractor AT-400, AT-500, and AT-800 series 
airplanes of the same type design;
--The actions specified in the previously-referenced service 
information (as specified in this AD) should be accomplished on the 
affected airplanes; and
--AD action should be taken in order to correct this unsafe condition.

What Does This AD Require?

    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.

Will I Have the Opportunity to Comment Prior to the Issuance of the 
Rule?

    Because the unsafe condition described in this document could 
result in possible separation of the wing from the airplane during 
flight, FAA finds that notice and opportunity for public prior comment 
are impracticable. Therefore, good cause exists for making this 
amendment effective in less than 30 days.

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 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.

[[Page 27016]]

Sec. 39.13  [Amended]

    2. FAA amends Sec. 39.13 by removing AD 2000-14-51, Amendment 39-
11837 (65 FR 46567, July 31, 2000), and by adding a new airworthiness 
directive (AD) to read as follows:

2001-10-04  Air Tractor, Inc.: Amendment 39-12230; Docket No. 2000-
CE-72-AD; Supersedes 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 limit (presented 
in hours time-in-service (TIS)) of the wing lower spar cap for all 
airplane models and serial numbers:

----------------------------------------------------------------------------------------------------------------
           Model                          Serial numbers                                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.........................  4,132 hours TIS.
AT-802A...................  0003 through 0059.........................  4,969 hours TIS.
AT-802....................  0060 through 0091.........................  4,188 hours TIS.
AT-802....................  0092 through 0101 except those equipped     8,163 hours TIS.
                             with the factory-supplied part number
                             80540 computerized fire gate.
AT-802A...................  0060 through 0091 except those equipped     4,531 hours TIS.
                             with the factory-supplied part number
                             80540 computerized fire gate.
AT-802A...................  0092 through 0101 except those equipped     8,648 hours TIS.
                             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:

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

[[Page 27017]]

 
(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 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) Where can I get information about any already-approved 
alternative methods of compliance? 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.
    (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 approved this incorporation by reference under 5 
U.S.C. 552(a) and 1 CFR part 51. 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 7, 2001.
Melvin D. Taylor,
Acting Manager, Small Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 01-11968 Filed 5-15-01; 8:45 am]
BILLING CODE 4910-13-P

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