[Federal Register Volume 61, Number 229 (Tuesday, November 26, 1996)]
[Rules and Regulations]
[Pages 60015-60016]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-29863]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 96-CE-49-AD; Amendment 39-9833; AD 96-24-08]
RIN 2120-AA64


Airworthiness Directives; Air Tractor, Inc. Models AT-250, AT-
300, 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; request for comments.

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SUMMARY: This amendment adopts a new airworthiness directive (AD) that 
applies to certain Air Tractor, Inc. (Air Tractor) Models AT-250, AT-
300, AT-301, AT-302, AT-400, AT-400A, AT-401, AT-402, AT-501, and AT-
502 airplanes that are equipped with a Gerdes part number (P/N) A-850-5 
or Cleveland P/N 60-9 parking brake valve. This action requires 
replacing the parking brake valve with a Scott P/N 4500A-2 parking 
brake valve. This AD results from several reports of the parking brake 
valve inadvertently slipping to the ``PARK'' position during flight, 
which causes constant pressure on the brakes. When the pilot applies 
the brake upon landing, this pressure causes the airplane to overturn. 
The actions specified by this AD are intended to prevent the airplane 
from overturning because of extreme pressure applied to the brake if 
the parking brake valve inadvertently slips to the ``PARK'' position 
during flight.

DATES: Effective December 23, 1996.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of December 23, 1996.
    Comments for inclusion in the Rules Docket must be received on or 
before February 14, 1997.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Central Region, Office of the Assistant Chief 
Counsel, Attention: Rules Docket 96-CE-49-AD, Room 1558, 601 E. 12th 
Street, Kansas City, Missouri 64106.
    Service information that applies to this AD may be obtained from 
Air Tractor Inc., P. O. Box 485, Olney, Texas 76374; telephone (817) 
564-5616; facsimile (817) 564-2348. 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-
49-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: Mr. Werner Koch, Aerospace Engineer, 
FAA, Aircraft Certification Office, 2601 Meacham Boulevard, Fort Worth, 
Texas 76193-0150; telephone (817) 222-5133; facsimile (817) 222-5960.

SUPPLEMENTARY INFORMATION:

Events Leading to This AD

    The FAA has received several reports of the parking brake valve 
inadvertently slipping to the ``PARK'' position during flight on Air 
Tractor Models AT-250, AT-300, AT-301, AT-302, AT-400, AT-400A, AT-401, 
AT-402, AT-501, and AT-502 airplanes. When the parking brake is in the 
``PARK'' position, a constant pressure is applied to the brakes, which 
cannot be relieved or reduced when the pilot removes pressure from the 
brake pedals. This pressure builds to the point that when the pilot 
applies the brake upon landing to slow the airplane, the airplane 
overturns.
    The airplanes in the incidents described above were equipped with 
Gerdes part number (P/N) A-850-5 or Cleveland P/N 60-9 parking brake 
valves. The FAA has determined that these Gerdes or Cleveland parking 
brake valves should be replaced with Scott parking brake valves, P/N 
4500A-2, on certain Air Tractor Models AT-250, AT-300, AT-301, AT-302, 
AT-400, AT-400A, AT-401, AT-402, AT-501, and AT-502 airplanes.

Applicable Service Information

    Air Tractor has issued Snow Engineering Co. Service Letter #76, 
dated December 12, 1988, which specifies replacing Gerdes part number 
A-850-5 and Cleveland P/N 60-9 parking brake valves with Scott parking 
brake valves, P/N 4500A-2. Air Tractor Service Letter #76 Instructions 
specify procedures for accomplishing this parking brake valve 
replacement.

The FAA's Determination

    After examining the circumstances and reviewing all available 
information related to the incidents described above, including the 
referenced service information, the FAA has determined that AD action 
should be taken to prevent the airplane from overturning because of 
extreme pressure applied to the brake if the parking brake valve 
inadvertently slips to the ``PARK'' position during flight.

Explanation of the Provisions of This AD

    Since an unsafe condition has been identified that is likely to 
exist or develop in other Air Tractor Models AT-250, AT-300, AT-301, 
AT-302, AT-400, AT-400A, AT-401, AT-402, AT-501, and AT-502 airplanes 
of the same type design that are equipped with a Gerdes (P/N) A-850-5 
or Cleveland P/N 60-9 parking brake valve, the FAA is implementing AD 
action. This AD requires replacing these Gerdes or Cleveland parking 
brake valves with a Scott P/N 4500A-2 parking brake valve. 
Accomplishment of this replacement is in accordance with Air Tractor 
Service Letter #76 Instructions, as referenced in Snow Engineering Co. 
Service Letter #76, dated December 12, 1988.
    Since a situation exists (possibility of the airplane overturning 
during landing) that requires the immediate adoption of this 
regulation, it is found that notice and opportunity for public prior 
comment hereon are impracticable, and that good cause exists for making 
this amendment effective in less than 30 days.

Comments Invited

    Although this action is in the form of a final rule that involves 
requirements affecting immediate flight safety and, thus, was not 
preceded by notice and opportunity to comment, comments are invited on 
this rule. Interested persons are invited to comment on this 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 will be considered, 
and this rule may be amended in light of the comments received. Factual 
information that supports the commenter's ideas and suggestions is 
extremely helpful in evaluating the effectiveness of the AD action and 
determining whether additional rulemaking action would be needed.
    Comments are specifically invited on the overall regulatory, 
economic, environmental, and energy aspects of the rule that might 
suggest a need to modify the rule. All comments

[[Page 60016]]

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 AD will be filed in the Rules Docket.
    Commenters wishing the FAA to acknowledge receipt of their comments 
submitted in response to this rule must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket No. 96-CE-49-AD.'' The postcard will be date stamped and 
returned to the commenter.

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.
    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, 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 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:

96-24-08  Air Tractor, Inc.: Amendment 39-9833; Docket No. 96-CE-49-
AD.

    Applicability: The following airplane models and serial numbers, 
certificated in any category, that are equipped with a Gerdes part 
number (P/N) A-850-5 or Cleveland P/N 60-9 parking brake valve :

------------------------------------------------------------------------
                Model                           Serial Numbers          
------------------------------------------------------------------------
AT-250..............................  250-0491.                         
AT-300..............................  300-0001 through 300-0708.        
AT-301..............................  301-0001 through 301-0708.        
AT-302..............................  302-0001 through 302-0708.        
AT-400..............................  400-0001 through 400-0708.        
AT-400A.............................  400A-0001 through 400A-0708.      
AT-401..............................  401-0001 through 401-0708.        
AT-402..............................  402-0001 through 402-0708.        
AT-501..............................  501-0001 through 501-0036.        
AT-502..............................  502-0001 through 502-0036.        
------------------------------------------------------------------------

    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 (c) 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 75 hours time-in-
service after the effective date of this AD, unless already 
accomplished.

    To prevent the airplane from overturning because of extreme 
pressure applied to the brake if the parking brake valve 
inadvertently slips to the ``PARK'' position during flight, 
accomplish the following:
    (a) Replace the Gerdes P/N A-850-5 or Cleveland P/N 60-9 parking 
brake valve with a Scott P/N 4500A-2 parking brake valve. Accomplish 
this replacement in accordance with Air Tractor Service Letter #76 
Instructions, as referenced in Snow Engineering Co. Service Letter 
#76, dated December 12, 1988.
    (b) 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.
    (c) 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, Aircraft 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 ACO.

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

    (d) The replacement required by this AD shall be done in 
accordance with Air Tractor Service Letter #76 Instructions, as 
referenced in Snow Engineering Co. Service Letter #76, dated 
December 12, 1988. 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 
Inc., 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.
    (e) This amendment (39-9833) becomes effective on December 23, 
1996.

    Issued in Kansas City, Missouri, on November 15, 1996.
Michael Gallagher,
Manager, Small Airplane Directorate, Aircraft Certification Service.
[FR Doc. 96-29863 Filed 11-25-96; 8:45 am]
BILLING CODE 4910-13-U