[Federal Register Volume 61, Number 141 (Monday, July 22, 1996)]
[Rules and Regulations]
[Pages 37814-37817]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-18395]


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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39
[Docket No. 95-ANE-26; Amendment 39-9693; AD 96-15-02]
RIN 2120-AA64

Airworthiness Directives; Pratt & Whitney Wasp Series and R-1340 
Series (Military) Reciprocating Engines
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 
is applicable to Pratt & Whitney Wasp series and R-1340 series 
(military) reciprocating engines. This action requires initial and 
repetitive visual and dye penetrant inspections of the crankshaft 
counterweights for cracks, and replacement of cracked crankshaft 
counterweights with improved crankshaft counterweights. This amendment 
is prompted by reports of crankshaft counterweight cracking. The 
actions specified in this AD are intended to prevent engine failure due 
to crankshaft counterweight failure, which could result in damage to or 
loss of the aircraft.

DATES: Effective August 12, 1996.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of August 12, 1996.
    Comments for inclusion in the Rules Docket must be received on or 
before September 20, 1996.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), New England Region, Office of the Assistant Chief 
Counsel, Attention: Rules Docket No. 95-ANE-26, 12 New England 
Executive Park, Burlington, MA 01803-5299. Comments may also be 
submitted to the Rules Docket by using the following Internet address: 
``[email protected]''. All comments must contain the 
Docket No. in the subject line of the comment.
    The service information referenced in this AD may be obtained from 
Air Tractor, Inc., Olney Municipal Airport, Olney, TX 76374; telephone 
(817) 564-5616, fax (817) 564-2348. This

[[Page 37815]]

information may be examined at the FAA, New England Region, Office of 
the Assistant Chief Counsel, 12 New England Executive Park, Burlington, 
MA; or at the Office of the Federal Register, 800 North Capitol Street, 
NW., suite 700, Washington, DC.

FOR FURTHER INFORMATION CONTACT: Richard D. Karanian, Aerospace 
Engineer, Special Certification Office, FAA, Rotorcraft Directorate, 
2601 Meacham Blvd., Fort Worth, TX 76137-4298; telephone (817) 222-
5195, fax (817) 222-5959.

SUPPLEMENTARY INFORMATION: The Federal Aviation Administration (FAA) 
has received reports of counterweight cracking on Air Tractor, Inc., 
Part Number (P/N) 90114 Parts Manufacturer Approval (PMA) replacement 
crankshafts installed on Pratt & Whitney (PW) Wasp series and R-1340 
series (military) reciprocating engines. Cracks have been found in 
three rear counterweights, P/N 90134, immediately adjacent to the 4\1/
2\ order flyweight, or dynamic counterweight. In two cases, the cracks 
were observed during overhaul inspections after a normal runout; in one 
case, Air Tractor, Inc. has advised the FAA that a counterweight crack 
may have caused or contributed to an engine failure during agricultural 
spraying operations in Argentina. This condition, if not corrected, 
could result in engine failure due to crankshaft counterweight failure, 
which could result in damage to or loss of the aircraft.
    The manufacturer advised the FAA of the crankshaft counterweight 
failure in Argentina and the possible connection between this failure 
and a crack found in a second crankshaft counterweight with 900 hours 
in agricultural service in the United States. Air Tractor, Inc. 
released an initial Service Letter (SL), Snow Engineering Co. SL No. 
134, dated November 29, 1994, advising all owners of Air Tractor, Inc. 
PMA crankshafts to perform within the next 10 hours time in service 
(TIS) a visual and dye penetrant inspection of the crankshaft 
counterweights to detect cracking. This SL detailed an inspection 
procedure which required the removal of one cylinder to gain access to 
the crankshaft. Air Tractor, Inc. demonstrated this inspection 
procedure to the FAA on November 28, 1994.
    In January and February 1995, Air Tractor, Inc. performed an engine 
test at their facility to demonstrate a reasonable interval for engine 
operation between inspections. The test consisted of cutting through 
the counterweight at the location where cracks were initially found and 
running the engine at a series of loads simulating actual flight loads 
for 202.5 hours (recording tachometer) without failure. This test was 
run using an FAA-approved test procedure with FAA oversight.
    Based on this experience, Air Tractor, Inc. has issued Snow 
Engineering Co. SL No. 135, dated February 1, 1995, that supersedes the 
inspection requirements of Snow Engineering Co. SL No. 134; however, 
the rework procedure described in Snow Engineering Co. SL No. 134 
remains in effect for the purpose of this AD. The FAA has reviewed and 
approved the technical contents of Snow Engineering Co. SL No. 135, 
dated February 1, 1995, that describes procedures for an initial 
inspection of crankshaft counterweights prior to 300 hours TIS, with 
repetitive inspections every 150 hours TIS. Snow Engineering Co. SL No. 
134 describes replacement of crankshaft counterweights, P/N 90133 and 
90134, with redesigned FAA-PMA crankshaft counterweights, P/N 90133-1 
and 90134-1 at the next overhaul or if a crack is found during an 
inspection. Air Tractor, Inc. has advised the FAA that it will replace 
crankshaft counterweights in accordance with Snow Engineering Co. SL 
No. 134, dated November 29, 1994, on all crankshafts delivered to their 
facility under warranty, free of charge.
    Air Tractor, Inc. has advised the FAA that crankshafts manufactured 
and shipped after November 18, 1994, incorporate the FAA-approved 
redesigned crankshaft counterweights, P/N 90133-1 and 90134-1, and are 
not subject to inspections. Only Air Tractor, Inc. crankshaft 
counterweights, P/N 90133-1 and 90134-1, are eligible for installation 
in accordance with the rework procedures described in Snow Engineering 
Co. SL No. 134. No other parts are currently approved for installation 
in compliance with this AD.
    Since an unsafe condition has been identified that is likely to 
exist or develop on other engines of the same type design, this AD is 
being issued to prevent engine failure due to crankshaft counterweight 
failure, which could result in damage to or loss of the aircraft. This 
AD requires initial and repetitive visual and dye penetrant inspections 
of the crankshaft counterweights for cracks, and replacement of 
crankshaft counterweights with improved crankshaft counterweights if a 
crack is found during inspection, at the next overhaul, or at the next 
crankshaft removal, whichever occurs first. The actions are required to 
be accomplished in accordance with the SL described previously.
    Since a situation exists that requires the immediate adoption of 
this regulation, it is found that notice and opportunity for prior 
public 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 flight safety and, thus, was not preceded by 
notice and an opportunity for public 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 under the caption ADDRESSES. 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 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 notice must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 95-ANE-26.'' The postcard will be date stamped and 
returned to the commenter.
    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

[[Page 37816]]

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. 
A copy of it, if filed, may be obtained from 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 adding the following new 
airworthiness directive:

96-15-02  Pratt & Whitney: Amendment 39-9693. Docket 95-ANE-26.

    Applicability: Pratt & Whitney (PW) Wasp Models S1H1 and S3H1, 
and Model R-1340-AN-1 (military) reciprocating engines, 
incorporating Air Tractor, Inc. Parts Manufacturer Approval (PMA) 
crankshafts, Part Number (P/N) 90114. These engines are installed on 
but not limited to the following aircraft: Ag Cat Corporation 
(formerly Schweizer Aircraft Corporation) Models G-164A, G-164B, and 
G-164C; Air Tractor, Inc. Models AT-301 and AT-401; Ayres 
Corporation Models 600 S-2C, 600 S2D, S-2R, S2R-R1340; EMAIR Model 
MA-1; North American Aviation, Inc. Models BC-1A, AT-6, AT-6A, AT-
6B, AT-6C, AT-6D, AT-6F, and T-6G; and Transland Model Ag-2.

    Note: This airworthiness directive (AD) applies to each engine 
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 engines 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 (h) 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 as indicated, unless accomplished 
previously.
    To prevent engine failure due to crankshaft counterweight 
failure, which could result in damage to or loss of the aircraft, 
accomplish the following:
    (a) For crankshafts with 290 or more hours time in service (TIS) 
on the effective date of this AD, perform an initial visual and dye 
penetrant inspection of the crankshaft counterweights for cracks 
within 10 hours TIS after the effective date of this AD in 
accordance with Snow Engineering Co. Service Letter (SL) No. 135, 
dated February 1, 1995. If cracks are found, prior to further 
flight, remove from service and rework the crankshaft by replacing 
cracked counterweights in accordance with the rework procedures 
described in Snow Engineering Co. SL No. 134, dated November 29, 
1994, or replace with a serviceable part.
    (b) For crankshafts with less than 290 hours TIS on the 
effective date of this AD, perform an initial visual and dye 
penetrant inspection of the crankshaft counterweights for cracks 
prior to accumulating 300 hours total TIS on the crankshaft, in 
accordance with Snow Engineering Co. SL No. 135, dated February 1, 
1995. If cracks are found, prior to further flight, remove from 
service and rework the crankshaft by replacing cracked 
counterweights in accordance with the rework procedures described in 
Snow Engineering Co. SL No. 134, dated November 29, 1994, or replace 
with a serviceable part.
    (c) For crankshafts that have not been reworked in accordance 
with the rework procedures described in Snow Engineering Co. SL No. 
134, dated November 29, 1994, perform repetitive visual and dye 
penetrant inspections of the crankshaft counterweights for cracks, 
at intervals not to exceed 150 hours TIS since last inspection, in 
accordance with Snow Engineering Co. SL No. 135, dated February 1, 
1995. If cracks are found, prior to further flight remove from 
service and rework the crankshaft by replacing cracked 
counterweights in accordance with the rework procedures described in 
Snow Engineering Co. SL No. 134, dated November 29, 1994, or replace 
with a serviceable part.
    (d) If a cylinder assembly is removed for any reason, perform a 
visual and dye penetrant inspection of the crankshaft counterweights 
for cracks in accordance with Snow Engineering Co. SL No. 135, dated 
February 1, 1995. If cracks are found, prior to further flight, 
remove from service and rework the crankshaft by replacing cracked 
counterweights in accordance with the rework procedures described in 
Snow Engineering Co. SL No. 134, dated November 29, 1994, or replace 
with a serviceable part. Count the 150 hours TIS interval for the 
repetitive inspections in accordance with paragraph (c) of this AD 
at cylinder assembly removal.
    (e) At the next overhaul after the effective date of this AD, or 
at the next crankshaft removal, whichever occurs first, remove from 
service and replace crankshaft counterweights in accordance with the 
rework procedures described in Snow Engineering Co. SL No. 134, 
dated November 29, 1994. Incorporation of the improved crankshaft 
counterweights, Air Tractor, Inc. P/N 90133-1 and 90134-1, 
constitutes terminating action to the repetitive inspections 
required by paragraph (c) of this AD.
    (f) No action is required for reworked and new manufactured 
crankshafts incorporating improved crankshaft counterweights, Air 
Tractor, Inc. P/N 90133-1 and 90134-1, which are indelibly marked on 
the counterweight front and rear surfaces.
    (g) No action is required for other FAA-approved crankshafts 
besides those manufactured by Air Tractor, Inc. However, intermixing 
of Air Tractor, Inc. and other crankshaft assembly parts other than 
PW crankshaft assembly parts is prohibited.

    Note: Air Tractor, Inc. Top Drawing No. 90U4 permits use of PW 
components, and virtually all Air Tractor, Inc. crankshafts have 
some PW parts installed.

    (h) An alternative method of compliance or adjustment of the 
compliance time that provides an acceptable level of safety may be 
used if approved by the Manager, Special Certification Office. The 
request should be forwarded through an appropriate FAA Maintenance 
Inspector, who may add comments and then send it to the Manager, 
Special Certification Office.

    Note: Information concerning the existence of approved 
alternative methods of compliance with this airworthiness directive, 
if any, may be obtained from the Special Certification Office.

    (i) 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 aircraft to a location where 
the inspections can be accomplished.
    (j) The actions required by this AD shall be done in accordance 
with the following service documents:

------------------------------------------------------------------------
             Document No.               Pages             Date          
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Snow Engineering Co., SL No. 134.....     1-5  November 29, 1994.       
  Total pages: 5                                                        
Snow Engineering Co., SL No. 135.....     1-4  February 1, 1995.        
  Total pages: 4                                                        
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    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., Olney 
Municipal Airport, Olney, TX 76374; telephone (817) 564-5616, fax 
(817) 564-2348. Copies may be inspected at the FAA, New England 
Region, Office of the Assistant Chief Counsel, 12 New England 
Executive Park, Burlington, MA; or at the Office of the Federal 
Register, 800 North Capitol Street, NW., suite 700, Washington, DC.
    (k) This amendment becomes effective on August 12, 1996.


[[Page 37817]]


    Issued in Burlington, Massachusetts, on July 12, 1996.
Jay J. Pardee,
Manager, Engine and Propeller Directorate, Aircraft Certification 
Service.
[FR Doc. 96-18395 Filed 7-19-96; 8:45 am]
BILLING CODE 4910-13-U