[Federal Register Volume 62, Number 132 (Thursday, July 10, 1997)]
[Rules and Regulations]
[Pages 36978-36981]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-17728]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 97-CE-44-AD; Amendment 39-10071; AD 97-13-11]
RIN 2120-AA64


Airworthiness Directives; Ayres Corporation S2R Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule; request for comments.

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SUMMARY: This document publishes in the Federal Register an amendment 
adopting Airworthiness Directive (AD) 97-13-11, which was sent 
previously to known U.S. owners and operators of certain Ayres 
Corporation (Ayres) S2R series airplanes. This AD requires inspecting 
the \1/4\-inch and \5/16\-inch bolt hole areas on the lower spar caps 
for fatigue cracking, and replacing any lower spar cap if fatigue 
cracking is found. This AD results from an accident on an Ayres S2R 
series airplane where the wing separated from the airplane in flight. 
The actions specified by this AD are intended to prevent fatigue 
cracking of the lower spar caps, which, if not detected and corrected, 
could result in the wing separating from the airplane with consequent 
loss of control of the airplane.

DATES: Effective July 23, 1997, to all persons except those to whom it 
was made immediately effective by priority letter AD 97-13-11, issued 
June 20, 1997, which contained the requirements of this amendment.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of July 23, 1997.
    Comments for inclusion in the Rules Docket must be received on or 
before September 26, 1997.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Central Region, Office of the Assistant Chief 
Counsel, Attention: Rules Docket 97-CE-44-AD, Room 1558, 601 E. 12th 
Street, Kansas City, Missouri 64106.
    Service information that applies to this AD may be obtained from 
the Ayres Corporation, P.O. Box 3090, One Rockwell Avenue, Albany, 
Georgia 31706-3090. This information may also be examined at the Rules 
Docket at the address above, or at the Office of the Federal Register, 
800 North Capitol Street, NW., 7th Floor, suite 700, Washington, DC.

FOR FURTHER INFORMATION CONTACT: Cindy Lorenzen, Aerospace Engineer, 
FAA, Atlanta Aircraft Certification Office, Campus Building, 1701 
Columbia Avenue, suite 2-160, College Park, Georgia 30337-2748; 
telephone (404) 305-7357; facsimile (404) 305-7348.

SUPPLEMENTARY INFORMATION:

Discussion

    On June 20, 1997, the FAA issued priority letter AD 97-13-11, which 
applies to certain Ayres S2R series airplanes. That AD resulted from an 
accident on an Ayres S2R series airplane where the wing separated from 
the airplane in flight. Investigation of all resources available to the 
FAA show nine occurrences of fatigue cracking in the lower spar caps of 
Ayres S2R airplanes, specifically emanating from the \1/4\-inch and \5/
16\-inch bolt holes. Although the investigation of the above-referenced 
accident is not complete, the FAA believes that the cause can be 
attributed to fatigue cracks emanating from the \1/4\-inch and \5/16\-
inch bolt holes in the left lower spar cap.
    Data accumulated by the FAA indicates that the fatigue cracks on 
these Ayres S2R series airplanes become detectable at different times 
based upon the type of engines and design of the airplane. With this in 
mind, the FAA has categorized these airplanes into three groups:

--Group 1 airplanes have steel spar caps with aluminum webs. These 
airplanes are capable of carrying heavier loads and data indicates that 
inspections in the affected areas of the lower spar cap should begin 
upon the accumulation of 2,700 hours time-in-service (TIS);
--Group 2 airplanes have steel spar caps with steel webs. Because of 
the steel webs as opposed to aluminum, data indicates that inspections 
in the affected areas of the left lower spar cap should begin upon the 
accumulation of 4,300 hours TIS; and
--Group 3 airplanes, which are the ones manufactured first, have steel 
spars

[[Page 36979]]

with aluminum webs and low horsepower radial engines, and thus do not 
have the ability to carry as much weight as airplanes in the other two 
groups. Data indicates that inspections in the affected areas of the 
left lower spar cap should begin upon the accumulation of 9,000 hours 
TIS.

    Manufacture of the affected airplanes began in 1965 with the 
airplanes incorporating the lower horsepower radial engines. Many of 
the airplane models referenced in this AD are still currently in 
production. These airplanes are used in agricultural operations and 
average 500 hours TIS annually. With this in mind, some of the earlier 
manufactured airplanes could have as many as 16,000 hours total TIS.

Discussion of the Applicable Service Information

    Ayres Service Bulletin No. SB-AG-39, dated September 17, 1996, 
includes procedures for accomplishing a magnetic particle inspection 
around the lower spar caps' bolt holes. This service bulletin also 
specifies replacement of any lower spar cap where fatigue cracking is 
found.

The FAA's Determination and Explanation of the AD

    Since an unsafe condition has been identified that is likely to 
exist or develop in other Ayres S2R series airplanes of the same type 
design, the FAA issued priority letter AD 97-13-11 to prevent fatigue 
cracking of the lower spar caps, which, if not detected and corrected, 
could result in the wing separating from the airplane with consequent 
loss of control of the airplane.
    The AD requires inspecting the \1/4\-inch and \5/16\-inch bolt hole 
areas on the lower spar caps for fatigue cracking, and replacing any 
lower spar cap if fatigue cracking is found. Accomplishment of the 
inspection is in accordance with Ayres Service Bulletin No. SB-AG-39, 
dated September 17, 1996. This inspection utilizes magnetic particles 
procedures and must follow American Society for Testing Materials 
(ASTM) E1444-94A, using wet particles meeting the requirements of the 
Society for Automotive Engineers (SAE) AMS 3046. This inspection is to 
be accomplished by a Level 2 or Level 3 inspector certified using the 
guidelines established by the American Society for Nondestructive 
Testing or MIL-STD-410.

Determination of the Effective Date of the AD

    Since it was found that immediate corrective action was required, 
notice and opportunity for prior public comment thereon were 
impracticable and contrary to the public interest, and good cause 
existed to make the AD effective immediately by individual letters 
issued on June 20, 1997, to known U.S. operators of certain Ayres S2R 
series airplanes. These conditions still exist, and the AD is hereby 
published in the Federal Register as an amendment to Sec. 39.13 of the 
Federal Aviation Regulations (14 CFR 39.13) to make it effective as to 
all persons.

Possible Future Rulemaking

    AD 97-13-11 covers all airplanes manufactured as of the date this 
AD was issued. The manufacturer is currently working on a modification 
that, if successful, would increase the fatigue life of the lower spar 
caps on the affected airplanes.
    When the modification is complete and based on the FAA's subsequent 
evaluation of the modification described above, additional rulemaking 
action may be initiated in the future for the airplanes affected by 
this AD and airplanes currently being manufactured.

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 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. 97-CE-44-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. 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 a new airworthiness directive 
(AD) to read as follows:

97-13-11  Ayres Corporation: Amendment 39-10071; Docket No. 97-CE-
44-AD.

    Applicability: Airplanes with the following model and serial 
number designations with or without a -DC suffix, certificated in 
any category:

[[Page 36980]]



                            Group 1 Airplanes                           
------------------------------------------------------------------------
                 Model                            Serial numbers        
------------------------------------------------------------------------
S-2R...................................  5000R through 5099R.           
S2R-R1340..............................  R1340-011, R1340-012, R1340-   
                                          019, R1340-020, R1340-024,    
                                          R1340-025, and R1340-027.     
S2R-R1820..............................  R1820-001 through 1820-035.    
S2R-T34................................  6000R through 6049R, T34-001   
                                          through T34-143, T34-145, T34-
                                          147 through T34-167, T34-171, 
                                          T34-180, and T34-181*.        
S2R-T15................................  T15-001 through T15-033**.     
S2R-T11................................  T11-001 through T11-005.       
S2R-G1.................................  G1-101 through G1-108.         
------------------------------------------------------------------------
* The serial numbers of the Model S2R-T34 airplanes could incorporate   
  T34-xxx, T36-xxx, T41-xxx, or T42-xxx. This AD applies to all of these
  serial number designations as they are all Model S2R-T34 airplanes.   
** The serial numbers of the Model S2R-T15 airplanes could incorporate  
  T15-xx and T27-xx. This AD applies to both of these serial number     
  designations as they are both Model S2R-T15 airplanes.                


                            Group 2 Airplanes                           
------------------------------------------------------------------------
                 Model                            Serial numbers        
------------------------------------------------------------------------
S2R-R1340..............................  R1340-028 through R1340-035.   
S2R-R1820..............................  R1820-036.                     
S2R-T65................................  T65-001 through T65-017.       
S2RHG-T65..............................  T65-002 through T65-017.       
S2R-T34................................  T-34-144, T34-146, T34-168, T34-
                                          169, T34-172 through T34-179, 
                                          and T34-189 through T34-226*. 
S2R-T45................................  T45-001 through T45-014.       
S2R-G6.................................  G6-101 through G6-146.         
S2R-G10................................  G10-101 through G10-138.       
S2R-G5.................................  G5-101 through G5-105.         
------------------------------------------------------------------------
*  The serial numbers of the Model S2R-T34 airplanes could incorporate  
  T34-xxx, T36-xxx, T41-xxx, or T42-xxx. This AD applies to all of these
  serial number designations as they are all Model S2R-T34 airplanes.   


                           Group 3 Airplanes *                          
------------------------------------------------------------------------
                 Model                            Serial numbers        
------------------------------------------------------------------------
600 S2D................................  All serial numbers beginning   
                                          with 600-1311D.               
S-2R...................................  1380R and 1416R through 4999R. 
S2R-1340R..............................  R1340-001 through R1340-010,   
                                          R1340-013 through R1340-018,  
                                          R1340-021 through R1340-023,  
                                          and R1340-026.                
S2R-R3S................................  R3S-001 through R3S-011.       
------------------------------------------------------------------------
* Any Group 3 airplane that has been modified with a hopper of a        
  capacity over 400 gallons, a piston engine greater than 600           
  horsepower, or any gas turbine engine makes the airplane a Group 1    
  airplane for the purposes of this AD. The owner/operator must inspect 
  the airplane at the Group 1 compliance time specified in the          
  Compliance section of this AD.                                        

    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 (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 the unsafe condition has not been 
eliminated, the request should include specific proposed actions to 
address it.

    Compliance: Inspections required as indicated below and any 
necessary replacement required prior to further flight as indicated 
in the body of this AD, except to those operators receiving this:

--Group 1 Airplanes: Required initially upon the accumulation of 
2,700 hours time-in-service (TIS) on each lower spar cap or prior to 
further flight after the effective date of this priority letter AD, 
whichever occurs later, except to those operators receiving this 
action by priority letter issued June 6, 1997, which made the 
inspection effective prior to further flight after receipt of the 
priority letter on airplanes with 2,700 hours TIS or more.
--Group 2 Airplanes: Required initially upon the accumulation of 
4,300 hours TIS on each lower spar cap or prior to further flight 
after the effective date of this AD receipt of this priority letter 
AD, whichever occurs later, except to those operators receiving this 
action by priority letter issued June 6, 1997, which made the 
inspection effective prior to further flight after receipt of the 
priority letter on airplanes with 4,300 hours TIS or more.
--Group 3 Airplanes: Required initially upon the accumulation of 
9,000 hours TIS on each lower spar cap or prior to further flight 
after receipt of this priority letter AD, whichever occurs later, 
except to those operators receiving this action by priority letter 
issued June 6, 1997, which made the inspection effective prior to 
further flight after receipt of the priority letter on airplanes 
with 9,000 hours TIS or more.

    To prevent fatigue cracking of the lower spar caps, which, if 
not detected and corrected, could result in the wing separating from 
the airplane with consequent loss of control of the airplane, 
accomplish the following:
    (a) Inspect, using magnetic particle procedures, the \1/4\-inch 
and \5/16\-inch bolt hole areas on each lower spar cap for fatigue 
cracking. Accomplishment of the inspection is in accordance with 
Ayres Service Bulletin No. SB-AG-39, dated September 17, 1996.
    (1) The magnetic particle inspection must follow American 
Society for Testing Materials (ASTM) E1444-94A, using wet particles 
meeting the requirements of the Society for Automotive Engineers 
(SAE) AMS 3046.
    (2) This inspection is to be accomplished by a Level 2 or Level 
3 inspector certified using the guidelines established by the 
American Society for Nondestructive Testing or MIL-STD-410.
    (b) If any cracking is found during the inspection required by 
this AD, prior to further flight, replace the affected lower spar 
cap in accordance with the affected maintenance manual. Upon 
replacement, total hours TIS starts over for that particular lower 
spar cap. Use the initial compliance time specified in the 
Compliance section of this AD to determine the next inspection 
interval.
    (c) If cracks are found during any inspection required by this 
AD, submit a report of inspection findings to the Manager, Atlanta 
Aircraft Certification Office (ACO), Campus Building, 1701 Columbia 
Avenue, Suite 2-160, College Park, Georgia 30337-2748; facsimile 
(404) 305-7348; at the applicable time specified in paragraph (c)(1) 
or (c)(2) of this AD. The report must include a description of any 
cracks found, the

[[Page 36981]]

airplane serial number, and the total number of flight hours on the 
lower spar cap found cracked. Information collection requirements 
contained in this regulation have been approved by the Office of 
Management and Budget (OMB) under the provisions of the Paperwork 
Reduction Act of 1980 (44 U.S.C. 3501 et seq.) and have been 
assigned OMB Control Number 2120-0056.
    (1) For airplanes on which the inspection is accomplished after 
receipt of this priority letter AD: Submit the report within 10 days 
after performing the inspection required by paragraph (a) of this 
AD.
    (2) For airplanes on which the inspection has been accomplished 
prior to the receipt of this priority letter AD: Submit the report 
within 10 days after receipt of this priority letter AD.
    (d) 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 to 
accomplish the modification requirements of this AD provided the 
following is followed:
    (1) The hopper is empty.
    (2) Vne is reduced to 126 miles per hour (109 knots).
    (3) Flight into known turbulence is prohibited.
    (e) An alternative method of compliance or adjustment of the 
compliance time that provides an equivalent level of safety may be 
approved by the Manager, Atlanta Aircraft Certification Office 
(ACO), Campus Building, 1701 Columbia Avenue, Suite 2-160, College 
Park, Georgia 30337-2748. The request shall be forwarded through an 
appropriate FAA Maintenance Inspector, who may add comments and then 
send it to the Manager, Atlanta ACO.

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

    (f) The inspection required by this AD shall be done in 
accordance with Ayres Service Bulletin No. SB-AG-39, dated September 
17, 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 the Ayres 
Corporation, P.O. Box 3090, One Rockwell Avenue, Albany, Georgia 
31706-3090. 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.
    (g) This amendment (39-10071) becomes effective on July 23, 
1997, to all persons except those persons to whom it was made 
immediately effective by priority letter AD 97-13-11, issued June 
20, 1997, which contained the requirements of this amendment.
    Issued in Kansas City, Missouri, on June 30, 1997.
Michael Gallagher,
Manager, Small Airplane Directorate, Aircraft Certification Service.
[FR Doc. 97-17728 Filed 7-9-97; 8:45 am]
BILLING CODE 4910-13-U