[Federal Register Volume 65, Number 32 (Wednesday, February 16, 2000)]
[Proposed Rules]
[Pages 7789-7794]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 00-3623]


 ========================================================================
 Proposed Rules
                                                 Federal Register
 ________________________________________________________________________
 
 This section of the FEDERAL REGISTER contains notices to the public of 
 the proposed issuance of rules and regulations. The purpose of these 
 notices is to give interested persons an opportunity to participate in 
 the rule making prior to the adoption of the final rules.
 
 ========================================================================
 

  Federal Register / Vol. 65, No. 32 / Wednesday, February 16, 2000 / 
Proposed Rules  

[[Page 7789]]



DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-CE-56-AD]
RIN 2120-AA64


Airworthiness Directives; Ayres Corporation S2R Series and Model 
600 S2D Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Supplemental notice of proposed rulemaking (NPRM); Reopening of 
the comment period.

-----------------------------------------------------------------------

SUMMARY: This document proposes to revise an earlier proposed 
airworthiness directive (AD) that the Federal Aviation Administration 
(FAA) issued against Ayres Corporation (Ayres) S2R series and Model 600 
S2D airplanes. The earlier proposed rule would supersede the existing 
AD with a new AD that would require you to repetitively inspect the \1/
4\-inch and \5/16\-inch bolt hole areas on the lower spar caps for 
fatigue cracking, replace any lower spar cap where fatigue cracking is 
found, and report any fatigue cracking. The existing AD was the result 
of an accident of an Ayres S2R series airplane where the wing separated 
from the airplane in flight. Based upon our continuous evaluation of 
this situation, we are making minor changes to the most recent 
proposal; specifically regrouping the affected airplanes into six 
groups, adjusting the repetitive inspection intervals, providing 
alternatives for inspection methods, and including modification 
alternatives to replacing the spar cap. By reopening the comment 
period, we are allowing you the opportunity to comment on these 
changes. The actions specified by the proposed AD are intended to 
detect and correct fatigue cracking of the lower spar caps, which could 
result in the wing separating from the airplane with consequent loss of 
control of the airplane.

DATES: The FAA must receive any comments on the proposed rule on or 
before April 10, 2000.

ADDRESSES: Submit comments in triplicate to the FAA, Central Region, 
Office of the Regional Counsel, Attention: Rules Docket No. 98-CE-56-
AD, 901 Locust, Room 506, Kansas City, Missouri 64106.
    You may get the service information referenced in the proposed AD 
from the Ayres Corporation, P.O. Box 3090, One Rockwell Avenue, Albany, 
Georgia 31706-3090. You may examine this information at the Rules 
Docket at the address above.

FOR FURTHER INFORMATION CONTACT: Satish Lall, Aerospace Engineer, FAA, 
Atlanta Aircraft Certification Office, One Crown Center, 1895 Phoenix 
Boulevard, Suite 450, Atlanta, Georgia 30349; telephone: (770) 703-
6082; facsimile: (770) 703-6097.

SUPPLEMENTARY INFORMATION:  

Comments Invited

    The FAA invites comments on this 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. The FAA will consider 
all comments received on or before the closing date. We may amend the 
proposed rule in light of comments received. Factual information that 
supports your ideas and suggestions is extremely helpful in evaluating 
the effectiveness of the proposed AD action and determining whether we 
need to take additional rulemaking action.
    The FAA is re-examining 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 clearer, 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.
    The FAA specifically invites comments on the overall regulatory, 
economic, environmental, and energy aspects of the proposed 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 the 
proposed AD.
    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. 98-CE-56-AD.'' We will date stamp and mail the 
postcard back to you.

Discussion

    Has the FAA taken any action to this point? Yes. An accident on an 
Ayres S2R series airplane where the wing separated from the airplane in 
flight caused the FAA to issue AD 97-17-03, Amendment 39-10195 (62 FR 
43296, August 18, 1997). AD 97-17-03 currently requires you to 
accomplish the following:

--Inspect the \1/4\-inch and \5/16\-inch bolt hole areas on the lower 
spar caps for fatigue cracking;
--Replace any lower spar cap where fatigue cracking is found; and
--Report any fatigue cracking to the FAA.

    Investigation of all resources available to the FAA at the time of 
the accident showed 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. Investigation of the above-
referenced accident revealed that the cause can be attributed to 
fatigue cracks emanating from the \1/4\-inch and \5/16\-inch bolt holes 
in the lower spar caps. Because the Ayres Model 600 S2D airplanes have 
a similar type design to that of the S2R series airplanes, they were 
included in the Applicability of AD 97-17-03.
    Data 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 
categorized these airplanes into three groups for the Applicability of 
AD 97-17-03.
    Since issuing AD 97-17-03, we received data specifying 29 
additional occurrences of fatigue cracks found in the lower spar caps 
of Ayres S2R and Model 600 S2D airplanes. The data from

[[Page 7790]]

these occurrences indicate the following:

--Several of these occurrences involved airplanes that had not 
accumulated enough hours to require the initial inspection of AD 97-17-
03;
--Detectable cracks could still develop after the initial inspection on 
the affected airplanes; and
--Ayres has manufactured additional airplanes that have a similar type 
design to that of the airplanes affected by AD 97-17-03. The existing 
AD should also cover these airplanes.

    To address the above areas, the FAA issued a notice of proposed 
rulemaking (NPRM) to supersede AD 97-17-03. This NPRM was published in 
the Federal Register on January 13, 1999 (64 FR 2157). The NPRM 
proposed to supersede AD 97-17-03 with a new AD that would:

--Retain the inspection and replacement (if necessary) requirements of 
the lower spar caps that are currently required in AD 97-17-03;
--Make these inspections repetitive;
--Add additional airplanes to the Applicability of the AD;
--Change the initial compliance time for all airplanes; and
--Arrange the affected airplanes into four groups instead of three 
based on usage and configurations.

    Was the public invited to comment on the NPRM? Yes. Interested 
persons were afforded an opportunity to participate in the making of 
the amendment. A summary of the comments and the FAA's responses 
follow.

Comment Issue No. 1: Certain Repetitive Inspection Intervals Too 
Long

    What are the commenters' concerns? Two commenters question why the 
FAA would allow longer repetitive inspection intervals for airplanes 
with cold working done on the bolt holes. One commenter questions why 
longer repetitive inspection intervals are allowed for airplanes with 
the big butterfly plates (Ayres part numbers 20211-9/-11) installed. 
The commenters specify the following:

--One commenter bases the comment on cracks found on an airplane where 
cold working was previously accomplished on the bolt holes. The cracks 
were found 527 hours time-in-service (TIS) after the cold working and 
the previous inspection.
--The other commenter states that installing the big butterfly plates 
would not significantly lower the stress levels in the spar cap and 
would not delay crack initiation and growth. The commenter also has 
information that cracks have occurred on airplanes within 500 hours TIS 
after cold working the bolt holes. The commenter is concerned that 
corrosion pitting and other defects on the bolt hole inner surface are 
not adequately removed prior to cold working and that this reduces the 
effectiveness of cold working the bolt holes.

    What is the FAA's response to the concern? We have evaluated the 
information received to date, including the above comments. Airplanes 
where bolt holes have been cold worked have not shown a significant 
reduction in crack growth rates. The safety benefit for airplanes with 
big butterfly plates installed is not as large as the FAA originally 
calculated.
    Is it necessary to change the proposed AD? Yes. We have adjusted 
the repetitive inspection intervals for airplanes with the bolt holes 
cold worked and/or big butterfly plates installed.

Comment Issue No. 2: Change the Applicability Grouping of a 
Specific Airplane

    What are the commenter's concern? One commenter states that the 
Model S2R-G10 airplane, serial number G10-137, should be categorized as 
a Group 4 airplane in the Applicability of the proposed AD instead of 
Group 2. The commenter states that this airplane has big butterfly 
plates installed and should therefore be included with the other 
airplanes with big butterfly plates installed.
    What is the FAA's response to the concern? We concur that this 
airplane has big butterfly plates installed and should be re-
categorized.
    Is it necessary to change the AD? Yes. We have re-categorized the 
airplanes in the Applicability of the proposed AD into six categories 
instead of four. This re-categorization allows the FAA to structure the 
repetitive inspection intervals to coincide with the specific airplane 
configuration.

Comment Issue No. 3: Require Ultrasonic Inspections

    What is the commenter's concern? One commenter recommends using 
ultrasonic inspection techniques instead of utilizing the magnetic 
particle method. The commenter states that the magnetic particle method 
could be used as a final check if a crack is indicated while using the 
ultrasonic method. This commenter states that, while utilizing the 
magnetic particle inspection method, damage to the bolt holes can occur 
during removal and reassembly of the lower splice fitting. Ultrasonic 
inspections do not require removing the lower splice fitting.
    What is the FAA's response to the concern? The FAA concurs that 
damage can occur when the lower splice fitting is removed and 
reassembled while accomplishing a magnetic particle inspection. We 
included a ``CAUTION'' statement in the NPRM to instruct that the wings 
must be firmly supported during the inspection to prevent movement of 
the spar caps when the splice blocks are removed. This allows easier 
realignment of the splice block holes and the holes in the spar cap for 
bolt insertion. We are not eliminating the option of using magnetic 
particle methods because the equipment used in this method is the most 
readily available in the field.
    Is it necessary to change the AD? Yes. We have included different 
inspection methods as options to accomplishing the actions of the 
proposed AD. This includes ultrasonic and magnetic particle methods.

Comment Issue No. 4: Ream the \1/4\-inch Bolt Holes to \5/16\ 
Inches Diameter

    What is the commenter's concern? One commenter recommends that the 
FAA require the 1/4-inch bolt holes be reamed to 5/16 inches diameter. 
This commenter states that this will remove any damage caused by 
previous removal and reassembly of the splice fitting.
    What is the FAA's response to the concern? The FAA has approved 
reaming the \1/4\-inch bolt holes to \5/16\ inches through the 
procedures included in Ayres Custom Kit No. CK-AG-29, dated December 
23, 1997. We have determined that allowing this as an option is more 
appropriate than requiring it on all affected airplanes.
    Is it necessary to change the AD? No.

Comment Issue No. 5: Require a Hardness Test of All Spar Caps

    What is the commenter's concern? One commenter recommends a one-
time Rockwell hardness test of all spar caps as specified in National 
Transportation Safety Board (NTSB) Report No. 98-2. This report 
specifies that the spar cap on the accident aircraft (reason for the 
initial AD action on this subject) did not meet the strength 
specifications for the type of material.
    What is the FAA's response to the concern? The FAA has determined 
that all the spars, including the ones installed on the accident 
aircraft, have adequate static strength. No Rockwell hardness tests are 
required.

[[Page 7791]]

    Is it necessary to change the AD? No

The FAA's Determination and Followup Action

    What have we decided? After careful review of all available 
information related to the subject presented above, including the 
above-referenced comments, the FAA has determined that:

    --The changes to the proposed AD as described in the above comment 
disposition should be incorporated; and
    --AD action should be taken to incorporate these changes to 
continue to detect and correct fatigue cracking of the lower spar caps, 
which could result in the wing separating from the airplane with 
consequent loss of control of the airplane.

    What is our next action? Since the changes propose actions that go 
beyond the scope of what was already proposed, the FAA is reopening the 
comment period to allow the public additional time to comment on the 
proposed AD.

Cost Impact

    How many airplanes does the proposed AD impact? The FAA estimates 
that 1,000 airplanes in the U.S. registry would be affected by the 
proposed AD.
    What is the cost impact of the initial inspection on owners/
operators of the affected airplanes? We estimate that it would take 
approximately 3 workhours per airplane to accomplish the proposed 
initial inspection, and that the average labor rate is approximately 
$60 an hour. Parts to accomplish the proposed initial inspection cost 
approximately $417 per airplane. Based on these figures, the total cost 
impact of the proposed AD on U.S. operators is estimated to be 
$597,000, or $597 per airplane.
    What about the cost of repetitive inspections and possible repairs 
and replacements? The figures above only take into account the cost of 
the proposed initial inspection and do not take into account the cost 
of proposed repetitive inspections. We have no way of determining how 
many repetitive inspections each owner/operator of the affected 
airplanes would incur. These figures are based upon the presumption 
that no affected airplane operator has accomplished the proposed 
inspection, and does not take into account the cost for replacement if 
a crack is found. We have no way of determining the number of wing spar 
caps that may need to be replaced based upon the results of the 
proposed inspections.

Regulatory Impact

    The regulations proposed herein would 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, it 
is determined that this proposed rule would not have federalism 
implications under Executive Order 13132.
    For the reasons discussed above, I certify that this action: (1) Is 
not a ``significant regulatory action'' under Executive Order 12866; 
(2) is not a ``significant rule'' under DOT Regulatory Policies and 
Procedures (44 FR 11034, February 26, 1979); and (3) if promulgated, 
will not have a significant economic impact, positive or negative, on a 
substantial number of small entities under the criteria of the 
Regulatory Flexibility Act. A copy of the draft regulatory evaluation 
prepared for this action has been placed in the Rules Docket. A copy of 
it may be obtained by contacting the Rules Docket at the location 
provided under the caption ADDRESSES.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Safety.

The Proposed Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration proposes to amend 
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 removing Airworthiness Directive 
(AD) 97-17-03, Amendment 39-10105 (62 FR 43926, August 18, 1997), and 
by adding a new AD to read as follows:

Ayres Corporation: Docket No. 98-CE-56-AD Supersedes AD 97-17-03, 
Amendment 39-10105.

    (a) What airplanes are affected by this AD? Airplanes with the 
following model and serial number (S/N) designations with or without 
a -DC or -X suffix, certificated in any category:

                            Group 1 Airplanes
------------------------------------------------------------------------
                     Model                             Serial Nos.
------------------------------------------------------------------------
S-2R..........................................  5000R through 5099R,
                                                 except 5010R, 5031R,
                                                 5038R, 5047R, and
                                                 5085R.
SR-R1820......................................  R1820-001 through R1820-
                                                 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-..........................................  G1 G1-101 through G1-
                                                 106.
------------------------------------------------------------------------
* 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-XXX and T27-XXX. This AD applies to both of these serial number
  designations as they are both Model S2R-T15 airplanes.


                            Group 2 Airplanes
------------------------------------------------------------------------
                     Model                             Serial Nos.
------------------------------------------------------------------------
S2R-R1820.....................................  R1820-036.
S2R-T65.......................................  T65-001 through T65-017.
S2RHG-T65.....................................  T65-002 through T65-017.
S2R-T34.......................................  T34-144, T34-146, T34-
                                                 168, T34-169, T34-172
                                                 through T34-179, and
                                                 T34-189 through T34-
                                                 232. And T34-234.*
S2R-T45.......................................  T45-001 through T45-014.
S2R-G6........................................  G6-101 through G6-147.
S2R-G10.......................................  G10-101 through G10-136,
                                                 G10-138, G10-140, and
                                                 G10-141.

[[Page 7792]]

 
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 Nos.
------------------------------------------------------------------------
600 S2D.......................................  All serial numbers
                                                 beginning with 600-
                                                 1311D.
S-2R..........................................  1380R and 1416R through
                                                 4999R.
S2R-R1340.....................................  R1340-001 through R1340-
                                                 035.
S2R-R3S.......................................  R3S-001 through R3S-011.
S2R-T11.......................................  T11-001 through T11-005.
 
------------------------------------------------------------------------
* Any Group 3 airplane that has been modified with a hopper of a
  capacity over 410 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 this AD.


                            Group 4 Airplanes
------------------------------------------------------------------------
                     Model                             Serial Nos.
------------------------------------------------------------------------
S2R-T34.......................................  T34-225, T34-236, T34-
                                                 237, and T34-238.*
S2R-G1........................................  G1-107, G1-108, and G1-
                                                 109.
S2R-G10.......................................  G10-137, G10-139, and
                                                 G10-142.
------------------------------------------------------------------------
* 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 5 Airplanes
------------------------------------------------------------------------
                     Model                             Serial Nos.
------------------------------------------------------------------------
S2R-T34.......................................  T34-239 through T34-
                                                 266.*
S2RHG-T34.....................................  T34HG-102.
S2R-T15.......................................  T15-034 through T15-
                                                 040.**
S2R-T45.......................................  T45-015.
S2R-G1........................................  G1-110 through G1-114.
S2R-G6........................................  G6-148 through G6-151.
S2R-G10.......................................  G10-143 through G10-160.
 
------------------------------------------------------------------------
* 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-XXX and T27-XXX. This AD applies to both of these serial
  designations as they are both Model S2R-T15 airplanes.


                            Group 6 Airplanes
------------------------------------------------------------------------
                     Model                             Serial Nos.
------------------------------------------------------------------------
S2R...........................................  5010R, 5031R, 5038R,
                                                 5047R, and 5085R.
------------------------------------------------------------------------

    (b) Who must comply with this AD? Anyone who wishes to operate 
any of the above airplanes on the U.S. Register.
    (c) What problem does this AD address? The actions specified by 
the proposed AD are intended to detect and correct fatigue cracking 
of the lower spar caps. This could result in the wing separating 
from the airplane with consequent loss of control of the airplane.
    (d) What actions must I accomplish to address this problem? To 
address this problem, you must accomplish the following:
    (1) Repetitively inspect, using magnetic particle, ultrasonic, 
or eddy current procedures, the \1/4\-inch and \5/16\-inch bolt hole 
areas on each lower spar cap for fatigue cracking. Reference 
paragraph (e)(3) and (e)(4) of this AD (including all subparagraphs) 
to obtain the initial and repetitive inspection compliance times.
    (i) The cracks may emanate from the bolt hole on the face of the 
spar cap or they may occur in the shaft of the hole.
    (ii) You must inspect both of these areas.
    (2) If any cracking is found during any inspection required by 
this AD, you must accomplish the following:
    (i) Use the cold work process to ream out small cracks as 
defined in Ayres Service Bulletin No. SB-AG-39, dated September 17, 
1996; or replace the affected spar cap in accordance with the 
maintenance manual; or ream the \1/4\-inch bolt holes to \5/16\ 
inches diameter as defined in Part I of Ayres Custom Kit No. CK-AG-
29, dated December 23, 1997; and
    (ii) Submit a report of inspection findings to the Manager, 
Atlanta ACO, One Crown Center, 1895 Phoenix Boulevard, Suite 450, 
Atlanta, Georgia 30349; facsimile: (770) 703-6097. You must include 
the airplane serial number and engine model number; the total number 
of flight hours on the lower spar cap that is cracked; time on the 
spar cap since last inspection, if applicable; and the type of 
inspection used for the last inspection. Indicate if cold working 
has been accomplished or modifications incorporated such as 
installation of big butterfly plates. Include the time on the spar 
cap when the cold working or modifications were accomplished. 
Indicate which bolt hole is

[[Page 7793]]

cracked and the length of the crack. 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.
    (e) What is the compliance time of this AD? The compliance times 
for each of the actions of this AD are as follows:
    (1) Any required repair or replacement: Prior to further flight 
after the inspection where the crack(s) was/were found.
    (2) Reporting requirement:
    (i) Submit the report within 10 days after finding any crack(s) 
during any inspection required by this AD.
    (ii) For airplanes where cracking was found during any 
inspection accomplished in accordance with AD 97-17-03, which is 
superseded by this AD; or by AD 97-13-11, which was superseded by AD 
97-17-03, submit the report within 10 days after the effective date 
of this AD, unless already accomplished.
    (3) Initial Inspection: The following is for the initial 
inspections required by this AD. The affected airplanes are 
categorized into six different groups.
    (i) Group 1 Airplanes: Required upon the accumulation of 2,000 
hours time-in-service (TIS) on each lower spar cap or within 50 
flight hours after the effective date of this AD, whichever occurs 
later, unless already accomplished (compliance with AD 97-17-03 or 
AD 97-13-11).
    (ii) Group 2 Airplanes: Required upon the accumulation of 2,200 
hours TIS on each lower spar cap or within 50 flight hours after the 
effective date of this AD, whichever occur later, unless already 
accomplished (compliance with AD 97-17-03 or AD 97-13-11).
    (iii) Group 3 Airplanes: Required upon the accumulation of 6,400 
hours TIS on each lower spar cap or within 50 flight hours after the 
effective date of this AD, whichever occurs later, unless already 
accomplished (compliance with AD 97-17-03 or AD 97-13-11).
    (iv) Group 4 Airplanes: Required upon the accumulation of 2,500 
hours TIS on each lower spar cap or within 50 flight hours after the 
effective date of this AD, whichever occurs later, unless already 
accomplished (compliance with AD 97-17-03 or AD 97-13-11).
    (v) Group 5 Airplanes: Required upon the accumulation of 6,200 
hours TIS on each lower spar cap or within 50 flight hours after the 
effective date of this AD, whichever occurs later, unless already 
accomplished (compliance with AD 97-17-03 or AD 97-13-11).
    (vi) Group 6 Airplanes: As presented below.
    (A) For S/N 5010R: Required upon the accumulation of 5,530 hours 
TIS on each lower spar cap or within the next 50 hours TIS after the 
effective date of this AD, whichever occurs later.
    (B) For S/N 5038R: Required upon the accumulation of 5,900 hours 
TIS on each lower spar cap or within the next 50 hours TIS after the 
effective date of this AD, whichever occurs later.
    (C) For S/N's 5031R and 5047R: Required upon the accumulation of 
6,400 hours TIS on each lower spar cap or within the next 50 hours 
TIS after the effective date of this AD, whichever occurs later.
    (D) For S/N 5085R: Required upon the accumulation of 6,290 hours 
TIS on each lower spar cap or within the next 50 hours TIS after the 
effective date of this AD, whichever occurs later.
    (4) Repetitive Inspections: The following chart gives the 
required repetitive inspection intervals based on the work performed 
and the method of inspection utilized. Each time is hours TIS 
intervals after the last inspection:

--------------------------------------------------------------------------------------------------------------------------------------------------------
                         Work previously performed                             Magnetic  particle            Ultrasonic               Eddy current
--------------------------------------------------------------------------------------------------------------------------------------------------------
No Cracks with optional cold work accomplished per SB-AG-39; or optional    500 hours TIS...........  550 hours TIS...........  700 hours TIS.
 \1/4\-inch bolt hole reamed to \5/16\ inches diameter per CK-AG-29, Part
 I, or previous Alternative Methods of Compliance.**
No Cracks with optional cold work accomplished per SB-AG-39 or optional \1/ 900 hours TIS...........  950 hours TIS...........  1,250 hours with TIS.
 4\-inch bolt hole reamed to \5/16\ inches diameter per CK-AG-29, Part I,
 or previous Alternative Methods of Compliance**; and butterfly plates,
 part number (P/N) 20211-09 and P/N 20211-11, installed per CK-AG-29, Part
 II.***
--------------------------------------------------------------------------------------------------------------------------------------------------------
*Aircraft S/N's T45-007DC and T45-10DC had modified splice block assemblies installed at Ayres (Ayres/Kaplan Assembly No. 88-251) and must still follow
  the repetitive inspection intervals listed here.
**If a crack is found, the reaming associated with the cold work process may remove a crack if it is small enough. Some aircraft owners/operators were
  issued alternative methods of compliance with AD 97-17-03 to ream the \1/4\-inch bolt hole to \5/16\ inches diameter to remove small cracks. Ayres CK-
  AG-29, Part I, also provides procedures to ream the \1/4\-inch bolt hole to \5/16\ inches diameter. If you use either of these two methods to remove
  cracks and the airplane is reinspected immediately with no cracks found, you may continue to follow the repetitive inspection intervals listed above.
***Group 4 and Group 5 airplanes had the butterfly plates installed at the factory and may follow this repetitive inspection interval.

    (f) What procedures must I use to accomplish the actions 
required in this AD?
    (1) Inspections:
    (i) For the magnetic particle inspection, utilize the procedures 
contained in Ayres Service Bulletin No. SB-AG-39, dated September 
17, 1996. Use only sections titled ``Inspection Accomplishment 
Instructions'' and ``Lower Splice Fitting Removal and Installation 
Instructions.'' You 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. 
CAUTION: You must firmly support the wings during the inspection to 
prevent movement of the spar caps when the splice blocks are 
removed. This will allow easier realignment of the splice block 
holes and the holes in the spar cap for bolt insertion.
    (ii) The FAA must approve ultrasonic or eddy current inspection 
procedures. To obtain FAA approval, you must send your proposed 
procedure to the Manager, Atlanta Aircraft Certification (ACO), One 
Crown Center, 1895 Phoenix Boulevard, Suite 450, Atlanta, Georgia 
30349. You are not required to remove the splice block for either 
the ultrasonic or eddy current inspections, unless corrosion is 
visible.
    (iii) All inspections required by this AD must be accomplished 
by a Level 2 or Level 3 inspector certified for that inspection 
method using the guidelines established by the American Society for 
Nondestructive Testing or MIL-STD-410.
    (2) Repair: Utilize the procedures contained in Ayres Service 
Bulletin No. SB-AG-39, dated September 17, 1996; or in Part I of 
Ayres Custom Kit No. CK-AG-29, dated December 23, 1997 if necessary 
to remove small cracks. You must then immediately re-inspect and 
continue to accomplish the repetitive inspections.
    (3) Replacement: Utilize the procedures contained in the 
maintenance manual.
    (g) Can I comply with this AD in any other way? Yes.
    (1) You may use an alternative method of compliance or adjust 
the compliance time if:
    (i) Your alternative method of compliance provides an equivalent 
level of safety; and
    (ii) The Manager, Atlanta Aircraft Certification Office, 
approves your alternative. Submit your request through an FAA 
Principal Maintenance Inspector, who may add comments and then send 
it to the Manager.
    (2) 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 (g)(1) of this AD. The 
request should include an assessment of the effect of the 
modification, alteration, or repair on the unsafe condition 
addressed by

[[Page 7794]]

this AD; and, if you have not eliminated the unsafe condition, 
specific actions you propose to address it.
    (3) Alternative methods of compliance approved in accordance 
with AD 97-17-03, which is superseded by this AD; or in accordance 
with AD 97-13-11, which was superseded by AD 97-17-03, are approved 
as alternative methods of compliance with this AD, unless otherwise 
noted in this AD.
    (h) Where can I get information about any already-approved 
alternative methods of compliance? Contact the Atlanta ACO, One 
Crown Center, 1895 Phoenix Boulevard, Suite 450, Atlanta, Georgia 
303496; telephone: (770) 703-6082; facsimile: (770) 703-6097.
    (i) 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 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.
    (j) You may obtain copies of the documents referenced in this 
document from the Ayres Corporation, P.O. Box 3090, One Rockwell 
Avenue, Albany, Georgia 31706-3090. You may examine these documents 
at the FAA, Central Region, Office of the Regional Counsel, 901 
Locust, Room 506, Kansas City, Missouri 64106.
    (k) This amendment supersedes AD 97-17-03, Amendment 39-10105.

    Issued in Kansas City, Missouri, on February 8, 2000.
Michael K. Dahl,
Acting Manager, Small Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 00-3623 Filed 2-15-00; 8:45 am]
BILLING CODE 4910-13-P