[Federal Register: December 4, 2006 (Volume 71, Number 232)]
[Rules and Regulations]
[Page 70286-70294]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr04de06-4]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2004-19961; Directorate Identifier 2004-CE-48-AD;
Amendment 39-14839; AD 2006-24-10]
RIN 2120-AA64
Airworthiness Directives; Air Tractor, Inc. Models AT-501, AT-
502, AT-502A, AT-502B, and AT-503A Airplanes
AGENCY: Federal Aviation Administration (FAA), Department of
Transportation (DOT).
ACTION: Final rule.
-----------------------------------------------------------------------
SUMMARY: We are adopting a new airworthiness directive (AD) for certain
Air Tractor, Inc. Models AT-501, AT-502, AT-502A, AT-502B, and AT-503A
airplanes, which supersedes AD 2002-
[[Page 70287]]
26-05 and AD 2002-11-05 R1. Since we issued AD 2002-26-05 and AD 2002-
11-05 R1, we determined that additional airplanes should be added to
the applicability section and determined the safe life for new
production airplanes and replacement spar caps should be extended. We
also developed an alternative method of compliance (AMOC) to the
requirements of this AD. This AD retains the actions required in AD
2002-26-05 and AD 2002-11-05 R1, adds additional airplanes to the
Applicability section, extends the safe life for new production
airplanes and replacement spar caps, and incorporates an AMOC. We are
issuing this AD to prevent fatigue cracks from occurring in the wing
lower spar cap before the established safe life is reached. Fatigue
cracks in the wing lower spar cap could result in failure of the spar
cap and lead to wing separation.
DATES: This AD becomes effective on January 8, 2007.
As of January 8, 2007, the Director of the Federal Register
approved the incorporation by reference of certain publications listed
in the regulation.
ADDRESSES: For service information identified in this AD, contact Air
Tractor, Incorporated, P.O. Box 485, Olney, Texas 76374; or Marburger
Enterprises, Inc., 1227 Hillcourt, Williston, North Dakota 58801;
telephone: (800) 893-1420 or (701) 774-0230; facsimile: (701) 572-2602.
To view the AD docket, go to the Docket Management Facility; U.S.
Department of Transportation, 400 Seventh Street, SW., Nassif Building,
Room PL-401, Washington, DC 20590-001 or on the Internet at http://dms.dot.gov.
The docket number is FAA-2004-19961; Directorate
Identifier 2004-CE-48AD.
FOR FURTHER INFORMATION CONTACT: Direct all questions to:
For the airplanes that do not incorporate and never have
incorporated Marburger Enterprises, Inc. winglets: Rob Romero,
Aerospace Engineer, FAA, Fort Worth Airplane Certification Office, 2601
Meacham Boulevard, Fort Worth, Texas 76193-0150; telephone: (817) 222-
5102; facsimile: (817) 222-5960; e-mail: robert.a.romero@faa.gov; and
For airplanes that incorporate or have incorporated
Marburger Enterprises, Inc. winglets: John Cecil, Aerospace Engineer,
Los Angeles Aircraft Certification Office, FAA, 3960 Paramount
Boulevard, Lakewood, California 90712; telephone: (562) 627-5228;
facsimile: (562) 627-5210.
SUPPLEMENTARY INFORMATION:
Discussion
On August 3, 2006, we issued a proposal to amend part 39 of the
Federal Aviation Regulations (14 CFR part 39) to include an AD that
would apply to certain Air Tractor, Inc. Models AT-501, AT-502, AT-
502A, AT-502B, and AT-503A airplanes. This proposal was published in
the Federal Register as a notice of proposed rulemaking (NPRM) on
August 9, 2006 (71 FR 45457). The NPRM proposed to supersede AD 2002-
26-05 and AD 2002-11-05 R1 with a new AD that would:
retain the actions required in AD 2002-26-05 and AD 2002-
11-05 R1;
add additional airplanes to the Applicability section;
incorporate an alternative method of compliance (AMOC) to
the requirements of this AD; and
extend the safe life for new production airplanes and
replacement spar caps.
The table below summarizes the effects this AD will have on the
airplane models affected by this AD:
------------------------------------------------------------------------
Model Proposed Action
------------------------------------------------------------------------
AT-501................... Supersede AD 2002-11-05 R1.
Retain the safe lives from AD 2002-
11-05 R1.
Provide an AMOC that allows
extension of the safe life through an
inspection and modification program.
AT-502................... Supersede AD 2002-26-05.
Retain the safe lives from AD 2002-
26-05 and add S/Ns to applicability. AD 2002-
26-05 provided safe lives for S/Ns 0003
through 0236. Proposed action applies the
same safe life to all S/Ns beginning with
0003.
Provide an AMOC that allows
extension of the safe life through an
inspection and modification program.
AT-502A.................. Supersede AD 2002-26-05.
Retain the safe lives from AD 2002-
26-05.
Provide an AMOC that allows
extension of the safe life through an
inspection and modification program.
AT-502B.................. Supersede AD 2002-26-05.
Retain the safe lives from AD 2002-
26-05 for S/Ns 0187 through 0654, except
0643.
Increase the safe lives beyond those
listed in AD 2002-26-05 for S/Ns 0655 and
greater, as well as S/N 0643.
Add requirement to cold work
outboard wing center splice block bolt holes
in the lower spar cap on S/Ns 0643 and 0655
through 0692.
Provide an AMOC that allows
extension of the safe life through an
inspection and modification program for S/Ns
187 through 654, except 643.
AT-503A.................. Supersede AD 2002-26-05.
Retain the safe lives from AD 2002-
26-05.
Provide an AMOC that allows
extension of the safe life through an
inspection and modification program.
------------------------------------------------------------------------
Comments
We provided the public the opportunity to participate in developing
this AD. We received no comments on the proposal or on the
determination of the cost to the public.
Conclusion
We have carefully reviewed the available data and determined that
air safety and the public interest require adopting the AD as proposed
except for minor editorial corrections. We have determined that these
minor corrections:
are consistent with the intent that was proposed in the
NPRM for correcting the unsafe condition; and
do not add any additional burden upon the public than was
already proposed in the NPRM.
Costs of Compliance
We estimate that this AD affects 500 airplanes in the U.S.
registry.
We estimate the following costs to do each inspection:
[[Page 70288]]
----------------------------------------------------------------------------------------------------------------
Total cost per
Labor cost Parts cost airplane Total cost on U.S. operators
----------------------------------------------------------------------------------------------------------------
8 work-hours x $80 per hour = $640. No parts required for $640 $640 x 500 = $320,000
inspection.
----------------------------------------------------------------------------------------------------------------
We estimate the following costs to do the modification:
--------------------------------------------------------------------------------------------------------------------------------------------------------
Labor cost Parts cost Total cost per airplane Total cost on U.S. operators
--------------------------------------------------------------------------------------------------------------------------------------------------------
120 work-hours x $80 per hour = Approximately $3,700... $9,600 + $3,700 = $13,300................... $13,300 x 500 = $6,650,000
$9,600.
--------------------------------------------------------------------------------------------------------------------------------------------------------
We estimate the following costs to do the replacement:
--------------------------------------------------------------------------------------------------------------------------------------------------------
Labor cost Parts cost Total cost per airplane Total cost on U.S. operators
--------------------------------------------------------------------------------------------------------------------------------------------------------
254 work-hours x $80 per hour = Approximately $16,500.. $20,320 + $16,500 = $36,820................. $36,820 x 500 = $18,410,000
$20,320.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Authority for This Rulemaking
Title 49 of the United States Code specifies the FAA's authority to
issue rules on aviation safety. Subtitle I, Section 106 describes the
authority of the FAA Administrator. Subtitle VII, Aviation Programs,
describes in more detail the scope of the agency's authority.
We are issuing this rulemaking under the authority described in
Subtitle VII, Part A, Subpart III, Section 44701, ``General
requirements.'' Under that section, Congress charges the FAA with
promoting safe flight of civil aircraft in air commerce by prescribing
regulations for practices, methods, and procedures the Administrator
finds necessary for safety in air commerce. This regulation is within
the scope of that authority because it addresses an unsafe condition
that is likely to exist or develop on products identified in this AD.
Regulatory Findings
We have determined that this AD will not have federalism
implications under Executive Order 13132. This AD will not have a
substantial direct effect on the States, on the relationship between
the national government and the States, or on the distribution of power
and responsibilities among the various levels of government.
For the reasons discussed above, I certify that this AD:
1. Is not a ``significant regulatory action'' under Executive Order
12866;
2. Is not a ``significant rule'' under the DOT Regulatory Policies
and Procedures (44 FR 11034, February 26, 1979); and
3. 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.
We prepared a summary of the costs to comply with this AD (and
other information as included in the Regulatory Evaluation) and placed
it in the AD Docket. You may get a copy of this summary by sending a
request to us at the address listed under ADDRESSES. Include ``Docket
No. FAA-2004-19961; Directorate Identifier 2004-CE-48-AD'' in your
request.
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Incorporation by
reference, Safety.
Adoption of the Amendment
0
Accordingly, under the authority delegated to me by the Administrator,
the Federal Aviation Administration amends part 39 of the Federal
Aviation Regulations (14 CFR part 39) as follows:
PART 39--AIRWORTHINESS DIRECTIVES
0
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]
0
2. FAA amends Sec. 39.13 by removing Airworthiness Directive (AD)
2002-26-05, Amendment 39-12991 (68 FR 18, January 2, 2003) and AD 2002-
11-05 R1, Amendment 39-14564 (71 FR 19628, April 17, 2006), and by
adding a new AD to read as follows:
2006-24-10 Air Tractor, Inc.: Amendment 39-14839; Docket No. FAA-
2004-19961; Directorate Identifier 2004-CE-48-AD.
Effective Date
(a) This AD becomes effective on January 8, 2007.
Affected ADs
(b) This AD supersedes AD 2002-26-05, Amendment 39-12991, and AD
2002-11-05 R1, Amendment 39-14564.
Applicability
(c) This AD applies to certain Models AT-501, AT-502, AT-502A,
AT-502B, and AT-503A airplanes. Use Table 1 in paragraph (c)(1) of
this AD for airplanes that do not incorporate and never have
incorporated Marburger Enterprises, Inc. (Marburger) winglets. Use
Table 2 in paragraph (c)(4) of this AD for certain AT-500 series
airplanes that incorporate or have incorporated Marburger winglets.
(1) The following table applies to airplanes (certificated in
any category) that do not incorporate and never have incorporated
Marburger winglets along with the safe life (presented in hours
time-in-service (TIS)) of the wing lower spar cap for all affected
airplane models and serial numbers:
[[Page 70289]]
Table 1.--Safe Life for Airplanes that do not Incorporate and Never Have
Incorporated Marburger Winglets
------------------------------------------------------------------------
Wing lower spar cap safe
Model Serial Nos. life
------------------------------------------------------------------------
AT-501.................. 0002 through 0061... 4,531 hours TIS.
AT-501.................. All serial numbers 7,693 hours TIS.
beginning with 0062.
AT-502.................. All serial numbers 1,650 hours TIS.
beginning with 0003.
AT-502A................. All serial numbers 1,650 hours TIS.
beginning with 0158.
AT-502B................. 0187 through 0654, 1,650 hours TIS.
except 0643.
AT-502B................. 0643, and 0655 9,000 hours TIS.
through 0692.
AT-502B................. 0693 through 0701... 9,500 hours TIS.
AT-502B................. All serial numbers 9,800 hours TIS.
beginning with 0702.
AT-503A................. All serial numbers 1,650 hours TIS.
beginning with 0067.
------------------------------------------------------------------------
(2) If piston-powered airplanes have been converted to turbine
power, you must use the limits for the corresponding serial number
(S/N) turbine-powered airplanes.
(3) Airplanes that have been modified to install lower spar
caps, part numbers (P/N) 21058-1 and 21058-2, should use a safe life
of 9,800 hours TIS.
(4) The following table applies to airplanes (certificated in
any category) that incorporate or have incorporated Marburger
winglets. These winglets are installed following Supplemental Type
Certificate (STC) SA00490LA. Use the winglet usage factor in Table 2
of this paragraph, the safe life specified in Table 1 in paragraph
(c)(1) of this AD, and the instructions included in Appendix 1 to
this AD to determine the new safe life of airplanes that incorporate
or have incorporated Marburger winglets:
Table 2.--Winglet Usage Factor To Determine the Safe Life for Airplanes
That Incorporate or Have Incorporated Marburger Winglets Installed
Following STC SA00490LA
------------------------------------------------------------------------
Winglet usage
Model Serial numbers factor
------------------------------------------------------------------------
AT-501....................... 0002 through 0061....... 1.6
AT-501....................... All serial numbers 1.6
beginning with 0062.
AT-502....................... 0003 through 0236....... 1.6
AT-502A...................... 0158 through 0238....... 1.6
AT-502A...................... All serial numbers 1.2
beginning with 0239.
AT-502B...................... All serial numbers 1.2
beginning with 0187.
------------------------------------------------------------------------
(5) Model AT-502B airplanes, S/N 0643, all S/Ns beginning with
0655, and all other airplanes that have been modified with
replacement spar caps, P/N 21058-1 and P/N 21058-2, are not eligible
to have STC SA00490LA installed without additional fatigue data
being provided to the FAA at the address in paragraph (f) of this
AD.
Unsafe Condition
(d) This AD is the result of service reports and analysis done
on wing lower spar caps of Air Tractor, Inc. airplanes. The actions
specified by this AD are intended to prevent fatigue cracks from
occurring in the wing lower spar cap before the established safe
life is reached. Fatigue cracks in the wing lower spar cap, if not
detected and corrected, could result in failure of the spar cap and
lead to wing separation and loss of control of the airplane.
Compliance
(e) To address this problem, you must do the following:
------------------------------------------------------------------------
Actions Compliance Procedures
------------------------------------------------------------------------
(1) For all affected For airplanes Airplane Records
airplanes: Modify the previously affected Modification: The
applicable airplane records by AD 2002-26-05: owner/operator
(logbook) as follows to Do the logbook holding at least a
show the reduced safe life entry within the private pilot
for the wing lower spar cap next 10 hours TIS certificate as
(use the information from after January 15, authorized by
Table 1 in paragraph 2003 (the effective section 43.7 of the
(c)(1), Table 2 in date of AD 2002-26- Federal Aviation
paragraph (c)(4), and 05). For airplanes Regulations (14 CFR
Appendix 1 of this AD, as not previously 43.7) may modify
applicable): affected by AD 2002- the airplane
(i) Incorporate the 26-05: Do the records as
following into the airplane logbook entry specified in
logbook ``In accordance within the next 10 paragraph (e)(1) of
with AD 2006-24-10 (AD 2002- hours TIS after this AD. Make an
26-05 or AD 2002-11-05, as January 8, 2007 entry into the
applicable) the wing lower (the effective date airplane records
spar cap is life limited to of this AD), unless showing compliance
--.'' Insert the applicable already done. The with this portion
safe life number from the logbook language of the AD in
applicable tables in for AT-501 accordance with
paragraphs (c)(1) and airplanes is section 43.9 of the
(c)(4) of this AD and referenced as AD Federal Aviation
Appendix 1 of this AD. 2002-11-05 instead Regulations (14 CFR
(ii) If, as of the time of of AD 2002-11-05 R1 43.9). Spar Cap
the logbook entry to maintain Replacement: Do the
requirement of paragraph continuity and replacement when
(e)(1)(i) of this AD, your assures no further the safe life is
airplane is over or within action is necessary. reached following
50 hours of the safe life, Snow Engineering
an additional 50 hours TIS Drawing Number
after the effective date of 21050, Snow
this AD is allowed to do Engineering Service
the replacement.. Letters < greek-
i>197 or 205, both revised
March 26, 2001, as
applicable. The
owner/operator may
not do the spar cap
modification/
replacement, unless
he/she holds the
proper mechanic
authorization.
[[Page 70290]]
(2) To extend the safe life Inspection schedule Procedures included
of the wing lower spar cap included as part of as part of the AMOC
for certain airplanes, you the alternative in Appendix 2 to
may eddy-current inspect method of this AD.
and modify the wing lower compliance (AMOC)
spar cap. The inspection in Appendix 2 to
schedule, modification this AD.
procedures, and list of
eligible airplanes are
included in Appendix 2 to
this AD.
(3) For all affected Only if cracks are Send the form
airplanes: Report to the found, send the (Figure 1 of this
FAA any cracks detected as report within 10 AD) to FAA, Fort
the result of each days after the Worth Airplane
inspection required by inspection required Certification
paragraph (e)(2) of this AD in paragraph (e)(2) Office, Attn: Rob
on the form in Figure 1 of of this AD. Romero, 2601
this AD. The Office of Meacham Boulevard,
Management and Budget (OMB) Fort Worth, Texas
approved the information 76193-0150;
collection requirements telephone: (817)
contained in this 222-5102;
regulation under the facsimile: (817)
provisions of the Paperwork 222-5960.
Reduction Act and assigned
OMB Control Number 2120-
0056.
(4) For Model AT-502B Before accumulating Following Snow
airplanes, S/Ns 502B-0643 2,000 hours TIS or Engineering Service
and 502B-0655 through 502B- within the next 100 Letter < greek-
0692: Cold work the left- hours TIS after i>244, dated April
hand and right-hand two January 8, 2007 25, 2005.
outboard wing center splice (the effective date
block bolt holes (4 total) of this AD),
in the lower spar cap. whichever occurs
later.
(5) For all affected Not applicable...... Not applicable.
airplanes: Airplanes that
have the two-part
modification done following
the applicable service
bulletins (Snow Engineering
Service Letters < greek-
i>197 or 205, both
revised March 26, 2001; or
Snow Engineering Service
Letter 244, dated
April 25, 2005), but have
over-sized outboard bolt
holes at the splice block,
must obtain an AMOC from
FAA as specified in
paragraph (f) of this AD to
determine applicable
inspection intervals.
------------------------------------------------------------------------
BILLING CODE 4910-13-P
[[Page 70291]]
[GRAPHIC] [TIFF OMITTED] TR04DE06.000
BILLING CODE 4910-13-C
[[Page 70292]]
Alternative Methods of Compliance (AMOCs)
(f) The Manager, Fort Worth or Los Angeles Airplane
Certification Office (ACO), as applicable (see paragraphs (f)(1)(i)
and (f)(2)(ii) of this AD below for specific contacts), has the
authority to approve AMOCs for this AD, if requested using the
procedures found in 14 CFR 39.19.
(1) For information on any already approved AMOCs, contact:
(i) For the airplanes that do not incorporate and never have
incorporated Marburger Enterprises, Inc. winglets: Rob Romero,
Aerospace Engineer, FAA, Fort Worth ACO, 2601 Meacham Boulevard,
Fort Worth, Texas 76193-0150; telephone: (817) 222-5102; facsimile:
(817) 222-5960; e-mail: robert.a.romero@faa.gov.
(ii) For airplanes that incorporate or have incorporated
Marburger Enterprises, Inc. winglets: John Cecil, Aerospace
Engineer, Los Angeles ACO, FAA, 3960 Paramount Boulevard, Lakewood,
California 90712; telephone: (562) 627-5228; facsimile: (562) 627-
5210.
(2) AMOCs approved for AD 2001-10-04 and/or AD 2000-14-51 are
not considered approved for this AD.
(3) AMOCs approved for AD 2001-10-04 R1, AD 2002-11-03, AD 2002-
11-05, AD 2002-11-05 R1, or AD 2002-26-05 are considered approved
for this AD.
Special Flight Permit
(g) Under 14 CFR part 39.23, we are limiting the special flight
permits for this AD by the following conditions:
(1) Operate only in day visual flight rules (VFR).
(2) Ensure that the hopper is empty.
(3) Limit airspeed to 135 miles per hour (mph) indicated
airspeed (IAS).
(4) Avoid any unnecessary g-forces.
(5) Avoid areas of turbulence.
(6) Plan the flight to follow the most direct route.
Material Incorporated by Reference
(h) You must use the service information specified in Table 3 of
this AD to do the actions required by this AD, unless the AD
specifies otherwise.
(1) The Director of the Federal Register approved the
incorporation by reference of this service information under 5
U.S.C. 552(a) and 1 CFR part 51.
(2) For service information identified in this AD, contact Air
Tractor, Incorporated, P.O. Box 485, Olney, Texas 76374.
(3) You may review copies at the FAA, Central Region, Office of
the Regional Counsel, 901 Locust, Kansas City, Missouri 64106; or at
the National Archives and Records Administration (NARA). For
information on the availability of this material at NARA, call 202-
741-6030, or go to: http://www.archives.gov/[fxsp0]federal--
register/[fxsp0]code--of--federal--regulations/[fxsp0]ibr--
locations.html.
Table 3.--Material Incorporated by Reference
----------------------------------------------------------------------------------------------------------------
Service Bulletin No. Page Revision Date
----------------------------------------------------------------------------------------------------------------
Snow Engineering Drawing Number Sheet 1 and Sheet 3.. Not applicable....... January 30, 2003.
21050.
Sheet 2.............. Not applicable....... February 1, 2003.
Snow Engineering Service Letter 1 and 2.............. Not applicable....... March 26, 2001.
197.
3.................... Not applicable....... June 13, 2000.
Snow Engineering Service Letters 1, 2, and 4.......... Not applicable....... March 26, 2001.
205.
3.................... Not applicable....... October 25, 2000.
Snow Engineering Service Letter 1 through 12......... Not applicable....... April 25, 2005.
244.
----------------------------------------------------------------------------------------------------------------
Appendix 1 to AD 2006-24-10
The following provides procedures for determining the safe life
for those Models AT-501, AT-502, AT-502A, and AT-502B airplanes that
incorporate or have incorporated Marburger Enterprises, Inc.
(Marburger) winglets. These winglets are installed in accordance
with Supplemental Type Certificate (STC) No. SA00490LA.
If you have removed the Marburger winglets before further flight
after the effective date of this AD or before the effective date of
this AD, do the following:
1. Review your airplane's logbook to determine your airplane's
time-in-service (TIS) with winglets installed per Marburger STC No.
SA00490LA. This includes all time spent with the winglets currently
installed and any previous installations where the winglet was
installed and later removed.
Example: A review of your airplane's logbook shows that you have
accumulated 350 hours TIS since incorporating the Marburger STC.
Further review of the airplane's logbook shows that a previous owner
had installed the STC and later removed the winglets after
accumulating 150 hours TIS. Therefore, your airplane's TIS with the
winglets installed is 500 hours.
If you determine that the winglet STC has never been
incorporated on your airplane, then your safe life is presented in
Table 1 in paragraph (c)(1) of this AD. Any future winglet
installation will be subject to a reduced safe life per these
instructions.
2. Determine your airplane's unmodified safe life from Table 1
in paragraph (c)(1) of this AD.
Example: Your airplane is a Model AT-502B, serial number (S/N) 0292.
From Table 1 in paragraph (c)(1) of this AD, the unmodified safe-
life of your airplane is 1,650 hours TIS.
All examples from hereon will be based on the Model AT-502B, S/N
0292 airplane.
3. Determine the winglet usage factor from Table 2 in paragraph
(c)(4) of this AD.
Example: Again, your airplane is a Model AT-502B, S/N 0292. From
Table 2 in paragraph (c)(4) of this AD, your winglet usage factor is
1.2.
4. Adjust the winglet TIS to account for the winglet usage
factor. Multiply the winglet TIS (result of Step 1 above) by the
winglet usage factor (result of Step 3 above).
Example: Winglet TIS is 500 hours X a winglet usage factor of 1.2.
The adjusted winglet TIS is 600 hours.
5. Calculate the winglet usage penalty. Subtract the winglet TIS
(result of Step 1 above) from the adjusted winglet TIS (result of
Step 4 above).
Example:
Adjusted winglet TIS--the winglet TIS = Winglet usage penalty.
(600 hours TIS)--(500 hours TIS) = (100 hours TIS).
6. Adjust the safe life of your airplane to account for winglet
usage. Subtract the winglet usage penalty (result of Step 5 above)
result from the unmodified safe life from Table 1 in paragraph
(c)(1) of this AD (the result of Step 2 above).
Example:
Unmodified safe life--winglet usage penalty = Adjusted safe
life.
(1,650 hours TIS)--(100 hours TIS) = (1,550 hours TIS).
7. If you remove the winglets from your airplane before further
flight or no longer have the winglets installed on your airplane,
the safe life of your airplane is the adjusted safe life (result of
Step 6 above). Enter this number in paragraph (e)(1)(i) of this AD
and the airplane logbook.
If you have the Marburger winglets installed as of the effective
date of this AD and plan to operate your airplane without removing
the winglets, do the following:
1. Review your airplane's logbook to determine your airplane's
TIS without the winglets installed.
Example: A review of your airplane's logbook shows that you have
accumulated 1,500 hours TIS, including 500 hours with the Marburger
winglets installed. Therefore, your airplane's TIS without the
winglets installed is 1,000 hours.
2. Determine your airplane's unmodified safe life from Table 1
in paragraph (c)(1) of this AD.
Example: Your airplane is a Model AT-502B, S/N 0292. From Table 1 in
paragraph (c)(1) of this AD, the unmodified safe life of your
airplane is 1,650 hours TIS.
All examples from hereon will be based on the Model AT-502B, S/N
0292 airplane.
[[Page 70293]]
3. Determine the winglet usage factor from Table 2 in paragraph
(c)(4) of this AD.
Example: Again, your airplane is a Model AT-502B, S/N 0292. From
Table 2 in paragraph (c)(4) of this AD, your winglet usage factor is
1.2.
4. Determine the potential winglet TIS. Subtract the TIS without
the winglets installed (result of Step 1 above) from the unmodified
safe life (result of Step 2 above).
Example:
Unmodified safe life--TIS without winglets = Potential winglet
TIS.
(1,650 hours TIS)--(1,000 hours TIS) = (650 hours TIS).
5. Adjust the potential winglet TIS to account for the winglet
usage factor. Divide the potential winglet TIS (result of Step 4
above) by the winglet usage factor (result of Step 3 above).
Example:
Potential winglet TIS winglet usage factor = Adjusted potential
winglet TIS.
(650 hours TIS) (1.2) = (541 hours TIS).
6. Calculate the winglet usage penalty. Subtract the adjusted
potential winglet TIS (result of Step 5 above) from the potential
winglet TIS (result of Step 4 above).
Example:
Potential winglet TIS--adjusted potential winglet TIS = Winglet
usage penalty.
(650 hours TIS)--(541 hours TIS) = (109 hours TIS).
7. Adjust the safe life of your airplane to account for the
winglet installation. Subtract the winglet usage penalty (result of
Step 6 above) from the unmodified safe life from Table 1 in
paragraph (c)(1) of this AD (the result of Step 2 above).
Example:
Unmodified safe life--winglet usage penalty = Adjusted safe
life.
(1,650 hours TIS)--(109 hours TIS) = (1,541 hours TIS).
8. Enter the adjusted safe life (result of Step 7 above) in
paragraph (e)(1)(i) of this AD and the airplane logbook.
If you install or remove the Marburger winglets from your
airplane in the future, do the following:
If, at anytime in the future, you install or remove the
Marburger winglets STC from your airplane, you must repeat the
procedures in this Appendix to determine the airplane's safe life.
Appendix 2--Alternative Method of Compliance (AMOC) to AD 2006-24-10;
Optional Inspection Program
For all airplanes listed in this AD; except for Model AT-502B
airplanes, serial number (S/N) 0643 and all S/Ns beginning with
0655, and those airplanes that have been modified with the
replacement spar caps, part number (P/N) 21058-1 and P/N 21058-2;
you may begin a repetitive inspection interval program as an
alternative to the safe life requirement of this AD with the
following provisions:
For the Model AT-501 airplanes affected by this AD, you may
elect to follow this AMOC program and continue to operate your
airplane up to 8,000 hours TIS, provided you comply with this AMOC
in its entirety. If at the time of the effective date of this AD,
you are over 1,600 hours TIS (the time required for the first
inspection), you must inspect within 50 hours TIS. If at the time of
the effective date of this AD, you are over 4,000 hours TIS (the
time required for 2-part modification), you must have the
modification done within 50 hours TIS. If you choose not to follow
this inspection program, then you must replace your lower spar caps
and associated hardware at the applicable safe life listed in this
AD following the procedures in paragraph (e).
For airplanes that do not and never have had Marburger
Enterprise, Inc. winglets installed following Supplemental Type
Certificate (STC) SA00490LA:
1. Upon accumulating 1,600 hours time-in-service (TIS) or within
the next 50 hours TIS after January 8, 2007 (the effective date of
AD 2006-24-10), whichever occurs later, eddy-current inspect the
outboard two lower spar cap bolt holes following Snow Engineering
Process Specification 197, page 1, revised June 4, 2002;
pages 2 through 5, revised May 3, 2002. The inspection must be done
by one of the following:
a. A Level 2 or Level 3 inspector that is certified for eddy-
current inspection using the guidelines established by the American
Society for Nondestructive Testing or MIL-STD-410; or
b. A person authorized to do AD work and has completed and
passed the Air Tractor, Inc. training course on Eddy Current
Inspection on wing lower spar caps.
2. Repeat these inspections at intervals of (as applicable):
a. 800 hours TIS (all S/Ns except as noted in b); or
b. 600 hours TIS (S/Ns 502B-0187 through 502B-0618 that do not
have P/N 20998-1/-2 web plate installed).
c. If the outboard two lower spar cap bolt holes have been cold
worked following Snow Engineering Service Letter 233,
dated May 18, 2004, then you may double (1,600 hours TIS or 1,200
hours TIS, as applicable) the inspection interval (See Step 8--re:
mid cycle cold work).
d. Your logbook entry must include the work done and the
inspection intervals that are upcoming, as follows:
``Following AD 2006-24-10, at XXXX {insert hours TIS of the
initial pre-modification inspection{time} hours TIS an eddy-current
inspection has been performed. As of now, the safe life listed in
the AD no longer applies to this airplane. This airplane must be
eddy-current inspected at intervals not to exceed {800/600/1,600/
1,200, as applicable{time} hours TIS. The first of these
inspections is due at {insert the total number of hours TIS the
first of these inspections is due{time} hours TIS.''
3. If at any time a crack is found, and:
a. The crack indication goes away by doing the modification
following the applicable sheet of Snow Engineering Modification--
Wing Centersplice--502, Drawing Number 20989, then you may modify
your center splice following Snow Engineering Drawing 20989. After
modification, proceed to Step 5.
b. The crack indication does not go away by doing the
modification following the applicable sheet of Snow Engineering
Modification--Wing Centersplice--502, Drawing Number 20989, you must
replace all parts and hardware listed in Step 7.
c. Report to the FAA any cracks found using the form in Figure 1
of this AD.
4. For all S/Ns, upon accumulating 4,000 hours TIS, you must:
a. Modify your center splice connection following the applicable
sheet of Snow Engineering Modification--Wing Centersplice--502,
Drawing Number 20989, unless already done following Snow Engineering
Service Letter 197 or 205, both revised March 26,
2001, as applicable. The owners/operator may not do the spar cap
modification unless that person holds the proper mechanic
authorization. If, as of January 8, 2007 (the effective date of AD
2006-24-10), your airplane is over or within 50 hours of reaching
the 4,000 hour TIS modification requirement, do the modification
within the next 50 hours TIS.
b. Before doing the modification, do an eddy-current inspection
following Snow Engineering Process Specification 197, page
1, revised June 4, 2002; pages 2 through 5, revised May 3, 2002,
unless already done following the applicable Snow Engineering
Service Letter 197 or 205, both revised March 26,
2001.
c. Your logbook entry must include the work done and the
inspection intervals that are upcoming, as follows:
``Following AD 2006-24-10, at XXXX {insert hours TIS of the
modification{time} hours TIS an eddy-current inspection has been
done. As of now, the safe life listed in the AD no longer applies to
this airplane. This airplane must be eddy-current inspected at
{insert the number of hours TIS at modification plus 1,600 hours
TIS{time} hours TIS.
5. For all S/Ns, upon accumulating 1,600 hours TIS after
modification, inspect the left-hand and right-hand outboard two
lower spar cap bolt holes following Snow Engineering Process
Specification 197, page 1, revised June 4, 2002; pages 2
through 5, revised May 3, 2002.
6. Repeat the inspection at intervals of:
a. 800 hours TIS; or
b. 1,600 hours TIS if the outboard two lower spar cap bolt holes
have been cold worked following Snow Engineering Service Letter
234, dated May 18, 2004 (See Step 8).
c. Your logbook entry must include the work done and the post-
modification inspection intervals that are upcoming, as follows:
``This airplane must be eddy-current inspected at intervals not
to exceed {800/1,600, as applicable{time} hours TIS. The first of
these inspections is due at {insert the total number of hours TIS
the first of these inspections is due{time} hours TIS.''
d. If a crack is found at any time, before further flight you
must replace the lower spar caps, splice blocks, and wing attach
angles and hardware. You must also notify the FAA using the form in
Figure 1 of this AD.
7. Upon accumulating 8,000 hours TIS, before further flight you
must replace the lower spar caps, splice blocks, and wing attach
angles (P/N 20693-1), and associated hardware. No additional time
will be authorized for airplanes that are at or over 8,000 hours TIS
(see Step 9).
[[Page 70294]]
8. (Optional): If you decide to cold work your bolt holes
following Snow Engineering Service Letter 233 or
234, both dated May 18, 2002, at a TIS that does not
coincide with a scheduled inspection following this AD, then eddy-
current inspect at the time of cold working and then begin the
1,600/1,200 hour TIS inspection intervals (2 times the intervals
listed in Steps 2.a., 2.b., and 6.a. listed above).
9. (Optional): If you have modified your airplane in accordance
with Step 4 above before accumulating 4,000 hours TIS, then you may
continue to fly your airplane past (modification + 4,000 hours TIS)
provided you cut your inspection intervals in half. Make a logbook
entry following Step 6.c. above to reflect these reduced inspection
intervals. Upon accumulating 8,000 hours TIS, you must comply with
Step 7 above.
Example: An AT-502B airplane had the two-part modification
installed at 3,000 hours TIS and the bolt holes have not been cold
worked.
The first inspection would occur at 4,600 hours TIS. From Step
5, this is modification plus 1,600 hours TIS.
Example (continued): Inspections would follow at 5,400 hours
TIS, 6,200 hours TIS, and 7,000 hours TIS. From Step 6.a. above,
this is 800-hour TIS inspection intervals.
Regarding the inspection at 7,000 hours TIS (modification plus
4,000 hours TIS), this relates to the 8,000-hour TIS inspection from
Step 7 above, which is modification plus 4,000 hours TIS, except in
this example the modification took place at 3,000 hours TIS instead
of 4,000 hours TIS as specified in Step 4 above.
This airplane may continue to fly if inspected again at 7,400
hours TIS and 7,800 hours TIS, which is 400-hour TIS inspection
intervals. This 400-hour TIS inspection interval corresponds to Step
9 where you cut your inspection interval from Step 6.a. in half.
Upon accumulating 8,000 hours TIS (this is the same as Step 7
above), you must replace the parts listed in Step 7.
For airplanes that have or have had Marburger Enterprise, Inc.
winglets installed following Supplemental Type Certificate (STC)
SA00490LA:
If you have removed the winglets, calculate new, reduced hours
for Steps 1, 4, 5, and 7, as applicable, based on the winglet usage
factor listed in Table 2 of paragraph (c)(4) and Appendix 2 of this
AD.
You may repetitively inspect at the same intervals listed in
Step 2 above provided that you do not re-install the winglets.
Example: An AT-502 airplane, S/N 502-0200, had winglets
installed at 200 hours TIS and removed at 800 hours TIS.
The winglet usage factor is: 1.6
Calculate equivalent hours: 600 hours TIS with winglets x 1.6 = 960
hours TIS
Winglet usage penalty = 960 - 600 = 360
New Step 1 Pre-Modification Initial Inspection Time = 1,600 - 360 =
1,240 hours TIS
Retained Step 2 Pre-Modification Inspection Interval: Since the
winglets are removed, the Pre-Modification Inspection Interval
remains 800 hours TIS
New Step 4 Modification time = 4,000 - 360 = 3,640 hours TIS
New Step 5 Post-Modification Initial Inspection time = 3,640 + 1,600
= 5,240 hours TIS
Retained Step 6 Post-Modification Inspection interval: Since the
winglets are removed the Post-Modification Inspection interval
remains at 800/1,600 hours TIS.
New Step 7 replacement time = 8,000 - 360 = 7,640 hours TIS
Use the Retained Step 2 interval, the New Step 5 time, and the
Retained Step 6 interval to make appropriate logbook entries for the
pre- and post-modification intervals, using the format presented in
Steps 2.d., 4.c., and 6.c.
If you have not removed the winglets, then calculate new,
reduced hours for Steps 1, 2, 4, 5, 6, and 7 above, as applicable,
based on the winglet usage factor listed in Table 2 of paragraph
(c)(4) of this AD and Appendix 2 of this AD.
Repetitively inspect at the appropriate interval listed in the
step above divided by the winglet usage factor.
Example: An AT-502B, S/N 502B-0550, that has not had P/N 20998-
1/-2 web plate installed and has had winglets on since new.
The winglet usage factor is: 1.2
New Step 1 Pre-modification initial inspection time: 1,600 / 1.2 =
1,333 hours TIS
New Step 2 Pre-modification inspection interval: 600 / 1.2 = 500
hours TIS
New Step 4 Modification time: 4,000 / 1.2 = 3,333 hours TIS
New Step 5 Post-modification initial inspection time: 3,333 + 1,333
(1,600 / 1.2) = 4,666 hours TIS
New Step 6 Post-modification inspection interval: 800 / 1.2 = 667
hours TIS
New Step 7 Replacement time: 8,000 / 1.2 = 6,667 hours TIS
Use the reduced hours you calculate in New Step 2, New Step 5,
and New Step 6 to make appropriate logbook entries for the pre- and
post-modification inspection intervals, using the format presented
in Steps 2.d., 4.c., and 6.c. above.
Issued in Kansas City, Missouri, on November 22, 2006.
Kim Smith,
Manager, Small Airplane Directorate, Aircraft Certification Service.
[FR Doc. E6-20324 Filed 12-1-06; 8:45 am]
BILLING CODE 4910-13-P