FAA Grants Revised AMOC For T-34s
The FAA has granted a revised temporary alternative means of compliance (AMOC) for the T-34 based on completed and submitted engineering data obtained through a study funded in part by EAA Warbirds of America. On December 10, 2004, FAA grounded the entire T-34 fleet when pre-existing fatigue cracks were found in the center section of an aircraft that had crashed three days earlier. The T-34 Association managed to obtain a temporary AMOC allowing the fleet to fly for 240 hours with certain flight restrictions. This latest approved AMOC revises that original directive.


The revised AMOC allows two options:


Complete a surface eddy current inspection of the inner—31 channel of the lower forward carry through structure around each of the 9 fasteners (See Figure 1) that attach the wing attach fitting to the—31 channel in all 4 corners (36 fasteners in all). This option requires a repeat of the inspection at 120 hours TIS. At the end of the second 120 hours either #2 or #3 below must be completed to operate beyond the 240 TIS from the first inspection. This procedure has the following flight limitations of; +2.5 G’s / -0 G’s, 152 Knots Never exceed speed (Vne) and no aerobatics permitted. (This is basically the same as the AMOC that we have been operating on)


1. Complete a surface eddy current inspection of the 7 outboard fasteners (See Figure 1) as described in #1 above and remove all 4 #8 & #9 fasteners (Total of 8) and perform a rotating bolt hole eddy current inspection of all 8 fastener holes. The Bolt Hole inspection inspects both the—31 inner and—33 outer channels. Once this procedure is performed it allows for an additional 600 hours TIS. Once the Bolt Hole inspection is completed, the airspeed restrictions are removed and are returned to the normal 219 Kts Vne. This inspection increase the acceleration limits to +4.4 G’s / -2.5 G’s, and no aerobatic maneuvers are approved.


The revised AMOC, which supercedes all previous temporary AMOCs, expires on May 15, 2010. To operate a T-34 beyond this date, the airplane must be modified with an FAA-approved Modification/Replacement program specifically approved for AD2004-25-51.


Aircraft that have already been returned to service by the T-34 Spar Corporation temporary AMOC to AD2004-25-51 may continue to operate with those flight restrictions until they reach the maximum allowable of 240 hours TIS and then complete the Bolt Hole Inspection (#2 above) for an additional 600 hours TIS. Or, at the owner’s discretion, they can immediately perform the Bolt Hole Inspection for 600 hours TIS.


For those that have not yet complied with AD2004-25-51, at the owners discretion they can complete #1 above for a maximum of 240 hours TIS and then complete #2 for an additional 600 hours TIS, or perform #2 only for a total of 600 hours TIS.


Long-Term AMOCs:
Aviadesign has already been granted an AMOC to AD2004-25-51 by installing an external Spar Strap. This AMOC removes all flight restrictions. The airplane must be inspected in accordance with Aviadesign’s Continued Airworthiness Instructions specified within their AMOC to maintain compliance with AD2004-25-51.


Parks Industries has submitted engineering data to obtain an STC to remove the -31 Channel and install a new part (H Beam) in its place. FAA approval is expected shortly. This AMOC will also require the aircraft to be inspected in accordance with Parks Industries Instructions for Continued Airworthiness Instructions to maintain compliance with AD2004-25-51.


The T-34 Spar Corporation is developing an Internal Cable (“ALEC”-Airframe Life Extension Cable). They anticipate submitting the final data package to the FAA soon. This AMOC will also incorporate Instructions for Continued Airworthiness to maintain compliance with AD2004-25-51.


This AMOC applies to all T-34A/B airplanes that are approved by FAA letter “List of Airplanes in the list of T-34 Spar Corporation.”


If you would like further information on this AMOC or would like to use this AMOC please contact either:


Tim Roehl
T-34 Spar Corporation
888.359.6424


or


Jud Nogle
Nogle and Black Aviation, Inc.
217.253.4342

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  Oshkosh, WI 54903-3086

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