AD 2014-16-17 Airworthiness Directives; Air Tractor, Inc. Airplanes

Models named: AT-802, AT-802A. Read the applicability below — it usually turns on serial or part numbers too.

This AD applies to Air Tractor, Inc. Models AT-802 and AT-802A airplanes, all serial numbers, that are certificated in any category.

Comply with this AD within the compliance times specified in paragraphs (g) through (l) of this AD, including all subparagraphs, unless already done (compliance with AD 2010-17-18 R1).

(1) Eddy current inspect the center splice joint outboard two fastener holes in both the left and right wing main spar lower caps for cracks at the compliance times specified in paragraphs (g)(1)(i) or (g)(1)(ii) of this AD. Do the inspections following Snow Engineering Co. Process Specification #197, page 1, revised June 4, 2002; pages 2 through 4, dated February 23, 2001; and page 5, dated May 3, 2002. (i) For airplanes previously affected by AD 2010-17-18 R1: Initially inspect upon reaching 1,700 hours time-in-service (TIS) or within the next 50 hours TIS after April 21, 2006 (the effective date retained from AD 2006-08-09, Amendment 39-14565 (71 FR 19994, April 19, 2006; corrected 71 FR 27794, May 12, 2006)), whichever occurs later. Repetitively thereafter inspect at intervals not to exceed 800 hours TIS unless you installed the center splice plate and extended 8-bolt splice blocks before September 9, 2010 (the effective date retained from AD 2010-17-18, Amendment 39-16412 (75 FR 52255, August 25, 2010), “AD 2010-17-18”), then repetitively inspect following the compliance times in paragraphs (g)(5)(i) through (g)(5)(iii) of this AD. (ii) For airplanes not previously affected by AD 2010-17-18 R1: Initially inspect upon reaching 1,700 hours TIS or within the next 50 hours TIS after September 29, 2014 (the effective date of this AD), whichever occurs later. Repetitively thereafter inspect at intervals not to exceed 800 hours TIS unless you installed the center splice plate and extended 8-bolt splice blocks before September 29, 2014 (the effective date of this AD), then repetitively inspect following the compliance times in paragraphs (g)(6)(i) through (g)(6)(iii) of this AD. (2) If any cracks are found as a result of any inspection required in paragraph (g)(1) of this AD, before further flight after the inspection where a crack was found, do the actions specified in paragraphs (g)(2)(i) or (g)(2)(ii) of this AD. If you repair your airplane following paragraph (g)(2)(i) of this AD before the airplane reaches a total of 3,200 hours TIS, you must do the eddy current inspections following the compliance times in paragraphs (g)(5) and (g)(6) of this AD, as applicable. If you repair your airplane following paragraph (g)(2)(i) of this AD at 3,200 hours TIS or after, this repair terminates the repetitive inspections required in this AD. (i) For cracks that can be removed by repair, install center splice plate, P/N 20997-2, and extended 8-bolt splice blocks, P/N 20985-1/-2, cold-work the lower spar cap fastener holes, and eddy current inspect the center splice joint outboard two fastener holes in both the left and right wing main spar lower caps for cracks. This eddy current inspection is required as part of the modification and is separate from the inspections required in paragraph (g)(1) of this AD. Incorporating this repair modification extends the safe life of the wing main spar lower cap to a total of 8,000 hours TIS. Do the repair following Snow Engineering Co. Service Letter #284, dated October 4, 2009; Snow Engineering Co. Process Specification #197, page 1, revised June 4, 2002; pages 2 through 4, dated February 23, 2001; and page 5, dated May 3, 2002; Snow Engineering Co. Drawing Number 20995, Sheet 2, Rev. D., dated November 25, 2005; and Snow Engineering Co. Service Letter #240, dated September 30, 2004. (ii) For cracks that cannot be repaired by incorporating the repair modification specified in paragraph (g)(2)(i) of this AD, replace the lower spar caps and associated parts listed following paragraph (g)(3) of this AD. (3) Replace the wing main spar lower caps, the web plates, the center joint splice blocks and hardware, and the wing attach angles and hardware, and install the steel web splice plate at whichever of the compliance times specified in paragraphs (g)(3)(i), (g)(3)(ii), or (g)(3)(iii) of this AD that occurs first. If the wing main spar lower cap was replaced with P/N 21118-1/-2, the new spar safe life is 11,700 hours TIS. If the wing main spar lower cap is replaced with P/N 21083-1/-2 before September 9, 2010 (the effective date retained from AD 2010-17-18), the safe life for that P/N spar cap is 8,000 hours TIS until the wing main spar lower cap is replaced with P/N 21118-1/-2. This replacement terminates the inspections required in this AD. Do the replacement following Snow Engineering Co. Service Letter #284, dated October 4, 2009; Snow Engineering Co. Service Letter #80GG, revised December 21, 2005; and Snow Engineering Co. Drawing Number 20975, Sheet 4, Rev. A, dated January 7, 2009. (i) For all airplanes: Before further flight when cracks are found that cannot be repaired by incorporating the repair modification specified in paragraph (g)(2)(i) of this AD. (ii) For airplanes previously affected by AD 2010-17-18 R1: Before or when the airplane reaches the wing main spar lower cap safe life of a total of 4,100 hours TIS or within the next 50 hours TIS after September 9, 2010 (the effective date retained from AD 2010-17-18), whichever occurs later. (iii) For airplanes not previously affected by AD 2010-17-18 R1: Before or when the airplane reaches the wing main spar lower cap safe life of a total of 4,100 hours TIS or within the next 50 hours TIS after September 29, 2014 (the effective date of this AD), whichever occurs later. (4) To extend the initial 4,100-hour TIS safe life of the wing main spar lower cap to a total of 8,000 hours TIS, you may incorporate the repair modification specified in paragraph (g)(2)(i) of this AD between 3,200 hours TIS and 4,100 hours TIS. This modification terminates the repetitive inspections required in paragraphs (g)(1)(i) and (g)(1)(ii) of this AD, unless you do the modification before the airplane reaches a total of 3,200 hours TIS to repair cracks. (5) For airplanes previously affected by AD 2010-17-18 R1: If you modified your airplane to repair cracks before the airplane reached a total of 3,200 hours TIS, as required in paragraph (g)(2)(i) of this AD, or you previously modified your wing to extend the safe life but did not cold work the lower spar cap fastener holes, you must do the eddy current inspections required in paragraph (g)(1) of this AD following the compliance times specified in paragraphs (g)(5)(i) through (g)(5)(iii) of this AD, as applicable. (i) If the airplane already had the center splice plate and extended 8-bolt splice blocks installed at or after 3,200 hours TIS but the fastener holes have not been cold worked, you may cold work the fastener holes at any time to terminate the repetitive inspection requirements of this paragraph. Initially inspect when the airplane reaches a total of 2,400 hours TIS after the modification or within the next 100 days after September 9, 2010 (the effective date retained from AD 2010-17-18), whichever occurs later. Repetitively thereafter inspect at intervals not to exceed 1,200 hours TIS until the 8,000 hours TIS spar replacement time. (ii) If the airplane already had the center splice plate and extended 8-bolt splice blocks already installed before reaching 3,200 hours TIS but the fastener holes have not been cold worked, initially inspect when the airplane reaches a total of 2,400 hours TIS after the modification or within the next 100 days after September 9, 2010 (the effective date retained from AD 2010-17-18), whichever occurs later. Repetitively thereafter inspect at intervals not to exceed 1,200 hours TIS. Upon reaching 4,800 hours TIS after the modification, repetitively thereafter inspect at intervals not to exceed 600 hours TIS until the 8,000 hours TIS spar replacement time. (iii) If the airplane had the center splice plate and extended 8-bolt splice blocks installed before reaching 3,200 hours TIS and the fastener holes have been cold worked, initially inspect when the airplane reaches a total of 4,800 hours TIS after the modification or within the next 100 days after September 9, 2010 (the effective date retained from AD 2010-17-18), whichever occurs later. Repetitively thereafter inspect at intervals not to exceed 600 hours TIS until the 8,000 hours TIS spar replacement time. (6) For airplanes not previously affected by AD 2010-17-18 R1: If you modified your airplane to repair cracks before the airplane reached a total of 3,200 hours TIS, as required in paragraph (g)(2)(i) of this AD, or you previously modified your wing to extend the safe life but did not cold work the lower spar cap fastener holes, and your, you must do the eddy current inspections required in paragraph (g)(1) of this AD following the compliance times specified in paragraphs (g)(6)(i) through (g)(6)(iii) of this AD, as applicable. (i) If the airplane already had the center splice plate and extended 8-bolt splice blocks installed at or after 3,200 hours TIS but the fastener holes have not been cold worked, you may cold work the fastener holes at any time to terminate the repetitive inspection requirements of this paragraph. Initially inspect when the airplane reaches a total of 2,400 hours TIS after the modification or within the next 50 hours TIS after September 29, 2014 (the effective date of this AD), whichever occurs later. Repetitively thereafter inspect at intervals not to exceed 1,200 hours TIS until the 8,000 hours TIS spar replacement time. (ii) If the airplane had the center splice plate and extended 8-bolt splice blocks already installed before reaching 3,200 hours TIS but the fastener holes have not been cold worked, initially inspect when the airplane reaches a total of 2,400 hours TIS after the modification or within the next 50 hours TIS after September 29, 2014 (the effective date of this AD), whichever occurs later. Repetitively thereafter inspect at intervals not to exceed 1,200 hours TIS. Upon reaching 4,800 hours TIS after the modification, repetitively thereafter inspect at intervals not to exceed 600 hours TIS until the 8,000 hours TIS spar replacement time. (iii) If the airplane had the center splice plate and extended 8-bolt splice blocks installed before reaching 3,200 hours TIS and the fastener holes have been cold worked, initially inspect when the airplane reaches a total of 4,800 hours TIS after the modification or within the next 50 hours TIS after September 29, 2014 (the effective date of this AD), whichever occurs later. Repetitively thereafter inspect at intervals not to exceed 600 hours TIS until the 8,000 hours TIS spar replacement time. (7) If you find any cracks during any inspection required by paragraphs (g)(5) and (g)(6) of this AD, before further flight, replace the lower spar caps and the associated parts following the procedures identified in paragraph (g)(3) of this AD.

This AD was prompted by our determination that there is a need to establish a safe life for the wing main spar lower caps on all airplanes regardless of configuration or operational use. We are issuing this AD to detect and correct cracks in the wing main spar lower cap at the center splice joint, which could result in failure of the spar cap and lead to wing separation and loss of control of the airplane.

This AD supersedes AD 2010-17-18 R1, Amendment 39-16552 (75 FR 82219, December 30, 2010, (“ AD 2010-17-18 R1” )).