Airworthiness Directive · Amendment 39-13749 · Air Tractor, Inc. Models AT-401, AT-401B, AT-402, AT-402A, AT-402B, AT-501, AT-502, AT-502A, AT-502B, AT-503A, AT-602, AT-802, and AT-802A Airplanes
Air Tractor, Inc. Models AT-401, AT-401B, AT-402, AT-402A, AT-402B, AT-501, AT-502, AT-502A, AT-502B, AT-503A, AT-602, AT-802, and AT-802A Airplanes
This AD affects the following airplane models and serial numbers that are certificated in any category:
| Model | Serial Nos. |
|---|---|
| AT-401, AT-401B, AT-402, AT-402A, and AT-402B | 0716 through 1144 |
| AT-501, AT-502, AT-502A, AT-502B, and AT-503A | 0037 through 0658 |
| AT-602 | 0337 through 0664 |
| AT-802 and AT-802A | 0001 through 0139 |
The FAA supersedes Airworthiness Directive (AD) 2002-19-10, which applies to certain Air Tractor, Inc. (Air Tractor) Models AT-402, AT-402A, AT-402B, AT-602, AT-802, and AT-802A airplanes. AD 2002-19-10 currently requires you to repetitively inspect the upper longeron and upper diagonal tube on the left hand side of the aft fuselage structure for cracks and contact the manufacturer for a repair scheme if cracks are found. This AD is the result of reports of the same cracks recently found on AT-500 series airplanes. The manufacturer has also issued new and revised service information that incorporates a modification to terminate the repetitive inspection requirements. Consequently, this AD retains the inspection actions required in AD 2002-19-10, adds certain AT-500 series airplanes to the applicability section, changes the compliance times, and incorporates new and revised manufacturer service information that contains a terminating action for the repetitive inspection requirement. We are issuing this AD to detect and correct cracks in the upper aft longeron, which could cause the fuselage to fail. Such failure could result in loss of control of the airplane.
To address this problem, you must inspect the upper longeron and upper diagonal tube (as applicable) on the left hand side of the fuselage frame just forward of the vertical fin front spar attachment for cracks at the times specified below. You must also replace and modify any cracked upper and diagonal longerons (as applicable) found during any inspection required by this AD before further flight after the inspection in which cracks are found.
| Affected models and serial nos. | Inspection compliance times | Procedures |
|---|---|---|
| (1) AT-401, AT-401B, serial numbers (S/Ns) 0716 through 1144 | Initially inspect upon the accumulation of 1,250 total hours time-in-service (TIS) or within the next 100 hours TIS after September 7, 2004 (the effective date of this AD), whichever occurs later. Repetitively inspect thereafter at intervals not to exceed 100 hours TIS until the upper and diagonal longerons are replaced and modified. Replacing and modifying the upper and diagonal longerons is the terminating action for the repetitive inspection requirement in this AD | Inspect following Snow Engineering Co. Service Letter #218A, dated November 10, 2003, as specified in Snow Engineering Co. Service Letter #195, reissued November 10, 2003. Replace and modify following Snow Engineering Co. Service Letter #218B, dated November 10, 2003. |
| (2) AT-402, AT-402A, and AT-402B, S/Ns 0716 through 1144 | Initially inspect upon the accumulation of 1,250 total hours TIS or within the next 100 hours TIS after the last inspection required by AD 2002-19-10, whichever occurs later. Repetitively inspect thereafter at intervals not to exceed 100 hours TIS until the upper and diagonal longerons are replaced and modified. Replacing and modifying the upper and diagonal longerons is the terminating action for the repetitive inspection requirement in this AD | Inspect following Snow Engineering Co. Service Letter #218A, dated November 10, 2003, as specified in Snow Engineering Co. Service Letter #195, reissued November 10, 2003. Replace and modify following Snow Engineering Co. Service Letter #218B, dated November 10, 2003. |
| (3) AT-501, AT-502, AT-502B, and AT-503A, S/Ns 0037 through 0658 | Initially inspect upon the accumulation of 4,800 total hours TIS or within the next 100 hours TIS after September 7, 2004 (the effective date of this AD), whichever occurs later. Repetitively inspect thereafter at intervals not to exceed 100 hours TIS until the upper longeron is replaced and modified. Replacing and modifying the upper longeron is the terminating action for the repetitive inspection requirement in this AD | Inspect following Snow Engineering Co. Service Letter #195B, dated November 10, 2003, as specified in Snow Engineering Co. Service Letter #195, reissued November 10, 2003. Replace and modify following Snow Engineering Co. Service Letter #195A, revised November 10, 2003. |
| (4)AT-502A, S/Ns 0037 through 0658 | Initially inspect upon the accumulation of 2,800 total hours TIS or within the next 100 hours TIS after September 7, 2004 (the effective date of this AD), whichever occurs later. Repetitively inspect thereafter at intervals not to exceed 100 hours TIS until the upper longeron is replaced and modified. Replacing and modifying the upper longeron is the terminating action for the repetitive inspection requirement in this AD | Inspect following Snow Engineering Co. Service Letter #195B, dated November 10, 2003, as specified in Snow Engineering Co. Service Letter #195, reissued November 10, 2003. Replace and modify following Snow Engineering Co. Service Letter #195A, revised November 10, 2003. |
| (5) AT-602, S/Ns 0337 through 0661 | Initially inspect upon the accumulation of 700 total hours TIS or within the next 100 hours TIS after the last inspection required by AD 2002-19-10, whichever occurs later. Repetitively inspect thereafter at intervals not to exceed 100 hours TIS until the upper longeron is replaced and modified. Replacing and modifying the upper longeron is the terminating action for the repetitive inspection requirement in this AD | Inspect following Snow Engineering Co. Service Letter #213A, dated November 10, 2003, as specified in Snow Engineering Co. Service Letter #195, reissued November 10, 2003. Replace and modify following Snow Engineering Co. Service Letter #213B, revised November 10, 2003. |
| (6) AT-602, S/Ns 0662 through 0664 | Initially inspect upon the accumulation of 1,750 total hours TIS or within the next 100 hours TIS after the last inspection required by AD 2002-19-10, whichever occurs later. Repetitively inspect thereafter at intervals not to exceed 100 hours TIS until the upper longeron is replaced and modified. Replacing and modifying the upper longeron is the terminating action for the repetitive inspection requirement in this AD | Inspect following Snow Engineering Co. Service Letter #213A, dated November 10, 2003, as specified in Snow Engineering Co. Service Letter #195, reissued November 10, 2003. Replace and modify following Snow Engineering Co. Service Letter #213B, revised November 10, 2003. |
| (7) AT-802 and AT-802A, S/Ns 0001 through 0004 and 0012 through 0118 | Initially inspect upon the accumulation of 250 total hours TIS or within the next 100 hours TIS after the last inspection required by AD 2002-19-10, whichever occurs later. Repetitively inspect thereafter at intervals not to exceed 100 hours TIS until the upper longeron is replaced and modified. Replacing and modifying the upper longeron is the terminating action for the repetitive inspection requirement in this AD | Inspect following Snow Engineering Co. Service Letter #217A, dated November 10, 2003, as specified in Snow Engineering Co. Service Letter #195, reissued November 10, 2003. Replace and modify following Snow Engineering Co. Service Letter #217B, revised November 10, 2003. |
| (8) AT-802 and AT-802A, S/Ns 0005 through 0011 | Initially inspect upon the accumulation of 900 total hours TIS or within the next 100 hours TIS after the last inspection required by AD 2002-19-10, whichever occurs later. Repetitively inspect thereafter at intervals not to exceed 100 hours TIS until the upper longeron is replaced and modified. Replacing and modifying the upper longeron is the terminating action for the repetitive inspection requirement in this AD | Inspect following Snow Engineering Co. Service Letter #217A, dated November 10, 2003, as specified in Snow Engineering Co. Service Letter #195, reissued November 10, 2003. Replace and modify following Snow Engineering Co. Service Letter #217B, revised November 10, 2003. |
| (9) AT-802 and AT-802A, S/Ns 0119 through 0139 | Initially inspect upon the accumulation of 1,750 total hours TIS or within the next 100 hours TIS after the last inspection required by AD 2002-19-10, whichever occurs later. Repetitively inspect thereafter at intervals not to exceed 100 hours TIS until the upper longeron is replaced and modified. Replacing and modifying the upper longeron is the terminating action for the repetitive inspection requirement in this AD | Inspect following Snow Engineering Co. Service Letter #217A, dated November 10, 2003, as specified in Snow Engineering Co. Service Letter #195, reissued November 10, 2003. Replace and modify following Snow Engineering Co. Service Letter #217B, revised November 10, 2003. |
(f) You may replace and modify the upper and diagonal longeron (as applicable) at any time as a terminating action for the repetitive inspection requirement in this AD. However, you must replace and modify the upper and diagonal longeron (as applicable) before further flight after any inspection in which cracks are found.
The aircraft, engines and makers this AD names, by the model designations in its text. A model listed here may still be outside the AD's serial ranges.
