Airworthiness Directive · Amendment 39-16412 · Wings
Air Tractor, Inc. Models AT-802 and AT-802A Airplanes
Superseded. A later AD replaced this one: AD 2010-17-18 R1. Comply with the one in force.
This AD affects Models AT-802 and AT-802A airplanes, all serial numbers (SNs) beginning with -0001, that are:
(1) Certificated in any category;
(2) Engaged in agricultural dispersal operations, including those airplanes that have been converted from fire fighting to agricultural dispersal or airplanes that convert between fire fighting and agricultural dispersal;
(3) Not equipped with the factory-supplied computerized fire gate (part number (P/N) 80540); and
(4) Not engaged in only full-time fire fighting.
We are adopting a new airworthiness directive (AD) to supersede AD 2010-13-08, which applies to all Air Tractor, Inc. (Air Tractor) Models AT-802 and AT-802A airplanes. AD 2010-13-08 currently requires you to repetitively inspect (using the eddy current method) the two outboard fastener holes in both of the wing main spar lower caps at the center splice joint for cracks and repair or replace any cracked spar cap. Since we issued 2010-13-08, we evaluated service information issued by Air Tractor and determined we need to add inspections, add modifications, and change the safe life for certain serial number (SN) ranges. Consequently, this AD would retain the actions of AD 2010-13-08 and would add inspections, add modifications, and change the safe life for certain SN ranges. 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.
To address this problem for Models AT-802 and AT-802A airplanes, SNs -0001 through -0091, you must do the following, unless already done:
| Actions | Compliance | Procedures |
|---|---|---|
| (1) Eddy current inspect for cracks the center splice joint outboard two fastener holes in both the left and right wing main spar lower caps. | Initially inspect upon accumulating 1,700 hours time-in-service (TIS) or within the next 50 hours TIS after April 21, 2006 (the effective date of AD 2006-08-09), whichever occurs later, and repetitively thereafter at intervals not to exceed 800 hours TIS. If, before September 9, 2010 (the effective date of this AD), you installed the center splice plate and extended 8-bolt splice blocks, use the inspection compliance times found in paragraph (f)(5) of this AD. | Follow 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. |
| (2) If you find any cracks as a result of any inspection required in paragraph (f)(1) of this AD, do the following actions: (i) For cracks that can be repaired, repair the airplane by doing the following actions: (A) Install center splice plate, P/N 20997-2, and extended 8-bolt splice blocks, P/N 20985-1 & -2, and cold-work the lower spar cap fastener holes; and (B) Eddy current inspect for cracks the center splice joint outboard two fastener holes in both the left and right wing main spar lower caps. This eddy current inspection is required as part of the modification and is separate from the inspections required in paragraph (f)(1) of this AD. (ii) For cracks that cannot be repaired by incorporating the modification specified above, do the actions to replace the lower spar caps and associated parts listed following the procedures identified in paragraph (f)(3) of this AD. | Before further flight after the inspection where a crack was found. If, before the airplane reaches a total of 3,200 hours TIS, you repair your airplane following paragraph (f)(2)(i) of this AD, you must do the eddy current inspections following the compliance times found in paragraph (f)(5) of this AD. If, at 3,200 hours TIS or after, you repair your airplane following paragraph (f)(2)(i) of this AD, this repair terminates the inspection requirements of paragraph (f)(1) of this AD. | Follow 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. |
| (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. This replacement terminates the repetitive inspections required in paragraph (f)(1) of this AD. | (i) Do the replacement at whichever of the following compliance times occurs first: (A) Before further flight when cracks are found that cannot be repaired by incorporating the modification in paragraph (f)(2)(i) of this AD; or (B) 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 of this AD), whichever occurs later. (ii) After this replacement the new spar safe life is 11,700 hours TIS. If, before September 9, 2010 (the effective date of this AD), an airplane main spar lower cap was replaced with P/N 21083-1/-2, the spar safe life for that P/N spar cap is 8,000 hours TIS until the main spar lower cap is replaced with P/N 21118-1/-2. The new spar safe life for P/N 21118-1/-2 is 11,700 hours. (iii) To extend the initial 4,100 hours TIS safe life of the wing main spar lower cap to a total of 8,000 hours TIS, you may incorporate the optional modification specified in paragraph (f)(4) of this AD. | Follow Snow Engineering Co. Service Letter #284, dated October 4, 2009; Snow Engineering Co. Service Letter #80GG, revised December 21, 2005; Snow Engineering Co. Drawing Number 20975, Sheet 4, Rev. A, dated January 7, 2009. |
| (4) To extend the safe life of the wing main spar lower cap to a total of 8,000 hours TIS, you may incorporate the following optional modification. This modification terminates the repetitive inspections required in paragraph (f)(1) of this AD, unless you performed the modification before the airplane reaches a total of 3,200 hours TIS to repair cracks: (i) Install center splice plate, P/N 20997-2, and extended 8-bolt splice blocks, P/N 20985-1 & -2, and cold-work the lower spar cap fastener holes; and | Modify at whichever of the following compliance times occurs first: (A) Before further flight after any inspection required in paragraph (f)(1) of this AD where a crack is found. If you modify your airplane before the airplane reaches a total of 3,200 hours TIS to repair cracks as required in paragraph (f)(2)(i) of this AD, you must do the eddy current inspections following the compliance times found in paragraph (f)(5) of this AD. | Follow 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) Eddy current inspect for cracks the center splice joint outboard two fastener holes in both the left and right wing main spar lower caps. This eddy current inspection is required as part of the modification and is separate from the inspections required in paragraph (f)(1) of this AD. | (B) Between 3,200 hours TIS and 4,100 hours TIS. |
(5) If, before September 9, 2010 (the effective date of this AD) or as a result of performing the repair for cracks following paragraph (f)(2) of this AD, you installed the center splice plate and extended 8-bolt splice blocks, use the following table for compliance times to do the eddy current inspections required in paragraph (f)(1) of this AD. If you find any cracks as a result of any inspection following the compliance times in the following table, you must do the replacement action in paragraph (f)(2)(ii) of this AD:
| Condition of the airplane | Initially inspect | Repetitively inspect thereafter at intervals not to exceed |
|---|---|---|
| (i) If the airplane has 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, at any time you may cold work the fastener holes to terminate the repetitive inspection requirements of this paragraph | 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 of this AD), whichever occurs later | 1,200 hours TIS until the 8,000 hours TIS spar replacement time. |
| (ii) Before reaching 3,200 hours TIS, the airplane had the center splice plate and extended 8-bolt splice blocks already installed but the fastener holes have not been cold worked | 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 of this AD), whichever occurs later | 1,200 hours TIS. Upon reaching 4,800 hours TIS after the modification, inspect repetitively thereafter at intervals not to exceed 600 hours TIS until the 8,000 hours TIS spar replacement time. |
| (iii) Before reaching 3,200 hours TIS, the airplane had the center splice plate and extended 8-bolt splice blocks installed and the fastener holes have been cold worked | 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 of this AD), whichever occurs later | 600 hours TIS until the 8,000 hours TIS spar replacement time. |
(g) To address this problem for AT-802 and AT-802A airplanes, SNs -0092 through -0101, you must do the following, unless already done:
| Actions | Compliance | Procedures |
|---|---|---|
| (1) Eddy current inspect for cracks the center splice joint outboard two fastener holes in both the left and right wing main spar lower caps. | Initially inspect upon accumulating 1,700 hours TIS or within the next 50 hours TIS after September 9, 2010 (the effective date of this AD), whichever occurs later, and repetitively thereafter at intervals not to exceed 800 hours TIS. If the center splice plate, P/N 20994-2, is installed as specified in paragraph (g)(4) of this AD, do the repetitive inspections at intervals not to exceed 2,000 hours TIS. | Follow Snow Engineering Co. Service Letter #284, dated October 4, 2009; and 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. |
| (2) If you find any cracks as a result of any inspection required by paragraph (g)(1) of this AD, do the following actions. This repair modification terminates the repetitive inspections required in paragraph (g)(1) of this AD: (i) For cracks that can be repaired, repair the airplane by doing the following actions: (A) Install the 9-bolt splice blocks and cold-work the lower spar cap fastener holes; | Before further flight after the inspection where a crack was found. | Follow Snow Engineering Co. Service Letter #284, dated October 4, 2009; and 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. Service Letter #281, dated August 1, 2009; and Snow Engineering Co. Drawing Number 20995, Sheet 3, dated November 25, 2005. |
| (B) Eddy current inspect for cracks the center splice joint outboard two fastener holes in both the left and right wing main spar lower caps. This eddy current inspection is required as part of the repair and is separate from the inspections required in paragraph (g)(1) of this AD; and (C) Install the center splice plate, P/N 20994-2, per paragraph (g)(4) if not already installed. (ii) For cracks that cannot be repaired by doing the actions in paragraph (g)(2)(i) of this AD, replace the lower spar caps and associated parts listed following the procedures identified in 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. This replacement terminates the repetitive inspections required in paragraph (g)(1) of this AD. | (i) Do the replacement at whichever of the following compliance times occurs first: (A) Before further flight when cracks are found that cannot be repaired by incorporating the modification in paragraph (g)(2)(i) of this AD; or (B) 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 of this AD), whichever occurs later. (ii) To extend the initial 4,100 hours TIS safe life of the wing main spar lower cap to a total of 8,000 hours TIS, you may incorporate the optional modification specified in paragraph (g)(4) of this AD. (iii)After replacement of the old spar with the new lower spar cap, P/N 21118-1/-2, the new spar safe life is 11,700 hours TIS. | Follow Snow Engineering Co. Service Letter #284, dated October 4, 2009; Snow Engineering Co. Service Letter #80GG, revised December 21, 2005; Snow Engineering Co. Drawing Number 20975, Sheet 4, Rev. A, dated January 7, 2009. |
| (4) To extend the safe life of the wing main spar lower cap to a total of 8,000 hours TIS, you may incorporate the following optional modification: (i) Install center splice plate, P/N 20994-2, if not already installed as part of a repair, and cold-work the lower spar cap fastener holes; and (ii) Eddy current inspect for cracks the center splice joint outboard two fastener holes in both the left and right wing main spar lower caps. 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. | Before the airplane reaches a total of 4,100 hours TIS. After installation of the center splice plate, P/N 20994-2, do the repetitive inspections required in paragraph (g)(1) at intervals not to exceed 2,000 hours TIS. If as of September 9, 2010 (the effective date of this AD) you have already exceeded the 4,100 hours TIS threshold for extending the safe life to 8,000 hours TIS, you may be eligible for an alternative method of compliance following paragraph (m) in this AD. | Follow 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 20975, Sheet 4, Rev. A., dated January 7, 2009; and Snow Engineering Co. Service Letter #245, dated April 25, 2005. |
| (5) If you find any cracks as a result of any repetitive inspection required by paragraph (g)(4) of this AD, do the following actions. This repair modification terminates the repetitive inspections required in paragraph (g)(4) of this AD: (i) For cracks that can be repaired, repair the airplane by doing the following actions: (A) Install the 9-bolt splice blocks and cold-work the lower spar cap fastener holes; and | Before further flight after the inspection where a crack was found. | Follow Snow Engineering Co. Service Letter #284, dated October 4, 2009; and 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. Service Letter #281, dated August 1, 2009; and Snow Engineering Co. Drawing Number 20995, Sheet 3, dated November 25, 2005. |
| (B) Eddy current inspect for cracks the center splice joint outboard two fastener holes in both the left and right wing main spar lower caps. This eddy current inspection is required as part of the repair and is separate from the inspections required in paragraph (g)(1) of this AD. (ii) For cracks that cannot be repaired by doing the actions in paragraph (g)(5)(i) of this AD, replace the lower spar caps and associated parts listed following the procedures identified in paragraph (g)(3) of this AD. |
(h) To address this problem for AT-802 and AT-802A airplanes, SNs -0102 through -0178, you must do the following, unless already done:
| Actions | Compliance | Procedures |
|---|---|---|
| (1) Do an initial eddy current inspection for cracks of the center splice joint outboard two fastener holes in both the left and right wing main spar lower caps. After this initial inspection, you may do the optional cold-working of the lower spar cap fastener holes to increase the hours TIS between repetitive inspections required in paragraph (h)(2) of this AD. | Before the airplane reaches a total of 5,500 hours TIS or within the next 50 hours TIS after September 9, 2010 (the effective date of this AD), whichever occurs later. | Follow 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. Service Letter #245, dated April 25, 2005; and Snow Engineering Co. Service Letter #284, dated October 4, 2009. |
| (2) Repetitively eddy current inspect for cracks the center splice joint outboard two fastener holes in both the left and right wing main spar lower caps. | (i) For fastener holes that are cold-worked: After the initial inspection, repetitively thereafter inspect at intervals not to exceed 2,200 hours TIS. (ii) For fastener holes not cold-worked: After the initial inspection, repetitively thereafter inspect at intervals not to exceed 1,100 hours TIS. | Follow 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. Service Letter #284, dated October 4, 2009; and (optional) Snow Engineering Co. Service Letter #245, dated April 25, 2005. |
| (3) If you find any cracks as a result of any inspection required by paragraphs (h)(1) and (h)(2) of this AD, do the following actions. This modification terminates the repetitive inspections required in paragraph (h)(1) and (h)(2) of this AD: (i) For cracks that can be repaired, repair the airplane by doing the following actions: (A) Install the 9-bolt splice blocks and cold-work the lower spar cap fastener holes; and (B) Eddy current inspect for cracks the center splice joint outboard two fastener holes in both the left and right wing main spar lower caps. This eddy current inspection is required as part of the repair and is separate from the inspections required in paragraphs (h)(1) and (h)(2) of this AD. (ii) For cracks that cannot be repaired by doing the actions in paragraph (h)(3)(i) of this AD, replace the lower spar caps and associated parts listed following the procedures in paragraph (h)(4) of this AD. | Before further flight after the inspection where a crack was found. | Follow Snow Engineering Co. Service Letter #281, dated August 1, 2009; and Snow Engineering Co. Drawing Number 20995, Sheet 3, dated November 25, 2005. |
| (4) 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. This replacement terminates the repetitive inspections required in paragraphs (h)(1) and (h)(2) of this AD. | (i) Do the replacement at whichever of the following compliance times occurs first: (A) Before further flight when cracks are found that cannot be repaired by incorporating the repair in paragraph (h)(3)(i) of this AD; or (B) Before or when the airplane reaches the wing main spar lower cap safe life of a total of 8,000 hours TIS or within the next 50 hours TIS after September 9, 2010 (the effective date of this AD), whichever occurs later. | Follow Snow Engineering Co. Service Letter #284, dated October 4, 2009; Snow Engineering Co. Service Letter #80GG, revised December 21, 2005; Snow Engineering Co. Drawing Number 20975, Sheet 4, Rev. A, dated January 7, 2009. |
| (ii) After this replacement the new spar safe life is 11,700 hours TIS. |
(i) To address this problem for AT-802 and AT-802A airplanes, SNs -0179 through -0269, you must do the following, unless already done:
| Actions | Compliance | Procedures |
|---|---|---|
| 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. | By the 8,000 hours TIS safe-life or within the next 50 hours TIS after September 9, 2010 (the effective date of this AD), whichever occurs later. After this replacement the subsequent new spar safe life is 11,700 hours TIS. | Follow Snow Engineering Co. Service Letter #284, dated October 4, 2009; Snow Engineering Co. Service Letter #80GG, revised December 21, 2005; Snow Engineering Co. Drawing Number 20975, Sheet 4, Rev. A, dated January 7, 2009. |
(j) To address this problem for AT-802 and AT-802A airplanes, SNs -0270 and subsequent, you must do the following, unless already done:
| Actions | Compliance | Procedures |
|---|---|---|
| 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. | By the 11,700 hours TIS safe-life or within the next 50 hours TIS after September 9, 2010 (the effective date of this AD), whichever occurs later. After this replacement the subsequent new spar safe life is 11,700 hours TIS. | Follow Snow Engineering Co. Service Letter #284, dated October 4, 2009; Snow Engineering Co. Service Letter #80GG, revised December 21, 2005; Snow Engineering Co. Drawing Number 20975, Sheet 4, Rev. A, dated January 7, 2009. |
(k) Report any crack from any inspection required in paragraphs (f), (g), or (h) of this AD within 10 days after the cracks are found on the form in Figure 1 of this AD.
(1) Send your report to Andrew McAnaul, Aerospace Engineer, ASW-150 (c/o MIDO-43), 10100 Reunion Place, Suite 650, San Antonio, Texas 78216; telephone: (210) 308-3365; facsimile: (210) 308-3370.
(2) The Office of Management and Budget (OMB) approved the information collection requirements contained in this regulation under the provisions of the Paperwork Reduction Act and assigned OMB Control Number 2120-0056.
Under 14 CFR part 39.23, we are allowing special flight permits for the purpose of compliance with this AD under the following conditions:
(1) Only operate 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.
| General Information | |
| 1. Inspection Performed By: | 2. Phone: |
| 3. Aircraft Model: | 4. Aircraft Serial Number: |
| 5. Engine Model Number: | 6. Aircraft Total Hours TIS: |
| 7. Wing Total Hours TIS: | 8. Lower Spar Cap Hours TIS: |
| Previous Inspection/Repair History | |
| 9. Has the lower spar cap been inspected (eddy-current, dye penetrant, magnetic particle, or ultrasound) before? □ Yes □ No | If yes, an inspection has occurred: Date:____________ Inspection Method:______ Lower Spar Cap TIS:______ Cracks found? □ Yes □ No |
| 10. Has there been any major repair or alteration performed to the spar cap? □ Yes □ No | If yes, specify (Description and hours TIS): |
| Inspection for AD 2010-17-18 | |
| 11. Date of AD inspection: | 11a. Cracks found: |
| Inspection Results: | □ Left Hand □ Right Hand |
| 11b. Crack Length:______ | 11c. Does drilling hole to next larger size remove all traces of the crack(s)? |
| Location:______ | □ Yes □ No |
| 12d. Corrective Action Taken: |
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.
