# N504DD: 2022 Air Tractor AT-504

- Status: Valid registration
- Airframe: [Air Tractor AT-504](https://openairdocs.org/model/air-tractor-at-504) (registry code 0390310, 2 seats)
- Engine: [Pratt & Whitney PT6A series](https://openairdocs.org/engine/pratt-whitney-pt6a-series) (registry code 52032)
- Data sheets: [TCDS A17SW](https://openairdocs.org/tcds/A17SW) (Air Tractor Inc.) (OpenAirDocs)
- Serial number: 504-4042
- Year built: 2022
- Type: Fixed wing single engine
- Engine type: Turbo-prop
- Airworthiness: Restricted, agriculture and pest control, forest
- Airworthiness date: March 28, 2022
- Certificate issued: November 3, 2022
- Expires: November 30, 2029
- Mode S code: A6491B
- Registered owner: [Digger Doug'S Crop Dusting Service Inc](https://openairdocs.org/faa-owner/DIGGER%20DOUG'S%20CROP%20DUSTING%20SERVICE%20INC)
- Location: [Hollandale, WI](https://openairdocs.org/faa-place/WI/Hollandale)
- Owner type: Corporation
- Owner's area on the map: 42.8776° N, 89.9057° W: Placed by OpenAirDocs at the center of ZIP code 53544, within about 4 miles (OpenAirDocs). The owner's mailing address, not where the aircraft is based
- FAA registry: https://registry.faa.gov/AircraftInquiry/Search/NNumberResult?nNumberTxt=504DD
- Page: https://openairdocs.org/aircraft/N504DD

From the FAA registry file of October 24, 2026. ADs below are matched by the registry's airframe and engine model codes. They may apply; each AD's applicability can narrow it by serial number, part number or installed equipment. This is not a compliance determination. The registry lists only the engine series, so ADs for every Pratt & Whitney PT6A model are included.

## ADs that may apply (OpenAirDocs): 27 in force

### Matched by airframe (Air Tractor AT-504)

- [AD 2021-05-14](https://openairdocs.org/ad/2021-05-14): TE flap control system · Air Tractor AT-250, AT-300, AT-301 and 19 more. Effective Apr 29, 2021

### Matched by engine (Pratt & Whitney PT6A series)

- [AD 2024-04-51](https://openairdocs.org/ad/2024-04-51): Turbine Section · Pratt & Whitney Canada PT6A-64, PT6A-66, PT6A-66A and 17 more. Effective Mar 28, 2024
- [AD 2022-08-13](https://openairdocs.org/ad/2022-08-13): Turbine Section · Pratt & Whitney Canada PT6A-34, PT6A-34B, PT6A-34AG and 2 more. Effective May 27, 2022
- [AD 2016-05-13](https://openairdocs.org/ad/2016-05-13): Corrosion and perforation of the two-ply Cu-Be bellows in Woodward FCUs. · Pratt & Whitney Canada PT6A-60AG, PT6A-65AG, PT6A-67AF and 1 more. Effective Apr 22, 2016
- [AD 2014-17-08 R1](https://openairdocs.org/ad/2014-17-08-R1): Compressor turbine (CT) blades · Pratt & Whitney Canada PT6A-114 and PT6A-114A. Effective Jun 5, 2015
- [AD 2014-11-05](https://openairdocs.org/ad/2014-11-05): Reinforcement liner to the power turbine (PT) containment   
  ring and, for certain PT containment rings, adding scallops · Pratt & Whitney Canada PT6A-11, PT6A-110, PT6A-112 and 18 more. Effective Aug 5, 2014
- [AD 2012-09-10](https://openairdocs.org/ad/2012-09-10): First stage sun gears · Pratt & Whitney Canada PT6A-110, PT6A-112, PT6A-114 and 12 more. Effective May 23, 2012
- [AD 2011-25-12](https://openairdocs.org/ad/2011-25-12): Sun gear · Pratt & Whitney Canada PT6A-15AG, PT6A-27, PT6A-28 and 4 more. Effective Dec 28, 2011
- [AD 2011-20-51](https://openairdocs.org/ad/2011-20-51): Gears · Pratt & Whitney Canada PT6A-15AG, PT6A-27, PT6A-28 and 4 more. Effective Nov 1, 2011
- [AD 2004-25-18](https://openairdocs.org/ad/2004-25-18): Propeller governor assemblies · Pratt & Whitney Canada PT6A-60A and PT6A-65B. Effective Jan 18, 2005
- [AD 2002-23-13](https://openairdocs.org/ad/2002-23-13): Turbine Exhaust Ducts · Pratt & Whitney Canada PT6A-11, PT6A-110, PT6A-112 and 20 more. Effective Dec 31, 2002
- [AD 2001-20-01](https://openairdocs.org/ad/2001-20-01): Compressor Bleed Valve Assembly · Pratt & Whitney Canada PT6A-114A and PT6A-25C. Effective Nov 5, 2001
- [AD 97-04-12](https://openairdocs.org/ad/97-04-12): Compressor Bleed-off Valve · Pratt & Whitney Canada PT6A-11, PT6A-110, PT6A-112 and 52 more. Effective Mar 14, 1997
- [AD 95-13-08](https://openairdocs.org/ad/95-13-08): Compressor Turbine Disk · Pratt & Whitney Canada PT6A-67D. Effective Jul 12, 1995
- [AD 93-23-06](https://openairdocs.org/ad/93-23-06): Airframe Chip Detector Flag System · Pratt & Whitney Canada PT6A-50. Effective Jan 26, 1994
- [AD 92-15-11](https://openairdocs.org/ad/92-15-11): Compressor Delivery Air Line (P3) Filter Assembly · Pratt & Whitney Canada PT6A-20, PT6A-20A, PT6A-21 and 7 more. Effective Aug 17, 1992
- [AD 90-12-05](https://openairdocs.org/ad/90-12-05): Engine Overhaul · Pratt & Whitney Canada PT6A-15AG, PT6A-27, PT6A-28 and 3 more. Effective May 30, 1990
- [AD 86-10-05](https://openairdocs.org/ad/86-10-05): First Stage Compressor Hub · Pratt & Whitney Canada PT6A-42. Effective Jun 5, 1986
- [AD 80-08-12](https://openairdocs.org/ad/80-08-12): Fuel Pump Drive Coupling Splines · Pratt & Whitney Canada PT6A-11, PT6A-112, PT6A-135 and 24 more. Effective Apr 18, 1980
- [AD 80-04-02](https://openairdocs.org/ad/80-04-02): Push-Pull Control Terminal · Pratt & Whitney Canada PT6A-20, PT6A-6A, PT6A-6B and 1 more. Effective Feb 8, 1980
- [AD 78-17-07](https://openairdocs.org/ad/78-17-07): Fuel Control Unit · Pratt & Whitney Canada PT6A-38, PT6A-41 and PT6A-45A. Effective Aug 31, 1978
- [AD 78-12-04](https://openairdocs.org/ad/78-12-04): No. 2 Bearing Pressure Oil Transfer Tube Assembly · Pratt & Whitney Canada PT6A-38, PT6A-41 and PT6A-45A. Effective Jun 19, 1978
- [AD 75-06-01](https://openairdocs.org/ad/75-06-01): Gearbox Deterioration · Pratt & Whitney Canada PT6A-20, PT6A-20A, PT6A-20B and 11 more. Effective Apr 1, 1977
- [AD 75-11-04](https://openairdocs.org/ad/75-11-04): Reduction Gearbox Engine Distress · Pratt & Whitney Canada PT6A-20, PT6A-20A, PT6A-20B and 8 more. Effective May 20, 1975
- [AD 70-16-01](https://openairdocs.org/ad/70-16-01): Turbo Propeller Governors · Pratt & Whitney Canada PT6A-11, PT6A-11AG, PT6A-15AG and 5 more. Effective Aug 4, 1970
- [AD 69-23-06](https://openairdocs.org/ad/69-23-06): Fuel Pumps · Pratt & Whitney Canada PT6A-20, PT6A-27, PT6A-28 and 4 more. Effective Nov 15, 1969
- [AD 68-05-03](https://openairdocs.org/ad/68-05-03): Reverse Mode · Pratt & Whitney Canada PT6A-20 and PT6A-6B. Effective Feb 28, 1968

### Historical (superseded or no longer in force)

- [AD 2014-17-08](https://openairdocs.org/ad/2014-17-08) (historical): Compressor turbine (CT) blades · Pratt & Whitney Canada PT6A-114 and PT6A-114A. Effective Oct 8, 2014
- [AD 88-24-02](https://openairdocs.org/ad/88-24-02) (historical): Airframe Chip Detector Flag System · Pratt & Whitney Canada PT6A-50

## Information bulletins (advisory) (9 in force)

- [SAIB CE-18-06](https://openairdocs.org/saib/CE-18-06): Flight Controls, Rudder Control System. Issued Dec 1, 2017
- [SAIB CE-16-27](https://openairdocs.org/saib/CE-16-27): Flight Controls, Trailing Edge (TE) Flap Control System. Issued Oct 31, 2016
- [SAIB CE-11-41](https://openairdocs.org/saib/CE-11-41): Fuselage, Wing Attach Fittings. Issued Jun 29, 2011
- [SAIB CE-11-30](https://openairdocs.org/saib/CE-11-30): Aircraft Structures. Issued May 9, 2011
- [SAIB NE-15-21](https://openairdocs.org/saib/NE-15-21): Fuel Injector Nozzle. Issued Aug 19, 2015
- [SAIB NE-12-04](https://openairdocs.org/saib/NE-12-04): Turbine/ Turboprop Engine: Reduction Gearbox. Issued Nov 1, 2011
- [SAIB NE-10-47](https://openairdocs.org/saib/NE-10-47): Turbine Engine Compressor Section. Issued Aug 30, 2010
- [SAIB NE-06-34](https://openairdocs.org/saib/NE-06-34): . Issued Mar 21, 2006
- [SAIB CE-03-24](https://openairdocs.org/saib/CE-03-24): . Issued Feb 19, 2003

## NTSB investigations

None matched to N504DD.

## FAA accident and incident reports

None matched to N504DD.

## Service difficulty reports

None filed for this aircraft. Matched to this aircraft by N-number and event date, checked against the reported serial number, make and model.

## STCs that may be installed (OpenAirDocs) (86, first 50)

Approved for this aircraft's airframe or engine model, in force first, then newest. The registry doesn't record which STCs an aircraft has; its records do.

### Approved for the airframe (Air Tractor AT-504)

- [STC SA04484CH](https://openairdocs.org/stc/SA04484CH): Installation of a Reabe Aircraft Improvement Power Gate Control System. Reabe Design LLC
- [STC SA04837NY](https://openairdocs.org/stc/SA04837NY): Installation of AeroLED's Holdings, LLC., position lights, navigation lights, strobe lights and beacon lights. AeroLED's Holdings, LLC
- [STC SA02019SE-D](https://openairdocs.org/stc/SA02019SE-D): Installation of Garmin Model GTN 625/635/650; 725/750 Navigation System. Garmin International Inc
- [STC SA12204WI](https://openairdocs.org/stc/SA12204WI): Wing Spar Cap manufacturing process change. Air Tractor Inc
- [STC SA03040CH](https://openairdocs.org/stc/SA03040CH): Installation of a digital payload hopper quantity and spray boom pressure indicating system. Reabe Design LLC
- [STC SA04046CH PAGE 1](https://openairdocs.org/stc/SA04046CH%20PAGE%201): Installation of L-3 GENESIS (TM) Electronic Standby Instrument System (ESI-500/MAG-500). Acron Aviation Inc
- [STC SA04676CH](https://openairdocs.org/stc/SA04676CH): Installation of a True Quantity Gauge System. Reabe Design LLC
- [STC SA02266SE](https://openairdocs.org/stc/SA02266SE): Installation of a Lever Throttle Quadrant. Kawak Aviation Technologies Inc
- [STC SA02444AK](https://openairdocs.org/stc/SA02444AK): Approval of the L-3 Communications NGT 9000/9000R ADS-B system installed. ADS-B Technologies LLC
- [STC SA01714WI](https://openairdocs.org/stc/SA01714WI): Installation of a Garmin transponders: (a) GTX 330/330D/33/33D with ADS-B Out functionality; (b) GTX 335/335R/345/345R with ADS-B Out and In functionality; or (c) GTX 335R/345R with ADS-B Out functionality in select airplanes installed with G950/G1000 systems. Garmin International Inc
- [STC SA02135SE](https://openairdocs.org/stc/SA02135SE): Installation of Electronics International Inc. Glass Panel Engine Monitor (with In-Flight Data). Electronics International Inc
- [STC SA04165NY](https://openairdocs.org/stc/SA04165NY): Installation of Latitude Technologies Skynode S200 Satcom system must be performed. Latitude Technologies Corporation
- [STC SA01323CH](https://openairdocs.org/stc/SA01323CH): Installation of a ground single point fueling system. Turbine Conversions Ltd
- [STC SA04145NY](https://openairdocs.org/stc/SA04145NY): Installation of the Flight Data Acquisition Storage and Transmission System (Fast). Amtech Aeronautical Limited
- [STC SA01745WI](https://openairdocs.org/stc/SA01745WI): Installation of a Cable Cutter System on the Main Landing Gear. Hershey Flying Service Inc
- [STC SA01845WI](https://openairdocs.org/stc/SA01845WI): Installation of a Center Windshield. Hershey Flying Services
- [STC SA09873AC](https://openairdocs.org/stc/SA09873AC): Installation of Night Vision Goggle (NVG) compatible lighting system in Air Tractor, Inc. REB Technologies Inc
- [STC SA00382BO](https://openairdocs.org/stc/SA00382BO): Installation of Globalstar Antenna and Cradle provisions to support a Globalstar GPS-1700 in non-composite airplanes. Avidyne Corporation
- [STC SA02276AK](https://openairdocs.org/stc/SA02276AK): Installation of AMSAFE Aviation Inflatable Restraints. AMSAFE Inc
- [STC SA02119SE PAGE 1](https://openairdocs.org/stc/SA02119SE%20PAGE%201): Installation of Garmin GDL 88 ADS-B UAT Transceiver System. Garmin International Inc
- [STC SA03439CH](https://openairdocs.org/stc/SA03439CH): Installation of a Hartzell Propeller model .HC-B4TN-3C/T10702NS (4 Blade). Aero Innovations LLC
- [STC SA02442AK PAGE 1](https://openairdocs.org/stc/SA02442AK%20PAGE%201): Approval of the L-3 Communications NGT 2000/2500 ADS-B system. ADS-B Technologies, LLC
- [STC ST03554CH](https://openairdocs.org/stc/ST03554CH): Installation of Rotary Gatekeeper and provisions equipment. Turbine Conversions Ltd
- [STC SA00403SE](https://openairdocs.org/stc/SA00403SE): Installation of Vortex Generators on the wings. Micro AeroDynamics Inc
- [STC SA02985CH](https://openairdocs.org/stc/SA02985CH): Installation of a Cool Start System in accordance with Installation Instructions , Revision A, dated April 14, 2011, or later FAA Approved revision. Turbine Conversions Ltd
- [STC SA00068SE](https://openairdocs.org/stc/SA00068SE): Installation of fuel flow/pressure instruments. (W/TSIO-360-MB1). Electronics International Inc
- [STC SA02110CH](https://openairdocs.org/stc/SA02110CH): Installation of a Time Trac Data Recorder. P2 Incorporated
- [STC SA2693NM](https://openairdocs.org/stc/SA2693NM): Installation of Electronics International digital volt/amp gauges and accessories. Electronics International Inc
- [STC SA04677CH](https://openairdocs.org/stc/SA04677CH): Installation of a Powered Hopper Lid and Auger System. Reabe Design LLC

### Approved for the engine (Pratt & Whitney PT6A series)

- [STC SE12225AC](https://openairdocs.org/stc/SE12225AC): This STC will incorporate P&W 1700 rpm propeller reduction gearbox on P&WC engines to allow 1700 rpm propeller installation. High Cotton Aircraft Conversions, LLC. Lists PT6A-41
- [STC SE00010EN](https://openairdocs.org/stc/SE00010EN): Instructions for Continued Airworthiness for the PT6A-25, and, -25A engine models that define specific maintenance tasks and their associated maintenance schedules, and that are used as a supplement to the applicable Pratt & Whitney Canada manuals. MORE Company Inc. Lists PT6A-25
- [STC SE000010EN](https://openairdocs.org/stc/SE000010EN): Instructions for Continued Airworthiness for the PT6A-25 and PT6A-25A engine models that define specific maintenance tasks and their associated maintenance schedules, and that are used as a supplement to the applicable Pratt & Whitney Canada manuals. MORE Company, Inc. Lists PT6A-25
- [STC SE000011EN](https://openairdocs.org/stc/SE000011EN): Instructions for Continued Airworthiness for the PT6A-25C engine models that define specific maintenance tasks and their associated maintenance schedules, and that are used as a supplement to the applicable Pratt & Whitney Canada manuals. MORE Company, Inc. Lists PT6A-25C
- [STC SE00001EN](https://openairdocs.org/stc/SE00001EN): Engines will be maintained IAW 'Maintenance or Reliable Engines(MORE) Program,' Rev 2, 8/16/95. MORE Company Inc. Lists PT6A-38
- [STC SE00002EN](https://openairdocs.org/stc/SE00002EN): Instructions for Continued Airworthiness for the PT6A-34, -34AG, -34B, -36, -114, -114A, -116, -135, and -135A engine models that define specific maintenance tasks and their associated maintenance schedules, and that are used as a supplement to the applicable Pratt & Whitney Canada manuals. MORE Company Inc. Lists PT6A-114
- [STC SE00003EN](https://openairdocs.org/stc/SE00003EN): Instructions for Continued Airworthiness for the PT6A-6/C20, -20, -20A and, -20B engine models that define specific maintenance tasks and their associated maintenance schedules, and that are used as a supplement to the applicable Pratt & Whitney Canada manuals. MORE Company Inc. Lists PT6A-20
- [STC SE00004EN](https://openairdocs.org/stc/SE00004EN): Instructions for Continued Airworthiness for the PT6A-11, -11AG, -15AG, -110 and-112 engine models that define specific maintenance tasks and their associated maintenance schedules, and that are used as a supplement to the applicable Pratt & Whitney Canada manuals. MORE Company Inc. Lists PT6A-11
- [STC SE00006EN](https://openairdocs.org/stc/SE00006EN): Instructions for Continued Airworthiness for the PT6A-45A, -45B, and, -45R engine models that define specific maintenance tasks and their associated maintenance schedules, and that are used as a supplement to the applicable Pratt & Whitney Canada manuals. MORE Company Inc. Lists PT6A-45A
- [STC SE00011EN](https://openairdocs.org/stc/SE00011EN): Instructions for Continued Airworthiness for the PT6A-25C engine model that define specific maintenance tasks and their associated maintenance schedules, and that are used as a supplement to the applicable Pratt & Whitney Canada manuals. MORE Company Inc. Lists PT6A-25C
- [STC SE000EN](https://openairdocs.org/stc/SE000EN): Engines will be maintained IAW 'Maintenance or Reliable Engines(MORE) Program,' Rev 4, dated 8/16/95. MORE Company Inc. Lists PT6A-21
- [STC SE10947SC](https://openairdocs.org/stc/SE10947SC): The conversion of the Pratt & Whitney Canada, Model PT6A-21 to a PT6A-28 turboprop engine. Prime Turbines. Lists PT6A-21
- [STC SE00482SE](https://openairdocs.org/stc/SE00482SE): Incorporation of turbine engine into a twin power section turboprop assembly. Fifty-Ten-Yankee LLC. Lists PT6A-114A
- [STC SE10552SC](https://openairdocs.org/stc/SE10552SC): Conversion of Pratt & Whitney Canada Corp. Model PT6A-27 or -28 to a Model PT6A-34 turboprop engine. Prime Turbines LLC. Lists PT6A-27
- [STC SE11139SC](https://openairdocs.org/stc/SE11139SC): The conversion of the Pratt & Whitney Canada, Model PT6A-135 to a PT6A-135A turboprop engine. Airforce Turbine Service. Lists PT6A-135
- [STC SE11141SC](https://openairdocs.org/stc/SE11141SC): The conversion of the Pratt & Whitney Canada, Model PT6A-15AG to a PT6A-34AG turboprop engine. RT Turbines Inc. Lists PT6A-15AG
- [STC SE02170AT](https://openairdocs.org/stc/SE02170AT): Installation of Pc Safety Valve Kit. Bell Helicopter Textron Inc. Lists PT6A-27
- [STC SE11095SC](https://openairdocs.org/stc/SE11095SC): The conversion of the Pratt & Whitney Canada, Model PT6A-27 to a PT6A-34 turboprop engine. R.T. Turbines, Inc. Lists PT6A-27
- [STC SE01624WI](https://openairdocs.org/stc/SE01624WI): Conversion of Pratt & Whitney Canada, Model PT6A-60A to a North Star Aviation PT6A-60AG turboprop engine. Data required: 1. A copy of this certificate 2. North Star Aviation document, NSA No. 1200, Turboprop Engine Conversion of PT6A-60A Model to PT6A-60AG Configuration per FAA Approved STC , dated March 15, 2011, or later FAA approved revision 3. The ICA supplement for North Star Aviation PT6A-60AG models, Instructions for Continued Airworthiness, NSA No. 1200-ICA, Rev NC, dated March 9, 2011 or later applicable revision. North Star Aviation Inc. Lists PT6A-60A
- [STC SE02837NY](https://openairdocs.org/stc/SE02837NY): The conversion of the Pratt & Whitney Canada PT6A-21 engine to operate as a PT6A-28 engine to be done. Rocky Mountain Aircraft. Lists PT6A-21
- [STC SE02688NY](https://openairdocs.org/stc/SE02688NY): This modification would incorporate improved compressor components into the Pratt & Whitney PT6A-28 engine from the PT6A-135A engine. Standard Aero Limited. Lists PT6A-28

All 86: https://openairdocs.org/aircraft/N504DD/stcs.md

## Related

- Other Air Tractor AT-504 aircraft: https://openairdocs.org/model/air-tractor-at-504/aircraft.md
- The Pratt & Whitney PT6A series engine: https://openairdocs.org/engine/pratt-whitney-pt6a-series.md

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