# N493BN: 1962 Hiller UH-12D

- Status: Valid registration
- Airframe: [Hiller UH-12D](https://openairdocs.org/model/hiller-uh-12d) (registry code 4360118, 4 seats)
- Engine: [Allison 250 series](https://openairdocs.org/engine/allison-250-series) (registry code 03014)
- Data sheets: [TCDS 4H10](https://openairdocs.org/tcds/4H10) (Siam Hiller Holdings Inc.) (OpenAirDocs)
- Serial number: 1321
- Year built: 1962
- Type: Rotorcraft
- Engine type: Turbo-shaft
- Airworthiness: Restricted, agriculture and pest control
- Airworthiness date: March 24, 1993
- Certificate issued: February 20, 2025
- Expires: February 29, 2032
- Mode S code: A61B63
- Registered owners: [Stimart Rene D Trustee](https://openairdocs.org/faa-owner/STIMART%20RENE%20D%20TRUSTEE), [Stimart Dixie J Trustee](https://openairdocs.org/faa-owner/STIMART%20DIXIE%20J%20TRUSTEE)
- Location: [Harshaw, WI](https://openairdocs.org/faa-place/WI/Harshaw)
- Owner type: Co-owned
- Owner's area on the map: 45.6777° N, 89.6672° W: Placed by OpenAirDocs at the center of ZIP code 54529, within about 5 miles (OpenAirDocs). The owner's mailing address, not where the aircraft is based
- FAA registry: https://registry.faa.gov/AircraftInquiry/Search/NNumberResult?nNumberTxt=493BN
- Page: https://openairdocs.org/aircraft/N493BN

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 Allison 250 model are included.

## ADs that may apply (OpenAirDocs): 93 in force

### Matched by airframe (Hiller UH-12D)

- [AD 2015-20-51](https://openairdocs.org/ad/2015-20-51): Hiller UH-12, UH-12A, UH-12B and 6 more
- [AD 2000-24-21](https://openairdocs.org/ad/2000-24-21): Control System Linkage · Hiller UH-12, UH-12A, UH-12B and 6 more. Effective Jan 10, 2001
- [AD 97-20-15](https://openairdocs.org/ad/97-20-15): Outboard Tension-Torsion Bar Pin · Hiller UH-12A, UH-12B, UH-12C and 2 more. Effective Nov 12, 1997
- [AD 97-10-16](https://openairdocs.org/ad/97-10-16): Blade Spar Tube and Cuff Inspection · Allison 250-C20/250-C20B engine (Siam Hiller Holdings STC SH177WE or SH178WE). Effective Jun 27, 1997
- [AD 86-22-04](https://openairdocs.org/ad/86-22-04): Main Rotor Blades · Hiller UH-12D, UH-12E and UH-12E-L with STC SH177WE or SH178WE. Effective Nov 3, 1986
- [AD 86-17-02](https://openairdocs.org/ad/86-17-02): Main Rotor Blade Fork · Hiller UH-12D, UH-12E and UH-12E-L with STC SH177WE or SH178WE. Effective Aug 22, 1986
- [AD 84-19-08](https://openairdocs.org/ad/84-19-08): Engine Mount · Hiller UH-12D, UH-12E and UH-12E-L with STC SH177WE or SH178WE. Effective Sep 20, 1984
- [AD 83-25-02](https://openairdocs.org/ad/83-25-02): Main Rotor Blade Doublers · Allison 250-C20/250-C20B engine (Siam Hiller Holdings STC SH177WE). Effective Dec 29, 1983
- [AD 82-15-02](https://openairdocs.org/ad/82-15-02): Main And Tail Rotors · Hiller UH-12D, UH-12L, UH-12L4 and 2 more. Effective Jul 16, 1982
- [AD 81-18-02](https://openairdocs.org/ad/81-18-02): Tail Rotor Skin Cracks · Hiller UH-12, UH-12A, UH-12B and 6 more. Effective Sep 10, 1981
- [AD 81-17-03](https://openairdocs.org/ad/81-17-03): Main Transmission · Hiller UH-12, UH-12A, UH-12B and 6 more. Effective Aug 24, 1981
- [AD 81-17-01](https://openairdocs.org/ad/81-17-01): Starting Vibrator Assemblies · Bendix Starting Vibrator Assemblies, B-2, B-2A and 49 more. Effective Aug 13, 1981
- [AD 81-09-08](https://openairdocs.org/ad/81-09-08): Main Rotor Blade · Hiller UH-12D and UH-12E with STC SH177WE or SH178WE. Effective Jun 25, 1981
- [AD 81-04-01](https://openairdocs.org/ad/81-04-01): Rudder Cable Assembly · Hiller UH-12D, UH-12L and UH-12E. Effective Feb 9, 1981
- [AD 80-23-02](https://openairdocs.org/ad/80-23-02): Turbine Power Conversions · Allison 250-C20/250-C20B engine (Siam Hiller Holdings STC SH177WE or 2 others). Effective Nov 20, 1980
- [AD 80-19-02](https://openairdocs.org/ad/80-19-02): Turbine Power - Soloy Conversions · Hiller UH-12D and UH-12E with STC SH177WE or SH178WE. Effective Oct 11, 1980
- [AD 80-07-04](https://openairdocs.org/ad/80-07-04): Main Rotor Blade Anti-Node Bars · Hiller UH-12, UH-12D and UH-12E. Effective Mar 31, 1980
- [AD 79-03-07](https://openairdocs.org/ad/79-03-07): Main Rotor Tachometer Generator · Hiller UH-12D and UH-12E with STC SH177WE or SH178WE. Effective Feb 21, 1979
- [AD 78-23-07](https://openairdocs.org/ad/78-23-07): Finite Life Components Listed in AD · Hiller UH-12D and UH-12E. Effective Dec 14, 1978
- [AD 78-22-08](https://openairdocs.org/ad/78-22-08): Flight/Engine Control · Hiller UH-12D and UH-12E with STC SH177WE or SH178WE. Effective Nov 30, 1978
- [AD 78-22-02](https://openairdocs.org/ad/78-22-02): Rotor Blade Retention System · Hiller UH-12D and UH-12E. Effective Oct 27, 1978
- [AD 78-18-03](https://openairdocs.org/ad/78-18-03): Drive Shaft · Hiller UH-12D and UH-12E with STC SH177WE or SH178WE. Effective Oct 6, 1978
- [AD 77-24-03](https://openairdocs.org/ad/77-24-03): Fuel Control Valve · Hiller UH-12C, UH-12D, UH-12L and 3 more. Effective Jan 6, 1978
- [AD 75-10-01](https://openairdocs.org/ad/75-10-01): Rotor Drive System · Hiller UH-12D, UH-12L, UH-12L4 and 2 more. Effective May 8, 1975
- [AD 61-05-04](https://openairdocs.org/ad/61-05-04): Main Transmission · Hiller UH-12D and UH-12E. Effective Jun 4, 1974
- [AD 74-04-03](https://openairdocs.org/ad/74-04-03): Main Rotor Drag Struts · Hiller UH-12D and UH-12E. Effective Feb 18, 1974
- [AD 73-25-03](https://openairdocs.org/ad/73-25-03): Finite Life Components · Hiller UH-12D. Effective Jan 10, 1974
- [AD 73-20-03](https://openairdocs.org/ad/73-20-03): Main Rotor Hub · Hiller UH-12, UH-12A, UH-12B and 4 more. Effective Oct 30, 1973
- [AD 71-25-08](https://openairdocs.org/ad/71-25-08): Inspect Main Rotor Blades · Hiller UH-12, UH-12A, UH-12B and 6 more. Effective Dec 14, 1971
- [AD 69-13-07](https://openairdocs.org/ad/69-13-07): Collective Yoke Support Brackets · Hiller UH-12D, UH-12L, UH-12L4 and 2 more. Effective Apr 30, 1970
- [AD 69-08-08](https://openairdocs.org/ad/69-08-08): Tail Rotor Yoke · Hiller UH-12D, UH-12L, UH-12L4 and 2 more. Effective Apr 23, 1969
- [AD 67-08-03](https://openairdocs.org/ad/67-08-03): Cyclic Control Bracket · Hiller UH-12D and UH-12E. Effective Mar 9, 1967
- [AD 66-22-04](https://openairdocs.org/ad/66-22-04): Mercury Clutches · Hiller UH-12D, UH-12L, UH-12L4 and 2 more. Effective Sep 2, 1966
- [AD 76-20-06](https://openairdocs.org/ad/76-20-06): Cable Freezing Control · Hiller UH-12D and UH-12E with STC SH177WE or SH178WE
- [AD 63-21-03](https://openairdocs.org/ad/63-21-03): Main Rotor Blades · Hiller UH-12D and UH-12E
- [AD 62-06-03](https://openairdocs.org/ad/62-06-03): Transmission & Lubrication System Modification · Hiller UH-12D and UH-12E
- [AD 59-25-03](https://openairdocs.org/ad/59-25-03): Wobble Plate Screws · Hiller UH-12, UH-12A, UH-12B and 3 more
- [AD 59-05-05](https://openairdocs.org/ad/59-05-05): Cyclic Control Scissor Casting · Hiller UH-12, UH-12A, UH-12B and 3 more
- [AD 58-02-03](https://openairdocs.org/ad/58-02-03): Carburetor Mixture Control Removal · Hiller UH-12, UH-12A, UH-12B and 2 more

### Matched by engine (Allison 250 series)

- [AD 2022-10-06](https://openairdocs.org/ad/2022-10-06): Turbine Section · Rolls-Royce 250-C20, 250-C20B, 250-C20C (T63-A-720) and 9 more. Effective Jun 28, 2022
- [AD 2018-13-01](https://openairdocs.org/ad/2018-13-01): Turbine Governor · Rolls-Royce 250-C10 (T63-A-5), 250-C18, 250-C18A and 24 more. Effective Aug 16, 2018
- [AD 2006-20-07](https://openairdocs.org/ad/2006-20-07): Adds an additional life limit for third- and fourth-stage turbine wheels · Rolls-Royce 250-C30, 250-C30G, 250-C30G/2 and 11 more. Effective Nov 2, 2006
- [AD 2006-16-04](https://openairdocs.org/ad/2006-16-04): Inspection of the fuel nozzle screen · Rolls-Royce 250-B15A, 250-B15E, 250-B15G and 43 more. Effective Sep 7, 2006
- [AD 2006-13-06](https://openairdocs.org/ad/2006-13-06): Gas producer rotor assembly tie bolts · Rolls-Royce 250-B17, 250-B17B, 250-B17C and 16 more. Effective Jul 26, 2006
- [AD 2005-20-11](https://openairdocs.org/ad/2005-20-11): Airfoils at the hub and shroud of third-stage turbine wheels · Rolls-Royce 250-C28, 250-C28B and 250-C28C. Effective Oct 18, 2005
- [AD 2005-10-13](https://openairdocs.org/ad/2005-10-13): Turbine energy absorbing ring · Rolls-Royce 250-B17B, 250-B17C, 250-B17D and 7 more. Effective Jun 22, 2005
- [AD 2004-26-09](https://openairdocs.org/ad/2004-26-09): Compressor Adaptor Couplings · Rolls-Royce 250-B17, 250-B17B, 250-B17C and 8 more. Effective Feb 8, 2005
- [AD 2004-24-04](https://openairdocs.org/ad/2004-24-04): Hydromechanical unit (HMU) Power Lever Angle (PLA) potentiometer · Rolls-Royce 250-C30R/3, 250-C30R/3M, 250-C47B and 1 more. Effective Jan 3, 2005
- [AD 2004-14-02](https://openairdocs.org/ad/2004-14-02): SN third-stage turbine wheels · Rolls-Royce 250-C28, 250-C28B and 250-C28C. Effective Jul 26, 2004
- [AD 2002-06-08](https://openairdocs.org/ad/2002-06-08): Third Stage Turbine Wheels · Rolls-Royce 250-C28, 250-C28B and 250-C28C. Effective Apr 26, 2002
- [AD 2001-24-12](https://openairdocs.org/ad/2001-24-12): Helical Torquemeter Gearshaft Assembly · Rolls-Royce 250-B17, 250-B17C, 250-B17D and 13 more. Effective Dec 19, 2001
- [AD 98-24-28](https://openairdocs.org/ad/98-24-28): Main Fuel Control Bellows · Rolls-Royce 250-B15A, 250-B15E, 250-B15G and 36 more. Effective Jan 7, 1999
- [AD 98-10-03](https://openairdocs.org/ad/98-10-03): Hydromechanical Unit · Rolls-Royce 250-C47B. Effective May 26, 1998
- [AD 97-25-09](https://openairdocs.org/ad/97-25-09): Helical Power Takeoff Gearshaft Assembly · Rolls-Royce 250-C40B. Effective Dec 23, 1997
- [AD 96-19-01](https://openairdocs.org/ad/96-19-01): Superior Air Parts Manufacture Approval (PMA) Bearings · Rolls-Royce 250-B15G, 250-B17F, 250-B17F/1 and 17 more. Effective Sep 26, 1996
- [AD 93-25-05](https://openairdocs.org/ad/93-25-05): Driveshaft Flex Coupling Bolts, Bushings, and Nuts · Rolls-Royce 250-C20S with STC SE2352NM. Effective Feb 22, 1994
- [AD 89-23-12](https://openairdocs.org/ad/89-23-12): Turbine Nozzle Assembly · Rolls-Royce 250-C28B and 250-C28C. Effective Oct 29, 1989
- [AD 88-17-01](https://openairdocs.org/ad/88-17-01): Fuel Controls · Rolls-Royce 250-B17, 250-B17B, 250-B17C and 26 more. Effective Mar 1, 1989
- [AD 88-07-06](https://openairdocs.org/ad/88-07-06): Gas Producer Support Pressure Oil Tube Assembly · Rolls-Royce 250-C30, 250-C30M, 250-C30P and 2 more. Effective Mar 30, 1988
- [AD 86-20-13](https://openairdocs.org/ad/86-20-13): External Splines · Rolls-Royce 250-C28B, 250-C28C, 250-C30 and 9 more. Effective Dec 3, 1986
- [AD 86-19-12](https://openairdocs.org/ad/86-19-12): Gas Producer Turbine Rotor · Rolls-Royce 250-C30, 250-C30G, 250-C30G/2 and 7 more. Effective Oct 3, 1986
- [AD 85-25-07 R1](https://openairdocs.org/ad/85-25-07-R1): Outer Combustion Case Assembly · Rolls-Royce 250-C28, 250-C28B, 250-C28C and 10 more. Effective Aug 15, 1986
- [AD 86-16-03](https://openairdocs.org/ad/86-16-03): Scavenge Line Air/Oil Centrifugal Separator Assembly · Rolls-Royce 250-C28B and 250-C28C. Effective Aug 13, 1986
- [AD 85-25-12](https://openairdocs.org/ad/85-25-12): Turbine-To-Compressor-Coupling · Rolls-Royce 250-C28B and 250-C28C. Effective Jan 6, 1986
- [AD 85-25-09](https://openairdocs.org/ad/85-25-09): Turbine Shafts And Couplings · Rolls-Royce 250-C28B and 250-C28C. Effective Jan 6, 1986
- [AD 85-25-08](https://openairdocs.org/ad/85-25-08): Compressor Mount Assembly · Rolls-Royce 250-C28B, 250-C28C, 250-C30 and 2 more. Effective Jan 6, 1986
- [AD 84-24-54 R2](https://openairdocs.org/ad/84-24-54-R2): Gas Producer Turbine Rotor · Rolls-Royce 250-C30, 250-C30P, 250-C30R (T703-AD-700) and 1 more. Effective Jan 6, 1986
- [AD 85-06-51](https://openairdocs.org/ad/85-06-51): Magnetic Plugs · Rolls-Royce 250-C30 and 250-C30S. Effective May 10, 1985
- [AD 84-17-51](https://openairdocs.org/ad/84-17-51): Turbine Rotor Assembly · Rolls-Royce 250-C30 and 250-C30S. Effective Dec 26, 1984
- [AD 83-03-02 R1](https://openairdocs.org/ad/83-03-02-R1): Slotted Third Stage Turbine Wheels · Rolls-Royce 250-B17, 250-B17B, 250-B17C and 5 more. Effective Feb 28, 1984
- [AD 81-13-12 R1](https://openairdocs.org/ad/81-13-12-R1): 4th Stage Turbine Nozzle Assembly · Rolls-Royce 250-C30, 250-C30P and 250-C30S. Effective Sep 26, 1983
- [AD 83-01-04](https://openairdocs.org/ad/83-01-04): Turbine Assemblies · Rolls-Royce 250-C28B and 250-C28C. Effective Jan 24, 1983
- [AD 82-24-05](https://openairdocs.org/ad/82-24-05): Control Assembly and Power Turbine Governor Assembly · Rolls-Royce 250-B15A, 250-B15E, 250-B15G and 43 more. Effective Nov 26, 1982
- [AD 82-13-03](https://openairdocs.org/ad/82-13-03): Modify Engine High Pressure Fuel Control Filter Assembly · Rolls-Royce 250-C20 and 250-C20B. Effective Jul 1, 1982
- [AD 82-12-04](https://openairdocs.org/ad/82-12-04): Combined Power Turbine and Propeller Governor Assembly · Cessna 401, 401A, 401B and 11 more. Effective Jun 7, 1982
- [AD 82-03-02](https://openairdocs.org/ad/82-03-02): N2 (Electronic) Overspeed Control System · Rolls-Royce 250-C28B. Effective Feb 4, 1982
- [AD 79-21-01 R1](https://openairdocs.org/ad/79-21-01-R1): Third Stage Turbine Wheel Blade · Rolls-Royce 250-B17, 250-B17B, 250-B17C and 3 more. Effective Jun 3, 1981
- [AD 79-16-06](https://openairdocs.org/ad/79-16-06): Accessory Drive Gearbox · Rolls-Royce 250-C28, 250-C28B, 250-C28C and 10 more. Effective Jan 11, 1980
- [AD 78-14-08](https://openairdocs.org/ad/78-14-08): Fuel Pump Drive Spline · Rolls-Royce 250-C18, 250-C18A, 250-C18B and 3 more. Effective Oct 24, 1979
- [AD 79-18-13](https://openairdocs.org/ad/79-18-13): Third Stage Turbine Wheel · Rolls-Royce 250-C28B and 250-C28C. Effective Sep 6, 1979
- [AD 79-06-05](https://openairdocs.org/ad/79-06-05): Overspeed Control System · Rolls-Royce 250-C28B and 250-C30. Effective Mar 26, 1979
- [AD 78-26-01](https://openairdocs.org/ad/78-26-01): Engine Electrical System · Rolls-Royce 250-C28B. Effective Nov 3, 1978
- [AD 77-15-12](https://openairdocs.org/ad/77-15-12): Power Turbine Coupling Nut · Rolls-Royce 250-B15A, 250-B15E, 250-B15G and 23 more. Effective Sep 23, 1977
- [AD 77-09-08](https://openairdocs.org/ad/77-09-08): Bleed Valve Diaphragm · Rolls-Royce 250-B17, 250-B17B, 250-C20 and 2 more. Effective Jul 18, 1977
- [AD 74-14-03](https://openairdocs.org/ad/74-14-03): Fuel Control Rigging · Rolls-Royce 250-C20. Effective Jul 10, 1974
- [AD 73-19-07](https://openairdocs.org/ad/73-19-07): Turbine Governor-To-Fuel Control Tube · Rolls-Royce 250-C20. Effective Sep 14, 1973
- [AD 72-03-06](https://openairdocs.org/ad/72-03-06): Turbine Wheels · Rolls-Royce 250-B15A, 250-B15E, 250-B15G and 9 more. Effective Feb 8, 1972
- [AD 69-26-03](https://openairdocs.org/ad/69-26-03): Modify Power and Accessories Gear Box · Rolls-Royce 250-C18, 250-C18A, 250-C18B and 1 more. Effective Dec 25, 1969
- [AD 69-18-04](https://openairdocs.org/ad/69-18-04): Torquemeter Shaftgear · Rolls-Royce 250-C10 (T63-A-5), 250-C10B (T63-A-5A), 250-C10D (T63-A-700) and 4 more. Effective Oct 18, 1969

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

- [AD 77-07-05 R1](https://openairdocs.org/ad/77-07-05-R1) (historical): Control Rotor Blade Spar Tube and Cuff · Hiller UH-12, UH-12A, UH-12B and 3 more. Effective Jun 20, 1977
- [AD 77-07-05](https://openairdocs.org/ad/77-07-05) (historical): Control Rotor Blade Spar Tube and Cuff · Hiller UH-12, UH-12A, UH-12B and 3 more. Effective Jun 20, 1977
- [AD 2017-18-14](https://openairdocs.org/ad/2017-18-14) (historical): Turbine Section · Rolls-Royce 250-C20, 250-C20B, 250-C20F and 8 more. Effective Oct 13, 2017
- [AD 2015-02-22](https://openairdocs.org/ad/2015-02-22) (historical): Repetitive visual inspections · Rolls-Royce 250-B17, 250-B17B, 250-B17C and 15 more. Effective Mar 9, 2015
- [AD 2012-14-06](https://openairdocs.org/ad/2012-14-06) (historical): Released turbine blades and shrouds · Rolls-Royce 250-C20, 250-C20B and 250-C20R/2. Effective Aug 14, 2012
- [AD 2004-24-09](https://openairdocs.org/ad/2004-24-09) (historical): Fuel nozzle · Rolls-Royce 250-B15A, 250-B15E, 250-B15G and 40 more. Effective Jan 5, 2005
- [AD 2003-13-10](https://openairdocs.org/ad/2003-13-10) (historical): Hydromechanical unit (HMU) power lever angle (PLA) · 250-C30R/3, 250-C30R/3M, 250-C47B and 1 more. Effective Jul 15, 2003
- [AD 2001-20-51](https://openairdocs.org/ad/2001-20-51) (historical): Helical Torquemeter Gearshaft Assembly · 250-B17, 250-B17C, 250-B17D and 12 more
- [AD 97-21-09](https://openairdocs.org/ad/97-21-09) (historical): Engine Main Electrical Harness Assembly · 250-C47B. Effective Dec 3, 1997
- [AD 96-24-09](https://openairdocs.org/ad/96-24-09) (historical): Engine Main Electrical Harness Assembly · 250-C47B. Effective Nov 25, 1996

All 103: https://openairdocs.org/aircraft/N493BN/ads.md

## Information bulletins (advisory) (6 in force)

- [SAIB NE-06-52](https://openairdocs.org/saib/NE-06-52): . Issued Jul 6, 2006
- [SAIB NE-06-12R1](https://openairdocs.org/saib/NE-06-12R1): . Issued Jan 13, 2006
- [SAIB NE-04-58](https://openairdocs.org/saib/NE-04-58): . Issued Mar 24, 2004
- [SAIB NE-04-57](https://openairdocs.org/saib/NE-04-57): . Issued Mar 24, 2004
- [SAIB NE-04-56](https://openairdocs.org/saib/NE-04-56): . Issued Mar 24, 2004
- [SAIB CE-01-10](https://openairdocs.org/saib/CE-01-10): . Issued Jan 24, 2001
- [SAIB NE-06-12](https://openairdocs.org/saib/NE-06-12) (historical): . Issued Dec 2, 2005

## NTSB investigations

None matched to N493BN.

## FAA accident and incident reports (1)

From the FAA Accident/Incident Data System. Reports are matched to registry aircraft by N-number and event date, checked against the reported make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model.

- [Incident 19870824068479I](https://openairdocs.org/incident/19870824068479I), Aug 24, 1987: Hiller UH12D (N493BN), Osseo, WI. Helicopter struck an electrical wire during spray operation. No damage.

## 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) (53, 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 (Hiller UH-12D)

- [STC SH3319NM](https://openairdocs.org/stc/SH3319NM): Installation of Precise Flight Pulselite Control Unit in the Landing /Taxi Recognition Visual Control Light system,. Precise Flight Inc
- [STC SR02704SE](https://openairdocs.org/stc/SR02704SE): Installation and maintenance of the Sunspot 36 and 46 series lights. AeroLED's Holdings LLC
- [STC SR00359BO](https://openairdocs.org/stc/SR00359BO): Installation of Parmetheus Plus LED PAR36 and PAR46 taxi and landing lights. Whelen Aerospace Technologies
- [STC SR00420NY](https://openairdocs.org/stc/SR00420NY): Installation of Airwolf remote mounted engine oil filter Model AFC-600. Airwolf Filter, Corp
- [STC SR02487AK](https://openairdocs.org/stc/SR02487AK): Installation of L-3 Communications Avionics Systems ESI-500 Standby Instrument System. ADS-B Technologies, LLC
- [STC SR02470AK](https://openairdocs.org/stc/SR02470AK): Installation of the L-3 Communications NGT -1000/2000/2500 ADS-B System. ADS-B Technologies, LLC
- [STC SR02471AK](https://openairdocs.org/stc/SR02471AK): Installation of the L-3 Communications NGT -9000/9000R ADS-B System. ADS-B Technologies, LLC
- [STC SR02394AK](https://openairdocs.org/stc/SR02394AK): Replacement of existing landing and/or hover light bulbs with Light Emitting Diode (LED) lighting system. Seaplanes North LLC
- [STC SA00068SE](https://openairdocs.org/stc/SA00068SE): Installation of fuel flow/pressure instruments. (W/TSIO-360-MB1). Electronics International Inc
- [STC SA2693NM](https://openairdocs.org/stc/SA2693NM): Installation of Electronics International digital volt/amp gauges and accessories. Electronics International Inc
- [STC SA02033AT](https://openairdocs.org/stc/SA02033AT): Modification to install an air-oil separator to prevent oil from being aspirated from the engine breather line. M-20 Oil Separators LLC
- [STC SH247NW](https://openairdocs.org/stc/SH247NW): Installation and maintenance of exhaust ejector engine oil cooler system. (UH-12D (ARMY UH-23D modified per STC SH177WE). Siam Hiller Holdings Inc
- [STC SH295NW](https://openairdocs.org/stc/SH295NW): Installation of Hiller auxiliary fuel tanks kit No 72041. (UH-12D (ARMY UH-23D) modified per STC SH177WE). Siam Hiller Holdings Inc
- [STC SH297NW](https://openairdocs.org/stc/SH297NW): Installation and maintenance of a cabin heater system. (UH-12D (ARMY UH-23D modified per STC SH178WE). Siam Hiller Holdings Inc
- [STC SH299NW](https://openairdocs.org/stc/SH299NW): Installation of Soloy cargo racks. Siam Hiller Holdings Inc
- [STC SH321NW](https://openairdocs.org/stc/SH321NW): Installation of a Bendix fuel control/power governor system on the Allison 250-C20 turbine powered Hiller UH-12D rotorcraft. (UH-12D (ARMY UH-23D) modified per STC SH177WE). Siam Hiller Holdings Inc
- [STC SH338NW](https://openairdocs.org/stc/SH338NW): Installation of transmission oil cooling system on the Allison250-C20 turbine powered Hiller UH-12D rotorcraft. (UH-12D (ARMY UH-23D modified per STC SH177WE). Siam Hiller Holdings Inc
- [STC SH380NW](https://openairdocs.org/stc/SH380NW): Installation and maintenance of engine auto reignition system. (UH-12D (ARMY UH-23D) modified per STC SH177WE). Siam Hiller Holdings Inc
- [STC SH505NW](https://openairdocs.org/stc/SH505NW): Installation of cargo release pedal. Siam Hiller Holdings Inc
- [STC SH559NW](https://openairdocs.org/stc/SH559NW): Installation and maintenance of engine inlet air cleaner system. (UH-12D (ARMY UH-23D) modified per STC SH177WE). Siam Hiller Holdings Inc
- [STC SA00680SE](https://openairdocs.org/stc/SA00680SE): Installation of Electronics International model UBG-16 or UBG-16T bar graph engine analyzer. Electronics International
- [STC SH177WE](https://openairdocs.org/stc/SH177WE): Installation of Allison 250-C20/250-C20B engine and related changes. Siam Hiller Holdings Inc
- [STC SH287NW](https://openairdocs.org/stc/SH287NW): Installation of Hiller landing gear float kit No. 44012. (UH-12d (ARMY UH-23D modified per STC SH177WE). Siam Hiller Holdings Inc
- [STC SH475NW](https://openairdocs.org/stc/SH475NW): Installation of an agricultural spray system. (UH-12D (ARMY UH-23D) modifier per STC). Siam Hiller Holdings Inc
- [STC SR01430LA](https://openairdocs.org/stc/SR01430LA): Installation of Stainless Steel Skid shoes. Papas Gary Los Angeles Laboratories Inc
- [STC SA01258SE](https://openairdocs.org/stc/SA01258SE): Installation of the Automatic Flagman Dispenser Models in accordance with Automatic Flagman Master Drawing Lists specified in attached AML, or later FAA approved revision.This STC supercedes several existing STC s as listed in the notes on the attached AML. R-S Sales Inc
- [STC SA02520AT](https://openairdocs.org/stc/SA02520AT): Installation of M-20 Oil Separator, model 600-WP. M-20 Oil Separators LLC
- [STC SH849NW](https://openairdocs.org/stc/SH849NW): Installation of North American Industries, Inc., Model No. 5 Automatic Flagman. R-S Sales Inc
- [STC SA2687NM](https://openairdocs.org/stc/SA2687NM): Installation of Truboplus/ Electronics Int'l gauges and switches. Aero Manufacturing Inc
- [STC SR00135LA](https://openairdocs.org/stc/SR00135LA): Installation of Yehnert Tail Rotor Blades YH-278 as replacements for Hiller Tail Rotor Blades 55073. Yehnert Helicopters, Inc
- [STC SA1626NM PAGE 1](https://openairdocs.org/stc/SA1626NM%20PAGE%201): Installation of Electronics Int'l Digital EGT/CHT Instruments and accessories. (201 Series). Electronics International
- [STC SA2350NM PAGE 1](https://openairdocs.org/stc/SA2350NM%20PAGE%201): Installation of Electronics International Inc digital carburetor/outside air temperature gauges. Electronics International
- [STC SH359GL](https://openairdocs.org/stc/SH359GL): Installation of Facet Enterprises engine lubrication system scavenge filter. Facet Filter Products
- [STC SH2763SO](https://openairdocs.org/stc/SH2763SO): Installation of control rotor safety cable. JAARS Inc
- [STC SA4302NM](https://openairdocs.org/stc/SA4302NM): Installation of Electronics Int'l digital automatic engine analyzer. Electronics International
- [STC SA3862NM PAGE 1](https://openairdocs.org/stc/SA3862NM%20PAGE%201): Installation of Electronics International Primary TIT/EGT/CHT instruments, remote switches and associated accessories. Electronics International
- [STC SH3362NM](https://openairdocs.org/stc/SH3362NM): Installation of a Tail Rotor Blade Protective Coating. Columbia Helicopters Inc
- [STC SA2190NM PAGE 1](https://openairdocs.org/stc/SA2190NM%20PAGE%201): Installation of electronics International Digital Volt/Amp Gauges and Accessories. Electronics International
- [STC SH618NW](https://openairdocs.org/stc/SH618NW): Installation of the Onboard Weighing System Adapter No. 1500, for use with Eastern Rotorcraft Cargo Hook No 2A15E. Onboard Weighing Systems
- [STC SH877SO](https://openairdocs.org/stc/SH877SO): Installation of tail rotor guard assembly. Jungle Aviation & Radio Service, Inc
- [STC SA2350NM](https://openairdocs.org/stc/SA2350NM) (historical): Installation of Electronics International Inc digital carburetor/outside air temperature gauges listed on the attached continuation sheet and the associated accessories. Electronics International

### Approved for the engine (Allison 250 series)

- [STC SE2352NM](https://openairdocs.org/stc/SE2352NM): Modification of turbine engine. Fifty-Ten-Yankee LLC. Lists 250-C20S
- [STC SE00057AT](https://openairdocs.org/stc/SE00057AT): Installation of Aeronautical Accessories, Inc., Pc Safety Valve Kit. Bell Helicopter Textron Inc. Lists 250-C28
- [STC SE00327AT](https://openairdocs.org/stc/SE00327AT): Installation of PC Safety Valve Kit. Bell Helicopter Textron Inc. Lists 250-B17
- [STC SE5511NM](https://openairdocs.org/stc/SE5511NM): Installation of compressor discharge pressue (PC) valve. Bell Helicopter Textron Inc. Lists 250-C20
- [STC SE769NW](https://openairdocs.org/stc/SE769NW): Installation of Soloy Part No. 250-1001-1 fuel line. Siam Hiller Holdings Inc. Lists 250-C18
- [STC SE00014EN](https://openairdocs.org/stc/SE00014EN): Installation of the Pratt & Whitney Engine Services, Inc. CrossCheck Engine Monitor Kit P/N HUMS-K-071-1, Rev. A on the specified PT6A engine models and kit P/N HUMS-K-071-2 on the specified A250 engine models. Pratt & Whitney Engine Services Inc. Lists 250-C20B
- [STC SE00026EN](https://openairdocs.org/stc/SE00026EN): Installation of Pratt & Whitney Engine Services Inc. IntelliStart Plus Electronic Control Unit (ECU), P/N DPU-K-010 on specified 250 engine models. Pratt & Whitney Engine Services Inc. Lists 250-C28
- [STC SE00027EN](https://openairdocs.org/stc/SE00027EN): Installation of Pratt & Whitney Engine Services Inc. Intellistart plus electronic control unit (ECU), P/N DPU-K-010 on the specified 250 engine models. Pratt & Whitney Engine Services Inc. Lists 250-C10 (T63-A-5)
- [STC SE492GL](https://openairdocs.org/stc/SE492GL): Incorporation of a fuel flow transducer. Shadin Avionics. Lists 250-C18A

All 53: https://openairdocs.org/aircraft/N493BN/stcs.md

## Related

- Other Hiller UH-12D aircraft: https://openairdocs.org/model/hiller-uh-12d/aircraft.md
- The Allison 250 series engine: https://openairdocs.org/engine/allison-250-series.md

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