# N538AC: 1953 Hiller UH-12B

- Status: Valid registration
- Airframe: [Hiller UH-12B](https://openairdocs.org/model/hiller-uh-12b) (registry code 4360110, 4 seats)
- Engine: [Franklin 6V4 series](https://openairdocs.org/engine/franklin-6v4-series) (registry code 27033)
- Data sheets: [TCDS 6H2](https://openairdocs.org/tcds/6H2) (Siam Hiller Holdings Inc.), [TCDS E-244](https://openairdocs.org/tcds/E-244) (Franklin Sp. z.o.o.) (OpenAirDocs)
- Serial number: 538
- Year built: 1953
- Type: Rotorcraft
- Engine type: Reciprocating
- Airworthiness: Standard, normal
- Airworthiness date: March 24, 1992
- Certificate issued: May 2, 2025
- Expires: May 31, 2032
- Mode S code: A6CE28
- Registered owner: [Hardy John S](https://openairdocs.org/faa-owner/HARDY%20JOHN%20S)
- Location: [Fort Worth, TX](https://openairdocs.org/faa-place/TX/Fort%20Worth)
- Owner type: Individual
- Owner's area on the map: 32.9283° N, 97.2769° W: Placed by OpenAirDocs at the center of ZIP code 76244, within about 2 miles (OpenAirDocs). The owner's mailing address, not where the aircraft is based
- FAA registry: https://registry.faa.gov/AircraftInquiry/Search/NNumberResult?nNumberTxt=538AC
- Page: https://openairdocs.org/aircraft/N538AC

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 Franklin 6V4 model are included.

## ADs that may apply (OpenAirDocs): 26 in force

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

- [AD 2023-11-07](https://openairdocs.org/ad/2023-11-07): Ground Proximity System · Airbus Helicopters 47, 206, 210 and 237 more. Effective Jun 22, 2023
- [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 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 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 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 63-04-02](https://openairdocs.org/ad/63-04-02): Tail Rotor Blade · Hiller UH-12, UH-12A, UH-12B and 1 more. Effective Feb 12, 1963
- [AD 62-03-01](https://openairdocs.org/ad/62-03-01): Tail Rotor · Hiller UH-12A and UH-12B. Effective Jan 30, 1962
- [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
- [AD 56-27-02](https://openairdocs.org/ad/56-27-02): Engine Mount Welds · Hiller UH-12, UH-12A and UH-12B
- [AD 56-09-01](https://openairdocs.org/ad/56-09-01): Tail Rotor Torsion Bar · Hiller UH-12, UH-12A, UH-12B and 1 more
- [AD 55-19-01](https://openairdocs.org/ad/55-19-01): Tail Boom Rear Bulkhead · Hiller UH-12, UH-12A and UH-12B
- [AD 53-24-02](https://openairdocs.org/ad/53-24-02): Tail Rotor Pitch Change Rod · Hiller UH-12, UH-12A and UH-12B
- [AD 53-12-01](https://openairdocs.org/ad/53-12-01): Horizontal Stabilizer Spar · Hiller UH-12, UH-12A and UH-12B
- [AD 53-09-03](https://openairdocs.org/ad/53-09-03): Outboard Tension Bar Pins · Hiller UH-12, UH-12A and UH-12B
- [AD 52-29-01](https://openairdocs.org/ad/52-29-01): Tail Rotor Drive Slip Joint Assembly Inspection · Hiller UH-12, UH-12A and UH-12B
- [AD 52-01-08](https://openairdocs.org/ad/52-01-08): Collective Pitch Incidence Arms · Hiller UH-12, UH-12A and UH-12B

### Matched by engine (Franklin 6V4 series)

- [AD 69-09-01](https://openairdocs.org/ad/69-09-01): Eisemann Magnetos · Eisemann Magnetos, 2A4-45-B2, 2A4-49-B2 and 158 more
- [AD 51-28-02](https://openairdocs.org/ad/51-28-02): Oil Pump Gears · Wytwornia Sprzetu Komunikacyjnego 6V4-178-B3, 6V4-178-B31, 6V4-178-B32 and 3 more

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

- [AD 2021-23-13](https://openairdocs.org/ad/2021-23-13) (historical): Ground Proximity System · Airbus Helicopters K-225, K-190A, K-240 and 237 more. Effective Dec 9, 2021
- [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

## Information bulletins (advisory)

None matched.

## NTSB investigations

None matched to N538AC.

## FAA accident and incident reports

None matched to N538AC.

## 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) (38)

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-12B)

- [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 SH277WE](https://openairdocs.org/stc/SH277WE): Installation of UH-12C Upper Canopy. Heck Research 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 SA00680SE](https://openairdocs.org/stc/SA00680SE): Installation of Electronics International model UBG-16 or UBG-16T bar graph engine analyzer. Electronics International
- [STC SA02520AT](https://openairdocs.org/stc/SA02520AT): Installation of M-20 Oil Separator, model 600-WP. M-20 Oil Separators LLC
- [STC SA2687NM](https://openairdocs.org/stc/SA2687NM): Installation of Truboplus/ Electronics Int'l gauges and switches. Aero Manufacturing 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 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 SA2190NM PAGE 1](https://openairdocs.org/stc/SA2190NM%20PAGE%201): Installation of electronics International Digital Volt/Amp Gauges and Accessories. Electronics International
- [STC SA1351WE](https://openairdocs.org/stc/SA1351WE): Replace existing fabric on wings, fuselage, empennage, and/or control surfaces, with Ceconite101 material. (262A Series -12). Ceconite Inc
- [STC SH446EA](https://openairdocs.org/stc/SH446EA): Installation of Franklin engine Model 6V-350B in Fairchild Hiller UH-12A helicopter. Franklin Engine Co Inc. Lists UH-12 Series
- [STC SH82WE](https://openairdocs.org/stc/SH82WE): Installation of spray system and extended landing gear. Wayne Clevenger
- [STC SH83WE](https://openairdocs.org/stc/SH83WE): Installation of modified air induction system. Wayne Clevenger
- [STC SH80WE](https://openairdocs.org/stc/SH80WE): Installation of Simplex thirty-two foot spray boom. Simplex Manufacturing Co. Lists UH-12 Series
- [STC SH1-457](https://openairdocs.org/stc/SH1-457): Aircooler Motors 6VS-335B turbo-supercharged engine (derated). Carson Helicopters Inc. Lists UH-12 Series
- [STC SH160AL](https://openairdocs.org/stc/SH160AL): Airborne control survey system. US Dept of Interior. Lists UH-12 Series
- [STC SH4-178](https://openairdocs.org/stc/SH4-178): Curved control stick. Nystrom Aviation Inc. Lists UH-12 Series
- [STC SH52WE](https://openairdocs.org/stc/SH52WE): High volume fifty foot spray boom kit. Simplex Manufacturing Co. Lists UH-12 Series
- [STC SH77AL](https://openairdocs.org/stc/SH77AL): Tundra snow shoes. ERA Helicopters Inc. Lists UH-12 Series
- [STC SH9AL](https://openairdocs.org/stc/SH9AL): Airglas tundra pads L-100. Intl Helicopters. Lists UH-12 Series
- [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 (Franklin 6V4 series)

- [STC SE04651CH](https://openairdocs.org/stc/SE04651CH): To allow use of l00R grade aviation fuel meeting Swift Fuel, LLC specification SPEC-l00R-22. Swift Fuels LLC. Lists 6V4-200-C32
- [STC SE2932SW](https://openairdocs.org/stc/SE2932SW): Install carburetor air temperature indicator. Approved for Aircooled Motors (Franklin Engine Co.) equipped with float carburetors. Model eligibility included here may not be inclusive. Alcor LLC. Lists 6V4-178-B3
- [STC SE1311SO](https://openairdocs.org/stc/SE1311SO): Installation of Shivers carburetor temperature gauge with a Richter Aero Equipment B-5 carburetor temperature probe. LegacySTC.com. Lists 6V4-178-B3
- [STC SE03309CH](https://openairdocs.org/stc/SE03309CH): Installation of Engine Preheat Kit, p/n TSP6CYL-2927-115 for 115 volt application. Hartzell Propeller Inc. Lists 6V4-178-B3
- [STC SE01966WI](https://openairdocs.org/stc/SE01966WI): Use of GAMI G100UL High Octane Unleaded Avgas in spark ignition piston aircraft engines. General Aviation Modifications Inc. Lists 6V4-178-B3
- [STC SE1-201](https://openairdocs.org/stc/SE1-201): Installation of the Richter Aero Equipment Type B-4 or B-5 Temperature Probe. (O-360 SERIES (excl. A1C, C2B, C2D)). MidContinent Instru Co Inc. Lists 6V4-178-B3

## Related

- Other Hiller UH-12B aircraft: https://openairdocs.org/model/hiller-uh-12b/aircraft.md
- The Franklin 6V4 series engine: https://openairdocs.org/engine/franklin-6v4-series.md

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