# N49983: Hiller UH-12C - Status: Valid registration - Airframe: [Hiller UH-12C](https://openairdocs.org/model/hiller-uh-12c) (registry code 4360116, 4 seats) - Data sheets: [TCDS 6H2](https://openairdocs.org/tcds/6H2) (Siam Hiller Holdings Inc.) (OpenAirDocs) - Serial number: 850 - Type: Rotorcraft - Engine type: Reciprocating - Airworthiness: Experimental, showing compliance - Airworthiness date: May 22, 1979 - Certificate issued: March 11, 2011 - Expires: March 31, 2030 - Mode S code: A63513 - Registered owner: [Pockrus Pat B](https://openairdocs.org/faa-owner/POCKRUS%20PAT%20B) - Location: [Mineral Wells, TX](https://openairdocs.org/faa-place/TX/Mineral%20Wells) - Owner type: Individual - Owner's area on the map: 32.8024° N, 98.1425° W: Placed by OpenAirDocs at the center of ZIP code 76067, within about 8 miles (OpenAirDocs). The owner's mailing address, not where the aircraft is based - FAA registry: https://registry.faa.gov/AircraftInquiry/Search/NNumberResult?nNumberTxt=49983 - Page: https://openairdocs.org/aircraft/N49983 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. ## ADs that may apply (OpenAirDocs): 17 in force ### Matched by airframe (Hiller UH-12C) - [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 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 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 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 56-09-01](https://openairdocs.org/ad/56-09-01): Tail Rotor Torsion Bar · Hiller UH-12, UH-12A, UH-12B and 1 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 (2) From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. - [NTSB NYC98LA006](https://openairdocs.org/ntsb/NYC98LA006), Oct 5, 1997: Hiller UH-12C (N49983), Bennington, VT, substantial damage. Probable cause: The failure of the cyclic control due to an improper modification by the pilot/owner. - [NTSB ANC86LA058](https://openairdocs.org/ntsb/ANC86LA058), May 18, 1986: Hiller 12-C (N49983), Palmer, AK, substantial damage ## FAA accident and incident reports (3) 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. - [Accident 19971005047449A](https://openairdocs.org/incident/19971005047449A), Oct 5, 1997: Hiller UH12C (N49983), Bennington, VT, Substantial damage. (-16) Instructor was demonstrating hovering to student near runway at the airport (5B5). Student pilot at the controls began drifting aircraft to the right.… - [Incident 19910218013589I](https://openairdocs.org/incident/19910218013589I), Feb 18, 1991: Hiller UH12C (N49983), Pittsfield, MA, Minor damage. Throttle frozen engine entered into overspeed condition. Autoratated into field. Made a hard landing. - [Accident 19860518018569A](https://openairdocs.org/incident/19860518018569A), May 18, 1986: Hiller UH12C (N49983), Palmer, AK, Substantial damage. Allowed rotor RPM to decay while hovering at low altitude looking for a landing area. Rotors struck shoreline rocks. ## 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) (31) 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-12C) - [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 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 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 SH959NW](https://openairdocs.org/stc/SH959NW): Remobe battery from Sta 126 and install it on the original radio rack at Sta 25. Clover Park Vocational/Technical Institute - [STC SH954NW](https://openairdocs.org/stc/SH954NW): Remove battery from Sta 126 and install it on the original radio ract at Sta 25. Clover Park Vocational/Technical Institute - [STC SH141GL](https://openairdocs.org/stc/SH141GL): Installation of Bell 47 canopy and one piece doors. Stanley Tool & Die Co - [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 ## Earlier aircraft with N49983 The FAA can reassign an N-number once a registration is cancelled. These aircraft carried N49983 before. - [Cancelled 1965-05-21](https://openairdocs.org/deregistered/N49983-1965-05-21): Noorduyn UC-64A, S/N 190. Owner: [Wien Alaska Airlines Inc](https://openairdocs.org/faa-owner/WIEN%20ALASKA%20AIRLINES%20INC), [Fairbanks, AK](https://openairdocs.org/faa-place/AK/Fairbanks) ## Related - Other Hiller UH-12C aircraft: https://openairdocs.org/model/hiller-uh-12c/aircraft.md --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.