# N94AP: 1959 Hiller UH-12D

- Status: Valid registration
- Airframe: [Hiller UH-12D](https://openairdocs.org/model/hiller-uh-12d) (registry code 4360118, 4 seats)
- Data sheets: [TCDS 4H10](https://openairdocs.org/tcds/4H10) (Siam Hiller Holdings Inc.) (OpenAirDocs)
- Serial number: 1211
- Year built: 1959
- Type: Rotorcraft
- Engine type: Turbo-shaft
- Airworthiness: Standard, normal
- Airworthiness date: January 23, 1978
- Certificate issued: April 11, 2000
- Expires: April 30, 2030
- Mode S code: AD0ADD
- Registered owner: [Summit Helicopters Inc](https://openairdocs.org/faa-owner/SUMMIT%20HELICOPTERS%20INC)
- Location: [Salem, VA](https://openairdocs.org/faa-place/VA/Salem)
- Owner type: Corporation
- Owner's area on the map: 37.3034° N, 80.1131° W: Placed by OpenAirDocs at the center of ZIP code 24153, within about 6 miles (OpenAirDocs). The owner's mailing address, not where the aircraft is based
- FAA registry: https://registry.faa.gov/AircraftInquiry/Search/NNumberResult?nNumberTxt=94AP
- Page: https://openairdocs.org/aircraft/N94AP

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): 39 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

### 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

## Information bulletins (advisory)

None matched.

## NTSB investigations (1)

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 DEN79DQD03](https://openairdocs.org/ntsb/DEN79DQD03), Mar 22, 1979: Hiller UH-12D (N94AP), Tularosa, NM, substantial damage

## 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.

- [Accident 19790322005069A](https://openairdocs.org/incident/19790322005069A), Mar 22, 1979: Hiller UH12D (N94AP), Tularosa, NM, Destroyed. Helicopter struck a wire while spraying a field, lost control, and crashed.

## Service difficulty reports (1)

As reported by operators and repair stations. Matched to this aircraft by N-number and event date, checked against the reported serial number, make and model.

- [SDR 2015FA0000446](https://openairdocs.org/sdr/2015FA0000446), Sep 8, 2015: FORK. CRACKED. THE ACFT WAS PERFORMING AERIAL APPLICATION UNDER RESTRICTED CATEGORY. PRIOR TO 9/8/2015, THE PILOT REPORTED THE ACFT FLEW SMOOTH. PILOT REPORTED THAT THE LAST F

## STCs that may be installed (OpenAirDocs) (41)

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

## Related

- Other Hiller UH-12D aircraft: https://openairdocs.org/model/hiller-uh-12d/aircraft.md

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