Type Record · As of May 3, 2026
HILLER UH-12L4
Rotorcraft · LYCOMING VO-540-C2A
Registered
3
Year Range
1966–1966
NTSB Events
4
Airworthiness Directives
3
Aircraft Resources
01 / Distribution
Where the fleet lives and was built
Counts of currently-registered HILLER UH-12L4 aircraft by US state and decade of manufacture, sourced from the FAA Aircraft Registry.
By State (top 10)
- AZ 66.7% 2
- CA 33.3% 1
By Decade of Manufacture
- 1960s 66.7% 2
- Unknown 33.3% 1
02 / NTSB Records
Events involving HILLER UH-12L4 aircraft
4 event(s) on file. Showing the most recent 4.
-
Oct 9, 1972
N90487SAN ANDREAS, California
NTSB Docket → -
Jan 15, 1968
N90483CUCAMONGA, California Serious
NTSB Docket → -
May 23, 1967
N90457FAIRPLAY, Colorado
NTSB Docket → -
Nov 17, 1966
N90487CASTAIC, California
NTSB Docket →
03 / Airworthiness Directives
FAA directives applicable to HILLER UH-12L4
3 directive(s) on file. Showing the most recent 3.
-
Jun 12, 2023
Airworthiness Directives; Various Airplanes, Helicopters, and Engines
The FAA is adopting a new airworthiness directive (AD) for turbocharged, reciprocating engine-powered airplanes and helicopters and turbocharged, reciprocating engines with a certain v-band coupling installed. This AD was prompted by multiple failures of spot-welded, multi-segment v-band couplings at the tailpipe to t…
-
Dec 6, 2000
Airworthiness Directives; Siam Hiller Holdings, Inc. Model UH-12, UH-12A, UH-12B, UH-12C, UH-12D, UH-12E, UH-12E-L, UH-12L, and UH-12L4 Helicopters
This amendment adopts a new airworthiness directive (AD), for Siam Hiller Holdings, Inc. (Hiller), formerly Rogerson Hiller Corporation, Model UH-12, UH-12A, UH-12B, UH-12C, UH-12D, UH-12E, UH- 12E-L, UH-12L, and UH-12L4 helicopters, that requires replacing all undrilled-shank bolts at pivoting joints in the control s…
-
Aug 31, 2000
Airworthiness Directives; Siam Hiller Holdings, Inc. Model UH-12, UH-12A, UH-12B, UH-12C, UH-12D, UH-12E, UH-12E-L, UH-12L, and UH-12L4 Helicopters
This document proposes the adoption of a new airworthiness directive (AD) for Siam Hiller Holdings, Inc. (Hiller), formerly Rogerson Hiller Corporation, Model UH-12, UH-12A, UH-12B, UH-12C, UH- 12D, UH-12E, UH-12E-l, UH-12L, and UH-12L4 helicopters. The AD would require replacing all undrilled-shank bolts at pivoting…
04 / Type Certificate Data Sheets
FAA TCDS for HILLER UH-12L4
The TCDS is the legal certification document — weight limits, performance, equipment, AD compliance times, operating limitations. 1 match in the FAA catalog.
- H1WE Historical Rev 6 · 10/28/2014
Siam Hiller Holdings Inc.
Models: UH-12L, UH-12L4
06 / Supplemental Type Certificates
Modifications approved for HILLER UH-12L4
55 STCs on file — every FAA-approved modification, alteration, or installation for this aircraft. STOL kits, avionics, fuel systems, floats, engine swaps, you name it.
-
04/14/2023
STC SH3319NM
Installation of Precise Flight Pulselite Control Unit in the Landing /Taxi Recognition Visual Control Light system,
Precise Flight Inc
-
05/19/2020
STC SH3319NM (1 OF 2)
Installation of Precise Flight Pulselite Control Unit in the\nLanding /Taxi Recognition Visual Control Light system,
Precise Flight Inc
-
12/29/2016
STC SH3319NM
Installation of Precise Flight Pulselite Control Unit in the Landing /Taxi Recognition Visual Control Light system,
Precise Flight Inc
-
01/14/2015
STC SR02394AK
Replacement of existing landing and/or hover light bulbs with Light Emitting Diode (LED) lighting system
Seaplanes North LLC
-
06/09/2014
STC SH3319NM
Installation of Precise Flight Pulselite Control Unit in the Landing /Taxi Recognition Visual Control Light system,
Precise Flight Inc
-
07/25/2013
STC SH3319NM
Installation of Precise Flight Pulselite Control Unit in the Landing /Taxi Recognition Visual Control Light system,
Precise Flight Inc
-
10/17/2012
STC SH3319NM
Installation of Precise Flight Pulselite Control Unit in the Landing /Taxi Recognition Visual Control Light system,
Precise Flight Inc
-
05/23/2012
STC SR02394AK
Replacement of existing landing and/or hover light bulbs with Light Emitting Diode (LED) lighting system
Floats Alaska LLC
-
03/15/2012
STC SR02394AK
Replacement of existing landing and/or hover light bulbs with Light Emitting Diode (LED) lighting system per Installation Instructions LED03-20R, Rev. IR, dated October 27, 2010.
Floats Alaska LLC
-
02/21/2012
STC SH3319NM
Installation of Precise Pulselite Control System
Precise Flight Inc
-
10/20/2010
STC SA00068SE (PAGE 1)
Installation of fuel flow/pressure instruments. (W/TSIO-360-MB1)
Electronics International Inc.
-
12/10/2009
STC SA2693NM (PAGE 1)
Installation of Electronics International digital volt/amp gauges and accessories.
Electronics International Inc.
-
02/10/2009
STC SA593CH (Page 1)
Install Champion SlickSTART magneto booster system.
Champion Aerospace LLC
-
07/24/2008
STC SA02033AT (PAGE 5)
Modification to install an air-oil separator to prevent oil from being aspirated from the engine breather line (47J series w stc's SH4-235SW, SH4-826SW or SH479SW)
M-20 Oil Separators LLC
-
04/02/2006
STC SA01240SE (1 OF 5)
Installation of secondary voltage indication system
Visual Instruments LLC
-
03/29/2006
STC SA02268CH (PAGE 3)
Installation of Airwolf Filter Corp. Air Oil Separator
Airwolf Filter Corporation
-
07/08/2005
STC SA00680SE (5 OF 6
Installation of Electronics International model UBG-16 or UBG-16T bar graph engine analyzer.
Electronics International
-
01/24/2005
STC SA2693NM
Installation of Electronics International digital volt/amp gauges and accessories.
Electronics International Inc.
-
11/04/2004
STC SA02033AT (PAGE 3)
Modification to install an air-oil separator to prevent oil from being aspirated from the engine breather line (47J series w stc's SH4-235SW, SH4-826SW or SH479SW)
M-20 Oil Separators LLC
-
03/12/2004
STC SA593CH (2 OF 5)
Install Champion SlickSTART magneto booster system.
Champion Aerospace LLC
-
11/07/2003
STC SH3319NM
Installation of Precise Pulselite Control Unit in the Landing/Taxi/Recognition Visual Control Light System.
Precise Flight Inc
-
05/30/2002
STC SA02520AT
Installation of M-20 Oil Separator, model 600-WP.
M-20 Oil Separators LLC
-
12/03/2001
STC SH3319NM
Installation of Precise Pulselite Control Unit in the Landing/Taxi/Recognition Visual Control Light System.
Precise Flight Inc
-
10/25/2000
STC SA2687NM (PAGE 1)
Installation of Truboplus/ Electronics Int'l gauges and switches.
Aero Manufacturing Inc.
-
03/09/1999
STC SA00680SE (5 OF 6
Installation of Electronics International model UBG-16 or UBG-16T bar graph engine analyzer.
Electronics International
-
03/09/1993
STC SA1626NM Page 1
Installation of Electronics Int'l Digital EGT/CHT Instruments and accessories. (201 Series)
Electronics International
-
02/24/1992
STC SA2687NM
Installation of Truboplus/ Electronics Int'l gauges and switches.
ACD Corporation
-
06/06/1990
STC SA2350NM Page 1
Installation of Electronics International Inc digital carburetor/outside air temperature gauges
Electronics International
-
10/13/1989
STC SA4302NM (PAGE 2)
Installation of Electronics Int'l digital automatic engine analyzer.
Electronics International
-
10/13/1989
STC SA4302NM (PAGE 1)
Installation of Electronics Int'l digital automatic engine analyzer.
Electronics International
+ 25 more STCs on file
04 / Regulations watching this type
Advisory Circulars and Federal Register activity for HILLER UH-12L4
Advisory Circulars
ACs whose subject explicitly mentions HILLER or UH-12L4.
Recent Federal Register activity
Latest rulemakings touching general operating rules (Part 91) and maintenance rules (Part 43).
- 2026-04-17 Settlement Policy for Small Unmanned Aircraft System (UAS) Cases FR ↗
- 2026-02-10 Normalizing Unmanned Aircraft Systems Beyond Visual Line of Sight Operations; Reopening of Comment Period; Denial of Extension FR ↗
- 2026-02-02 25-Hour Cockpit Voice Recorder (CVR) Requirement, New Aircraft Production FR ↗
- 2026-01-28 Normalizing Unmanned Aircraft Systems Beyond Visual Line of Sight Operations; Reopening of Comment Period FR ↗
- 2026-01-07 Requirements for Interference-Tolerant Radio Altimeter Systems FR ↗
05 / Aircraft of this type
All 3 registered N-numbers
Every tail currently on the FAA registry for this make/model. Click an N-number to query the FAA Aircraft Inquiry; rows flagged ● have NTSB events on file. Tails seeded with full TallyAero pages link directly.
05 / Sources & Methodology
Every count traces back to a primary US-government source
- FAA Aircraft Registry →
Refreshed Apr 27, 2026
Available
- NTSB CAROL →
Refreshed Apr 27, 2026
Available
- Federal Register (FAA Airworthiness Directives) →
Refreshed Apr 27, 2026
Available
We render counts and lists as the agency publishes them. Read the methodology →