# N550HE: 1968 Helio HST-550A - Status: Valid registration - Airframe: [Helio HST-550A](https://openairdocs.org/model/helio-hst-550a) (registry code 4301006, 10 seats) - Engine: [Pratt & Whitney PT6A series](https://openairdocs.org/engine/pratt-whitney-pt6a-series) (registry code 52032) - Data sheets: [TCDS A4EA](https://openairdocs.org/tcds/A4EA) (Helio Aircraft LLC) (OpenAirDocs) - Serial number: 001 - Year built: 1968 - Type: Fixed wing single engine - Engine type: Turbo-prop - Airworthiness: Standard, normal - Airworthiness date: October 9, 1996 - Certificate issued: April 27, 2021 - Expires: April 30, 2028 - Mode S code: A7001F - Registered owner: [Teufel Nursery Inc](https://openairdocs.org/faa-owner/TEUFEL%20NURSERY%20INC) - Location: [Hillsboro, OR](https://openairdocs.org/faa-place/OR/Hillsboro) - Owner type: Corporation - Owner's area on the map: 45.5692° N, 122.9472° W: Placed by OpenAirDocs at the center of ZIP code 97124, within about 4 miles (OpenAirDocs). The owner's mailing address, not where the aircraft is based - FAA registry: https://registry.faa.gov/AircraftInquiry/Search/NNumberResult?nNumberTxt=550HE - Page: https://openairdocs.org/aircraft/N550HE 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 Pratt & Whitney PT6A model are included. ## ADs that may apply (OpenAirDocs): 28 in force ### Matched by airframe (Helio HST-550A) - [AD 2005-01-19](https://openairdocs.org/ad/2005-01-19): Mode S transponders · GARMIN International GTX 330D, GTX 330, GTX 33D and 830 more. Effective Feb 23, 2005 - [AD 79-07-02](https://openairdocs.org/ad/79-07-02): Batteries · Aircraft Parts & Development A, A-2, A-3 and 149 more. Effective Apr 3, 1979 ### Matched by engine (Pratt & Whitney PT6A series) - [AD 2024-04-51](https://openairdocs.org/ad/2024-04-51): Turbine Section · Pratt & Whitney Canada PT6A-64, PT6A-66, PT6A-66A and 17 more. Effective Mar 28, 2024 - [AD 2022-08-13](https://openairdocs.org/ad/2022-08-13): Turbine Section · Pratt & Whitney Canada PT6A-34, PT6A-34B, PT6A-34AG and 2 more. Effective May 27, 2022 - [AD 2016-05-13](https://openairdocs.org/ad/2016-05-13): Corrosion and perforation of the two-ply Cu-Be bellows in Woodward FCUs. · Pratt & Whitney Canada PT6A-60AG, PT6A-65AG, PT6A-67AF and 1 more. Effective Apr 22, 2016 - [AD 2014-17-08 R1](https://openairdocs.org/ad/2014-17-08-R1): Compressor turbine (CT) blades · Pratt & Whitney Canada PT6A-114 and PT6A-114A. Effective Jun 5, 2015 - [AD 2014-11-05](https://openairdocs.org/ad/2014-11-05): Reinforcement liner to the power turbine (PT) containment ring and, for certain PT containment rings, adding scallops · Pratt & Whitney Canada PT6A-11, PT6A-110, PT6A-112 and 18 more. Effective Aug 5, 2014 - [AD 2012-09-10](https://openairdocs.org/ad/2012-09-10): First stage sun gears · Pratt & Whitney Canada PT6A-110, PT6A-112, PT6A-114 and 12 more. Effective May 23, 2012 - [AD 2011-25-12](https://openairdocs.org/ad/2011-25-12): Sun gear · Pratt & Whitney Canada PT6A-15AG, PT6A-27, PT6A-28 and 4 more. Effective Dec 28, 2011 - [AD 2011-20-51](https://openairdocs.org/ad/2011-20-51): Gears · Pratt & Whitney Canada PT6A-15AG, PT6A-27, PT6A-28 and 4 more. Effective Nov 1, 2011 - [AD 2004-25-18](https://openairdocs.org/ad/2004-25-18): Propeller governor assemblies · Pratt & Whitney Canada PT6A-60A and PT6A-65B. Effective Jan 18, 2005 - [AD 2002-23-13](https://openairdocs.org/ad/2002-23-13): Turbine Exhaust Ducts · Pratt & Whitney Canada PT6A-11, PT6A-110, PT6A-112 and 20 more. Effective Dec 31, 2002 - [AD 2001-20-01](https://openairdocs.org/ad/2001-20-01): Compressor Bleed Valve Assembly · Pratt & Whitney Canada PT6A-114A and PT6A-25C. Effective Nov 5, 2001 - [AD 97-04-12](https://openairdocs.org/ad/97-04-12): Compressor Bleed-off Valve · Pratt & Whitney Canada PT6A-11, PT6A-110, PT6A-112 and 52 more. Effective Mar 14, 1997 - [AD 95-13-08](https://openairdocs.org/ad/95-13-08): Compressor Turbine Disk · Pratt & Whitney Canada PT6A-67D. Effective Jul 12, 1995 - [AD 93-23-06](https://openairdocs.org/ad/93-23-06): Airframe Chip Detector Flag System · Pratt & Whitney Canada PT6A-50. Effective Jan 26, 1994 - [AD 92-15-11](https://openairdocs.org/ad/92-15-11): Compressor Delivery Air Line (P3) Filter Assembly · Pratt & Whitney Canada PT6A-20, PT6A-20A, PT6A-21 and 7 more. Effective Aug 17, 1992 - [AD 90-12-05](https://openairdocs.org/ad/90-12-05): Engine Overhaul · Pratt & Whitney Canada PT6A-15AG, PT6A-27, PT6A-28 and 3 more. Effective May 30, 1990 - [AD 86-10-05](https://openairdocs.org/ad/86-10-05): First Stage Compressor Hub · Pratt & Whitney Canada PT6A-42. Effective Jun 5, 1986 - [AD 80-08-12](https://openairdocs.org/ad/80-08-12): Fuel Pump Drive Coupling Splines · Pratt & Whitney Canada PT6A-11, PT6A-112, PT6A-135 and 24 more. Effective Apr 18, 1980 - [AD 80-04-02](https://openairdocs.org/ad/80-04-02): Push-Pull Control Terminal · Pratt & Whitney Canada PT6A-20, PT6A-6A, PT6A-6B and 1 more. Effective Feb 8, 1980 - [AD 78-17-07](https://openairdocs.org/ad/78-17-07): Fuel Control Unit · Pratt & Whitney Canada PT6A-38, PT6A-41 and PT6A-45A. Effective Aug 31, 1978 - [AD 78-12-04](https://openairdocs.org/ad/78-12-04): No. 2 Bearing Pressure Oil Transfer Tube Assembly · Pratt & Whitney Canada PT6A-38, PT6A-41 and PT6A-45A. Effective Jun 19, 1978 - [AD 75-06-01](https://openairdocs.org/ad/75-06-01): Gearbox Deterioration · Pratt & Whitney Canada PT6A-20, PT6A-20A, PT6A-20B and 11 more. Effective Apr 1, 1977 - [AD 75-11-04](https://openairdocs.org/ad/75-11-04): Reduction Gearbox Engine Distress · Pratt & Whitney Canada PT6A-20, PT6A-20A, PT6A-20B and 8 more. Effective May 20, 1975 - [AD 70-16-01](https://openairdocs.org/ad/70-16-01): Turbo Propeller Governors · Pratt & Whitney Canada PT6A-11, PT6A-11AG, PT6A-15AG and 5 more. Effective Aug 4, 1970 - [AD 69-23-06](https://openairdocs.org/ad/69-23-06): Fuel Pumps · Pratt & Whitney Canada PT6A-20, PT6A-27, PT6A-28 and 4 more. Effective Nov 15, 1969 - [AD 68-05-03](https://openairdocs.org/ad/68-05-03): Reverse Mode · Pratt & Whitney Canada PT6A-20 and PT6A-6B. Effective Feb 28, 1968 ### Historical (superseded or no longer in force) - [AD 2014-17-08](https://openairdocs.org/ad/2014-17-08) (historical): Compressor turbine (CT) blades · Pratt & Whitney Canada PT6A-114 and PT6A-114A. Effective Oct 8, 2014 - [AD 88-24-02](https://openairdocs.org/ad/88-24-02) (historical): Airframe Chip Detector Flag System · Pratt & Whitney Canada PT6A-50 ## Information bulletins (advisory) (6 in force) - [SAIB SW-18-31](https://openairdocs.org/saib/SW-18-31): NAVIGATION, ATTITUDE, AND DIRECTION DATA SYSTEM. Issued Nov 21, 2018 - [SAIB NE-15-21](https://openairdocs.org/saib/NE-15-21): Fuel Injector Nozzle. Issued Aug 19, 2015 - [SAIB NE-12-04](https://openairdocs.org/saib/NE-12-04): Turbine/ Turboprop Engine: Reduction Gearbox. Issued Nov 1, 2011 - [SAIB NE-10-47](https://openairdocs.org/saib/NE-10-47): Turbine Engine Compressor Section. Issued Aug 30, 2010 - [SAIB NE-06-34](https://openairdocs.org/saib/NE-06-34): . Issued Mar 21, 2006 - [SAIB CE-03-24](https://openairdocs.org/saib/CE-03-24): . Issued Feb 19, 2003 ## NTSB investigations None matched to N550HE. ## FAA accident and incident reports None matched to N550HE. ## 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) (106, 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 (Helio HST-550A) - [STC SA02571SE](https://openairdocs.org/stc/SA02571SE): Installation of Garmin G500/G600 TXi Integrated Avionics System (Primary Flight Display, Multi-Function Display, and Engine Indicating System Display). Garmin International Inc - [STC SA01800SE](https://openairdocs.org/stc/SA01800SE): Fabrication and installation of new or replacement of existing instrument panel lights dimmer control. TCW Technologies, LLC - [STC SA01861SE](https://openairdocs.org/stc/SA01861SE): Fabrication and installation of Landing Light Controller. TCW Technologies, LLC - [STC SA02636SE](https://openairdocs.org/stc/SA02636SE): Installation of Garmin GPS 175 Navigation System and GNX 375 Navigation System with ADS-B In/Out Transponder. Garmin International Inc - [STC SA02019SE-D](https://openairdocs.org/stc/SA02019SE-D): Installation of Garmin Model GTN 625/635/650; 725/750 Navigation System. Garmin International Inc - [STC SA02738CH](https://openairdocs.org/stc/SA02738CH): Installation of L-3 Communications Avionics Systems. Acron Aviation Inc - [STC SA04046CH PAGE 1](https://openairdocs.org/stc/SA04046CH%20PAGE%201): Installation of L-3 GENESIS (TM) Electronic Standby Instrument System (ESI-500/MAG-500). Acron Aviation Inc - [STC SA02658SE](https://openairdocs.org/stc/SA02658SE): Installation of Garmin GI 275 Multi-Function Display System. Garmin International Inc - [STC SA02444AK](https://openairdocs.org/stc/SA02444AK): Approval of the L-3 Communications NGT 9000/9000R ADS-B system installed. ADS-B Technologies LLC - [STC SA09902AC](https://openairdocs.org/stc/SA09902AC): Installation of BendixKing KFD 900 Flight Display System. Honeywell International Inc. (Bendix King) - [STC SA11174SC PAGE 1](https://openairdocs.org/stc/SA11174SC%20PAGE%201): Installation of BendixKing by Honeywell KSN 770 and KSN 765 WAAS LPV approach capable nav/comm systems. Honeywell International Inc (Bendix King) - [STC SA10822SC](https://openairdocs.org/stc/SA10822SC): Installation of EFD1000 Primary Flight Display. Aspen Avionics Inc - [STC SA00401BO](https://openairdocs.org/stc/SA00401BO): Installation of a SkyTrax100B UAT receiver. Avidyne Corporation - [STC SA10236SC](https://openairdocs.org/stc/SA10236SC): Installation of a GDC 31 Roll Steering Converter. DAC International Inc - [STC SA01714WI](https://openairdocs.org/stc/SA01714WI): Installation of a Garmin transponders: (a) GTX 330/330D/33/33D with ADS-B Out functionality; (b) GTX 335/335R/345/345R with ADS-B Out and In functionality; or (c) GTX 335R/345R with ADS-B Out functionality in select airplanes installed with G950/G1000 systems. Garmin International Inc - [STC SA04165NY](https://openairdocs.org/stc/SA04165NY): Installation of Latitude Technologies Skynode S200 Satcom system must be performed. Latitude Technologies Corporation - [STC SA02153LA-D PAGE 1](https://openairdocs.org/stc/SA02153LA-D%20PAGE%201): Installation of Garmin G600 Primary Flight Display (PFD) and Multifunction Display (MFD) System. Garmin International Inc - [STC SA01933LA-D](https://openairdocs.org/stc/SA01933LA-D): Installation of Garmin Model 400W / 500W Series GPS-WAAS Navigation System. Garmin International Inc - [STC SA00382BO](https://openairdocs.org/stc/SA00382BO): Installation of Globalstar Antenna and Cradle provisions to support a Globalstar GPS-1700 in non-composite airplanes. Avidyne Corporation - [STC SA02428SE](https://openairdocs.org/stc/SA02428SE): Installation of an Air Stream Switch for an electric time recording device on non-pressurized aircraft. Henry F Rogers/David E Polley - [STC SA00343BO](https://openairdocs.org/stc/SA00343BO): Installation of a single configuration or a dual configuration Avidyne Corporation Integrated Flight Display, Model IFD540 loaded with Release 10.0 software (or later FAA approved release). Avidyne Corporation - [STC SA00352BO PAGE 1](https://openairdocs.org/stc/SA00352BO%20PAGE%201): Installation of an Avidyne Corporation Mode A/C/S Transponder with ADS-B Out capability, Model AXP340 loaded with Version 3.13 software (or later FAA approved version),. Avidyne Corporation - [STC SA02119SE PAGE 1](https://openairdocs.org/stc/SA02119SE%20PAGE%201): Installation of Garmin GDL 88 ADS-B UAT Transceiver System. Garmin International Inc - [STC SA01229SE PAGE 1](https://openairdocs.org/stc/SA01229SE%20PAGE%201): Installation of GNS 480 (CNX80) GPS WAAS Navigator with integrated VHF Navigation and Communication radios. Garmin International Inc - [STC SA02442AK PAGE 1](https://openairdocs.org/stc/SA02442AK%20PAGE%201): Approval of the L-3 Communications NGT 2000/2500 ADS-B system. ADS-B Technologies, LLC - [STC SA01933LA-D PAGE 1](https://openairdocs.org/stc/SA01933LA-D%20PAGE%201): Installation of Garmin Model 400W / 500W Series GPS-WAAS Navigation System. Garmin International Inc - [STC SA02717NY PAGE 1](https://openairdocs.org/stc/SA02717NY%20PAGE%201): Installation of VoiceFlight Systems LLC VFS101 Speech Recognition Module. VoiceFlight Systems LLC - [STC SA02015SE-D](https://openairdocs.org/stc/SA02015SE-D): Installation of Garmin G500 Primary Flight Display (PFD) and Multifunction Display (MFD) System. Garmin International Inc - [STC SA01692SE](https://openairdocs.org/stc/SA01692SE): Installation of a Garmin GMX 200 Multi-Function Display. Garmin International Inc - [STC SA03148NY](https://openairdocs.org/stc/SA03148NY): The installation of the Latitude Technologies Corporation S100 Tracking System. Latitude Technologies Corporation - [STC SA02016SE-D](https://openairdocs.org/stc/SA02016SE-D): Installation of Garmin GTS 800, GTS 820 or GTS 850 Traffic System. Garmin International Inc - [STC SA5156NM](https://openairdocs.org/stc/SA5156NM): Fabrication and installation of Pulsar-MOSFET Landing Light Flasher System. AvTek - [STC SA01487SE-D](https://openairdocs.org/stc/SA01487SE-D): Installation of a GDL 69 or GDL 69A XM Satellite Receiver. Garmin International Inc - [STC SA00243BO](https://openairdocs.org/stc/SA00243BO): Installation of Centurion Consulting, Inc. GPS Steering Assist Module (SAM) with roll steering (p/n 0025-5100), or without roll steering (p/n 0025-5200). Icarus Avionics, LLC - [STC SA02293AK](https://openairdocs.org/stc/SA02293AK): Installation of FlightLogic Synthetic Vision Electronic Flight Information System (EFIS-SV). Chelton Flight Systems Inc - [STC SA01473SE](https://openairdocs.org/stc/SA01473SE): Installation of a GTX 32 (mode C), GTX 33 (mode S), or GTX 33D (mode S with diversity) Remote Transponde. Garmin AT Inc - [STC SA4005NM](https://openairdocs.org/stc/SA4005NM): Precise Flight Inc. Pulselite Control System. Precise Flight Inc - [STC SA01695SE](https://openairdocs.org/stc/SA01695SE): Installation of an antenna. Garmin AT Inc - [STC SA01487SE](https://openairdocs.org/stc/SA01487SE): Installation of a GDL 69 or GDL 69A XM Satellite Receiver in accordance with Garmin Supplemental Type Certificate Master Data List, P/N 005-C0217-00, Revision A, dated December 20, 2004, or later FAA approved revision. Garmin AT Inc - [STC SA02154AK](https://openairdocs.org/stc/SA02154AK): Installation of the UPS Aviation Technologies Inc. Apollo MX20 multi-function display, P/N 430-0270-500. Garmin AT Inc - [STC SA02217AK](https://openairdocs.org/stc/SA02217AK): Installation of Garmin AT Model GDL90 UAT Data Link System, in accordance with Garmin AT, Inc., GDL 90 UAT Master Data List, P/N 560-0278-01, Revision A, dated November 12, 2004, or later FAA approved revision. Garmin AT Inc - [STC SA5927NM](https://openairdocs.org/stc/SA5927NM): Replace United Aircraft of Canada model PT6A-27 engine with model PT6A-34. Helio Enterprises Inc - [STC SA2325SO](https://openairdocs.org/stc/SA2325SO): Installation of a P&W PT6A-34 engine, derated to PT6A-27 power ratings. AirTec Aircraft Services - [STC SA1418SO](https://openairdocs.org/stc/SA1418SO): Replacement of rotor vanes in Airborne 211CC and 212CW vacuum pumps. (See limitations). Aircraft Products Supply Co Inc - [STC SA02019SE-D PAGE 2](https://openairdocs.org/stc/SA02019SE-D%20PAGE%202) (historical): Installation of Garmin GTN 6XX/7XX Navigation System. Garmin International Inc - [STC SA02153LA-D](https://openairdocs.org/stc/SA02153LA-D) (historical): Installation of Garmin G600 Primary Flight Display (PFD) and Multifunction Display (MFD) System. Garmin International Inc - [STC SA02717NY](https://openairdocs.org/stc/SA02717NY) (historical): Installation of VoiceFlight Systems LLC VFS101 Speech Recognition Module. VoiceFlight Systems LLC - [STC SA02153LA](https://openairdocs.org/stc/SA02153LA) (historical): Installation of Garmin G600 Primary Flight Display (PFD) and Multifunction Display (MFD) System. Garmin AT Inc - [STC SA01229SE](https://openairdocs.org/stc/SA01229SE) (historical): Installation of CNX80 GPS WAAS Navigator with integrated VHF Navigation and Communication radios. UPS Aviation Technologies ### Approved for the engine (Pratt & Whitney PT6A series) - [STC SE12225AC](https://openairdocs.org/stc/SE12225AC): This STC will incorporate P&W 1700 rpm propeller reduction gearbox on P&WC engines to allow 1700 rpm propeller installation. High Cotton Aircraft Conversions, LLC. Lists PT6A-41 All 106: https://openairdocs.org/aircraft/N550HE/stcs.md ## Related - Other Helio HST-550A aircraft: https://openairdocs.org/model/helio-hst-550a/aircraft.md - The Pratt & Whitney PT6A series engine: https://openairdocs.org/engine/pratt-whitney-pt6a-series.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.