# Lycoming O-540 series

- Type: Engine model (FAA registry)
- Registry code: 42713
- Manufacturer (registry): LYCOMING
- Model: O-540 SERIES
- Engine type: Reciprocating
- Power: 235 hp
- Data sheet: [TCDS E-295](https://openairdocs.org/tcds/E-295) (OpenAirDocs)
- Holder: Lycoming Engines
- Installed in: 17 registered aircraft
- Page: https://openairdocs.org/engine/lycoming-o-540-series

The registry names only the engine series, so ADs for every model in the series are matched.

## ADs that may apply (OpenAirDocs)

Matched to this engine model by model name and maker. Each AD's applicability may narrow it by serial number, part number or equipment.

- [AD 2026-17-10](https://openairdocs.org/ad/2026-17-10): Reciprocating Engine Cylinder Section · Lycoming Engines O-235, O-235-A, O-235-AP and 159 more. Effective Sep 14, 2026
- [AD 2026-04-11](https://openairdocs.org/ad/2026-04-11): Engine (Reciprocating) · Lycoming Engines AEIO-320-D1B, AEIO-320-D2B, AEIO-320-E1A and 605 more. Effective Apr 8, 2026
- [AD 2022-16-03](https://openairdocs.org/ad/2022-16-03): Engine (RECIPROCATING) · Continental Aerospace Technologies GTSIO-520-C, GTSIO-520-D, GTSIO-520-F and 236 more. Effective Aug 15, 2022
- [AD 2017-16-11](https://openairdocs.org/ad/2017-16-11): Reciprocating Engine Power Section · Lycoming Engines AEIO-320-D1B, AEIO-320-D2B, AEIO-360-B1G6 and 93 more. Effective Aug 15, 2017
- [AD 2012-19-01](https://openairdocs.org/ad/2012-19-01): Crankshafts · Lycoming Engines AEIO-360-A1A, AEIO-360-A1B, AEIO-360-A1B6 and 321 more. Effective Oct 24, 2012
- [AD 2012-03-07](https://openairdocs.org/ad/2012-03-07): Carburetor · Lycoming Engines GO-435, GO-435-C2 (O-435-17), GO-435-C2A and 389 more. Effective Mar 27, 2012
- [AD 2011-13-03](https://openairdocs.org/ad/2011-13-03): Turbocharger Turbine · Lycoming Engines LTO-360-E1A6D, O-540-L3C5D, TIGO-541-E1A and 20 more. Effective Jul 13, 2011
- [AD 2010-07-08](https://openairdocs.org/ad/2010-07-08): Turbochargers · Kelly Aerospace Energy Systems HIO-360-E1AD, HIO-360-E1BD, HIO-360-F1AD and 137 more. Effective Apr 19, 2010
- [AD 2009-26-12](https://openairdocs.org/ad/2009-26-12): Cylinder assemblies · Engine Components Reciprocating Engine Cylinder Assemblies, AEIO-320-D1B, AEIO-320-D2B and 264 more. Effective Feb 4, 2010
- [AD 2007-04-19 R1](https://openairdocs.org/ad/2007-04-19-R1): SAP cylinder assemblies · Lycoming Engines AEIO-320-D1B, AEIO-320-D2B, AEIO-320-E1A and 314 more. Effective May 7, 2007
- [AD 2006-12-07](https://openairdocs.org/ad/2006-12-07): ECi cylinder assemblies · Aerostar AEIO-320-D1B, AEIO-320-D2B, AEIO-320-E1A and 386 more. Effective Jul 11, 2006
- [AD 2006-10-21](https://openairdocs.org/ad/2006-10-21): ECi connecting rods · Engine Components Reciprocating Engine Connecting Rods, AEIO-360-B1B, AEIO-360-B1D and 171 more. Effective Jun 22, 2006
- [AD 2005-19-11](https://openairdocs.org/ad/2005-19-11): Crankshafts · Lycoming Engines AEIO-360-A1B6, AEIO-360-A1E6, AEIO-540-D4A5 and 59 more. Effective Oct 21, 2005
- [AD 2005-12-06](https://openairdocs.org/ad/2005-12-06): Riveted-impulse coupling assemblies and snap-ring coupling assemblies · Lycoming Engines AEIO-540-D4A5, AEIO-540-D4B5, AEIO-540-D4C5 and 154 more. Effective Jul 19, 2005
- [AD 2004-10-14](https://openairdocs.org/ad/2004-10-14): Crankshaft gear · Lycoming Engines AEIO-320-D1B, AEIO-320-D2B, AEIO-320-E1A and 642 more. Effective Jun 25, 2004
- [AD 2004-05-24](https://openairdocs.org/ad/2004-05-24): Zinc-plated Crankshaft Gear Retaining Bolts · Lycoming Engines AEIO-540-D4A5, AEIO-540-D4B5, AEIO-540-D4C5 and 161 more. Effective Mar 30, 2004
- [AD 2002-12-07](https://openairdocs.org/ad/2002-12-07): Oil Filter Converter Plate Gasket or the Converter Plate Kit · Lycoming Engines HIO-360-E1AD, HIO-360-E1BD, HIO-360-F1AD and 95 more. Effective Jul 3, 2002
- [AD 99-04-04](https://openairdocs.org/ad/99-04-04): Impulse Coupling Pawl · Lycoming Engines IO-540-K1A5, IO-540-K1B5, IO-540-K1G5 and 6 more. Effective Feb 25, 1999
- [AD 99-03-05](https://openairdocs.org/ad/99-03-05): Crankshaft Gear Retaining Bolts · Lycoming Engines O-540-F1B5. Effective Feb 18, 1999
- [AD 98-17-11](https://openairdocs.org/ad/98-17-11): Crankshafts · Continental Motors A-65-3, A-65-8, A75-8 and 90 more. Effective Oct 19, 1998
- [AD 97-15-11](https://openairdocs.org/ad/97-15-11): Cylinder kits · Lycoming Engines AEIO-320-D1B, AEIO-320-D2B, AEIO-320-E1A and 538 more. Effective Aug 12, 1997
- [AD 96-23-03](https://openairdocs.org/ad/96-23-03): High pressure fuel pumps · Lycoming Engines AEIO-320-D1B, AEIO-320-D2B, AEIO-320-E1A and 174 more. Effective Dec 23, 1996
- [AD 96-09-10](https://openairdocs.org/ad/96-09-10): Oil pump · Lycoming Engines AEIO-320-E1A, AEIO-320-E1B, AEIO-320-E2A and 334 more. Effective Jul 15, 1996
- [AD 95-26-02](https://openairdocs.org/ad/95-26-02): Aviation Gasoline · Lycoming Engines IO-320-B1A, IO-320-B1B, IO-320-B1C and 182 more. Effective Jan 24, 1996
- [AD 95-07-01](https://openairdocs.org/ad/95-07-01): Connecting Rod Bolt · Lycoming Engines AEIO-360-A1E, AEIO-360-B1G6, AEIO-360-H1A and 177 more. Effective Apr 12, 1995
- [AD 92-12-05](https://openairdocs.org/ad/92-12-05): Piston Pins · Lycoming Engines AEIO-320-D1B, AEIO-320-D2B, AEIO-320-E1A and 532 more. Effective Jul 10, 1992
- [AD 87-10-06 R1](https://openairdocs.org/ad/87-10-06-R1): Rocker Arm Assembly · Lycoming Engines IO-360-B4, IVO-360-A1A, O-340-A1A and 243 more. Effective Sep 1, 1989
- [AD 89-04-02](https://openairdocs.org/ad/89-04-02): Carburetors · Continental Motors O-470-11, O-470-11-CI, O-470-11B and 175 more. Effective Mar 8, 1989
- [AD 79-08-06](https://openairdocs.org/ad/79-08-06): Carburetors · Lycoming Engines O-540-L3C5D and Carburetors. Effective Apr 25, 1979
- [AD 75-08-09](https://openairdocs.org/ad/75-08-09): Oil Pump Drive Shaft · Lycoming Engines AEIO-360-A1B, AEIO-360-A1B6, AEIO-360-A1C and 365 more. Effective Aug 18, 1977
- [AD 73-23-01](https://openairdocs.org/ad/73-23-01): Piston Pin Assembly · Lycoming Engines AIO-360-A1A, AIO-360-A1B, AIO-360-A2A and 215 more. Effective Jan 13, 1977
- [AD 69-24-03](https://openairdocs.org/ad/69-24-03): Carburetors · Continental Motors A-65-1, A-65-12, A-65-12F and 321 more. Effective Nov 29, 1969
- [AD 66-06-03](https://openairdocs.org/ad/66-06-03): Connecting Rod Assemblies · Lycoming Engines GO-435-C2 (O-435-17), GO-435-C2A, GO-435-C2A2 and 317 more. Effective Jan 16, 1969
- [AD 66-20-04](https://openairdocs.org/ad/66-20-04): Oil Filter Adapter Gasket · Lycoming Engines IO-320-A1A, IO-320-A2A, IO-320-B1A and 121 more. Effective Aug 27, 1966
- [AD 66-14-03](https://openairdocs.org/ad/66-14-03): Crankshaft Idler Shafts · Lycoming Engines O-540-B2B5. Effective Jul 9, 1966
- [AD 64-16-05](https://openairdocs.org/ad/64-16-05): AC Pumps · Lycoming Engines HIO-360-B1A, HIO-360-B1B, IO-320-B1A and 86 more. Effective Jul 10, 1964
- [AD 63-22-03](https://openairdocs.org/ad/63-22-03): Carburetors · Continental Motors GO-300-A, GO-300-B, GO-300-C and 143 more. Effective Dec 2, 1963
- [AD 63-14-03](https://openairdocs.org/ad/63-14-03): Oil Pump Drive Shaft · Lycoming Engines IO-540-A1A5, IO-540-B1A5, IO-540-B1B5 and 21 more. Effective Jul 6, 1963
- [AD 59-10-07](https://openairdocs.org/ad/59-10-07): Cylinder Baffle Clamps · Lycoming Engines GO-480-A1A, GO-480-B, GO-480-B1A6 and 58 more

Historical (superseded or no longer in force):

- [AD 2024-21-02](https://openairdocs.org/ad/2024-21-02) (historical): Engine (Reciprocating) · Lycoming Engines AEIO-320-D1B, AEIO-320-D2B, AEIO-320-E1A and 548 more. Effective Dec 5, 2024
- [AD 2008-19-05](https://openairdocs.org/ad/2008-19-05) (historical): Parallel Valve'' reciprocating engines · Engine Components Reciprocating Engine Cylinder Assemblies, AEIO-320-D1B, AEIO-320-D2B and 262 more. Effective Oct 20, 2008
- [AD 2006-20-09](https://openairdocs.org/ad/2006-20-09) (historical): Certain crankshafts replacing · Lycoming Engines AEIO-360-A1B6, AEIO-360-A1E6, AEIO-540-D4A5 and 82 more. Effective Nov 3, 2006
- [AD 2005-26-10](https://openairdocs.org/ad/2005-26-10) (historical): ECi cylinder assemblies. · Lycoming Engines AEIO-320-D1B, AEIO-320-D2B, AEIO-320-E1A and 413 more. Effective Jan 31, 2006
- [AD 2002-23-06](https://openairdocs.org/ad/2002-23-06) (historical): Crankshaft gear retaining bolts · Textron Lycoming, AVCO AEIO-540, AEIO-540-D4A5, AEIO-540-D4B5 and 46 more. Effective Nov 19, 2002
- [AD 2002-20-51](https://openairdocs.org/ad/2002-20-51) (historical): Crankshaft gear retaining bolts · Textron Lycoming, AVCO AEIO-540, IO-540 Series (all), LTIO-540-F2BD and 39 more
- [AD 2000-18-53](https://openairdocs.org/ad/2000-18-53) (historical): Oil Filter Converter Plate Gaskets · Textron Lycoming, AVCO AEIO-540, IO-360-A1B6D, IO-360-A1D6D and 73 more
- [AD 81-18-04 R2](https://openairdocs.org/ad/81-18-04-R2) (historical): Engine Oil Pump Driven Impeller and Shaft · Textron Lycoming, AVCO AEIO-320-D1B, AEIO-320-D2B, AEIO-320-E1A and 376 more. Effective Jun 7, 1982

## Information bulletins (advisory) (11)

- [SAIB NE-19-08](https://openairdocs.org/saib/NE-19-08): Reciprocating Engine Cylinder Section - Lycoming Engines Parallel Valve Cylinders. Issued May 2, 2019
- [SAIB NE-08-32R1](https://openairdocs.org/saib/NE-08-32R1): Propeller Governor  Idler Gear Shaft Set Screw. Issued May 13, 2016
- [SAIB NE-14-13](https://openairdocs.org/saib/NE-14-13): Reciprocating Engine - Cylinder Mounting Studs. Issued Mar 24, 2014
- [SAIB NE-13-06](https://openairdocs.org/saib/NE-13-06): Pushrod Shroud Spring Retainers, Engine Components Part No. AEL14995, for Lycoming Engines 320, 360, and 540 Series Engines. Issued Nov 21, 2012
- [SAIB NE-08-26R3](https://openairdocs.org/saib/NE-08-26R3): Magneto/Distributor. Issued Mar 31, 2011
- [SAIB NE-06-32R1](https://openairdocs.org/saib/NE-06-32R1): Reciprocating Engine - Crankshaft. Issued Sep 10, 2008
- [SAIB NE-08-26R1](https://openairdocs.org/saib/NE-08-26R1) (historical): Dual Magnetos. Issued Jul 8, 2008
- [SAIB NE-08-32](https://openairdocs.org/saib/NE-08-32) (historical): Propeller Governor Set Screw. Issued Jul 3, 2008
- [SAIB NE-05-40](https://openairdocs.org/saib/NE-05-40): . Issued Mar 18, 2005
- [SAIB NE-03-18](https://openairdocs.org/saib/NE-03-18): . Issued Jan 22, 2003
- [SAIB NE-03-12](https://openairdocs.org/saib/NE-03-12): . Issued Dec 30, 2002

## Registered aircraft (17)

- [N241DK](https://openairdocs.org/aircraft/N241DK): [Wilmington, DE](https://openairdocs.org/faa-place/DE/Wilmington), built 2022, S/N 367, Sale reported
- [N255Z](https://openairdocs.org/aircraft/N255Z): [Small Terry A](https://openairdocs.org/faa-owner/SMALL%20TERRY%20A), [Vernal, UT](https://openairdocs.org/faa-place/UT/Vernal), built 2019, S/N 048-171/172-544
- [N27AZ](https://openairdocs.org/aircraft/N27AZ): [Gilbert John K](https://openairdocs.org/faa-owner/GILBERT%20JOHN%20K), [Austin, TX](https://openairdocs.org/faa-place/TX/Austin), built 2022, S/N 1217
- [N358BH](https://openairdocs.org/aircraft/N358BH): [Kelley Zachary](https://openairdocs.org/faa-owner/KELLEY%20ZACHARY), [Anchorage, AK](https://openairdocs.org/faa-place/AK/Anchorage), built 2019, S/N 1028
- [N410PJ](https://openairdocs.org/aircraft/N410PJ): [Volk Timothy](https://openairdocs.org/faa-owner/VOLK%20TIMOTHY), [Springfield, OH](https://openairdocs.org/faa-place/OH/Springfield), built 2005, S/N 40009
- [N521TY](https://openairdocs.org/aircraft/N521TY): [Olympia, WA](https://openairdocs.org/faa-place/WA/Olympia), built 2023, S/N M5-5-9M5/10M5-5018, Registration pending
- [N540BC](https://openairdocs.org/aircraft/N540BC): [Beranek James](https://openairdocs.org/faa-owner/BERANEK%20JAMES), [Cottage Grove, OR](https://openairdocs.org/faa-place/OR/Cottage%20Grove), built 2019, S/N 008
- [N545SF](https://openairdocs.org/aircraft/N545SF): [Crabtree William D](https://openairdocs.org/faa-owner/CRABTREE%20WILLIAM%20D), [Big Lake, AK](https://openairdocs.org/faa-place/AK/Big%20Lake), built 2026, S/N 001
- [N61XB](https://openairdocs.org/aircraft/N61XB): [Bickham John G](https://openairdocs.org/faa-owner/BICKHAM%20JOHN%20G), [Los Lunas, NM](https://openairdocs.org/faa-place/NM/Los%20Lunas), built 2020, S/N 1117BH4
- [N644EZ](https://openairdocs.org/aircraft/N644EZ): [Northern Air Spray LLC](https://openairdocs.org/faa-owner/NORTHERN%20AIR%20SPRAY%20LLC), [Maple Grove, MN](https://openairdocs.org/faa-place/MN/Maple%20Grove), built 2007, S/N 11971
- [N6707Z](https://openairdocs.org/aircraft/N6707Z): [Hood River Soaring Inc](https://openairdocs.org/faa-owner/HOOD%20RIVER%20SOARING%20INC), [Hood River, OR](https://openairdocs.org/faa-place/OR/Hood%20River), built 1963, S/N 25-2316
- [N789CB](https://openairdocs.org/aircraft/N789CB): [Bolan Walter Thomas](https://openairdocs.org/faa-owner/BOLAN%20WALTER%20THOMAS), [Gresham, OR](https://openairdocs.org/faa-place/OR/Gresham), built 2026, S/N B32-64B/65B-1671B
- [N789WM](https://openairdocs.org/aircraft/N789WM): built 2025, S/N 093-177/178-1044
- [N811S](https://openairdocs.org/aircraft/N811S): [Smith Helicopters Inc](https://openairdocs.org/faa-owner/SMITH%20HELICOPTERS%20INC), [Cotulla, TX](https://openairdocs.org/faa-place/TX/Cotulla), built 2020, S/N 30072
- [N8627L](https://openairdocs.org/aircraft/N8627L): [Southern Cub & Aircraft Restoration LLC](https://openairdocs.org/faa-owner/SOUTHERN%20CUB%20%26%20AIRCRAFT%20RESTORATION%20LLC), [Pensacola, FL](https://openairdocs.org/faa-place/FL/Pensacola), built 1969, S/N 25-5060
- [N904PM](https://openairdocs.org/aircraft/N904PM): [Branson Matthew R](https://openairdocs.org/faa-owner/BRANSON%20MATTHEW%20R), [Granger, IN](https://openairdocs.org/faa-place/IN/Granger), built 1977, S/N 7090C
- [N949PW](https://openairdocs.org/aircraft/N949PW): [Mcphillips Flying Service Inc DBA](https://openairdocs.org/faa-owner/MCPHILLIPS%20FLYING%20SERVICE%20INC%20DBA), [Beaver Island, MI](https://openairdocs.org/faa-place/MI/Beaver%20Island), built 1970, S/N 121

## 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 CEN23LA086](https://openairdocs.org/ntsb/CEN23LA086), Jan 10, 2023: Robinson Helicopter R44 (N811S), Fowlerton, TX, substantial damage. Probable cause: The pilot’s failure to maintain clearance with trees, which resulted in an uncontrollable spin due to tail rotor 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 20230110000379A](https://openairdocs.org/incident/20230110000379A), Jan 10, 2023: Robinson Helicopter R44 (N811S), Fowlerton, TX, Substantial damage. Pilot was herding cattle. One steer attempted to break from herd. Pilot turned helicopter to cut off warward steer. Heard a bang and lost tailrotor authority…

## Service difficulty reports (107, newest 50)

As reported by operators and repair stations, by the model named in the report.

- [SDR 2026FA0000347](https://openairdocs.org/sdr/2026FA0000347), May 9, 2026: THRUST BUTTON. FAULTY. DURING MAJOR OVERHAUL INSTALLED SUPERIOR ROCKER SHAFT THRUST BUTTONS P/N SL12893.INFORMATION THAT WE RECEIVED STATED THAT FAULTY THRUST BUTTONS WILL FLOAT IN WA
- [SDR 2020FA0000280](https://openairdocs.org/sdr/2020FA0000280), Jun 4, 2020: GEARBOX. MAKING METAL. DURING THE ANNUAL INSPECTION OF THE AIRCRAFT, IT HAS BEEN FOUND MAGNETIC PARTICLES ON THE MGB DETECTOR CHIP. THE QUANTITY OF MAGNETIC PARTICLES IS HIGH, BUT THE
- [SDR 2019FA0000145](https://openairdocs.org/sdr/2019FA0000145), May 8, 2019: PUSH-PULL CABLE. DEFECTIVE. AFTER ENGINE INSTALLATION THROTTLE SPRING BACK WAS EXCESSIVE WITH LOSS OF THROTTLE CONTROL. THROTTLE WOULD GLADLY GO TO IDLE AND STAY THERE EVEN WHEN FULLY ADVA
- [SDR CA190213015](https://openairdocs.org/sdr/CA190213015), Feb 13, 2019: PIN. DISLODGED. (CAN) IMPULSE COUPLING PIN (NO PART NUMBER FOR ONLY THE PIN) NORMALLY PRESSED INTO MAGNETO HOUSING HAD COME OUT OF THE HOUSING ALLOWING OIL TO ENTER THE CASE OF
- [SDR EVGR2019030600001](https://openairdocs.org/sdr/EVGR2019030600001), Jun 29, 2018: CONTACT BREAKER. OPEN. THE OVERHAULED MAGNETO WAS PURCHASED. UPON INSTALLATION OF THE MAGNETO, THE TACHOMETER DID NOT WORK. FURTHER TROUBLESHOOTING REVEALED THAT THE TACHOMETER CONTAC
- [SDR JIKA2018041260001](https://openairdocs.org/sdr/JIKA2018041260001), Apr 13, 2018: ENGINE. MAKING METAL. AFTER DEPARTING, THE PILOT NOTICE DURING CLIMB THROUGH 9000 TO 10500 FEET THAT THE MANIFOLD PRESSURE ON THE LEFT ENGINE WAS SLOWLY DROPPING. AS THE PILOT ATTEMP
- [SDR 2017FA0000602](https://openairdocs.org/sdr/2017FA0000602), Nov 2, 2017: ALTERNATOR. FAILED. PILOT DISCOVERED ALTERNATOR HAD FAILED DURING FLIGHT. THE BATTERY WAS QUICKLY DEPLETED AND PILOT MANUALLY EXTENDED GEAR. THE RIGHT MAIN SLOWLY RETRACTED ON LAND
- [SDR 2017FA0000412](https://openairdocs.org/sdr/2017FA0000412), Nov 9, 2016: OIL COOLER. VAPOR LOCK. AFTER FACTORY REMANUFACTURED, INSTALLED THE ENGINE, FOUND THE TURBO LEAKING FROM CENTER SECTION DURING IDLE, BUT NOT ABOVE 1000 RPM. TROUBLESHOT OIL LEAK AND DE
- [SDR E4FR2015FA0000621](https://openairdocs.org/sdr/E4FR2015FA0000621), Dec 3, 2015: ATTACH BRACKET. CORRODED. DURING AN ANNUAL INSPECTION THE HORIZONTAL COUNTERBALANCE TUBE ATTACH BRACKET, FOUND TO BE SEVERLY CORRODED AND WORN. THE FLIGHT CONTROL WAS REMOVED FOR MAINTEN
- [SDR 2015FA0000342](https://openairdocs.org/sdr/2015FA0000342), Jul 24, 2015: HUB. CRACKED. ACFT BROUGHT IN FOR AN ON WING INSPECTION UNDER AD 2009-22-03. INDICATION NOTED BY EDDY CURRENT INSPECTION. PROPELLER HUB REJECTED. THE PROPELLER HAS HAD MANY P
- [SDR 2014FA0000599](https://openairdocs.org/sdr/2014FA0000599), Oct 10, 2014: AIR FILTER. DEFECTIVE. DURING A VFR STAGE CHECKOUT. AFTER A NORMAL START UP, PILOT EXECUTED A MAX PERFORMANCE TAKEOFF FROM THE DEPARTURE. NO ISSUES, AND ACFT BEHAVED NORMALLY. PILOT E
- [SDR 2013FA0000137](https://openairdocs.org/sdr/2013FA0000137), Feb 28, 2013: DISTRIBUTOR GEAR. BROKEN. DURING INSPECTION, DISCOVERED MAGNETO DISTRIBUTOR GEAR , MISSING TEETH ON BOTH GEARS.
- [SDR 2012FA0000715](https://openairdocs.org/sdr/2012FA0000715), Oct 22, 2012: AIR BOX. DAMAGED. DURING FLIGHT, POWER LOSS FROM ENGINE. SUCCESSFUL OFF FIELD LANDING WAS MADE. INSPECTION REVEALED A BAFFLE INSIDE THE CARBURETOR AIR BOX, CAME LOOSE STARTVING T
- [SDR 2012FA0000471](https://openairdocs.org/sdr/2012FA0000471), Jul 1, 2012: POINTS. LOOSE. FOUND MAGNETO CONTACT POINTS LOOSE WHEN POINTS ARE OPEN.
- [SDR 2011FA0000697](https://openairdocs.org/sdr/2011FA0000697), Oct 14, 2011: CARBURETOR. MISOVERHAULED. UPON INSPECTION OF THE CARBURETOR, FOUND THAT THREAD SEALANT HAD BEEN APPLIED TO THE FILTER SCREEN ASSY AS WELL AS THE DRAIN PLUG.
- [SDR 2011FA0000696](https://openairdocs.org/sdr/2011FA0000696), Oct 13, 2011: CARBURETOR. MISOVERHAULED. UPON INSPECTION, CARBURETOR THE THREAD SEALANT HAD BEEN APPLIED TO THE DRAIN PLUG AS WELL AS THE FUEL FITTINGS.
- [SDR 2011FA0000494](https://openairdocs.org/sdr/2011FA0000494), Jul 5, 2011: BAFFLE. LOOSE. CONE SHAPED BAFFLE IN MUFFLER CAME LOOSE AND COMPLETELY BLOCKED EXHAUST STACK.
- [SDR 2010FA0001249](https://openairdocs.org/sdr/2010FA0001249), Dec 16, 2010: SPRING. BROKEN. TRACING AN ENGINE OIL LEAK, IT WAS DISCOVERED THAT THE PUSHROD SHROUD TUBE RETAINING SPRINGS (SL14995)HAD FAILED ON ALL 6 CYLINDERS. THE PART FAILED BY BREAKING
- [SDR 2010FA0001131](https://openairdocs.org/sdr/2010FA0001131), Oct 22, 2010: ANTENNA. FAILED. THE GNS 430W INDICATED NO SATELLITE COVERAGE WHILE IN FLIGHT. AN ADDITIONAL PORTABLE GPS ALSO INDICATED A LOSS OF SATELLITE COVERAGE. ATC INDICATED THAT THERE W
- [SDR 2010FA0001090](https://openairdocs.org/sdr/2010FA0001090), Sep 22, 2010: IMPULSE COUPLING. BROKEN. PILOT REPORTED LT MAGNETO FAULTY DURING RUN-UP. INVESTIAGTION REVEALED HOLE IN MAGNETO ADAPTER PLATE, WITH ALUMINUM SHAVINGS IN ENGINE COMPARTMENT. REMOVED ENGI
- [SDR 2010FA0000790](https://openairdocs.org/sdr/2010FA0000790), Aug 6, 2010: OIL COOLER. LEAKING. THE FIRST UNIT THAT FAILED WAS AN O/H COOLER, PN 8000074, SN 1041411 MFG. 04/05, INSTALLED 12/01/09 AND FAILED ON 3/19/10. THE REPLACEMENT COOLER WAS NEW WITH S
- [SDR 2010FA0000526](https://openairdocs.org/sdr/2010FA0000526), Jun 7, 2010: OIL COOLER. FAILED. NEW OIL COOLER INSTALLED FAILED WITH ONLY A TOTAL OF 29 CUMMLATIVE HOURS AT THE BRAZE WELD OF THE CASING.
- [SDR 2009FA0000759](https://openairdocs.org/sdr/2009FA0000759), Jul 7, 2009: BEAM. CRACKED. WHILE PERFORMING FLUORESCENT DYE PENETRANT INSP IAW AD 2002-25-03 OF CAPTAINS RUDDER PEDAL BEAMS FOUND CRACKED ON (LT) INNER SIDE FWD BEAM. (K)
- [SDR CA080709008](https://openairdocs.org/sdr/CA080709008), Jul 4, 2008: EXHAUST VALVE. SEIZED. (CAN) DURING A FLIGHT IN THE R44 HELICOPTER, THE PILOT NOTICED A SIGNIFICANT VIBRATION APPROX. 2 HOURS INTO THE FLIGHT. THE VIBRATION LASTED 45 SECONDS. THERE W
- [SDR 2008FA0000235](https://openairdocs.org/sdr/2008FA0000235), Mar 1, 2008: SCREW. IMPROPER PART. MFG SB NR SEB07-3 TO CHECK THE LENGTH OF THE SCREWS IN ACCESS PLATE UNDER REAR SEAT. THE PLATE MAY HAVE HAD TOO LONG A SCREW INSTALLED WHICH COULD CAUSE A FAILU
- [SDR 2007FA0000982](https://openairdocs.org/sdr/2007FA0000982), Oct 28, 2007: BEARING. BROKEN. RT OB HEIM BEARING BROKE AT THREADS NEXT TO JAM NUT ON ACTUATOR ROD DURING TAKEOFF ROLL W/RESULTANT GEAR COLLAPSE. INCREASE SIZE AND STRENGTH OF PART. (K)
- [SDR 2007FA0000583](https://openairdocs.org/sdr/2007FA0000583), May 24, 2007: STARTER. DEFECTIVE. REMOVED THIS STARTER FROM SAME AIRCRAFT FOR THE 4TH TIME WITH 11.3 HOURS SINCE OVERHAUL. STARTER BENDIX WOULD NOT ENGAGE ANYMORE DURING STARTUP. NO PROBLEM COUL
- [SDR 2007FA0000581](https://openairdocs.org/sdr/2007FA0000581), May 18, 2007: STARTER. MALFUNCTIONED. REMOVED THIS STARTER FROM SAME AIRCRAFT FOR THE 3RD TIME WITH 62.3 HRS SINCE OVERHAUL. STARTER BENDIX WOULD NOT ENGAGE ANYMORE DURING START UP. NO PROBLEM COULD
- [SDR 2007FA0000383](https://openairdocs.org/sdr/2007FA0000383), Apr 30, 2007: HORN. CRACKED. FOUND STABILATOR HORN P/N 20397-00 SEVERELY CRACKED FROM THE INSIDE WHERE THE ATTACH BOLTS CONNECT THE BALANCE WEIGHT TUBE P/N 20398-02 AND STABILATOR TORQUE TU
- [SDR 2007FA0000582](https://openairdocs.org/sdr/2007FA0000582), Apr 30, 2007: STARTER. FAILED. REMOVED THIS STARTER WITH 3.3 HOURS SINCE OVERHAUL. STARTER BENDIX STAYED ENGAGED DURING START UP. NO PROBLEM COULD BE FOUND WITH AIRCRAFT ELECTRICAL SYSTEM. (K
- [SDR 2007FA0000580](https://openairdocs.org/sdr/2007FA0000580), Apr 27, 2007: STARTER. FAILED. REMOVED THIS STARTER FROM AIRCRAFT DUE TO BENDIX FAILURE. TIME ON THIS STARTER IS UNKNOWN. (K)
- [SDR 2007FA0000096](https://openairdocs.org/sdr/2007FA0000096), Jan 3, 2007: CONDUIT. SEPARATED. THE LT MAIN LANDING GEAR PUSH PULL CONDUIT SEPARATED AT THE BALL END WHERE IT IS ATTACHED TO THE SUPPORT STRUCTURE IN THE WHEEL WELL. BELIEVE THIS FAILURE OCCUR
- [SDR 2007FA0000055](https://openairdocs.org/sdr/2007FA0000055), Dec 12, 2006: HYDRAULIC LINE. FAILED. HYDRAULIC HOSE ON RETRACT SIDE OF NOSE GEAR ACTUATOR FAILED AS AIRCRAT WAS ON APPROACH AND GEARDOWN WAS SELECTED. RESULTED IN AIRCRAFT MAKING AN EMERGENCY GEARU
- [SDR 2006FA0001171](https://openairdocs.org/sdr/2006FA0001171), Dec 4, 2006: BOOT. LEAKING. FLUID LEAKING FROM MAIN ROTOR BLADE PITCH BEARING HOUSING.
- [SDR 2006FA0001172](https://openairdocs.org/sdr/2006FA0001172), Dec 4, 2006: BOOT. LEAKING. FLUID LEAKING FROM MAIN ROTOR BLADE PITCH BEARING HOUSING.
- [SDR 2006FA0001056](https://openairdocs.org/sdr/2006FA0001056), Oct 22, 2006: PIN. BROKEN. LOCKDOWN PINS BROKE AT GROOVE FOR ROLL PINS. THIS ALLOWED THE PINS TO MOVE OUT OF ACTUATOR BEARING END AND JAM THE ACTUATOR. IN THE UNLOCKED POSITION, SEB95-20 
- [SDR 608062](https://openairdocs.org/sdr/608062), Jun 8, 2006: CLAMP. CRACKED. BLADE CLAMPS CRACKED.
- [SDR 608063](https://openairdocs.org/sdr/608063), Jun 8, 2006: CLAMP. CRACKED. BLADE CLAMP CRACKED.
- [SDR 2006FA0000627](https://openairdocs.org/sdr/2006FA0000627), Jun 5, 2006: WASHER. CRACKED. COUNTER WEIGHT RETAINING WASHER P/N 71907 CRACKED AND BROKE. THIS ALLOWED THE COUNTER WEIGHT RETAINING PIN TO FALL OUT. ENGINE SEIZED.
- [SDR 2006FA0000459](https://openairdocs.org/sdr/2006FA0000459), Apr 19, 2006: ATTACH FITTING. OUT OF LIMITS. ATTACHMENT CONNECTIONS AT RT AND LT SIDES ARE BELOW MINIMUM SPECIFIED IN AD. INSPECTION METHOD- ULTRASONIC. (K)
- [SDR IBI2006F00000](https://openairdocs.org/sdr/IBI2006F00000), Mar 21, 2006: ALTERNATOR. FAILED. ALTERNATOR FAILED AT 18.51 HOURS SINCE OVERHAUL. WITH FAILURE, AMMETER WAS STUCK AT 35 AMPS INDICATED. VOLTAGE REGULATOR WAS ALSO DISABLED FROM ALTERNATOR FAILU
- [SDR 2006FA0000184](https://openairdocs.org/sdr/2006FA0000184), Dec 19, 2005: SELECTOR. INOPERATIVE. RT FUEL PRESSURE WOULD OCCASIONALLY DROP OFF TO BOTTOM OF GREEN RANGE AFTER AIRCRAFT IN CRUISE CONFIGURATION, (ELECTRIC PUMPS OFF) AFTER EXTENDED TROUBLESHOOTIN
- [SDR BG001](https://openairdocs.org/sdr/BG001), Oct 6, 2005: LINE. FAILED. DOWN HYDRAULIC PRESSURE LINE FAILED AT ACTUATOR. LINE PULLED OUT OF SWAGED END FITTING.
- [SDR 2005FA0001317](https://openairdocs.org/sdr/2005FA0001317), Sep 20, 2005: BLADDER. COLLAPSED. FOUND AC TO HAVE DAMAGE TO L G BUNGEE, LT BOOM OB ATTACH POINT AT AFT WING CLOSEOUT. NO FUEL IN TANK, VERIFIED BY REMOVAL OF FUEL LINE AT FUEL VALVE ON BOTTOM O
- [SDR 2005FA0000754](https://openairdocs.org/sdr/2005FA0000754), May 11, 2005: GASCOLATOR. CONTAMINATED. DURING AN ACCIDENT INVESTIGATION FUEL GASCOLATOR WAS FOUND WITH LARGE AMOUNTS OF WATER AND SOLID CONTAMINANTS. IT WAS NOTED THAT THE PART COULD NOT BE ROTATED T
- [SDR 2005FA0001578](https://openairdocs.org/sdr/2005FA0001578), Apr 15, 2005: TUBE. CORRODED. ANNUAL INSPECTION DISCOVERED WIDESPREAD CORROSION OF 4130 STEEL FUSELAGE STRUCTURE. LOWER DOOR POST TUBES WERE CORRODED NEARLY THROUGH, RENDERING AIRPLANE UNAIR
- [SDR 2005FA0000132](https://openairdocs.org/sdr/2005FA0000132), Jan 28, 2005: SUPPORT. DAMAGED. WHILE COMPLETING GROUND RUN, PRIOR TO 100 HOUR INSPECTION, NOTICED RUDDER PEDALS DID NOT FEEL RIGHT. FURTHER INVESTIGATION REVEALED THAT THE NUT-PLATES HAD RIPP
- [SDR R7S2005F00000](https://openairdocs.org/sdr/R7S2005F00000), Nov 2, 2004: NUT. WORN. DURING A 100 HOUR INSPECTION, THE ROD END BEARING JAM NUT ON CONTROL TUBE (C336-1) AT THE CARBURETOR ATTACHMENT ARM WAS FOUND TO BE ONLY HAND TIGHT. THE ORIGINA
- [SDR UIA9317](https://openairdocs.org/sdr/UIA9317), Oct 8, 2004: TUBE. DEFORMED. NO.2 BLEED HOT CAUTION LIGHT ON (IN FLIGHT),AFTER LANDING IAW AMM21-11-00 AND AMM 49-10-00 CHECK FOUND ENG BLEED HEATSHIELD DEFORM.REPLACED HEATSHIELD PIPE AND 
- [SDR 2005FA0000759](https://openairdocs.org/sdr/2005FA0000759), Oct 6, 2004: ACTUATOR. OBSTRUCTED. AC NOSE DAMAGE DUE TO FAILURE OF NOSE GEAR TO EXTEND FOR LANDING. PROP LINKAGE RUNS DOWN OUTSIDE NLG TUNNEL, IS ATTACHED TO IT IN 2 PLACES WITH ADEL CLAMPS, STA

All 107: https://openairdocs.org/engine/lycoming-o-540-series/reports.md

## STCs that may be installed (OpenAirDocs) (59, first 50)

Approved for this engine model: the STC's model list names it on its data sheet, or a series that includes it. In force first, then newest. The registry doesn't record which STCs an aircraft has.

- [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 O-540-A1A
- [STC SE00825WI](https://openairdocs.org/stc/SE00825WI): Installation of Specialty Products Spin-on oil filter on Lycoming Engines. B & C Specialty Products Inc. Lists O-540-A1A
- [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
- [STC SE208SO](https://openairdocs.org/stc/SE208SO): Installation of ice indicator in the carburetor. LegacySTC.com
- [STC SE04349CH](https://openairdocs.org/stc/SE04349CH): Installation of SureFly electronic ignition. SureFly Partners Ltd. Lists O-540-A1A
- [STC SE01954SE](https://openairdocs.org/stc/SE01954SE): Installation of engine crankcase seal. Ly-Con Rebuilding Company. Lists O-540-A1A
- [STC SE02352CH](https://openairdocs.org/stc/SE02352CH): Installation of Challenger cleanable oil filter assembly. Challenger Aviation Products Inc. Lists O-540-A1A
- [STC SE00939WI](https://openairdocs.org/stc/SE00939WI): Installation of B&C Specialty Products Model BC 315-( ) Starter on Lycoming engines. B & C Specialty Products Inc. Lists O-540-A1A
- [STC SE2388CE](https://openairdocs.org/stc/SE2388CE): Installation of B&C Speciality Products lightweight (10.2) pounds) engine starter, part number BC-315-100-1 (12 volts) or part number BC-315-100-3 (24 volts). B & C Specialty Products Inc
- [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 O-540-A1A
- [STC SE40WE](https://openairdocs.org/stc/SE40WE): Installation of two Roto-Master Turbochargers Model No. 3DT5FF10J2, P/N 600572-00 (formerly Rayjay Model No. 315F10 P/N RJ0080-100, -101, or - 102). TALCO Aviation. Lists O-540-A1A
- [STC SE01436LA](https://openairdocs.org/stc/SE01436LA): Installation of Firewall Forward Technologies LLC modified camshaft. Centri-lube Technologies LLC. Lists O-540-A1A
- [STC SE04577CH](https://openairdocs.org/stc/SE04577CH): Install an electronic engine ignition system. Electroair Acquisition Corp. Lists O-540-A1A
- [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 O-540-A1A
- [STC SE01537AT](https://openairdocs.org/stc/SE01537AT): Replace counterweights on Lycoming O-540-A1A5, -A1B5, -A1C5, -A1D5, and IO-540-C1B5 engines. Whelen Aerospace Technologies. Lists O-540-A1A5
- [STC SE8628SW](https://openairdocs.org/stc/SE8628SW): Installation of oil nozzles for lubrication of cam and filters. Cygnet Aerospace Corp. Lists O-540-A1A
- [STC SE1339SW](https://openairdocs.org/stc/SE1339SW): Modify pistons to Drawings 11007 and 11015; piston rings. Continental Motors, Inc. Lists O-540-E4A5
- [STC SE4408SW](https://openairdocs.org/stc/SE4408SW): Miscellaneous engine cylinder replacement parts. Continental Motors, Inc
- [STC SE8776SW](https://openairdocs.org/stc/SE8776SW): Installation of coated cylinders and piston rings. Continental Motors, Inc
- [STC SE00218NY](https://openairdocs.org/stc/SE00218NY): Replacement of Lycoming starter with SKY-TEC 12 volt starter installed. Hartzell Engine Technologies, LLC
- [STC SE00226NY](https://openairdocs.org/stc/SE00226NY): Replacement of Lycoming starter with SKY-TEC 24-volt starter Models 149-24HT and 122-24HT. Approval limited to 24-volt DC source available to the starter. Hartzell Engine Technologies, LLC. Lists O-540-A1A
- [STC SE00357NY](https://openairdocs.org/stc/SE00357NY): Replacement of Lycoming starter with SKY-TEC 24-volt starter installed. Hartzell Engine Technologies, LLC
- [STC SE04241AT](https://openairdocs.org/stc/SE04241AT): Installation of (Bendix) Precision Airmotive fuel injection system which replaces the original Marvel Schebler carburetor model MA-4-5, P/N 10-5042. Nicky L. Watts. Lists O-540-B4B5
- [STC SE2901NM](https://openairdocs.org/stc/SE2901NM): Lycoming valve cover gasket. Real Gaskets Tennessee. Lists O-540-A1A
- [STC SE02051AK](https://openairdocs.org/stc/SE02051AK): Grind nitrided high compression cylinder barrels to plus 0.010 overside and install P10 piston, P10 compression rings, and P10 oil rings. Custom Aircraft Inc. Lists O-540-J1A5D
- [STC SE5869SW](https://openairdocs.org/stc/SE5869SW): Install turbosupercharger. Desert Wind Air Service. Lists O-540-A1D5
- [STC SE00768CH](https://openairdocs.org/stc/SE00768CH): Replace Slick 6000, 6100, 6200 and 6300 series magnetos and TCM/Bendix S6-20, S6-200 and S6-1200 series magnetos with the Champion Limited Authority Spark Advance Regulator (LASARTM) ignition system. Champion Aerospace LLC
- [STC SE8193SW](https://openairdocs.org/stc/SE8193SW): Grind nitriden high compression cylinder barrles to plus .010 oversize and install SL75089 P10 piston, SL74242 P10 compression ring, and SL73857 P10 oil ring. Superior Air Parts Inc. Lists O-540-A1A
- [STC SE922GL](https://openairdocs.org/stc/SE922GL): Installation of a Shadin Company fuel flow transducer. Shadin Avionics. Lists O-540-A1A
- [STC SE7734SW](https://openairdocs.org/stc/SE7734SW): Modification of engine for operation with ethanol fuel. Shauck Dr Maxwell E Jr. Lists O-540-A1A
- [STC SE01943CH](https://openairdocs.org/stc/SE01943CH): Add the following approved fuels: unleaded automotive gasoline 87 minimum antiknock index, per ASTM Specification D-439 or D-4814 of any volatility class, A through E, or 82UL AVGAS per ASTM D-6227. Experimental Aircraft Association Inc. Lists O-540-B1A5
- [STC SE956GL](https://openairdocs.org/stc/SE956GL): Superseded by STC SE01943CH. Add approved fuel: unleaded automotive gasoline, 87 minimum antiknock index. EAA Aviation Foundation. Lists O-540-B1A5
- [STC SE1779NM](https://openairdocs.org/stc/SE1779NM): Installation of Precise Flight, Inc. Standby Vacuum System SVS III. Precise Flight Inc. Lists O-540-A1A
- [STC SE17WE](https://openairdocs.org/stc/SE17WE): Installation of AiResearch Turbosupercharger 406330. GE Engine Services-Corporate Aviation Inc. DBA Garrett Aviation Services. Lists O-540-A1A
- [STC SE5743NM](https://openairdocs.org/stc/SE5743NM): Intallation of adapter for externally mounted oil filter. Aviation Development Corporation. Lists O-540-A1A
- [STC SE00337NY](https://openairdocs.org/stc/SE00337NY): Installation of 'second wind' auxiliary vacuum system carburetor adapter assembly. To be performed with STC SA00336NY. Flight Life, Inc. Lists O-540-A1A
- [STC SE1433GL](https://openairdocs.org/stc/SE1433GL): Convert Lycoming aircraft engine Model O-540-B2B5 or O-540-B2C5 rated at 235 hp at 2575 rpm to a O-540-B2B5-C-AlD5 or O-540-B2C5-C-A1D5 rated at 250 hp at 2575 rpm maximum. Kron Howard. Lists O-540-B2B5
- [STC SE00890LA](https://openairdocs.org/stc/SE00890LA): Installation of Nickson's cylinder barrels on Lycoming reciprocating engine models. Nickson's Machine Shop Inc
- [STC SE01949AT](https://openairdocs.org/stc/SE01949AT): Engine modification to convert Lycoming model O-540-D4A5 and install engine turbonormalization systme which includes 2 ea. Rotomaster model 30T5FF10J2 turbochargers (part number 600572-00) and 1 ea. Harrison Intercooler (part number KA-128). K-Aero. Lists O-540-E4A5
- [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
- [STC SE09492SC](https://openairdocs.org/stc/SE09492SC): Installation and usage of Exxon 20W50 multigrade aircraft engine oil conforming to Exxon Oil formulation WS-3013. Exxon Company USA
- [STC SE00663WI](https://openairdocs.org/stc/SE00663WI): Add the following approved fuel: Leaded and unleaded automotive gasoline, 91 minimum antiknock index. Intermixing with aviation gasoline also approved. Petersen Aviation Inc. Lists O-540-F1B5
- [STC SE8023SW](https://openairdocs.org/stc/SE8023SW): Installation and usage of AEROSHELL. Shell Development Co
- [STC SE2653CE](https://openairdocs.org/stc/SE2653CE): Add leaded and unleaded automotive gasoline, 91 minimum antiknock index (RON+MON)/2 per ASTM Specification D-439. Petersen Aviation Inc. Lists O-540-A1A
- [STC SE741NE](https://openairdocs.org/stc/SE741NE): Installation of 'Auto-Vac-4' primary vacuum system. Raymond Ives. Lists O-540-B1B5
- [STC SE452NE](https://openairdocs.org/stc/SE452NE): Installation and usage of 'Mobil AV 1' aviation oil. Mobil Research & Development Corp
- [STC SE318NE](https://openairdocs.org/stc/SE318NE): Installation of 'auto-vac-2' auxiliary instrument vacuum system. Raymond Ives. Lists O-540-A1A
- [STC SE3552NM](https://openairdocs.org/stc/SE3552NM): Modification of crankshaft damper configuration. Johnston Aircraft Svc, Inc. Lists O-540-A1A
- [STC SE3360NM](https://openairdocs.org/stc/SE3360NM): Installation of a vacuum pump on the hydraulic pump pad. Ron & John's Comanche Service. Lists O-540-E4A5
- [STC SE5879SW](https://openairdocs.org/stc/SE5879SW): Use of Phillips X/C II 20W-50 and25W-60 oil (OSS 55875) in all Avco reciprocating aircraft engines from 65 to 450 BHP. Phillips Petroleum Co

All 59: https://openairdocs.org/engine/lycoming-o-540-series/stcs.md

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