SA02254AKOther aircraft modifications
Installation of "Single Screen", "2 or 3 Screen", "Dual Screen", or "4 or 6 screen".
FAA holder: Genesys Aerosystems Inc.
Aircraft STC directory
Cessna Aircraft 421C STCs
The Jun 30, 2026 FAA DRS snapshot contains 50 selected supplemental type certificates with status Current whose public applicability data names the Cessna Aircraft 421C. Use it to identify modification scope and recorded holders—not to determine serial-number effectivity, compatibility, installation approval, or commercial availability.
50
listed Current at snapshot
29
holder directories
11
modification categories
Jun 16, 2022
latest recorded revision
Modification demand surface
Other aircraft modifications21
Engine and powerplant6
Avionics5
Cargo and special mission5
Fuel systems3
Propellers3
Landing gear and brakes2
Cabin and interiors2
Electrical systems1
Flight controls1
Aircraft structures1
Recorded holders
RAM Aircraft Limited Partnership11Aviation Fabricators Inc3Sandel Avionics LLC2SMR Technologies2S-TEC Corporation2Genesys Aerosystems Inc.1Air Comm Corporation1LifePort LLC1SMR Technologies Inc1Spectrum Aeromed LLC dba Spectrum Aeromed1OCR Aviation1Griggs Aircraft Refinishing LLC1Paul/ Lanna Egan LLC1Spoilers Inc1Bell Helicopter Textron Inc.1Avcon Industries Inc1P2 Incorporated1Snaky Creek Enterprises LLC dba Spectrum Aeromed1M-20 Oil Separators LLC1MT- Propeller Entwicklung GmbH1
Recently revised 421C STCs
Showing the 50 most recently revised records. Each entry links to the FAA source and separates public approval data from private commercial claims.
View record
SA4270SWEngine and powerplant
Mount collision avoidance lights in engine nacelle.
FAA holder: Johnson Aviation Products
SA01316LAAvionics
Installation of Sandel Avionics Terrain Awareness and Warning System.
FAA holder: Sandel Avionics LLC
SA01815LAAvionics
Installation of Sandel Avionics SN3500 Electronic Horizontal Situation Indicator (EHSI).
FAA holder: Sandel Avionics LLC
SA8RMOther aircraft modifications
Installation of a vapor cycle air-conditioning system.
FAA holder: Air Comm Corporation
SA00057SEElectrical systems
Installation of emergency medical stretcher, oxygen, and electrical systems.
FAA holder: LifePort LLC
SA00571SEOther aircraft modifications
Replacement of certain BF Goodrich pneumatic deicer boots.
FAA holder: SMR Technologies Inc
SA01213CHCargo and special mission
Install air ambulance conversion in accordance with Spectrum Aeromed Inc. Drawings as listed on AML SA01213CH, or later FAA approved revision.
FAA holder: Spectrum Aeromed LLC dba Spectrum Aeromed
SA01935LAOther aircraft modifications
Installation of external aft body strakes.
FAA holder: Aircraft Performance Modifications
SA1361SOOther aircraft modifications
Replaces original reciprocating engines with Pratt & Whitney of Canada PT6A-135 or PT6A-112 turbopropeller engines and related changes.
FAA holder: American Aviation Industries LLC
SA2514CEEngine and powerplant
Installation of wing nacelle locker tanks and fuel transfer system.
FAA holder: Griggs Aircraft Refinishing LLC
SA1048GLCargo and special mission
Install Egan Aviation air ambulance stretcher P/N 125 using Installation Kit P/N 801.
FAA holder: Paul/ Lanna Egan LLC
SA02430LALanding gear and brakes
Installation of fiberglass dome hubcaps on Cleveland 40-135, 40-135A, 40-138A, 40-169 and Goodyear 500364 wheels with various attach brackets and associated parts using existing or new hardware as appropriate to outer wheel halves.
FAA holder: Premiere-Aviation, Inc.
SA10801SC-DLanding gear and brakes
Install wheel hub caps.
FAA holder: RAM Aircraft Limited Partnership
SA1146SOOther aircraft modifications
Installation of nose cone erosion cap.
FAA holder: Bell Helicopter Textron Inc.
SA3458WECargo and special mission
Modification of fuselage to install camera window, with the option to allow unpressurized operations when the optical glass is removed and camera door is open.
FAA holder: Avcon Industries Inc
SA00103WIOther aircraft modifications
Installation of a heated windshield panel.
FAA holder: Aviation Fabricators Inc
SA02110CH (PAGE 2)Other aircraft modifications
Installation of a Time Trac Data Recorder.
FAA holder: P2 Incorporated
SA1535GLCargo and special mission
Install air ambulance conversion.
FAA holder: Snaky Creek Enterprises LLC dba Spectrum Aeromed
SA8352SW-DOther aircraft modifications
Install vortex generators.
FAA holder: RAM Aircraft Limited Partnership
SA5796SW-DFuel systems
Installation of Alcor Tru-Flow indicating system, or SDI Hoskins fuel flow indicating system, or Silver Instruments Fueltron fuel flow indicating system.
FAA holder: RAM Aircraft Limited Partnership
SA02033AT (PAGE 6)Engine and powerplant
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).
FAA holder: M-20 Oil Separators LLC
SA02550NYPropellers
Installation of a 4-blade MT-Propeller Models MTV-16-I-E-C-F/CF225-37a on a Cessna 421C airplanes.
FAA holder: MT- Propeller Entwicklung GmbH
SP00400SEPropellers
Installation of various propeller electrical de-icer models.
FAA holder: SMR Technologies
SA3522NMOther aircraft modifications
Installation of Precise flight series 400 speedbrake system.
FAA holder: Precise Flight Inc
SA00161BO (2 OF 3Avionics
Installation of Avidyne Corporation FlightMax 700-00007-( ) EX500 Multi-Function Display.
FAA holder: Avidyne Corporation
SA02217AK (3 OF 5Other aircraft modifications
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.
FAA holder: Garmin AT Inc.
SA00556DEEngine and powerplant
Installation of a left-hand exhaust stack assembly.
FAA holder: Heliarc Welding Service Inc.
SA09635ACAvionics
Installation of S-TEC Meggitt Engine Instrument Display System (EIDS) in accordance with Master Data List 921230, Revision 7, dated September 17, 2004, or later FAA approved revision for Cessna 425. FAA approved Airplane Flight Manual Supplement No. 892137, dated September 20, 2004, or later FAA approved revision is required for Cessna 425 with S-TEC Meggitt EIDS.
FAA holder: S-TEC Corporation
SA2650NMOther aircraft modifications
Cockpit Sun Visor Installation.
FAA holder: Rosen Sunvisor Systems LLC
SA2715CECabin and interiors
Installation of single place composite commuter seats on the seat rails per Aviation Fabricators Drawing list No. AF-130 stamped "FAA Approved" May 2, 1991, or later FAA approved revision.
FAA holder: Aviation Fabricators Inc
SA2716CECabin and interiors
Installation of double composite commuter seats on the seat rails per Aviation Fabricators Drawing List No. AF-130 stamped "FAA Approved" May 2, 1991, or later FAA approved revision.
FAA holder: Aviation Fabricators Inc
SA10185SCOther aircraft modifications
Installation of Hartzell model HC-C3YN-2UF/FC9587D-7 or HC-C3YN-2UF/FC9587DB-7 propellers.
FAA holder: RAM Aircraft Limited Partnership
SA00823CHOther aircraft modifications
Installation of various de-icer wire harnesses.
FAA holder: SMR Technologies
SA802NEOther aircraft modifications
Installation of Cessna SK310-114-0 electric windshield heated panel installation kit.
FAA holder: Aviation Management Services, Inc
SA09544SCOther aircraft modifications
Installation of a wastegate in-line oil strainer.
FAA holder: RAM Aircraft Limited Partnership
SA4592SWEngine and powerplant
Installation of improved engine cooling baffle and improved exhaust system slip joints.
FAA holder: RAM Aircraft Limited Partnership
SA4851SWOther aircraft modifications
Installation of combination aft position/strobe light on aircraft tail stinger.
FAA holder: RAM Aircraft Limited Partnership
SA5811SWFuel systems
Increase maximum ramp weight to 7610 pounds; maximum takeoff weight to7560 pounds; maximum landing weight is 7200 pounds; decrease zero fuel weight to 6533 pounds; install winglets.
FAA holder: RAM Aircraft Limited Partnership
SA5878SWOther aircraft modifications
Installation of range-marked EGT, CHT, oil temperature, and pressure gauges.
FAA holder: RAM Aircraft Limited Partnership
SA5981SWFuel systems
Increase maximum ramp weight to 7610 pounds, maximum takeoff weight to 7560 pounds, maximum landing weight is 7200 pounds, maximum zero fuel weight is 6533 pounds.
FAA holder: RAM Aircraft Limited Partnership
SA7594SWPropellers
Installation of Cablecraft throttle, mixture, and propeller control cables.
FAA holder: RAM Aircraft Limited Partnership
SA08996AC-DOther aircraft modifications
Installation of S-TEC System 55/55X Two Axis automatic flight guidance system, Model ST-578.
FAA holder: S-TEC Corporation
SA01117ATOther aircraft modifications
Installation of Composite Spinner.
FAA holder: TCB Composite Co.
SA3003WEOther aircraft modifications
Installation of recognition light assembly on horizontal stabilizer.
FAA holder: DeVore Aviation Corporation of America, a New Mexico Corporation