How many Cessna 421Cs are registered in the US?

493, in the FAA aircraft registry.

When was the Cessna 421C built?

From about 1975 to 1985. Half of those registered today were built by 1978.

What engine does the Cessna 421C have?

Most have the Continental GTSIO-520 (64% of those registered); others have the Continental TSIO-520.

What are common problems with the Cessna 421C?

In 33 Service Difficulty Reports filed with the FAA since 2016, the systems reported most were reciprocating engine cylinder section, dc generator-alternator, engine air intake system, and the part most often reported was a failed alternator.

How many accidents has the Cessna 421C had?

33 in the NTSB's database since 2008, 18 of them fatal. The most common defining event was loss of control in flight. These are counts, not rates: how many hours the fleet flew is not published.

How many Airworthiness Directives does the Cessna 421C have?

27 current ADs name the 421C airframe, 2 of them with a repeat action, and 63 more name its engines. Whether each applies to one aircraft depends on its serial number and installed equipment.

Ownership guide

Cessna 421C

493 registered in the US, built from about 1975 to 1985, 8 seats, most with the Continental GTSIO-520. Its Airworthiness Directives, its engines', and what to check before buying one.

The fleet

Registered in the US: 493
Built: 1975 to 1985
Half built by: 1978
Seats: 8
Engine type: Piston
Most common engine: Continental GTSIO-520

Engines installed

Continental GTSIO-520315 aircraft (64%) · 18 ADs, 1 with a repeat action
Continental TSIO-52013 aircraft (3%) · 45 ADs, 3 with a repeat action

From the FAA aircraft registry, rebuilt daily. Years are those recorded on each registration.

Airworthiness Directives

27 current ADs name the 421C airframe, 2 with a repeat action; 3 more were superseded. Its engines carry 63 more. 13 equipment ADs name the model.

The ones that come back

ADs with a repeat action: an inspection or replacement at an interval, for as long as the AD applies. These are the airworthiness costs an owner keeps paying.

Every AD for the Cessna 421C

What gets reported

33 Service Difficulty Reports since 2016: a mechanic or operator files one when a part fails or is found defective.

Systems reported most

Reciprocating Engine Cylinder Section4
DC Generator-Alternator3
Engine Air Intake System3
Engine (Reciprocating)2
Heating System2
Hydraulic System, Main1

Parts reported most

Alternator, failed4
Engine, failed1
Line, failed1
Fuel tank, leaking1
Spar, corroded1
Intake duct, loose1

The latest reports

2026-06-30 · Cabin Cooling System · Gasket, degraded
Failed gasket pn: 5154056-2 for the ac compressor, resulting in a severe engine oil leak, spraying engine oil on the exhaust system.
2026-06-10 · Wheel/Ski/Float · Wheel, cracked
3-piece nose gear wheel assembly cracks on middle hub assembly #d30321.
2026-06-10 · Fuselage, Wing Attach Fittings · Angle, cracked
Left hand upper angle at wing root and fuselage cracks under pressurization/depressurization with flex.
2026-05-03 · Engine Air Intake System · Intake duct, loose
On 3 may 2026, approximately 11:55 am, n123np departed bil for fbl and found that the right engine wouldn't make red line map and aborted his takeoff. maintenance found a couple induction tube clamps loose. the mechanic tightened both clamps and and the pilot departed to fbl without incident.

From the FAA's Service Difficulty Reporting System, refreshed monthly. Counts of what was reported, not failure rates: most of general aviation reports voluntarily, and a busy training fleet reports more than a private one.

Accident record

33 accidents since 2008, 18 fatal (46 people killed in them, a midair counting both aircraft), 8 aircraft destroyed.

What happened

Loss of control in flight10
Landing gear collapse4
System or component failure (not the engine)2
Part(s) separation from AC1
Airport occurrence1
Powerplant sys/comp failure1

Phase of flight

Enroute10
Initial climb6
Landing6
Prior to flight3
Takeoff3

The latest

Date	Where	What happened	Injuries	NTSB number
2026-05-04	Kirksville, MO	Enroute: Part(s) separation from AC	None	CEN26LA179
2024-08-31	Fairview, OR	Unknown: Loss of control in flight	Fatal	WPR24FA289
2024-07-18	Tofino	Initial climb: Unknown or undetermined	Fatal	GAA24WA258
2024-01-08	Carson city, NV	Prior to flight: Airport occurrence	None	WPR24LA068
2023-12-08	Mcgregor, TX	Enroute: Powerplant sys/comp failure	None	CEN24LA061
2023-11-10	Sunshine coast	Initial climb: Loss of control in flight	Fatal	GAA24WA034

From the NTSB's aviation accident database, refreshed monthly; accidents only, homebuilts left out. Counts, not rates: nobody publishes how many hours each model flies, and a training fleet flies far more than a private one. Look up any case by its number in the NTSB's CAROL.

What it costs to run

Per hour flown

Hours flown a yearhr/yrFuel burngal/hrTypical cruise; your POH and how you fly decide it.Fuel price$/galEngine overhaul$A quote from an engine shop.Hours to overhaulhrThe engine maker's published time between overhauls.Maintenance reserve$/hrEverything else that wears: tires, brakes, avionics, the unexpected.

Per year, flown or not

Insurance$/yrHangar or tiedown$/yrAnnual inspection$/yrLoan payments$/yrEverything else$/yrSubscriptions, database updates, the property tax some states charge.

Fuel: $0/hr
Engine reserve: $0/hr
A year: $0
All in, per hour: $0/hr

Everything else is yours to fill in: insurance, hangar and overhaul prices vary too much by pilot, airport and shop for a default to mean anything. Nothing you type leaves this page.

Before you buy one

Run its N-number through the AD check: every AD that names its airframe and engine, as a checklist to take to the logbooks.
For each repeat-action AD (2 on the airframe), find the last compliance in the logbooks and when the next one is due.
Compare the engine's time since overhaul with its maker's published overhaul time, and look for the reason behind any long gap in flying.
Ask the mechanic doing the pre-buy to look hard at the reciprocating engine cylinder section and for failed alternators: they are what gets reported most on this model.
13 equipment ADs name the 421C (a muffler, a seat belt, a display): find out which of that equipment is installed.
Check the registration, the airworthiness certificate and the date of the last annual inspection.
Work out the sales or use tax your state will charge with the aircraft tax calculator.

The rest of the 421 family

Cessna 421B · 220 Cessna 421 · 25 Cessna 421A · 19

Questions

How many Cessna 421Cs are registered in the US?: 493, in the FAA aircraft registry.
When was the Cessna 421C built?: From about 1975 to 1985. Half of those registered today were built by 1978.
What engine does the Cessna 421C have?: Most have the Continental GTSIO-520 (64% of those registered); others have the Continental TSIO-520.
What are common problems with the Cessna 421C?: In 33 Service Difficulty Reports filed with the FAA since 2016, the systems reported most were reciprocating engine cylinder section, dc generator-alternator, engine air intake system, and the part most often reported was a failed alternator.
How many accidents has the Cessna 421C had?: 33 in the NTSB's database since 2008, 18 of them fatal. The most common defining event was loss of control in flight. These are counts, not rates: how many hours the fleet flew is not published.
How many Airworthiness Directives does the Cessna 421C have?: 27 current ADs name the 421C airframe, 2 of them with a repeat action, and 63 more name its engines. Whether each applies to one aircraft depends on its serial number and installed equipment.

Figures from the FAA aircraft registry and the FAA's Airworthiness Directives, rebuilt daily. An AD listed for a model is one to read; whether it applies to one aircraft depends on its serial number, equipment and records.