Cessna 421 Guide and Specs: Everything You Need To Know


Cessna 421

When a company sells 200 aircraft in its first year of production, you can be sure the money invested in the design development has been worth it. So it was in 1968 when Cessna introduced the first model Cessna 421, a design based on that of the Cessna 411. The company designed the aircraft as an alternative for those wanting a turboprop’s performance and load-carrying abilities but without the cash to fund them.

A cabin-class, pressurized, low wing, metal, tricycle undercarriage aircraft, the Golden Eagle assumed the crown of Cessna’s piston-engined twins. The company chose the geared, injected, and turbocharged Continental GTSIO-520-D engines to achieve the performance required while producing less noise from the lower prop speed. Each engine produces 375 horsepower with a low TBO of 1200 hours.

There are Cessna 310 hints in the design of the earlier 421, with electromechanical gear, bladdered ‘stabila-tanks’ on the wingtips, and a fuel capacity of 170 gallons. However, a series of upgrades followed, the first within 12 months of introduction. The 421A was introduced in 1969 with an increased gross weight of 40 lbs from 6,800 to 6,840 lbs, a 3-inch longer fuselage, and a fuel capacity increased by 5 gallons.

Within twelve months, a more substantial modification was introduced as the 421B.  The nose was lengthened by two feet to give a large baggage compartment, the wings were lengthened by two feet giving a higher service ceiling, and the -H series engine was utilized.

From these modifications, the B model increased in gross weight by 610 lbs, added 5000 ft to the service ceiling, and gave a 600 lb forward cargo capacity. More minor modifications continued over the next four years, with the next significant change coming in 1975.

The Cessna 421C saw a major change to the aircraft design. At that time, Cessna was carrying out widespread changes to its product line in terms of modernization.  Gone were the bladdered stabila-tip fuel tanks, replaced by a wet wing, and a larger vertical stabilizer and rudder added.

With the change in fuel tank design, Cessna fitted an upgraded undercarriage with a faster hydraulic system, blow-down tanks, and allowing the inner undercarriage door removal. L series engines were fitted, with a new turbocharger and an enlarged intercooler installed. Finally, a trailing link landing gear installation occurred a few years later, giving the aircraft a more level appearance on the ramp.

Like many of the Cessna twins, the company curtailed 421 production in1985. Yet, by that time, Cessna had produced 1,916 of the series. The 421C was the most sought-after of the models, with 859 built, followed by the 421B selling 699, the 421A only 158, and the original 421 at 200 aircraft.

1979 Cessna 421C Golden Eagle Specifications

Engines     Weights and Capacities  
Model: GTSIO-520-L   T/O / Landing Weights Normal: 7,450 lbs
Cylinders: Six   Standard Empty Weight: 4,500 lbs
Displacement: 520 cu. in   Baggage Capacity: 1,340
Horsepower: 375   Oil Capacity – per engine: 12 quarts
Aspirated Injected – Turbocharged   Passenger Configuration: 4 to 6
TBO: 1600 hrs   Crew: 1 or 2
T/O Manifold Press: 28.75      
      Aircraft Dimensions  
Propellers     Wing Span: 41.15 ft
Model: McCauley or Hartzell 90 in   Length: 36.8 ft
Blades: 3   Height: 11.45 ft
Octane: 100/130      
Capacity: 213 gallons (std)      
Burn @ 75% Power: 42      

Cessna 421 Prices


The average price for a used Cessna 421/A/B series at print was US$175,000, having approximately 6,200 hours total time airframe (TTAF) and engine times around half-life.  The prices range from low-hour models with less than 3,200 hours TTAF, which are selling for just over US$185,000, while older aircraft will sell for approximately US$160,000.

For the Cessna 421C, the average pricing was US$350,000, having approximately 5,500 hours total time airframe (TTAF) and mid-life engines. Prices range from low-hour well-modded models of circa 4,000 hours TTAF, selling for just over US$580,000, while older aircraft sell for approximately US$270,000.

Cessna 421 Performance & Handling

Described as stable, incredibly comfortable, quiet, and ‘surprisingly forgiving,’ the 421 has met Cessna’s original intent for the aircraft to be an alternative for those wanting a turboprop. Operators recommend the -C model for stability in turbulence, given the larger wings, vertical and horizontal stabilizers, and the absence of tip-tanks.

The geared engines require gentle handling to ensure achieving TBO. Sudden throttle changes and rapid power reductions on descent will be a costly exercise. These engines are not cheap to overhaul.

Most operators report cruising in the mid-teens to low 20s flight levels, achieving 210 knots on sub-40-liter fuel flows at 65% power. At these flight levels, you can maintain cabin altitude around 7,000 to 8,00 feet.

1979 Cessna 421C Golden Eagle Performance and Handling Specifications

Cruise Speed (Kts)     Service Ceiling (ft) 30,200
75% @ 25,000 ft 220   Service Ceiling (ft) Single Eng. 14,900
Fuel Consumption (GPH)     Best sea-level rate-of-climb (fpm) 1940
75% 40   Single-engine rate-of-climb (fpm) 350
Max Range (nm)     Take-off Ground Roll (ft) 1,786
75% @ 25,000 ft 1,200   T/O Dist. over 50-foot obstacle 2,323
Do Not Exceed Speed (kts) 256   Landing Ground Roll (ft) 720
      Ldg Dist. Over 50-foot obstacle 2,293
Stall Speed (kts) 74      

Cessna 421 Maintenance Schedule

Cessna Paint Work

The 421 is a sophisticated, older, twin-engined aircraft, and if not managed and maintained appropriately, maintenance costs can get out of control. There are several airworthiness directives on the aircraft, the most notorious being AD 2000-01-16, which I talk to below in the common problems section.  Other ADs include undercarriage inner barrel bearing inspection and inspection of the front upper spar caps.

That aside, the area most observing of maintenance attention is that of the engines. The GTSIO-520 is expensive to overhaul; therefore, it requires attention both airborne and in the maintenance hangar. Owners report that with due attention, and timely intervention, the engines have no difficulty making or exceeding TBO. 

Cessna 421 has a viscous damper on the starter adaptors that have proved troublesome, causing complete engine failures. It is the subject of AD 2007-05-15. The viscous damper helps the engine run smoothly, but when it fails, the ensuing vibrations will rapidly destroy the engine. AD 2007-05-15 states that should a pilot feel any vibration in a GTSIO, the pilot should reduce power immediately, and if manipulation of the cannot clear the roughness, the engine should be checked by a maintenance organization immediately upon landing.

Average maintenance costs for the 421 appear to be circa US$20,000 per year once the aircraft is stabilized on a maintenance system with outstanding issues resolved.

Cessna 421 Modifications and Upgrades

Powerpack Spoilers in Gig Harbor, Washington, produce spoiler mods for the 421B & C series. Providing far higher descent rates than un-modded aircraft, spoilers prevent engine shock cooling and allow maintenance of cabin pressurization.

Vortex generators are another popular modification supplied by Micro Aerodynamics, Robertson, or V/G Systems. Vortex generators allow increased aileron and rudder control authority at low speeds.

Arguably the most popular modification is the addition of fuselage strakes. These fit under the tail on the aft fuselage, improving yaw control, performance in turbulence, and a higher cruise speed.

Cessna 421 Where To Find Replacement Parts

Finding parts to support the 421 series is not difficult.  Preferred Airparts, based in Ohio, provide worldwide customers with surplus new Cessna original components and used parts from dismantled aircraft.

The rise in FAA-PMA approved manufacturers ensure many manufacturers support a particular aircraft type and finding trim (knots2u, Texas Aeroplastics or AvFab), landing gear components (Robair Repair), or lighting (Whelen Aerospace Technologies or AeroLeds) for your aircraft is straightforward. Generic components such as filters, wheels, tires, and brakes are off the shelf and stocked by large aviation suppliers like Aircraft Spruce & Specialty or Wag Aero.

Cessna 421 Common Problems

The predominant issue with the 421 is the exhaust system, which has had its share of ADs over the years. There is a ball and slip joint in the exhaust run to allow movement between the engine and the turbocharger mounted on the airframe. These joints leak and crack, torching hot exhaust gases onto the aluminum engine mounting beam.

Once this is cut through, hot gases eat their way through the firewall and impinge on some fuel lines running on the other side. The lines have no fire protection or shut-off valves, and if severe, can result in an uncontained fire and double engine failure. The hot gases can also distemper the main wing spar, causing wing failure.

The most recent AD is 2000-01-16, which has clear and stringent inspection requirements. The joint and surrounding pipework is challenging to access, and therefore owners should be sure they have a diligent and experienced maintenance shop carry out the work.

The other known engine issue is crankcase cracking. While the engines have a higher TBO due to a more robust crankcase, mistreatment can still damage them. Over-boosting on takeoff and clumsy or rough power movements are the main problems.

Cessna 421 Insurance Options

Golden Eagle

The standard aviation insurance all aircraft owners take is liability coverage, while hull coverage is optional. The greater the experience of the owner/pilot, the lower the premiums.

Liability coverage covers damage caused by the aircraft, including passengers, while hull coverage covers damage to the aircraft itself.

For a private pilot with 2,500 hours total time, an IFR/MEL rating, 1000 hours on multi-engined aircraft, and 25 hours on type, the 2020 cost per year for US$1,000,000 liability coverage is in the range of US$1,450 to US$1,720 per year. Pilots with less experience can expect this range to rise to between 1,670 to 1,925 per year.

If the insurance includes additional hull cover for US$488,000, the annual premium for the experienced pilot will be between US$7,500 to US$11,200 per year, while the lesser experienced pilot can expect US$9,850 to US$14,000 per year.

Cessna 421 Model Resale Value

The 421C is a sought-after aircraft, and low hour well-specified aircraft command decent prices. If you’re looking for comparable turboprop performance on a piston-twin budget, look no further than the Cessna 421C.

Good quality, low hour 421Cs are very much in demand, so expect to pay a premium compared to the higher hour and earlier model alternatives. Older A/B models have a price average of US$170,000 with airframe times around 6,500 hours. The 421C aircraft are US$350,000 and upwards, with 5,500 hours on the airframe. For top-shelf low-hour models, you’ll be nudging US$600,000. 

Cessna 421 Owner Reviews

Owners speak highly of the 421, particularly its quietness, smoothness, stability, and large cockpit and cabin. Operators have carried out economic and operational comparisons between the 421 and turbo-props; however, depending on the mission profile, the 421 comes in as the cheapest and best option.

Flight planning cruise speeds appear to be between 210 to 220 knots at high-teens flight levels, achieving 38 to 42 gph fuel consumption.  Reported operating costs per hour, with reserves, average US$650.

One owner described his 421C as a “personal airliner,” providing “better than first-class” comfort.

Cessna 421 Similar Aircraft

Piper Cheyenne

If you’re looking for aircraft of similar configuration, age, and role, include in your search the Piper Cheyenne, Beechcraft Duke, Beechcraft Queen Air, AeroCommander 690, and the Piper Pa-31 Navajo. The most frequent comparisons, however, are with the Cessna 414.

Cessna 421 Clubs You Can Join

Owners recommend two groups—the Cessna Pilots Association, located at www.cessna.org, and the Twin Cessna Flyer, at www.twincessna.org.

FAQ: Frequently Asked Questions

Question: What does service ceiling mean?

Answer: An aircraft’s service ceiling is defined as the height at which the aircraft cannot climb at a rate greater than 100 feet per minute.

Question: What is the meaning of the term TBO?

Answer: TBO means Time Between Overhaul, which is the manufacturer’s recommended running time, in hours or calendar time, before overhaul.

Question: To what does TTAF refer?

Answer: TTAF stands for Total Time Airframe, which refers to the number of flying hours the airframe has accumulated since the new one. Thus, it is an indication of age and use.

Question: Aircraft Gross Weight refers to what?

Answer: Gross Weight is the total aircraft weight, including pilots, passengers, fuel, oil, and cargo.

Question: What are FAA-PMA Approved Parts?

Answer: FAA refers to the Federal Aviation Administration, and PMA means Parts Manufacturer Approval. It is an approval granted to a parts manufacturer to manufacture specific aircraft components.

Question: To what does the term IFR/MEL refer?

Answer: IFR means Instrument Flight Rules. When pilots are flying IFR, it means they are under the control of Air Traffic Control. MEL, in this case, refers to Multi-Engine – Land. Both refer to ratings or approvals that a pilot must achieve to enable the operation of a multi-engined aircraft or flight under instrument flight rules.

Question: What is an STC?

Answer: An STC refers to a Supplemental Type Certificate. An STC is an approved modification to an aircraft, engine, or component. All aircraft, engines, and components have type certificates that approve their use. That is why an approval to modify them is classed as ‘supplemental.’

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