Cessna 421 Golden Eagle

The top-of-the-line Cessna piston twin is unfortunately saddled with troublesome geared engines.

The 421 Golden Eagle stands at the head of Cessnas 400-series piston twins. Its roomy and relatively quiet, fast and efficient. Performance approaches that of some turboprops, but purchase and operating costs are considerably lower (though still considerable – they only look good when compared to propjets).

However, the 421 uses unusual geared engines that must be operated with care, and have seriously high overhaul costs.

The 421, which shares its basic airframe with most of the other 400-series Cessna twins, was introduced in 1968. Cessna aimed it at buyers who wanted better carrying capacity and performance than other piston twins offered, but who were put off by the high cost of turboprops.

To get the performance these buyers were looking for, Cessna decided to use Continental GTSIO-520 geared engines producing a healthy 375 horsepower apiece. Thats nearly three-quarters of a horsepower per cubic inch, and the inevitable stress meant short service life. Originally, the TBO was a mere 1200 hours. Later engines sported heavier crankcases that increased TBO to a still-low 1600 hours.

While most owners report that the engines will reach TBO with good care, the fact that theyre so unusual means that theyre very expensive to overhaul: an estimated $31,000 each. While thats pretty steep, its actually less than the overhaul cost for the 421s two direct competitors. The Beech Dukes mills cost $35,000 each, and the Piper P-Navajos engines cost $39,000 a side to overhaul.

The first 421s shared many of the features of the smaller 400s and the 300 series. The Stabila-Tip fuel tanks, 170-gallon fuel system, and electromechanical landing gear were all quite similar to those of the 310. The original 421 also had a short nose. Maximum gross weight was a respectable 6800 pounds. The standard fuel system gave a range of some 800 miles, while an optional 255-gallon system boosted the range to nearly 1200 miles.

The airplane was an immediate hit, with 200 sold that first year. Clearly, the Golden Eagle was something the market was looking for.

As is common, refinements were immediately applied and the 1969 model was redesignated 421A. The alterations were minor: a three-inch stretch, five more gallons of fuel, and a 40-pound increase in gross weight.

In 1971 the 421B got some more significant improvements. Weights (both gross and empty) increased significantly, with a maximum gross of 7450 pounds. The wingspan was increased two feet, raising the service ceiling by 5000 feet. The nose was stretched two feet to accommodate a baggage compartment capable of carrying a six-foot-long, 600-pound object, assuming the space was not taken up with extra avionics. (The compartment is about 51 inches long with the avionics bay fully occupied.) The aft cabin area could handle another 340 pounds, with a further 200 in each wing locker for a total capacity of 1340 pounds. The wing lockers serve as bays for optional fuel tanks, so they may or may not be usable for baggage.

The B model gained a few extra refinements over the next four years. The pressurization system was improved, raising the pressure differential first to 4.2, then 4.4 inches. The cabin and windows were made larger, and in 1975 a known-icing package was made available.

In 1976, Cessna brought out the 421C, incorporating the sweeping design changes that the company was applying to most of its twins at the time. The distinctive Stabila-Tip tanks (with their bladders) were gone, replaced by a simpler, bonded wet-wing fuel system. This system raised the standard fuel system capacity to 213 gallons, or 270 with all optional tanks installed.

Removing all that weight from the wing tips increased the airplanes stability, as did an increase in the size of the fin and rudder. The end result was better handling in both normal and single-engine operations.

The new wing also improved single-engine performance, with increased single-engine service ceiling and rate of climb.

The electromechanical landing gear was replaced by a hydraulic system. This featured trailing-link mains and a high-pressure nitrogen blow-down bottle for emergencies. The new system increased reliability slightly.

The maximum gross weight of the C model was 7450 pounds – the same as the B – but the standard empty weight was higher.

The C model was produced, relatively unchanged, for nine years. In 1985 it, like all the other piston Cessnas, was discontinued for lack of sales. Overall, the 4212C represents about half of the production run of 1920 aircraft.

Creature comfort
Where the 421 really shines is in its comfort, especially for passengers. While aircraft owners and pilots can debate the relative noisiness of various airplanes, the fact remains that theyre all loud: its just a question of how loud. The 421s cabin is among the quietest in the business, thanks mostly to its geared engines that produce plenty of power at low prop speeds.

The pressurization system delivers shirt-sleeve comfort at altitude, providing sea-level pressure up to 10,000 feet and maintaining at 10,000-foot cabin altitude at true altitudes of more than 26,000 feet.

The cabin is also quite wide at 55 inches, and has sufficient room for such amenities as a galley and toilet.

All of this translates into lower fatigue levels at the end of a flight. Noise and cramped quarters are tiring, and using oxygen dehydrates the crew and passengers.

The 421s ample baggage compartments also contribute to usable cabin space. For most flights, its not necessary to carry anything in the cabin.

As is common in many cabin-class twins, the door is blocked by the left-rear seat. To get in or out, its necessary to move that seat all the way forward. This can complicate emergency egress and make for some musical chairs during loading.

Up front, the cockpit is generally we’ll laid-out, with good seats offering plenty of adjustability. The view outside is hindered a bit by the thick window pillars. On ice-equipped 421s, the entire windshield is heated, eliminating the flat hot plate common on many twins.

The panel shows good design for the most part, with the engine gauges right up top and near the pilots line-of-sight, where they ought to be. On the 421C we examined, the fuel gauge is way over on the right (out of sight, out of mind), but is a capacitance type calibrated in pounds (more accurate than float gauges).

Owners report that the 421 has no real vices, and makes for a good, stable instrument platform.

If it comes down to a choice between models, however, we recommend the C version. Eliminating the tip tanks, increasing the wing span and enlarging the fin and rudder made for somewhat improved handling, particularly in roll and during single-engine operations. The changes also improved stability in turbulence.

Loading and performance
Cessnas sales literature is full of direct comparisons to turboprops, and indeed the 421 holds up well. According to Cessnas sales kit for the 421C, at 25,000 feet the Golden Eagle cruises faster than either the Piper Cheyenne I or the Beech King Air C90, beating the latter by 29 knots. All-engine rate of climb is almost 200 FPM better than the Cheyenne, and within 15 FPM of the King Air. Service ceiling is much higher with both engines running, and quite close with only one prop turning. Single-engine rate of climb is not as good – no surprise there – but its still within striking distance, about 200 FPM less than the King Air.

On paper, the 421 is quite fast. In the real world, though, cruise speeds are a bit less. Pilots report flight planning for anywhere from 195 to 215 KTAS at about 20,000 feet. Fuel burn is 50 gallons first hour, 40 thereafter.

On shorter hops, however, it doesnt pay to climb that high. Trips of 300 miles or less are normally flown at lower altitudes and speeds.

Like most aircraft, the 421 is not able to fill all the seats, baggage compartments and fuel tanks at the same time. It will, however, carry four or five adults, their bags, and full or near-full fuel. Owners are unanimous in their praise of the airplanes real-world usefulness in load carrying.

Systems-wise, the 421 is quite complex, with both good and bad points. The fuel system is a case in point. The 421C has a simpler system than earlier 421s, which generally simplifies management. Its far less complicated than, say, a 310. But the wing locker tanks, which have no gauges (just empty lights), are used by transferring fuel to the mains via an electric pump. If there isn’t room, the fuel goes overboard. Also, the pump is fuel-lubricated, and will burn out if left to run too long after the locker tanks are dry.

Good points include the availability of fire detection and extinguishing systems for the engine nacelles in later models, a good annunciator panel, and an available angle of attack indicator.

Cessna chose the geared Continentals for their combination of high power and low prop speeds, which allowed the 421 to deliver good performance without punishing noise levels. But, the geared engines proved to be more delicate than their direct-drive siblings, developing a reputation for cracking cases.

The 421s engines have gotten lots of attention for being delicate. The owners who responded to our survey all noted that they will go to TBO if treated well. That TBO was, in the early models, a dismally short 1200 hours. Later engines had beefed-up cases that raised the mark to 1600, typical for engines of this size, but this did not eliminate the case-cracking problem entirely.

Temperature and throttle abuse are pure poison: those GTSIO-520 engines need to be carefully managed. Overboosting on takeoff is one of the big reasons behind the GTSIOs case-cracking reputation. The throttles must be handled slowly and carefully, with the pilot constantly checking manifold pressure during the ground roll, watching for upward deviations.

In flight, engine temperatures demand attention. Cylinder-head temperatures that go too high or too low lead to cylinder problems. Letting down calls for precise planning to prevent shock cooling. Steady climbs demand equally good management.

One charter operator who wrote in had a different engine complaint, one aimed at Continental for taking a very long time (several months) to deliver factory remanufactured engines.

Utter exhaustion
The 421 shares the same problems as other 400-series Cessna twins (e.g. gear difficulties), but aside from the service history of the engines has no unique problems.

Of course, the 421 also shares the exhaust system design with other turbocharged Cessna twins, and as noted in The Aviation Consumer, June 1997, this system was implicated in a string of accidents over the previous 31 months that resulted in 29 deaths.

The apparent difficulty with the system stems from the location of the turbocharger, which is mounted to the airframe rather than the engine. This requires a flexible exhaust system to allow for differential movement of the engine and turbo. Cessna achieved this flexibility through a combination of ball and slip joints. This system can develop cracks, which allow hot exhaust gases to escape.

The hot exhaust then hits the aluminum box-beam keels that serve as engine mounts. These burn through, serving as a conduit to allow the gases to strike and burn through the firewall to the unprotected fuel crossfeed lines beyond. These lines have no shutoff valves.

In some cases the exhaust weakens the wing spar, which then fails. In others, the loss of the fuel lines results in dual engine failure due to fuel starvation.

The fact that the exhaust is a weak link is nothing new. A 1975 AD requires visual inspections every 50 hours, but the plumbing is so convoluted and tightly packed that this is difficult to do.

The string of accidents prompted the Cessna Pilots Association to call for immediate, thorough visual inspections of the exhaust system, including removal of top and bottom cowls, induction air filter canisters, head shield and anything else that might block an inspection. The Association also called for a complete pressure check of the system. The CPA and AOPA also called on the FAA to issue an emergency AD, though none appeared.

Aside from the exhaust inspection AD noted above (75-23-8), recent and notable ADs include: 95-9-13, replacement of non-compliant fuel inlet valves; 92-16-8, modification of commuter seats and tracks; 91-25-8, repetitive inspection of the wing front spar upper caps; and 90-2-13, inspection/replacement of the main landing gear inner barrel bearings.

The same mods available for other 400-series Cessnas can also be had for the 421. Notable ones include engine upgrades and winglets from RAM, vortex generators from Micro Aerodynamics, Robertson and V/G Systems, STOL kits from Sierra Industries, speed brakes/spoilers from Precise Flight and Spoilers, Inc., and intercoolers from American Aviation.

Owner groups
A club that covers the 421, in addition to all other twin Cessnas, is The Twin Cessna Flyer. Its headed by Larry A. Ball. (219) 749-2520. Also worth joining is the Cessna Pilots Association (www.cessna.org, (805) 922-2580).

Owner Comments
I professionally represent both the buyers and sellers of Cessna 421Bs and Cs. As such, I would like to provide some insight drawn from my daily contacts with 421 buyers and sellers.

Often, a 421 buyer is moving up from a light twin such as a 310 or Baron.

The 421s geared engines generate comments that are either positive or absolutely no way negative. Many callers tell me of their engine concerns or relate all that they have heard. I often feel that theyre hoping I can convince them that the engines are okay: they can be, if treated properly.

When evaluating an aircraft for buyers, the age and quality of the avionics are, of course, at issue. The 421Bs and many Cs left the factory with ARC 800 series radios, which are difficult to get worked on. Many panels are a mix of Cessna, King, Collins, Bendix and others. Often, these installations were done without proper wiring, circuit breakers and so forth. Often, the equipment list was never updated and the weight and balance records are a mess. After purchase, it is wise to have a fresh weight and balance done and a new equipment list drawn up.

If purchasing a 421, I recommend that buyers employ avionics specialists to be a part of the pre-purchase inspection process, along with a properly qualified and experienced mechanic. Its money well-spent.

Ive written to urge that buyers take the term due diligence seriously. Every week I listen to the problems and mistakes 421 buyers have made. Many could have avoided these problems. Some give the 421 and unfair rap.

It never ceases to amaze me that I observe buyers obtain well-paid professional support when purchasing a new $15,000 computer or telephone system for their business, then purchase a 20-year-old, quarter-million-dollar airplane with little or no professional support. Go figure.

-Jerry Temple
Jerry Temple Aviation
Carrollton, Texas

I have owned a 1978 Cessna 421C for four years and went through an exhaustive process in choosing it. I thoroughly researched Navajos, 340s, 414s and even the earlier King Airs. In the end, none of these other planes could beat the overall combined comfort, size, speed, power, load carrying capability and economy of the 421.

I have a family of five and often travel with one or two others. Most of our bags, including skis and the kids bikes, can easily fit into the cavernous nose baggage compartment, and, once airborne, we are all flying in pressurized comfort (at up to 30,000 feet) in a wide, quiet cabin while 750 horsepower propel us to our destination. (Incidentally, our highest time engine, while only 30 hours away from its 1600 hour TBO, is still running perfectly.) The airplane is rated for known icing and, even in some rather severe weather, the cabin remains comfortable and provides an incredibly stable environment. Further, because one is usually sitting down in flight the wide cabin really adds to the feeling of spaciousness. Also, the potty and overflow relief valve really come in handy for our three young boys.

While stepping up to a twin resulted in a rather disproportionate increase in maintenance costs, the problems we have had with our plane cannot be unique to a 421. In fact, with the exception of the higher-powered engines, both the 340 and 414 share systems with the airplane.

Incidentally, I ruled the King Air out fairly quickly. While an A model could have been had for just a touch more money than the 421, the operating and maintenance costs would have been out of the question. The 421 seats just as many passengers, has more baggage room and similar performance.

Granted, with such an incredibly complex airplane, we have had our fair share of problems. One incident involved a possible failure of the landing gear and, even after using the emergency nitrogen system, we still had to land with two main gear lights showing unlocked. As it turned out we landed on all three. While we never learned whether they were locked or not, our mechanic did discover the cause: water in the hydraulic fluid. This should be checked by all owners.

While we love our 421C, the proof of this airplanes prowess really can be found by talking to the individual 400 series instructors at Flight Safety. All of them have nothing but good things to say about the 421, putting at the top of their list.

-Geoffrey Clafflin Rusack
Solvang, Calif.

Our firm has owned a 1977 Cessna 421C since 1989 and uses it exclusively in our charter business.

Our passengers love it. Its quietest piston plane commonly available. Our pilots like it as a stable IFR platform. They flight plan it at about 190 knots true at lower altitudes and plan on burning 45-50 gallons the first hour, then about 40 GPH in cruise. Climbs to the high teens or low 20s are not usually justified on trips of less than 300 miles.

Far and away the biggest problem is the engines. Twice in four years weve been down for over two months waiting for Continental to deliver remans wed ordered months previous.

An experienced hand is needed on the throttles, and each year there seems to be a new crop of controllers that expect the airplane to be able to descend at 5000 FPM. If you do that, you’ll be buying new cylinders all the time. While our airplane is flown exclusively by professionals, a highly experienced owner-operator would probably do okay; an inexperienced pilot, however, would soon wind up in the poor house buying engines.

Other than the engines and usual 400-series glitches, the exhaust system is weak and the original ARC 800/1000 series radios need an experienced hand for maintenance.

With all costs added in over several years, we figure about $300 an hour to fly a 421 and keep it in good shape. Thats based on the fact that we get parts and fuel at wholesale and fly 400-500 hours per year.

On a positive note, the airplanes value has almost doubled in the last eight years!

-Pete Schoeninger, Manager
Waukesha Flying Services
Waukesha, Wisc.

My wife and I own a 1978 Cessna 421C and absolutely love the comfort, speed and convenience of this flying limousine. After looking at all the options, including turboprops, nothing really fits the bill quite like it. You can haul six people in air conditioned, pressurized comfort for a long distance, or up to eight for a modest distance. The baggage capacity is wonderful. We easily take six people, their luggage and skis without putting any baggage in the cabin from Los Angeles to Lake Tahoe. Useful load is around 2450 pounds with VGs (a must).

The spacious wide-bodied cabin is extremely quiet thanks to the props spooling along at 1750 RPM. No one in the back ever wears headsets and conversation is always at comfortably low levels.

We typically flight plan for 215 knots at 20,000 to 25,000 feet where it is distinctly uncrowded and on occasion have ventured to 30,000 to go around a thunderhead. Fuel burn runs 50 gallons for the first hour and 40 GPH thereafter. High gear and flap speeds really help in slowing down when needed.

Here in the West, we very seldom have use for the 421s known-ice capabilities, but on the occasions when we have needed it, it has performed splendidly. The full heated window is much nicer to look through than a hot strip such as you’ll find on a 340.

Another seldom-used, but on occasion extremely handy, item is the potty in the aft cabin area.

Maintenance, while not insignificant, is on par with other large twins such as the Navajo, but nothing like the high cost of a Duke. Our high-time engine is at 1550 SMOH and runs like a top.

Judging from the nice appreciation that these aircraft have enjoyed recently, I can assume that others are discovering what a wonderful machine a 421 really is. You simply cant find another plane that can haul you along above the weather at 25,000 feet in the quiet, pressurized comfort of a 421, with no need for headsets, at the price and operating cost of a 421.

-Name withheld

I owned a 1981 Cessna 421C for 2 years. I recently sold it, and am replacing it with a King Air B200. The airplane was operated part 135 during that entire time. I personally flew the plane 150 hours in that two-year period. I kept exact records of all costs.

These were my hourly costs:
Average fuel burn: 46 GPH
Maintenance (parts and labor): $174.50/hour
Engine reserve: $39.04/hour
Propeller reserve: $4.37/hour

I enjoyed flying the 421. It was a very stable IFR platform. I flew many flights at night and in hard IFR over mountainous and desert terrain, and I never felt behind the airplane. Everyone I flew in the plane liked the comfort and quietness of the cabin.

The only complaint that I have was with the RAM engines. I actually had a love-hate relationship with them. When I bought the plane it had two RAM engines installed. I definitely liked the increased gross weight (up by 150 lbs.) that came with them. I also liked the higher power settings for climbout and cruise approved for the engines. However, neither engine made it to TBO. The left engine started making metal around 1200 hours, and the right engine blew out the number 5 connecting rod at 1100 hours while I was flying with my wife in the right seat and my family in the back.

I highly recommend Flight Safetys initial and recurrent training for any owner/pilot of the 421. I took the initial training before I ever flew my 421, and I attended the recurrent training every six months. When the right engine failed my reaction was automatic, immediate, and appropriate for the problem. We were able to fly to the nearest airport and land without any additional incidents or problems.

-David Moore
Seattle, Wash.

I have owned a 73 C421B for about four years and have flown it 400 hours. I believe the 421 is the best airplane burning gasoline. I use the airplane for business, with trips being from 300 NM to 1400 NM. I carry anywhere from just me to eight people (including two or three children). Useful load is about 2200 pounds, so there is a lot of loading flexibility. I typically climb to around 12,000 feet for short trips, and as high as 25,000 for long trips. I get 1000 FPM from takeoff at maximum gross down to 400 FPM at 25,000. I plan for 50 gallons the first hour and 40 each hour after that. I actually do a little better than that at 60 percent. I can get it down to under 35 GPH if I lean aggressively. I true about 180 knots down low and 220 knots up high. I have seen ground speeds up to 300 knots in level flight.

Any bad stories told about the engines come from the person flying not being the same person who pays the bills. I have not touched an engine or turbocharger (other than minor leaks) since buying the plane. On descent, I don’t touch the throttles from cruise until within 20 miles of the airport. I have multi-probe EGT and CHT gauges which I monitor closely. I fully expect to get 1500 hours from each of my engines, which is good considering they are about $35,000 each for an overhaul.

My insurance is about $5500 per year for $150,000 hull value, and they require me to attend SimCom or Flight Safety every year. That probably costs another $3500 with travel from Texas. I have 1200 hours, with 700 multi, and 400 in type. SimCom is great: they teach you a lot about the airplane. Simulator training allows you to do so many things you would never do in the airplane, but biennial training should be good enough.

My biggest maintenance problem has been with the factory air conditioning. If I had put a new JB air system in when I bought the airplane, I would be ahead of the game money wise. Face it, 24 years is old for an air conditioner. Other than that I have had the problems you would expect from a 24 year old, high performance, pressurized, turbocharged airplane. I have heard it said that if they were still making 421s, they would be over a million dollars, so plan maintenance expenditures accordingly. My maintenance expenses in 1996 were about $7000. But with two prop overhauls, we are past that already this year.

I think the 421 is a fabulous airplane, but it is a very complex and old airplane. It must be treated with respect. It is fast, comfortable, and can carry a good load. It is a stable instrument platform. I love mine and recommend one for anyone who needs pressurization, and needs to carry more than five people.

-Roy Zesch
San Angelo, Texas

Also With This Article
Click here to view charts for Resale Values, Payload Compared and Prices Compared.
Click here to view the Cessna 421 Golden Eagle features guide.
Click here to view “Cessna 421 Engines: Handle With Care.”