Big, cabin-class turbocharged piston twins are a bit of a niche item these days. Too large and costly for personal transport, yet lacking sufficient performance to satisfy high-rolling corporate clients yearning for the whine of turbines and the comfort of pressurization, they’re used mostly for air taxi and specialty cargo operations. The businesses that once bought this class of airplane are in many cases now looking to more cost-effective alternatives, including time-sharing of the new crop of efficient jets and even airline travel to get executives to their destinations.
But when the mission matches the capabilities of a large piston twin through accidents of geography or flight profile, they cant be beat. Here in the Northeast is a perfect example: The offshore islands of Nantucket and Martha’s Vineyard are just a short hop from either Boston or New Bedford, too short a run for a turbine aircraft to make sense, but a perfect place to use a cabin-class twin. Operating costs are relatively low, especially if the seats are full.
Back in the 1960s, when this class of aircraft first arrived, Cessnas entries into the market were the popular 400 series. The direct competition came from Piper in the form of the PA-31 Navajo, Beech aimed higher with the Duke, which was a big step up in horsepower and cost from the Cessna and Piper entries.
Cessna developed the 400 series airframe into a variety of models, ranging from the 401 and 402 up to the 441 Conquest turboprop. Piper, too, created a wide variety of PA-31s, including its own turboprop versions (the troubled Cheyenne series).
In the 400 series, the 402 is Cessnas workhorse, designed from the outset with commuters and cargo in mind. It was, however, available with a corporate-transport-oriented interior, and made a credible business craft. Its primary appeal isn’t speed or aesthetics, but versatility.
That versatility is impressive. Configured as a commuter or cargo hauler (i.e. Utililiner), the 402 can carry 10 passengers and 100 gallons of fuel, or a total load of more than one and a quarter tons. Outfitted as a six-place corporate transport (Businessliner), it can fly coast-to-coast with one fuel stop. Of course, it will take quite a while to make that trip compared to the turbine-powered competition, but then the 402 doesn’t cost nearly as much as a propjet.
Such versatility helped Cessna sell more than 1,900 402s (and close to another 600 401s) during its production run, which lasted from 1967 to 1985.
When these airplanes came out in the mid-1960s, the general aviation manufacturers hadn’t as yet quite developed the knack for producing really complex airplanes. Most of the higher-end craft of the time (both singles and twins) were terribly trouble-prone, with complicated, expensive, maintenance-intensive systems and equipment that just didnt hold up very well.
Fortunately, the manufacturers learned their lessons well over the years, and later examples of these airplanes are vastly improved over the earlier versions. That goes not only for the 400 series Cessnas, but for other complex airplanes as well.
The difference in quality shows up in market value. Early examples of the 402 fetch only a bit more than $125,000, simply because they’re so costly to keep. Later versions of the airplane, with all the fixes, are much more desirable, commanding prices of $360,000 or more. Early Navajos, by comparison, bring a little bit more, while the last of them have prices comparable to same-year 402s (the Navajo was dropped before the 402 was).
History
The first of Cessnas 400 series twins was also the worst: the 411, which had severe engine-out handling problems combined with unreliable geared powerplants. It racked up an astoundingly bad accident rate, and lasted only four years with fewer than 300 delivered. Prices for them are in the mid-60s, and we advise you stay away no matter what the tag says. The 402 was the follow-on model, with fixes that took care of the 411s shortcomings including new engines and a bigger rudder.
The interior (featuring a reinforced bonded-honeycomb floor) was designed to accommodate up to ten seats, all quickly removable for conversion to cargo operations. A non-cargo version of the 402, called the 401, was offered concurrently, with six-passenger seating standard. Except for interior appointments and an optional cargo door on the 402, the two airplanes were the same.
In 1969, the 402 got a stretched nose for added baggage space, and was redesignated the 402A; the 401, however, retained its shorter beak. The advent of the 402B the following year saw optional fuel go to 184 gallons (nearly all are so equipped). Also, various systems changes were made; for example, fuel pumps were put in the Stabila-tip tanks in response to an AD.As acceptance of the workhorse 402 increased, sales of the 401 lagged. Consequently, in 1971 Cessna resorted to the somewhat unusual tactic of lowering its price by $1,450, to $108,500. The tactic flopped, however. Only 21 airplanes were sold at the lower price, and Cessna axed the 401 the following year.
Meanwhile, numerous improvements were made to the 402B:
1971: Padded window posts, instrument panel trim, and control yokes became standard safety features, and an engine nacelle fire extinguishing system was offered as an option.
1972: Heat-resistant silicone engine shock mounts were introduced, along with stainless steel turbocharger heat shields. Also, a simpler exhaust system was made standard; access was improved to the landing gear and flap motors; and a new landing gear system, featuring an aural annunciator coupled to the throttles and the flap preselect switch, was incorporated.
1973: The familiar Cessna portholes were replaced on the 402B with rectangular windows, for an increase of 711 square inches in window area; the cabin interior was lengthened by 16 inches; a fold-down instrument panel (for easier access) was made standard; optional fuel went to 207 gallons; an avionics master was added; and improved turbo controllers were made standard.
1975: A known icing option equipment package was offered.
1977: Polyurethane paint became standard, and an optional flushing toilet was offered.
1978: A Halon cabin fire extinguishing system was offered, to put out avionics and nose baggage compartment fires.
Far and away the most significant year in the 402s history was 1979, when Cessna introduced the 402C. With the C model, the 402 got 325 HP engines to replace the 300 HP mills in use until then. The new engines also boasted a TBO increase of 200 hours, up to 1,600. The familiar tip tanks were dropped in lieu of rivetless, bonded wet wings with a five-foot greater span. The ground track increased by four feet, and the complex mechanical landing gear was supplanted by a simpler, faster hydraulic system borrowed from the 414A. Useful load went up by 348 pounds. Along with all these improvements the price went up by $27,400, to $231,740. Production stopped after the 1985 model year.
In all, 322 402s were built, 125 402As, 1,384 402Bs and 1,022 402Cs. Of the 401, there were 321 originals, 132 As and 221 Bs.
Performance and handling
Cessnas 400-series twins are not noted for their crisp handling. Nonetheless, the series is generally given the nod for honest flight characteristics, albeit the mass of the fuel in the tip tanks tends to make the early models a bit less responsive in roll than the 402C. As you might expect in an airplane that can haul ten people, pitch stability and stick force varies with cg: The further aft the center of gravity, the lighter the elevator control and the less stable the aircraft. At far-aft CGs, according to one 402C pilot, the airplane can feel squirrelly longitudinally.
Yaw stability in most twins is not something you write home about, and this seems to be the case for the 402. One might suppose that the late-model 402Cs, lacking the tip tanks, would dampen out yaw excursions better than the earlier models; but according to one pilot, even the 402C wiggles vigorously in turbulence without the optional yaw damper.
Load-carrying capacity, not handling, is what people buy 402s for, and this is where the airplane truly excels. The 150-cubic-foot cabin-wider than a 90-series King Air-will carry up to a ton of people or freight; with the optional cargo door, a 47- by 40-inch hole can be opened up in the side of the fuselage for loading bulky objects. In addition, 55.5 cubic feet of storage is available outside the cabin, in two wing lockers (120 lb. each), a standard 26 cu ft. nose baggage area (350 lbs.) and an optional 11 cu ft. nose compartment (250 lbs.). In some models the nose compartment can hold objects up to 6 5 long. Non-cabin baggage areas can thus take on an amazing 840 lbs. of freight. No wonder drug smugglers like the 402.
Of course, all of this capacity makes overloading the 402 relatively easy, particularly if optional fuel tanks are installed. With full aux fuel, the 402 can carry 1,242 pounds of fuel alone; thus the full-fuel payload for a moderately-equipped 402C is on the order of 1,000 pounds. Early 401s and 402s were limited to a maximum of 1,200 pounds aft of the front spar (i.e., in wing lockers and/or aft cabin). We know of at least one 402 that banged its tail on the ramp when all of its passengers stepped to the rear to deplane.
Perhaps it is worth noting that the wing lockers are not really suited to carrying anything but the lightest of light-duty baggage; the bottoms of the locker bays are wing skin structure. Even if padded carpeting is in place, it is easy to dent the underwing skins-a point that prospective buyers should bear in mind.
Properly loaded, the 402 turns in creditable takeoff and climb performance, even at gross weight. A fully loaded 402B lifts off after 1,695 feet of ground roll at sea level (no wind), assuming an unstick speed of 105 MPH. To clear a 50-ft. obstacle under the same conditions requires 2,220 feet. (Flaps are left retracted on takeoff, since Cessnas split flaps-a holdover from the 310-produce vastly more drag than lift.) Once airborne, the 402 climbs initially at 1,610 FPM (1450 FPM for the 402C) at its all-engine Vy of 126 MPH. After initial power reduction, a cruise-climb of 140 MPH produces 1,000 FPM, each engine burning 17 GPH.
In cruise flight, an early 401/402 will deliver an honest 200 MPH at 10,000 feet on 66-percent power (27 and 2,450 RPM). Book fuel flow under those conditions is listed as 28.9 GPH. (At 20,000 feet, the same power setting yields 223 MPH TAS, according to the book-but most 402s are flown at non-oxygen altitudes.) The higher horsepower, tip-tankless 402C is slightly faster, delivering 221 MPH at 10,000 feet with 72 percent power.
Range-in the older models-varies from 675 miles with standard fuel (100 gallons usable) at 72 percent power at 10,000 feet, to just over 1,400 miles at 55 percent power and 20,000 feet with full optional fuel (180 gallons usable), with no reserves. The 402C comes with a standard fuel capacity of 213 gallons, which gives the aircraft long legs indeed-up to 1,400 miles with reserves. Some cabin payload must be sacrificed to fly with full fuel, naturally, but even with all tanks topped, you can count on carrying five people and baggage.
On landing, the 401/402 requires 1,765 feet past a 50-ft. obstacle (777 ft. of ground roll) at its maximum touchdown weight of 6,200 pounds (100 below gross). The heavier 402C requires 2,485 ft. over the 50-ft. obstacle and 1,055 feet of pavement. A Robertson STOL kit is available for the 402 which cuts these distances by approximately 20 percent.
As with its chief competitors in this class (the Piper Navajos), the 401/402 suffers from very marginal single-engine rates-of-climb. At sea level, a 402B loaded to gross can only manage 225 FPM on one engine, which-at the planes Vxse (engine-out best angle of climb speed) of 114 MPH-gives a climb gradient of just 138 feet per nautical mile. Needless to say, the slightest defect in piloting technique will quickly knock such numbers into the ditch. (One wonders how many commuter airline customers would willingly board a 402, if they knew the planes engine-out performance capabilities-or lack of same.)
The 402s single-engine climb rate improves somewhat with the offloading of fuel or cargo, but not dramatically. According to Cessnas charts, one can expect a 150-FPM gain (at sea level) for every 500 pounds below gross.
The 402s Vmc (minimum single-engine control speed) isn’t particularly good, either: At 95 MPH, the 402s Vmc is 10 MPH higher than the Navajos. (The Robertson conversion lowers the 402s Vmc to 83 MPH.) Cessna lists a safe single engine speed of 105 MPH for the 401/402 and suggests this be used as the decision speed below which a takeoff, in the event of engine failure, should not be continued.
Its worth noting, however, that the 402s 225 FPM single-engine climb rate is predicated on a Vyse (engine-out best ROC speed) of 118 MPH, plus gear and flaps retracted, cowl flap on the bad engine retracted, the faulty engine feathered, and five degrees of bank maintained in the direction of the good engine. If all of these conditions are not met, then the 225 FPM figure is no longer valid, even at 118 MPH. On balance, Cessnas 105-MPH Vsse seems more than a trifle optimistic.
Cessnas redesign of the 402 in 1979 resulted in improved engine-out performance for the C model: The 402C, while 300 pounds heavier than its predecessor, nonetheless manages a 3,100-foot higher SE service ceiling (14,800 feet) and can climb at 301 FPM (for a gradient of 173 feet per nautical mile)-by no means rocket-like, but considerably better than the previous models.
Interestingly, the heavier 402C requires a longer distance to accelerate and then stop (3,740 feet for the C versus 3,055 feet for early model 402s), but the distance needed to lose an engine and then continue takeoff is less for the 402C: 2,870 feet versus the tip-tanked 402s 3,990 to 4,370 feet (the exact distance depends on the year model). Obviously, in any aircraft of this class, it pays to study single-engine performance charts carefully before shoving the throttle levers forward.
Safety
Notwithstanding the 402s lackluster engine-out performance numbers, the airplane gets relatively high marks for safety. A 1980 NTSB study of light-twin engine failure accidents showed its group to be better than average in engine-out safety, in terms of total accident rate per 100,000 night hours as well as fatal accident rate per 100,000 hours following engine failure.
But when the data for the 401/402 is separated from other data, it comes out looking spectacular, with a total engine-failure accident rate of 0.5 per 100,000 hours-better, in fact, than any other piston twin examined by the study. (The next-best score was turned in by the Navajo series. The worst scores were provided by the Aero Commander 500s, at 3.46; the Beech 18, 2.78; and the Cessna Skymaster, 2.39.)
A broader look at the safety picture isn’t quite as good. An examination of FAA Accident and Incident Report data for the 401/402 series during a five-year period around the time of the NTSB engine-failure study (and representative of the record as a whole) reveals a total of 20 fatal accidents. One of these was a midair collision. The rest were a mixed bag, with the majority typical of aircraft that see a lot of commercial use: At least ten accidents occurred in IFR weather, with pilots of four aircraft descending below minimums or landing short. Four planes hit the ground during climb or cruise, at least one of them apparently involved in a buzzing episode. Two aircraft crashed after in-flight engine fires developed. Two more planes-one of them a 401 flown by a pilot with medical problems-rolled inverted on final approach with one engine out. One aircraft overran the end of the runway on a high density altitude takeoff.
Among the nonfatal accidents, several patterns are noticeable. An astounding 82 instances of landing gear failure or collapse (11 on takeoff, 71 on landing) were recorded during the period, 35 of them involving late-model C aircraft. Broken bellcranks, brackets, torque tubes, rod ends, and scissors bolts were among the items mentioned in the write-ups. Poor maintenance was cited in a handful of instances; but in most cases, simple fatigue seemed to be the chief contributing cause.
Maintenance considerations
Like all complex twins the 402 comes with a formidable repertoire of mechanical and operational quirks. The airplanes landing gear, fuel and exhaust systems are notoriously complex and require a lot of maintenance to keep in tip-top condition; the 402s turbocharged Continental TSIO-520 engines (TBO: 1,400 hours) are prone to crankcase cracks; and the wing structure on pre-79 models must be eddy-current inspected at 6,500 hours, and every 1,000 hours thereafter, to detect cracks.
The good news is that Cessna did its homework when it came to ease of maintenance. Unlike some other complex twins, operators report that the 402 (and 400-series Cessnas in general) have good maintenance access and are easy to work on.
Overall, the airplane is said to be reliable, though commercial use is hard on equipment and problems do occur. Aside from the tendency for crankcase cracks (even in the so-called heavy case versions) and notoriously poor ARC radios in some aircraft, there are no glaring maintenance bugaboos to watch for.
There have, however, been a few notable ADs. The most recent of these, 97-26-15, calls for repetitive inspections of the engine mount beams. 95-9-13 mandated replacement of non-compliant fuel inlet valves, and 92-16-18 addressed the need to modify Cessnas Enviroform commuter seats to prevent them from breaking loose. Looking farther back, 90-2-13 called for inspection/replacement of the main landing gear inner barrel bearings, and 75-23-8 required repetitive inspection of the exhaust system.
Modifications
There are a few noteworthy aerodynamic mods for the 401/402. Sierra Industries offers STOL kits, and vortex generators can be had from Micro Aerodynamics and Robertson. Given the airplanes marginal (read typical) single-engine performance, we recommend both. At the other end of the envelope, Precise Flight speed brakes can help with arrivals.
RAM Aircraft Modifications offers powerplant conversion packages for the 402A and B in which the early models TSIO-520-E engines (300-HP, 1400-hr. TBO) are replaced by intercooled TSIO-520-N engines with pressurized magnetos, for a slight improvement in top speed and up to 35 percent improvement in rate of climb.
Organizations
Owners of twin Cessnas have their own support organization in the form of The Twin Cessna Flyer, headed by Larry Ball. Membership gets you a newsletter and the right to attend well-worthwhile seminars on operations. Call (219) 749-2520. The general Cessna group of choice is the Cessna Pilots Association (www.cessna.org, (805) 922-2580).
Owner Comments
What can I say about this aircraft? It is a wonderful machine! We own and operate 11 of these, of all types.
The operating costs are roughly:
Fuel burn: 36 GPH, Engine Reserves: $30/hr, Labor: $20/hr, Parts $20/hr, Insurance $850/mo., $10M liability.
This is probably the most undervalued cabin class twin aircraft in the world. Where else can you find an airplane that lets you haul nine passengers (7 executive) at 180 MPH for $150 an hour?
Handling qualities are great and the ease of maintenance is unsurpassed. Easy access to engine compartments and access panels.
For operations that do not require pressurization this is the aircraft of choice. The A models can actually carry a little bit more weight than the Bs and of course the Cs are unsurpassed in their payload and range as they can carry twice the fuel and have twice the range.
I would invite and challenge the operator of any cabin class twin in the 6-7,000 pound range to stack their aircraft up against the C-402. I wish Cessna built more!
-Larry Balter, President
Sunshine Airlines
Los Angeles, Calif.
The 402B is a benignly conventional airplane-an ordinary, viceless airplane in most ways (if you can call anything with that kind of single-engine performance viceless). Its a big airplane, which is one of the things that makes it nice for smuggling-you cant see in the windows while its parked on the ramp.
We didn’t have particularly good range; three and a half hours was about as far as we could go. We just had wing aux tanks and tips, no locker tanks. We would stop in Albuquerque, then Wichita or St. Louis. Wed often have to stop in Ohio. We could have made it to the East Coast in three hops if we had used small fields, but we wanted to use major airports as much as possible. We flight-planned for 170 knots, flying mostly at 10,000 to 12,000 feet.
Its a pretty uncomfortable airplane on long trips. It makes you want pressurization, if only because the airplane would be quieter, more comfortable. You’re sitting there droning away, and the noise level is high. Its not a true transcontinental airplane.
The airplane does have tremendous cubic capacity. Its unbeatable. We looked at a number of other airplanes, but there was no way to get that kind of space. Our problem was not weight, but cubes-cubic feet. (We were never in any danger of going over gross; our cargo was low-density,) We wanted to avoid having to stack the stuff up against the windows. The nose baggage compartment was great. You can hide a lot of stuff up there.
Other comments about the plane: Single-engine performance was not great. The aircraft would just about hold altitude on a typical California day. That’s about it. The panel was nice, logical-well laid out. We had King radios. Not a hell of a lot of the avionics worked much of the time. It was a nice airplane to land, tremendous crosswind capabilities. It handled like a big, heavy aircraft-which, of course, it was.
The plane handled well overall. You never got the violent pitch-down on initial deployment of flaps, for instance, that you got with the Cessna 310. The book figures were pretty much accurate, for our plane.
The only problem we had with the airplane was that the shrouding of the engines was pretty cheaply done; you had to be very careful to keep the baffles tight.
Also, we had a lot of problems with the left engine, which turned out, eventually, to have zero compression on one cylinder. It ran pretty hot. As a result, the engine gauges were always askew, and you were never quite sure which gauges were right or wrong. (The throttle quadrant was a forest of staggered levers-we never could get anything to line up.) One thing you were sure of was that the paint was discoloring aft of the cooling louvers on the left cowl. So we always ran full rich on that side.
The other slight problem with the 402 is that its too tacky an airplane, in its interior, to be used as the quick-change airplane that it was intended to be. The interior parts are cheap and will not stand up to constant removal and reinstallation. The plastic cracks, the rugs come up, etc. The decals and placards are forever peeling off, too. Its really tacky.
The general feeling the airplane gives you, looking back on it, is one of shoddiness; there’s no quality anywhere. We eventually sold our 402, but you can see why a lot of people in the drug business have no hesitation in simply torching the thing when they’re done with it.
-Name withheld
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