|Cessna 421: Flight of the Golden Eagle|
|Written by Bill Cox|
|Thursday, 24 February 2011 15:03|
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Like many of you, I subscribe to several car magazines, and I’m as much a fan of BMWs and Porsches as the next guy. I’m also just as intimidated by their price tags, but the law of supply and demand is a prime directive. If the car companies could build more units, the prices would come down.
Porsche sells about 75,000 cars a year, most of them under $100,000. Should we really be surprised when Cessna sells somewhere between 700 and 1,000 piston airplanes in a year and the average new airplane costs $350,000 to $400,000?
Such realities sometimes encourage pilots to shop the used market. Consider for a moment what $400,000 will buy on the “pre-owned aircraft” market. You could opt for a used Malibu, a six-seater that will lift two plus four and speed cross country at 200 knots. You could select a used 36 Bonanza, one of the standards of the industry, and fly at lower altitude for shorter distance but still in the lap of luxury.
…Or you could choose one of the ultra-wide-body, cabin-class twins in Cessna’s 400 series. The top of that class was the Cessna 421, the premier piston product from the Wichita company, produced between 1968 and 1985. Though Beech fans might argue in favor of the Duke, the 421 became known as the top pressurized business airplane, if only by weight of numbers. Cessna built nearly 2,000 421s during the airplane’s 17-year model run, and nearly all of those 421s were pressed into corporate service as business transports.
The 421’s fuselage and wing served as templates for the later turboprop Conquest II and I (produced in that order), and the top piston Cessna was almost universally considered the peak of the piston pyramid. As the premier entry in the class, with up to eight seats, a pair of low-revving, geared, 375-hp Continental engines, and a cruise speed better than 220 knots, the 421 quickly assumed the mantle of the most popular and in-demand mode of corporate transport on avgas.
An efficient air conditioning/heating system kept everyone comfortable, and the pressurization system provided air compressed to the equivalent of 8,000 feet while the airplane cruised at FL250, well above 80 percent of the world’s weather and turbulence, most often cruising in smooth air and sunshine. That’s exactly the scenario CEOs and executives of mid-level companies expected of a corporate transport.
The Cessna 421 Golden Eagle, as it was named, seemed to offer it all. Everyone boarded through an airstair door at aft left, and, once seated, passengers luxuriated in a business-class enclosure with dimensions appropriate to the price tag. The cabin was generous, accommodating pilots and passengers in a space that measured 55 inches across by 51 inches tall. It wasn’t standup headroom, but the aisle was wide, and climbing into any seat was a pleasure.
Better still, once you were settled into your bucket, you were typically wrapped in leather, adjacent to fold-down convenience tables. Even the original 421s could be ordered with a wide variety of electronic conveniences, and today’s used airplanes often sport such accoutrements as individual DVD players, game stations, and iPod outlets, plus the usual intercoms, in-flight phone, and even teleconferencing capabilities.
From a pilot’s point of view, especially pilots entering the corporate world in the late 1960s/early 1970s, the 421 must have seemed a monster, nearly 7,000 pounds gross in 1968 and 7,500 pounds on the later models. For an entry-level business airplane (compared to turboprops and jets), the Golden Eagle was a complex machine, fitted with some of the most sophisticated systems in General Aviation. Contrary to sometimes popular belief, turboprops and jets are often easier to fly than the top-level piston twins.
The engines required more than a little study. The 421’s powerplants were various dash letters of the Continental IO-520s. As the designation implies, these were 520-cubic-inch engines, and Cessna used variations of the type on a wide variety of its models. These Continentals were rated between 250 and 375 hp, and Cessna employed them on the company’s big-bore products, from the single-engine Stationair and Centurion to the twin-prop 303, 310, 320, 335, 340, 401, 402, 404, 411, 414, and 421.
The 421’s variation was, predictably, the largest and most powerful of the group, specifically the GTSIO-520-N, a geared (G), turbosupercharged (TS), injected (I), opposed (O) mill approved for 375 hp. The turbocharger had a critical altitude of about 18,000 feet, so the airplane could maintain 75 percent power at 25,000 feet. Technically, the 421 was alleged to have a service ceiling above 30,000 feet, and in the old days when there were no limitations on altitude, some pilots did try to cruise at such tall heights.
Today, reduced vertical separation minima (RVSM) rules have made flying above FL280 more expensive, so few 421s are certified for operation at the top of their ceiling (assuming you could get there in the first place). Complying with RVSM regulations to allow flight above 28,000 feet can cost as much as $100,000, making such an expensive mod unlikely on an airplane in the $300,000 to $400,000 class.
Climbing to altitude was expedited by a power loading of less than 10 to one, one of the primary indicators of efficient climb. In an ascent from sea level, the 421 could manage 1,800 feet per minute (fpm) or more, allowing climb to the lower flight levels in less than 15 minutes. A climb to the airplane’s optimum height of 25,000 feet required less than 25 minutes.
Once you were established at your chosen altitude, speed could be pretty much as you liked it, depending upon how much fuel you were willing to pour through the engines. Max cruise at 75 percent demanded about 20 gallons per engine per hour, but the reward was cruise speeds in the area of 220 knots. Standard fuel capacity was 213 gallons, so a trip at max cruise allowed the airplane to linger aloft for 4.5 hours and cover 1,000 nautical miles (nm) in the process. Optional, long-range fuel capacity was 262 gallons, a worthwhile option for corporate flight departments that needed to travel long distances.
To increase range and reduce fuel burn, smart pilots reduced to 65 or even 55 percent power, still traveling at 200 knots and extending range to 1,200 nm, enough to cross the lower United States with one stop in a single day.
The 421’s engines were initially demanding machines, rated for only 1,200 hours on the early models, one of the lowest TBOs of any modern engine. Overhauls cost $40,000-$50,000, so there’s a strong incentive to treat them gently. (Later versions on the 1978-and-later 421s were rated for 1,600 hours.)
Ham-handed slamming of throttles fore and aft has always been regarded as a bush-league technique on any airplane, but the gearing system on the 421 demanded kid-glove treatment. Power applications had to be slow and deliberate, and power reductions needed to be even slower to avoid any possibility of shock cooling. Engines are constructed of a number of metals with different rates of expansion and contraction related to temperature change, so the slower you change internal operating temps, the better. Some pilots even used the rule of no more than one inch of manifold pressure reduction per minute. That’s probably a little extreme, but it was important to keep throttle jockeying to a minimum.
Runway requirements for the 421 wouldn’t allow operation into short strips, but most reasonably sized airports with paved runways could accommodate the big twin. The 50-foot obstacle clearance distance was typically about 2,200 feet for both takeoff and landing, and that opened up most runways of 3,000 feet or more located near sea level. The turbos provided sea-level power at higher altitudes, but while turbochargers could provide the engines with full power, there was no way to turbocharge the wings. This dictated some caution for both takeoff and landing.
For takeoff, most Golden Eagle pilots taxied into position, brought power up to 50 to 60 percent with the brakes set, then released the binders and eased the power forward to the stops. This allowed the airplane to accelerate at max rate without undue wear on the brakes and without subjecting the engines to poor cooling in a dead stopped condition.
For landing, the rule was to allow aircraft drag configuration to govern speed and descent rather than adjust power to control velocity. The type was never offered with speed brakes (an STC offered later), but an experienced pilot could control altitude and speed by using all of the drag devices he had; expeditious deployment of landing gear and flaps.
Once you were used to the airplane, you could graduate both speed and altitude by setting the power at a predetermined level, then extending the wheels and flaps to regulate the glide path.
Landing the airplane wasn’t that difficult, as long as you kept the speed up. Dirty stall was 74 knots, so approaches worked best at 110 knots or more. Some pilots preferred to land the airplane with some power on. Others gradually wiped out all power in the flare and eased the 421 onto the ground.
Today, the 421’s performance pales in comparison to some of the single-engine turboprops that can deliver more speed on the same burn of jet fuel. The Piper Meridian, SOCATA TBM 850, and Pilatus PC-12 all deliver speeds in excess of 250 knots. The question is whether two piston engines provide more reliability than a single, turbine engine.
The obvious difference is the price tag. Even older, used examples of the three single-engine turboprops rarely sell for less than $1.0 million, whereas later-model 421s can be had for $400,000 or less. If you’re willing to drop back to Golden Eagles from the late 1970s, you can buy a reasonable example for $200,000.
Obviously, operating costs and maintenance are major considerations for corporate operators. Another factor that may affect the buying decision is configuration. Some companies’ insurance policies don’t allow executives to travel on airplanes with less than two engines. Though pilots may believe a single-engine turboprop is more reliable than a twin piston, insurance companies control the world. Corporate operators have no choice but to live with policy demands.
With the gradual improvement of metallurgy and the state of the art in engine overhaul, the Cessna 421 has transitioned from a corporate lifting body to a family transport, easily capable of hauling Mom, Dad, and four kids on trips near and far. More and more of the type are making the shift from business to pleasure flying.
Cessna’s 421 Golden Eagle most definitely is not the cheapest airplane to operate, but it does offer more than enough for less than too much.
From the November 2010 issue of Cessna Owner