The ultimate King Air

Photography by Mike Fizer

When most general aviation pilots think of the biggest King Air, they’re most apt to name the King Air 350i. That’s the eight-seat, double-club executive model, the one with Rockwell Collins’s Venue entertainment system, the 313-knot maximum cruise speed, and the 15,000-pound max takeoff weight. The airplane’s been in the news lately. Last year, Wheels Up, a club-style private membership aviation company, bought 105 of them in a deal worth some $788 million.

By passing the 12,500-pound max takeoff weight mark, Beechcraft certified the 350i and its predecessor variant, the model 300, under FAR Part 23’s Commuter category. This category allows already certified airplane designs with maximum takeoff weights up to 19,000 pounds and fewer than 19 seats to come under rules less stringent than those for FAR Part 25 Transport Category—but more strict than the basic FAR Part 23 rules affecting light airplanes. There must be multiple load paths for structural elements, dual trim tabs, fire detection and extinguishing systems, and published one-engine-inoperative climb gradients, for example. A type rating is still required to fly the King Airs 300 and 350i, but the airplanes can be flown by a single pilot as long as the necessary training is completed.

But the biggest, most versatile King Air—the 350ER—hit the market in 2007. Because of its principal intended market, most may not be familiar with the ER. Like the 350i, the heavy-hauling ER (and its executive version, the 350iER) is powered by twin Pratt & Whitney PT6A-60 engines of 1,050 shaft horsepower apiece. But its max fuel capacity is 775 gallons, which is 236 more gallons than the 350i. And its max takeoff weight is 16,500 pounds—1,500 pounds more than the 350i. The result is an airplane with a max payload of 2,792 pounds, a full-fuel payload of 1,215 pounds, a maximum range of up to 2,450 nautical miles, and a maximum endurance of 12 hours. Oh, and the ER is approved for operations off of dirt, grass, or gravel landing strips.

Special missions

It’s this combination of attributes that makes the ER variants adaptable to a wide range of special missions. Under Textron’s Project Liberty, some 40 ERs (dubbed MC–12Ws) were sold to the United States Air Force for use in combat intelligence, surveillance, and reconnaissance missions. Some of them augment Predator and Reaper drone operations. The Iraqi air force has 350ERs it calls “Peace Dragons,” armed with Predator payloads. The U.S. Customs and Border Protection also uses 350ERs, and a maritime patrol variant also is in use. These airplanes are fitted with electro-optical, infrared, and television cameras, plus search radars and drop hatches. The MC–12Ws even have missile warning systems, complete with flare and chaff dispensers. Still other 350ERs see duty as air ambulances, aerial survey platforms, and navaid inspections systems. And yes, the executive version—the 350iER—is usually fitted out with eight plush, swiveling leather seats.

Big-rig features

A quick walkaround showcases the ER’s special design and systems elements. To handle the ship’s extra weight, the landing gear have been beefed up. This includes sturdier struts and drag links, plus larger and thicker tires. A brake-heating system, fed by engine bleed air, keeps rotors and pads free of ice and is also standard. In all, the heavied-up landing gear add 90 pounds to the ship’s empty weight.

For that off-runway approval, there are large Kevlar panels on the undersides of the inboard wing area, erosion-resistant tape on the leading edges of belly-mounted antennas, and a metal cage around the belly’s rotating beacon. As for the engines ingesting dirt and other foreign objects, their inertial separators take care of the job by routing debris away from engine induction air and send it overboard via what is in essence a trap door.

You can’t miss the distinctive shape of the nacelle fuel tanks, which contain the ER’s extra fuel—118 gallons per side. A redesigned fuel control panel keeps track of the increased maximum fuel load. The fuel system has three fuel tanks per side: main, auxiliary, and the ER’s nacelle tank. Normally, the nacelle tanks draw fuel first, then the auxiliary tanks and then the mains, which use gravity feed and motive-flow pumps to move fuel to collector tanks before being sent to the engines.

The ER also has a new environmental system, one with vapor cycle air conditioning that uses two condensors and two evaporators for faster cabin temperature drawdowns in hot weather. There are also more gaspers/Wemacs in the newer models of all 350s.

To boost rudder effectiveness in engine-out situations, a spanwise, airfoil-shaped strip is attached to the rudder’s trailing edge. This “tricks” the rudder into behaving as though its area is enlarged, according to Roger Hubble, Textron’s senior vice president for special missions. A similar strip is on the airplane’s left aileron, as is the case with all other 350s.

And what happens should an engine lose power? Its igniters will come on automatically as soon as torque drops below 17 percent. If that doesn’t work, and torque decreases further, the propeller autofeathers. When sensors detect asymmetric torque, an electronic servo actuation system automatically applies the correct amount of rudder deflection to help the pilot compensate for the associated yawing moments.

A long cross-country

N350KA is a 350ER special-missions demonstrator that’s been making the rounds worldwide. A few months ago it was in Wichita, at the Beech Factory Field, which gave us the opportunity to test it.

The nonstop trip was from Beech Factory Field to AOPA’s home base at the Frederick Municipal Airport in Maryland—a distance of 948 nm on our cleared route. Demonstration pilot Luke Scott fed the numbers into the Rockwell Collins Pro Line 21 before startup: A +5-degree Celsius outside air temperature and a field elevation of 1,408 feet, a takeoff weight of 14,820 pounds, with five and bags aboard—and an interior designed to show off a hybrid setup, one with forward club seating and an aft section set up with single-stretcher air ambulance gear. (The airplane is capable of handling two stretchers). Our V1 came up as 106 knots, VR was 110 knots, and V2 was 117 knots. Our balanced-field takeoff length was 4,680 feet. Those are light jet numbers.

For takeoff, it was push up the power levers until the torque values were just shy of redline, release the brakes, and monitor torque as the airplane stormed down the runway and ram air pushed torque slightly upwards. All King Airs are non-FADEC (full authority digital engine controls) airplanes, meaning, among other things, that the pilot must manually ensure that torque limits and interturbine temperature redlines aren’t exceeded. There are no computers to automatically suppress redline excursions, or automatically shut down an engine during a hot start.

Initially, our climb rate was 2,500 fpm. Passing through 24,000 feet, the climb rate held strong at 1,400 fpm. Altogether, using a cruise-climb airspeed of 170 knots, it took us 22 minutes to reach our cruise altitude of 31,000 feet. There, conditions were ISA +2 degrees Celsius. After consulting the flight manual, power was set for max cruise: 66 percent torque and 1,500 propeller rpm, for a fuel burn of 300 pph (about 45 gph) per side. The Pro Line 21 posted a true airspeed of 291 knots. Meanwhile, the 6.6 psi differential pressurization system yielded a cabin altitude of 8,800 feet.

According to Textron, the 350ER’s fastest speed—303 KTAS—happens at FL240, where fuel burns run around 380 pph (57 gph) per side. But today, FL310 worked out just fine, what with 60-knot tailwinds. We could have gone higher (the airplane is capable of operations in RVSM—reduced vertical separations minimums) because its certified ceiling is 35,000 feet.

Soon, we were over West Virginia with a 363-knot groundspeed and it was time to descend. I won’t claim proficiency in working the Pro Line 21, but Scott can make it sing and he quickly programmed the crossing fixes and altitudes for the descent phase, and the autopilot followed along.

For the visual approach, Scott advised pulling back the torque to 20 percent, then using 120 knots for pattern entry, followed by the first notch of flaps, then gear down at the key position, followed by full flaps on final and a deceleration to the VREF of 104 knots as we crossed the threshold. At the radar altimeter’s 50-foot countdown mark, power goes to flight idle. Then it’s pitch up a degree or so for the flare, wait for touchdown, and go into reverse thrust after the nosewheel contacts the runway. That’s in an ideal world. Me, I floated too much but all ended well.

After shutdown, the Pro Line 21 told the story. We flew the trip in two hours, 53 minutes, averaging a 275-knot true airspeed, a 328-knot groundspeed, and a total fuel burn of 2,040 pounds (about 304 gallons). We had approximately 3,000 pounds (about 448 gallons) of fuel left in the tanks, and could have flown at least another 1,000 miles!

ER as VIP

It’s easy to understand the 350ER’s appeal in military or surveillance roles, but its capabilities as a people-mover can’t be discounted. Sure, 1,000- to 2,000-nautical-mile trips are best served by jets. But that’s not the whole story. Of the 120 ERs delivered so far, 18 have been put in airline service in Africa, where only 20 percent of airports have fuel—and even more have sporadic fuel service or poorly controlled fuel quality. The ER’s ability to tanker fuel comes in handy here. The Saudi Arabian government operates ERs with club seating in front and forward-facing seats in the aft cabin. Private owners have also bought 350iERs. One Canadian owner likes to fly groups from California to Hawaii, and then use the airplane to visit islands within the chain.

No question about it, King Airs have retained a strong hold on the turboprop market—even though they retain their legacy systems and panel layouts. And even though competing models are designed and manufactured by computer, and fly higher and faster. What’s the secret? From the beginning, customers always cite the cabin dimensions and appointments; the sense of substance and quality, inside and out; and the airplane’s ramp appeal. Over its 50-year production run the airplane has also proven adaptable to change, amenable to several cabin stretches and hikes in engine power. The ER model is more proof of that. But you have to ask yourself: How much further can the design evolve?

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SPEC SHEET

Textron Aviation Beechcraft King Air 350ER

2015 base Price: $ 7.98 million

Average equipped price, executive interior: $ 8.4 million

Specifications

Powerplants | (2) Pratt & Whitney PT6A-60A, 1,050 shp ea

Recommended TBO | 3,600 hr

Recommended HSI | 1,800 hr

Length | 46 ft 8 in

Height | 14 ft 4 in

Wingspan | 57 ft 11 in

Wing area | 310 sq ft

Wing loading | 53.23 lb/sq ft

Power loading | 7.86 lb/hp

Seats (includes pilot) | 11

Cabin length (between pressure bulkheads) | 24 ft 10 in

Cabin width | 4 ft 6 in

Cabin height | 4 ft 9 in

Basic operating weight (1 pilot, slick interior) | 9,460 lb

Max ramp weight | 16,600 lb

Max takeoff weight | 16,500 lb

Zero fuel weight | 13,000 lb

Max useful load | 7,140 lb

Max useful load, as tested (1 pilot) | 6,407 lb

Payload w/full fuel | 1,948 lb

Payload w/full fuel, as tested | 1,215 lb

Max landing weight | 15,675 lb

Fuel capacity | 775 gal usable 5,192 lb usable

Baggage capacity, aft | 550 lb, 55 cu ft

Performance

Balanced field length, SL @ 15 deg C/ 59 deg F, | 4,056 ft

Balanced field length, 5,000 ft @ 25 deg C / 77 deg F | 7,675 ft

Max demonstrated crosswind component | 20 kt

Rate of climb, sea level | 2,400 fpm

Single-engine ROC, sea level | 337 fpm Cruise speed/1 + 4 pax range w/NBAA fuel rsv, std fuel (fuel consumption, ea engine) @ Max power setting, 28,000 ft | 298 kt/1,930 nm (332 pph/49.6 gph per engine) @ Max range setting, 33,000 ft | 238 kt/2,513 nm (201 pph/30 gph per engine)

Max operating altitude | 35,000 ft

Service ceiling | 35,000 ft

Single-engine service ceiling | 17,100 ft

Sea-level cabin | 15,293 ft

Limiting and recommended airspeeds

V_R (rotation) | 104 KIAS

V₁ (takeoff decision speed) | 100 KIAS

V_MCA (min control w/one engine inoperative, air) | 101 KIAS

V₂ (takeoff safety speed) | 111 KIAS

V_A (design maneuvering) | 182 KIAS

V_FE (max flap extended) | 202 KIAS

V_LE (max gear extended) | 182 KIAS

V_LO (max gear operating) Extend | 182 KIAS, Retract | 164 KIAS

V_REF (reference speed, final approach) | 107 KIAS

V_MO (max operating speed) | 192-245 KIAS

M_MO (max Mach number) | 0.58 M

V_S1 (stall, clean) | 98 KIAS

V_SO (stall, in landing configuration) | 80 KIAS

For more information contact Beechcraft Corporation, Post Office Box 85, Wichita, Kansas 67201-0085; telephone 800-949-6640; www.beechcraft.com

All specifications are based on manufacturer’s calculations. All performance figures are based on standard day, standard atmosphere, sea level, maximum gross weight conditions unless otherwise noted.

Extra: The 350ER’s landing gear are virtually identical to the design used in Beechcraft’s 1900D, which has a max takeoff weight of 17,120 pounds.

Video Extra: Fly along with us in this online video.