Piper Cheyenne

piper cheyenneThose in the market for a used, entry-level turboprop twin have a lot of choices these days. The trick, as always, is to find the airplane that offers the most features for the money, fits typical mission requirements, and hits a prospective owner’s emotional hot buttons. Of course, high on the list of importance is speed. But good looks, affordability, and ease of maintenance are just as important. For a large number of buyers, the early models of Piper’s Cheyenne series fulfill these requirements. By “early models,” we mean the original Cheyenne (later renamed Cheyenne II), the Cheyenne IA, and the stretched Cheyenne IIXL. The other three Cheyenne models, the III, IIIA, and 400LS, don’t really fit into the entry-level category.

Design work on the Cheyenne began in 1965 as a turboprop-powered version of Piper’s Pressurized Navajo. The Navajo airframe was fitted out with 620-shaft-horsepower Pratt & Whitney PT6A-28 engines, given a pair of 30 gallon wing-tip fuel tanks, and certified in May 1972. This model, designated the PA-31T-620, was manufactured from 1974 to 1977. Some 178 of these Cheyennes were built, and they were very popular in their day.

The Cheyenne is no slouch in the cruise department, either. Its maximum speed at optimum altitude is advertised as 283 KTAS, and it has range-verses-payload numbers very comparable to the King Airs.

In 1978, Piper came out with another version of the Cheyenne, the Cheyenne I. In acknowledgement of the original faults (too powerful engines making the aircraft less stable longitudinally- don’t worry Piper had a stability augmentation system fix for this but it’s important to be aware of in a high angle of attack situation, such as during takeoff or go-around), the I was given less powerful, 500-shp PT6A-11 engines, and the aft CG limit was brought 2 inches forward. Because of the reduced power, initial climb rate dropped by almost 1,000 fpm compared to the original model, and maximum cruise speed fell by 40 knots. However, the Cheyenne I’s changes allowed the airplane to be certified without a stability augmentation system. To sweeten the deal, the Cheyenne I was some $100,000 less than the 620-shp model. A standard Cheyenne I came without wing-tip fuel tanks, but they were available as an option, and almost everyone anted up.

At the same time, the original Cheyenne was renamed the Cheyenne II. Nothing much changed but the name, though many still think the Cheyenne and Cheyenne II are two different airplanes. They aren’t. There were some cabin changes but that was about it. In 1981, auto-ignition was first offered as an option.

Cheyennes I and II were manufactured from 1978 to 1983. The Cheyenne I, with 189 sales formed a solid niche but was no match for the II’s impressive sales record of 343 airplanes.
The Cheyenne IIXL, manufactured from 1981 to 1984, is basically a Cheyenne II with a 2-foot stretch – all of it forward of the main spar. This forward movement of the airplane’s empty-weight CG, along with a climb power limitation of 500-shp, allowed the IIXL to be certified without the stability augmentation system. The IIXL is also the most versatile load-hauler of the all the early Cheyennes. Its possible to fill up all eight of the IIXL’s seats (with 170-pounders, that is), put 200 pounds each in the nose and aft baggage areas, still be within the loading envelope, and be just 20 gallons shy of full fuel. In this condition, you could take off, climb to 29,000 ft, cruise at 250 KTAS or so, and have an IFR range of about 1,170 nautical miles and an endurance of 4 hours 30 minutes. A total of 81 IIXLs were sold.

The Cheyenne IA, a slightly modified version of the Cheyenne I, came along in 1984. Wing-tip fuel tanks were standard with this airplane, and so were redesigned engine air intakes and elongated exhaust stacks. Compared to the I, these engine improvements gave the IA up to 12 more knots at the IA’s service ceiling of 29,000 feet and about 6 knots at maximum cruise power and 12,000 feet. As with the Cheyenne I, there is no stability augmentation system.

With just 20 sales, the IA is the rarest Cheyenne. Production was halted after just one year of production.

But take a high-performance turboprop twin at a bargain-basement price, add a macho pilot with limited experience and training, then toss in an engine failure, IFR weather, or any kind of distraction. That’s a recipe for a bad accident rate. The record shows that, when it comes to safely stepping up to turboprops, there is simply no substitute for a regimen of structured recurrent training. The courses offered by outfits such as FlightSafety International and SimCom, which include extensive classroom and simulator time, are excellent for obtaining and maintaining Cheyenne proficiency.

For an aging airplane, the Cheyennes have remarkably few major maintenance problems or airworthiness directives. Structurally, they have weathered well over the years. Corrosion of the airframe has been rare, thanks to Piper’s use of extensive anti-corrosion treatments and epoxy primers. Parts availability for older Cheyennes hasn’t been a problem. Piper still stocks a lot of parts, but if a Cheyenne part is unavailable, Piper will still make you one.

For both individual and corporate owners, the early Cheyennes make sense as step-up purchases, as long as the combination of low price, low maintenance, and high-performance remains in vogue. If you train for and respect the airplane’s high performance, understand the II’s loading limitations, and look beyond the stability augmentation system brouhaha, the Cheyenne will reward you with pleasant handling, great capability, and classy ramp presence.

Used Turbine Review: Cheyennes: The I, IA, II, AND IIXL
Thomas A. Horne, AOPA Pilot, June 1993

The airplane is a six/seven-place, twin-engine, low wing, retractable landing gear, turbine-powered airplane with a pressurized cabin available
This airplane is certified in the normal category. In the normal category all aerobatic maneuvers including spins are prohibited. The airplane is approved for day and night VFR/IFR operations when equipped in accordance with F.A.R. 91 or F.A.R 135.

The Cheyenne I is powered by two Pratt & Whitney PT6A-11 turboprop engines, each rated at 500 horsepower and with a maximum propeller speed of 2200 RPM. This engine has a reverse flow, free turbine arrangement.

The fuel system for the turbine powered PA-31T1 has a total capacity of 308 U.S. gallons. Fuel is carried in six tanks – three interconnected tanks in each wing: a wet nacelle tank, and two bladder-type fuel cells. With the optional tip tanks installed, the fuel capacity is increased to 390 U.S. gallons. The right and left furl systems are independent of each other and are connected only when a crossfeed system is activated. Each inboard main cell has two submerged boost pumps to supply fuel to the engine. Vents for the fuel system are NACA type, anti-icing, non-siphoning vents which incorporate flame arrestors. The fuel system can be monitored through several gauges on the instrument panel through a dual needle type fuel quantity indicator, two fuel flow gauges, and two fuel pressure gauges.

Electrical power is supplied by a 28 volt, direct current, negative ground electrical system. Two 30 volt, 200 ampere, D.C. starter/generators in parallel provide torque for engine starting and generate D.C. electrical power. One 24 volt, 43 ampere hour air-cooled nickel-cadmium battery, located in the nose section furnished power for engine starting and also serves as a reserve source of emergency electrical power.

  1978 PA-31T1
 Piper Cheyenne I
1984 PA-31T1
 Piper Cheyenne 1A
1984 PA-31T2-620 Piper Cheyenne II XL
Engine:      
Model 2 P&W PT6A-11 2 P&W PT6A-11 2 P&W PT6A-135
No. Cylinders N/A N/A N/A
Displacement N/A N/A N/A
HP 500-shp each engine 500-shp each 620-shp each
Carbureted Or Fuel Injected N/A N/A N/A
Fixed Pitch/ Constant Speed Propeller Constant Speed Constant Speed Constant Speed
       
Fuel:      
Fuel Capacity 308 gallons
Long Range Tanks: 390 gallons
390 gallons 390 gallons
Recommended Engine Fuels PWA-555/CPV-46 grade PWA-555/ CPW-46 PWA-555/ CPW-46
Fuel Burn-Maximum Cruise Power at ISA S.L.-648 lbs./hr.
14,000ft- 544 lbs./hr.
29,000ft- 340 lbs./hr.
Unknown Unknown
       
Weights and Capacities:      
Takeoff/Landing Weight Normal Category 8,700 lbs. 8,700 lbs. 9,474/9,000 lbs.
Takeoff/Landing Weight Utility Category N/A N/A N/A
Standard Empty Weight 4,900 lbs. 5,111 lbs. 5,487 lbs.
Max. Useful Load Normal Category 3,800 lbs. 3,589 lbs. 3,987 lbs.
Max. Useful Load Utility Category N/A N/A N/A
Baggage Capacity 500 lbs. 500 lbs. 500 lbs.
Oil Capacity 2.3 gallons each engine 2.3 gallons each engine 2.3 gallons each engine
       
Performance      
Max Operating Speed – see POH for speeds above listed altitudes 246 KCAS
Up to 9,500ft
With Tip Tanks
246 KCAS
Up to 9,500ft
246 KCAS
Up to 12,000ft
Max. Structural Cruising Speed N/A N/A N/A
Stall Speed Clean 86 Knots 85 Knots 86 Knots
Stall Speed Landing Configuration 72 Knots 72 Knots 77 Knots
Climb Best Rate 1750 FPM 1750 FPM 1750 FPM
Wing Loading 38 lbs./sq. ft. 38 lbs./sq. ft. 41.37 lbs./sq. ft.
Power Loading 8.7 lbs./hp 8.7 lbs./hp 7.64 lbs./hp
Service Ceiling 29,000 ft. 28,200 ft. 32,400 ft.