Cheyenne III

The PA-42 Cheyenne III was announced in September 1977. The first production Cheyenne III flew for the first time on May 18, 1979, and FAA certification was granted in early 1980. Compared with the Cheyenne II, the PA-42-720 was about 1 m (3 ft) longer, was powered by 537 kW (720-shp) PT6A-41 turboprops and introduced a T-tail, the most obvious external difference between the PA-31T and PA-42, as well as the most significant change to the series. Deliveries of production Cheyenne IIIs began on June 30, 1980.^[2]

Cheyenne 400

In the late 1970s, Piper avoided developing a clean-sheet light business jet to compete with the Cessna Citation I and upgraded its PT6As from 720 to 1,000 hp (540 to 750 kW) Honeywell TPE331-14s.^[3] The PA-42-1000 Cheyenne IV was certified in 1984, 44 were built until 1991 and 37 remain in service in 2018.^[3]

Due to its top speed over 400 mph, it was renamed the Cheyenne 400LS when Lear Siegler owned Piper, then the Cheyenne 400.^[3]

Flat rated to ISA+37, the turboprops maintain their power to almost 20,000 ft (6,100 m). The 106 in (2.7 m) Dowty Rotol propellers had four round-tip composite blades and 8 in (20 cm) of ground clearance. Its empennage was enlarged for stability at higher speeds and altitudes, and its fuselage was strengthened. Pressurization was increased to 7.6 psi (0.52 bar) to elevate its ceiling from 35,000 to 41,000 ft (10,700 to 12,500 m) while maintaining a 10,000 ft (3,000 m) cabin.^[3]

The aircraft's top speed is 351 kn (650 km/h; 404 mph) and was faster than the Citation I on most trips while burning one-third less fuel. It can cruise at the same long-range speed over 1,842 nmi (3,411 km), 400 nmi (740 km) more; it can carry eight passengers farther than a King Air 200 while cruising 50 kn (93 km/h) faster. It can operate out of 3,000 ft (900 m) runways with a 97 kn (180 km/h) minimum control speed, similar to a King Air 300; it can operate from much shorter hot and high runways than a Citation I and landing is shortened by the rotating speedbrake effect of the propellers in beta pitch.^[3] It can climb directly to FL 410 at its 12,050 lb (5,470 kg) MTOW and typical single-pilot BOWs are 7,850–7,900 lb (3,560–3,580 kg). It can hold 3,819 lb (1,732 kg) of fuel plus two passengers with baggage, while each extra passenger costs 100 nmi (190 km) of range. It has a 98% dispatch reliability and its cabin is quieter than a King Air.^[3]

The 400LS made aviation history on 16 April 1985 by setting two new time-to-climb records for its class (C-1e Group 2, 3000m and 9,000m) and shattering two time-to-climb records for all turboprop classes (6,000m and 12,000m): with retired United States Air Force Brigadier General Chuck Yeager at the helm of N400PS (with co-pilot Renald "Dav" Davenport flying right-seat), the aircraft departed from Portland-Hillsboro Airport's Runway 31L, immediately reached a 5,959-foot-per-minute climbout and achieved its 3,000m record in 1 minute, 47.6 seconds; the 6,000m record in 3 minutes, 42.0 seconds; its 9,000m record at 6 minutes, 34.6 seconds; the 12,000m record at 11 minutes, 8.3 seconds (time-to-altitude records were captured by on-board video camera aimed at relevant panel gauges, timed with superimposed timer; also verified by Hillsboro Airport tower personnel via radar, using encoded altimeter data transmitted from aircraft to tower via transponder). Other records later set by the 400LS, again piloted by Yeager in 400LS N4118Y (later reregistered as N46HL) for the C-1e Group 2 class, were: Miami-to-Boston, Miami-to-New York City, San Francisco-to-Charleston, West Virginia, San Francisco-to-Cincinnati, San Francisco-to-Los Angeles, New York City-to-Paris, Washington, DC-to-Paris and Gander-Paris.^[4][5][6]

The 400LS has 100-hour inspection intervals, engine midlife inspections are due at 1,500 hours and overhauls come at 3,000 hours. The fuselage is limited to a 15,000-hour life, while the wing and empennage have 20,000-hour life limits.^[3]