Piper PA-31 Navajo explained

The Piper PA-31 Navajo is a family of twin-engined utility aircraft designed and built by Piper Aircraft for small cargo and feeder airlines, and as a corporate aircraft. Production ran from 1967 to 1984. It was license-built in a number of Latin American countries.

Development

In 1962, Piper began developing a six- to eight-seat twin-engined corporate and commuter transport aircraft under the project name Inca, at the request of company founder William T. Piper. Looking like a scaled-up PA-30 Twin Comanche, the PA-31 made its first flight on 30 September 1964, and was announced later that year. It is a low-wing monoplane with a conventional tail, powered by two Lycoming TIO-540-A turbocharged engines in "tiger shark" cowlings, a feature shared with the Twin Comanche and the PA-23 Aztec.

As testing proceeded, two cabin windows were added to each fuselage side and the engines were moved further forward. The PA-31, named "Navajo" after the native American tribe, was certified by the FAA on 24 February 1966, again in mid-1966 with an increase in maximum takeoff weight (MTOW) from, and deliveries began in 1967.

The PA-31-300 was certified by the FAA in June 1967, the only variant without turbocharged engines: Lycoming IO-540-M1A5 engines driving two-bladed propellers. Unofficially, the initial model was referred to as the PA-31-310. Only 14 PA-31-300 were built in 1968 and 1969: the smallest variant production.

In January 1966, development of the PA-31P Pressurized Navajo had begun : Piper's first pressurized aircraft. The PA-31P (or PA-31P-425 unofficially) was certified in late 1969. It was powered by Lycoming TIGO-541-E engines, had a longer nose, fewer and smaller windows, fuel tanks in the engine nacelles and a one-piece airstair cabin entry door instead of the split pair of doors. MTOW was increased to . The PA-31P was produced from 1970 to 1977.

The 1971 Navajo B featured air conditioning, new storage lockers in the rear of the engine nacelles, increased baggage space, a third door next to the cabin doors for easier baggage loading, and an optional separate door for the pilot to enter the cockpit.

In September 1972, Piper unveiled the PA-31-350 Navajo Chieftain, a Navajo B stretched by for up to ten seats, with more powerful engines and counter-rotating propellers to prevent critical engine handling problems. The Chieftain was powered by Lycoming TIO-540 variants, with an opposite-rotation LTIO-540 on the right-hand wing, and MTOW was increased to . Deliveries started in 1973, after a delay due to a flood caused by Hurricane Agnes at Piper's factory in Lock Haven, Pennsylvania.

The 1974 PA-31-325 Navajo C/R was base on the Navajo B. The Navajo C/R had, lower rated versions of the Chieftain's counter-rotating engines. It was certified in May 1974, and production commenced in the 1975 model year. The Navajo B was also superseded in 1975 by the Navajo C.

In May 1981, Piper established its T1000 Airliner Division at its Lakeland, Florida, factory. The PA-31-350T1020 (or T1020) was a PA-31-350 Chieftain optimized for and marketed for the commuter airline market, without the auxiliary fuel tanks in each wing. Up to eleven seats could be fitted, and baggage capacity was reduced from maximum. The first T1020 was delivered in December 1981.

The PA-31T3 (T1040) was a hybrid with the PA-31-350T1020 main fuselage, and the nose and tail of the PA-31T1 Cheyenne I. The wings were similar to the Cheyenne I's, but with reduced fuel capacity and baggage lockers in the engine nacelles similar to those of the Chieftain. An optional underbelly cargo pod was also available. The Pratt & Whitney Canada PT6A-11 turboprop engines were the same as those of the Cheyenne I. Deliveries began in July 1982. A T1050 variant was proposed, with a fuselage stretch of and seating capacity for 17, but did not proceed.

The PA-31P-350 Mojave was also a hybrid, a piston-engined Cheyenne. The Mojave combined the Cheyenne I fuselage with the Chieftain tail. The Chieftain's wings were strengthened, their span was wider and the fuel capacity was enlarged to . The engines variants had intercoolers, and the rear part of the nacelles were baggage lockers. The Mojave's MTOW rose by to . Certified in 1983, like the T1020 and T1040, the Mojave was produced in 1983 and 1984; combined production with the T1020 and T1040 was below 100 aircraft. Two experimental PA-31-353s were also built in the mid-1980s.

Licensed manufacture

The PA-31 series was manufactured under licence in several countries from kits of parts supplied by Piper. Chincul SACAIFI in Argentina assembled most of the series as the PA-A-31, PA-A-31-325, PA-A-31P and PA-A-31-350 and Aero Industrial Colombiana SA (AICSA) in Colombia assembled PA-31, PA-31-325 and PA-31-350 aircraft. The PA-31-350 Chieftain was also assembled under licence in Brazil by Embraer as the EMB 820C Navajo. In 1984, Embraer subsidiary company Indústria Aeronáutica Neiva began converting Embraer EMB 820Cs by installing Pratt & Whitney Canada PT6 turboprop engines; Neiva called the converted aircraft the Carajá.

Variants

Initial production version, also known unofficially as the PA-31-310.
  • PA-31-300 Navajo
  • Variant of the Navajo with normally aspirated engines; 14 built.
    PA-31 Navajo B
  • Marketing name for 1971 improved variant with 3100NaN0 Lycoming TIO-540-E turbo-charged piston engines, new airconditioning and optional pilot access door and optional wide utility door.[1]
    PA-31 Navajo C
  • Marketing name for 1974 improved variant with 3100NaN0 Lycoming TIO-540-A2C engines and other minor improvements.
    PA-31P Pressurized Navajo
  • Pressurized version of the PA-31 Navajo, powered by two 425-hp (317-kW) Lycoming TIGO-541-E1A piston engines.
    Referred to as the "Navajo C/R" for Counter-rotating; variant of Navajo with counter-rotating engines introduced with the PA-31-350 Chieftain. 325hp Lycoming TIO-540 / LTIO-540 engines
  • Stretched version of the Navajo with more powerful 350-hp (261-kW) counter-rotating engines (a Lycoming TIO-540 and a Lycoming LTIO-540) to eliminate critical engine issues.
  • PA-31P-350 Mojave
  • Piston-engined variant of the PA-31T1 Cheyenne I; 50 aircraft built.
    PA-31-350T1020
  • Also known as the T1020/T-1020; variant of the PA-31-350 Chieftain optimised for commuter airline use, with less baggage and fuel capacity and increased seating capacity (nine passengers). First flight September 25, 1981. 21 built.[2]
    PA-31T3
  • Also known as the T1040/T-1040; turboprop-powered airliner with fuselage of the PA-31-350T1020, and wings, tail and Pratt & Whitney Canada PT6A-11 engines of PA-31T Cheyenne. First flight July 17, 1981. 24 built.[3]
    PA-31-353
  • Experimental version of PA-31-350; two built.
    T1050
  • Unbuilt airliner variant with fuselage lengthened by 11feet compared to the PA-31-350.
    EMB 820C
  • Version of Chieftain built under license by Embraer in Brazil.
    Neiva Carajá
  • Turboprop conversion of EMB 820C, fitted with two Pratt & Whitney Canada PT6A-27 engines flat-rated to 550shp. The Carajá's MTOW of 8003lb was 1000lb more than that of the Chieftain.
    Colemill Panther
  • Re-engined Navajo with 3500NaN0 Lycoming TIO-540-J2B engines, four-blade Hartzell "Q-Tip" propellers and optional winglets. Conversion designed by Colemill Enterprises of Nashville, Tennessee.[4] [5] The supplemental type certificates (STCs) were subsequently sold to Mike Jones Aircraft Sales, which continues to convert PA-31, PA-31-325 and PA-31-350 variants with Colemill-developed features.[6] [7]
    Number built
    TypeBuiltLocation
    PA-311785Lock Haven
    Lakeland
    PA-31-3501825Lock Haven
    Lakeland
    T-102021Lakeland
    PA-31-3532Lakeland
    PA-31P259Lock Haven
    PA-31P-35050Lock Haven
    Total3942

    Operators

    Civil

    The Navajo family is popular with air charter companies, small feeder airlines and commuter air carriers in many countries, and is also operated by private individuals and companies.

    The PA-31 Navajo was also formerly operated in scheduled passenger airline service in the U.S. in 1968 by Air West, the predecessor of Hughes Airwest which in turn subsequently became an all-jet airline.[8] [9] West Coast Airlines, the predecessor of Air West, began operating the PA-31 Navajo in passenger service in 1967 and called the aircraft the "MiniLiner".[10] West Coast, which was also operating Douglas DC-9-10 jets and Fairchild F-27 turboprops at the time, claimed to be the first "regular airline" to operate the PA-31 Navajo in scheduled service.[11]

    Military

    Chile
    Colombia
    Dominican Republic
    Finland
    France
    Honduras
    Kenya
    Spain
    United Kingdom

    Accidents and incidents

    Aircraft on display

    Spain

    References

    Bibliography

    Notes and References

    1. Peperell 1987, pp. 179-201
    2. Taylor 1982, pp. 450–451.
    3. Taylor 1982, p. 451.
    4. Web site: Colemill Pather conversion. 21 May 2011. Colemill Enterprises. dead. https://web.archive.org/web/20100815083347/http://www.colemill.com/Conversions/Panther1.php. 15 August 2010.
    5. Michell 1994, p. 305.
    6. Web site: FAA Supplemental Type Certificate SA970SO. faa.gov. 20 April 2017.
    7. Web site: A total renovation of the PA-31.
    8. http://www.timetableimages.com, July 1, 1968 Air West system timetable, page 9
    9. https://www.timetableimages.com/i-or/rw7203a.jpg
    10. Web site: WCgigantic67 .
    11. Web site: West Coast Airlines .
    12. Hatch. Paul. Air Forces of the World: Chilean Naval Air Service. Air Pictorial. August 1985. 47. 8. 291.
    13. Web site: World Air Forces 2022. Flightglobal . 2022 . 18 July 2022. registration.
    14. Hoyle Flight International 4–10 December 2018, p. 43.
    15. Sixma and Laukkanen Air International July 1986, p. 12.
    16. Web site: Piper PA31 Navajo . Netmarine.net . 2014-04-03.
    17. Wheeler Flight International 4 August 1979, p. 364.
    18. Web site: Aircraft ZF622 (1980 Piper PA-31-350 Navajo Chieftain C/N 31-8052033) Photo by Malcolm Clarke (Photo ID: AC437577). airport-data.com. 20 April 2017.
    19. Web site: Korean Air Lines McDonnell Douglas DC-10-30, HL7339, SouthCentral Air Piper PA-31-350, N35206, Anchorage, Alaska, December 23, 1983. 9 August 1984. National Transportation Safety Board. https://web.archive.org/web/20210825194138/https://www.ntsb.gov/investigations/AccidentReports/Reports/AAR8410.pdf. 25 August 2021. 29 August 2021.
    20. Web site: Findings of Inquest. Chivell, Wayne. airsafety.com.au. 24 July 2003.
    21. Web site: Air crash inquest enters final chapter. Milovanovic, Selma. The Age. 29 January 2003.
    22. “Piper Navajo”, information placard, Museo del Aire

    This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Piper PA-31 Navajo".

    Except where otherwise indicated, Everything.Explained.Today is © Copyright 2009-2024, A B Cryer, All Rights Reserved. Cookie policy.