PA-31
Piper PA-31 Navajo, with aftermarket winglets installed
Role Utility aircraft
Manufacturer Piper Aircraft
First flight 30 September 1964[1]
Introduction 30 March 1967
Status Active service
Produced 1967–1984[2]
Number built 3942[3]
Variants Piper PA-31T Cheyenne

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

Early Navajo with two-bladed propellers and two-part entry door

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.[2][4] 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.[1][4] It is a low-wing monoplane with a conventional tail, powered by two 310 hp (231 kW) Lycoming TIO-540-A turbocharged engines in "tiger shark" cowlings, a feature shared with the Twin Comanche and the PA-23 Aztec.[4][5][6]

As testing proceeded, two cabin windows were added to each fuselage side and the engines were moved further forward.[6][7] 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 6,200 to 6,500 lb (2,812 to 2,948 kg), and deliveries began in 1967.[2][8]

The PA-31-300 was certified by the FAA in June 1967, the only variant without turbocharged engines: 300 hp (224 kW) Lycoming IO-540-M1A5 engines driving two-bladed propellers.[8] 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.[2][9]

Pressurized PA-31P with fewer and smaller windows

In January 1966, development of the PA-31P Pressurized Navajo had begun : Piper's first pressurized aircraft.[10] The PA-31P (or PA-31P-425 unofficially) was certified in late 1969.[11] It was powered by 425 hp (317 kW) Lycoming TIGO-541-E engines, had a longer nose, fewer and smaller windows, 25 US gal (95 L) fuel tanks in the engine nacelles and a one-piece airstair cabin entry door instead of the split pair of doors.[2][11][10] MTOW was increased to 7,800 lb (3,538 kg).[11] The PA-31P was produced from 1970 to 1977.[2]

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.[3][12]

The PA-31-350 Chieftain, stretched by 2 ft (61 cm)

In September 1972, Piper unveiled the PA-31-350 Navajo Chieftain, a Navajo B stretched by 2 ft (61 cm) for up to ten seats, with more powerful engines and counter-rotating propellers to prevent critical engine handling problems.[8][13] The Chieftain was powered by 350 hp (261 kW) Lycoming TIO-540 variants, with an opposite-rotation LTIO-540 on the right-hand wing, and MTOW was increased to 7,000 lb (3,175 kg).[8] Deliveries started in 1973, after a delay due to a flood caused by Hurricane Agnes at Piper's factory in Lock Haven, Pennsylvania.[13][14]

The 1974 PA-31-325 Navajo C/R was base on the Navajo B.[15] The Navajo C/R had 325 hp (242 kW), lower rated versions of the Chieftain's counter-rotating engines.[8] It was certified in May 1974, and production commenced in the 1975 model year.[15] The Navajo B was also superseded in 1975 by the Navajo C.[15]

In May 1981, Piper established its T1000 Airliner Division at its Lakeland, Florida, factory.[16] The PA-31-350T1020 (or T1020) was a PA-31-350 Chieftain optimized for and marketed for the commuter airline market, without the 40 US gal (151 L) auxiliary fuel tanks in each wing.[8] Up to eleven seats could be fitted, and baggage capacity was reduced from 700 to 600 lb (318 to 272 kg) maximum.[8] The first T1020 was delivered in December 1981.[17]

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.[18] 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.[11] An optional underbelly cargo pod was also available.[11][18] The Pratt & Whitney Canada PT6A-11 turboprop engines were the same as those of the Cheyenne I.[11] Deliveries began in July 1982.[17] A T1050 variant was proposed, with a fuselage stretch of 11 ft 6 in (3.51 m) and seating capacity for 17, but did not proceed.[18]

Pressurized PA-31P-350 Mojave

The PA-31P-350 Mojave was also a hybrid, a piston-engined Cheyenne.[19] The Mojave combined the Cheyenne I fuselage with the Chieftain tail.[19] The Chieftain's wings were strengthened, their span was 4 ft (1.2 m) wider and the fuel capacity was enlarged to 243 US gal (920 L).[19] The engines variants had intercoolers, and the rear part of the nacelles were baggage lockers.[19] The Mojave's MTOW rose by 200 lb (91 kg) to 7,200 lb (3,266 kg).[8][11] 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.[11][14][18] Two experimental PA-31-353s were also built in the mid-1980s.[14]

Licensed manufacture

The PA-31 series was manufactured under licence in several countries from kits of parts supplied by Piper.[20][21] 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.[22] The PA-31-350 Chieftain was also assembled under licence in Brazil by Embraer as the EMB 820C Navajo.[23][21] 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.[24]

Variants

commuter cabin
PA-31 Navajo
Initial production version, also known unofficially as the PA-31-310.[2][8]
PA-31-300 Navajo
Variant of the Navajo with normally aspirated engines; 14 built.[2][9]
PA-31 Navajo B
Marketing name for 1971 improved variant with 310 hp (231 kW) Lycoming TIO-540-E turbo-charged piston engines, new airconditioning and optional pilot access door and optional wide utility door.[3]
PA-31 Navajo C
Marketing name for 1974 improved variant with 310 hp (231 kW) Lycoming TIO-540-A2C engines and other minor improvements.[3]
PA-31P Pressurized Navajo
Pressurized version of the PA-31 Navajo, powered by two 425-hp (317-kW) Lycoming TIGO-541-E1A piston engines.[2][11]
PA-31-325 Navajo
Referred to as the "Navajo C/R" for Counter-rotating; variant of Navajo with counter-rotating engines introduced with the PA-31-350 Chieftain. 325 hp (242 kW) Lycoming TIO-540 / LTIO-540 engines
PA-31-350 Chieftain
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.[11]
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.[8][25][26]
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.[14][27]
PA-31-353
Experimental version of PA-31-350; two built.[14]
license-built EMB 820C
T1050
Unbuilt airliner variant with fuselage lengthened by 11 ft 6 in (3.51 m) 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 8,003 pounds (3,630 kg) was 1,000 pounds (454 kg) more than that of the Chieftain.[24]
Panther conversion with four-blade propellers
Colemill Panther
Re-engined Navajo with 350 hp (261 kW) Lycoming TIO-540-J2B engines, four-blade Hartzell "Q-Tip" propellers and optional winglets. Conversion designed by Colemill Enterprises of Nashville, Tennessee.[28][29] 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.[30][31]
Number built[3]
Type Built Location
PA-31 1785 Lock Haven
Lakeland
PA-31-350 1825 Lock Haven
Lakeland
T-1020 21 Lakeland
PA-31-353 2 Lakeland
PA-31P 259 Lock Haven
PA-31P-350 50 Lock Haven
Total 3942

Operators

Civil

The Navajo family is popular with air charter companies, small feeder airlines and commuter air carriers in many countries,[citation needed] 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.[32][33] 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".[34] 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.[35][36]

Military

Chile
Colombia
Dominican Republic
Finland
France
Honduras
Kenya
Spain
United Kingdom

Accidents and incidents

Aircraft on display

Spain

Specifications (PA-31 Navajo)

cockpit
PA-31-350 Navajo Chieftain

Data from Jane's All The World's Aircraft 1976–77 [48]

General characteristics

Performance

See also

Related development

Aircraft of comparable role, configuration, and era

References

Citations

  1. ^ a b Taylor 1976, p.354.
  2. ^ a b c d e f g h i "The Piper PA-31 Navajo/Pressurized Navajo". airliners.net. 2009. Archived from the original on April 28, 2010. Retrieved January 13, 2009.
  3. ^ a b c d e Peperell 1987, pp. 179-201
  4. ^ a b c "World News: Piper's New Medium Twin". Flight International, Volume 86, Number 2911, 24 December 1964, p.1065. Retrieved 2010-04-05
  5. ^ Lambert (1963), p.470
  6. ^ a b "Refinements in the Piper range". Flight International, Volume 87, Number 2922, 11 March 1965, p.367. Retrieved 2010-04-05
  7. ^ "Air Report", Flight Magazine (1965), p.7
  8. ^ a b c d e f g h i j k FAA Type Certificate A20SO for Piper PA-31 / PA-31-300 / PA-31-325 / PA-31-350 series aircraft retrieved 2010-04-01
  9. ^ a b Piper Aircraft Inc. Customer Service Information, p.38
  10. ^ a b "Light Commercial & Business: High-flying Navajo". Flight International, Volume 97, Number 3191, p.775. Retrieved 2010-04-08
  11. ^ a b c d e f g h i j FAA Type Certificate A8EA for Piper PA-31P / PA-31T1 / PA-31T2 / PA-31T3 / PA-31P-350 series aircraft retrieved 2010-04-03
  12. ^ "NBAA and after" Flight International magazine, 14 October 1971, p.603 (online archive version) retrieved 2010-04-05
  13. ^ a b "Piper announces Navajo Chieftain" Flight International magazine, 14 September 1972, p.360 (online archive version) retrieved 2010-04-06
  14. ^ a b c d e "Piper PA-31 Chieftain/Mojave/T-1020/T-1040". airliners.net. Archived from the original on April 28, 2010. Retrieved April 6, 2010.
  15. ^ a b c Manual P/No. 753-703, Introduction, p.3
  16. ^ Levy (1983), p.1152
  17. ^ a b Levy (1983), p.1153
  18. ^ a b c d Barnett (1983), p.833
  19. ^ a b c d Barnett, Cliff. "Pressurised comfort, piston costs: Mojave flight test", Flight International magazine, 5 November 1983, p.1232 (online archive version) retrieved 2010-04-05
  20. ^ "Argentine Piper factory" Flight International magazine, 10 May 1973, p.700 (online archive version) retrieved 2010-04-11
  21. ^ a b Agência Nacional de Aviação Civil Type Certificate EA-7505-02 for EMB 820C Navajo aircraft Archived 2010-12-14 at the Wayback Machine retrieved 2010-04-11
  22. ^ Marsh (2006), p.49
  23. ^ Bonelli and Pinheiro, (2008), p.34.
  24. ^ a b "Caraja deliveries start", Flight International magazine, 12 January 1985, p.12 (online archive version) retrieved 2010-04-03
  25. ^ Manual P/No. 761-775, Introduction, p.3
  26. ^ Taylor 1982, pp. 450–451.
  27. ^ Taylor 1982, p. 451.
  28. ^ Colemill Enterprises. "Colemill Pather conversion". Archived from the original on August 15, 2010. Retrieved May 21, 2011.
  29. ^ Michell 1994, p. 305.
  30. ^ "FAA Supplemental Type Certificate SA970SO" (PDF). faa.gov. Retrieved April 20, 2017.
  31. ^ "A total renovation of the PA-31".
  32. ^ http://www.timetableimages.com, July 1, 1968 Air West system timetable, page 9
  33. ^ https://www.timetableimages.com/i-or/rw7203a.jpg
  34. ^ "WCgigantic67".
  35. ^ "West Coast Airlines".
  36. ^ "WCgigantic67".
  37. ^ Hatch, Paul (August 1985). "Air Forces of the World: Chilean Naval Air Service". Air Pictorial. Vol. 47, no. 8. p. 291.
  38. ^ a b "World Air Forces 2022". Flightglobal. 2022. Retrieved July 18, 2022.
  39. ^ a b Hoyle Flight International 4–10 December 2018, p. 43.
  40. ^ Sixma and Laukkanen Air International July 1986, p. 12.
  41. ^ "Piper PA31 Navajo". Netmarine.net. Retrieved April 3, 2014.
  42. ^ Wheeler Flight International 4 August 1979, p. 364.
  43. ^ a b “Piper Navajo”, information placard, Museo del Aire
  44. ^ "Aircraft ZF622 (1980 Piper PA-31-350 Navajo Chieftain C/N 31-8052033) Photo by Malcolm Clarke (Photo ID: AC437577)". airport-data.com. Retrieved April 20, 2017.
  45. ^ "Korean Air Lines McDonnell Douglas DC-10-30, HL7339, SouthCentral Air Piper PA-31-350, N35206, Anchorage, Alaska, December 23, 1983" (PDF). National Transportation Safety Board. August 9, 1984. Archived from the original (PDF) on August 25, 2021. Retrieved August 29, 2021.
  46. ^ Chivell, Wayne (July 24, 2003). "Findings of Inquest". airsafety.com.au.
  47. ^ Milovanovic, Selma (January 29, 2003). "Air crash inquest enters final chapter". The Age.
  48. ^ Taylor 1976, p.354–355.

Bibliography