Aero Commander 500 family

Aero Commander twins
Aero Commander model 695A operated by the US National Oceanic and Atmospheric Administration
Role Utility and business aircraft
Manufacturer Aero Design and Engineering Company
Aero Commander
Rockwell-Standard Corporation
North American Rockwell
Rockwell International
Gulfstream Aerospace
First flight 23 April 1948 (Model L3085)
Introduction October 1952
Produced 1951-1986

The Aero Commander 500 family is a series of light-twin piston-engined and turboprop aircraft originally built by the Aero Design and Engineering Company in the late 1940s, renamed the Aero Commander company in 1950, and a division of Rockwell International from 1965. The initial production version was the 200-mph, seven-seat Aero Commander 520. An improved version, the 500S, manufactured after 1967, is known as the Shrike Commander. Larger variants are known by numerous model names and designations, ranging up to the 330-mph, 11-seat Model 695B/Jetprop 1000B turboprop.[1]

Design and development

Updated Aero Commander Panel

The idea for the Commander light business twin was conceived by Ted Smith, a project engineer at the Douglas Aircraft Company.[2] Working part-time after hours throughout 1944, a group of A-20 engineers formed the Aero Design and Engineering Company to design and build the proposed aircraft with a layout similar to their A-20 bomber.[2][3] Originally, the new company was going to build three pre-production aircraft, but as the first aircraft was being built, they decided to build just one prototype.[2] The final configuration was completed in July 1946 and was designated the Model L3805.[2]

Registered NX1946, the prototype first flew on 23 April 1948.[2] The L3805 accommodated up to five people and was powered by two Lycoming O-435-A piston engines.,[1] it was an all-metal high-wing monoplane with retractable undercarriage using components from a Vultee BT-13 Valiant. The market segment planned for this aircraft to be sold to small feeder airliner firms and was originally designed to carry seven passengers, but instead found use in the private business aircraft and military market.[4] Walter Beech test flew the aircraft in 1949 and expressed interest in buying the project, but passed on it, to instead develop the Beechcraft Twin Bonanza. Fairchild Aircraft also evaluated the prototype at its Hagerstown, Maryland, headquarters.[3]

The prototype flew successfully and the company leased, at no cost, a new 26,000 square-foot factory at Bethany near Oklahoma City to build a production version, certified on 30 June 1950. Nearly 10,000 hours of redesign work went into the model, including more powerful Lycoming GO-435-C2 engines, with a combined rating of 520 horsepower. The production model was named the Commander 520. The first Commander 520 was rolled out of the new factory in August 1951. Serial number 1 was used as a demonstrator, then sold in October 1952 to the Asahi Shimbun Press Company of Tokyo.

Operational history

In military service, it was initially designated the L-26, though in 1962 this was changed to U-4 for the United States Air Force and U-9 for the United States Army.

Bob Hoover's Shrike Commander on display

Under ownership of Rockwell in the 1960s, World War II pilot R. A. "Bob" Hoover demonstrated the Shrike Commander 500S for decades in a variety of "managed energy" routines, including single-engine and engine-out aerobatics.[5][6] His Shrike Commander is displayed in the colors of his last sponsor, Evergreen International Aviation, at the Steven F. Udvar-Hazy Center of the Smithsonian Air and Space Museum. Bob Odegaard continued the tradition in 2012, flying a 1975 Shrike 500S in a Bob Hoover tribute routine.[7]

One U-4B became a presidential transport aircraft for Dwight D. Eisenhower between 1956 and 1960. This was the smallest "Air Force One," and the first to wear the now-familiar blue-and-white livery.

As of 2004, Shrike Commanders remained in service with the United States Coast Guard and United States Customs Service.[1]

A single 560F was operated by the Belgian Air Force as the personal transport of the late king Boudewijn from 1961 to 1973.[8]

The unpressurized, long-fuselage 680FL was operated as a small package freighter by Combs Freightair in the 1970s and 1980s, and by Suburban Air Freight in the 1980s and 1990s. The aircraft was popular with pilots, because it was extremely "pilot friendly" and with its 380 hp supercharged engines did well in icing meteorological conditions. A number are still operated on contracts for cargo and fire control applications, as their piston engines offer good fuel specifics at low altitudes and longer loiter times.

Safety concerns

Single-engine safety

Single-engine flight to Washington

In 1950, when the developers were working to satisfy Civil Aeronautics Authority (CAA) regulations for certification of the 500, they chose a novel method of demonstrating its single-engine safety and performance: they removed one of the two-bladed propellers, secured it in the aft cabin, and flew from Bethany to Washington, D.C. on one engine. There they met with CAA personnel, then replaced the propeller and returned to Oklahoma in the conventional manner. The flight received nationwide coverage in the press.[9][10]

However, the stunt had been performed with the propeller stowed inside the aircraft, rather than dragging in the open on the front of the engine (as would happen in an actual engine failure). Consequently, the famous demonstration did not demonstrate an actual failed-engine scenario (in which the propeller normally creates substantial drag, and adds to single-engine control and performance problems).[9][10][11]

NTSB Single-engine safety study

In fact, in a 1979 government study of light-twin engine-failure accident rates, reviewing accidents involving the 24 most popular model-groups of light twins between 1972 and 1976, the National Transportation Safety Board found that the piston-engined twin-Commanders had, by far, the worst number of engine-failure accidents, per hundred-thousand hours flown, of any popular light-twin model -- except for Piper's notoriously underpowered small-engine versions of the out-of-production Piper Apache (barely able to function on one engine).[12][13]

The piston-powered Aero Commanders averaged slightly over 3.4 engine-failure accidents per hundred-thousand hours (vs. 6.9 for the Apache, and 2.9 for the next-worst, the Beechcraft Travel Air; the overall average for all models was only 1.6).[12][13]

Hoover single-engine airshow routine

Countering the statistical evidence, Rockwell demonstration pilot Bob Hoover's famous airshow stunt routine, with the Shrike Commander, included a full aerobatic routine performed first with both engines, then with one engine out (and the critical engine, at that), then both engines out, gliding.[14][15]

Turboprop Commanders' single-engine safety

The turboprop twin-Commanders -- with much more powerful engines (and most with longer bodies, allowing greater rudder leverage, critical for single-engine control[10][11]) -- came out on the opposite end of the rankings, with one of the lowest rates of engine-failure accidents of all "light" twins examined, at only 0.4 per hundred-thousand hours.[12]

Wing spar fatigue

Beginning in June 1991, senior engineers met with FAA officials to discuss concerns over the Aero Commander's main wing spar, which was believed to be susceptible to stress fatigue and subsequent cracking, and was believed to have resulted in a number of fatal crashes.[16] From approximately 1961 to 1993, 24 aircraft crashed when spar failures caused the loss of the wing in flight.[16] Thirty-five more spars were found cracked during inspections.[16]

Notable accidents

  • World War II hero and actor Audie Murphy died in an Aero Commander 680 crash while flying as a passenger on 28 May 1971. The aircraft was flying in bad weather at night and was on approach to Roanoke, Virginia when it flew into the side of Brush Mountain outside Blacksburg, Virginia, West of Roanoke. Four others and the pilot were also killed.[21]

Variants

Aero Commander 560 at Centennial Airport
Aero Commander 500-B at Colorado Springs Airport
Aero Commander 500U Shrike Commander
Aero Commander 680FL at Colorado Springs Airport
Aero Commander 680W at Eagle County Regional Airport
Aero Commander L.3805
Prototype, one built, Lycoming O-435-A engines.
Aero Commander 520
First production version, a developed L.3805 with a taller fin and larger cabin with two 260 hp Lycoming GO-435-C engines, 150 built.
Aero Commander 560
Model 520 with swept tail, increased takeoff weight, seven seats and more powerful engines (two 270 hp Lycoming GO-480B engines) and refined wing,[23] 80 built.
Aero Commander 560A
New undercarriage, stretched fuselage and other numerous refinements, 99 built.
Aero Commander 560E
Larger wings and greater payload, 93 built.
Aero Commander 560F
Powered with 350 hp Lycoming IGO-540 engines.
Aero Commander 360
Lightened version of the 560E with four seats and two 180 hp engines, one built.
Aero Commander 500
Economy version introduced in 1958, a 560E with 250 hp Lycoming O-540-A engines, 101 built.
Aero Commander 500A
First Aero Commander model – new nacelles to house 260 hp fuel-injected Continental IO-470M engines, 99 built.[24]
Aero Commander 500B
500A with 290 hp fuel injected Lycoming IO-540 engines, 217 built.
Aero Commander 500U/Shrike Commander
500B with pointed nose and squared off tail, two 290 hp Lycoming IO-540 engines, replaced 500A, 500B, 560F and 680F, 56 built.
Aero Commander 500S/Shrike Commander
500U with minor changes, 316 built.[25]
Aero Commander 680 Super
Development of 560A with supercharged 340 hp Lycoming GSO-480-A engines and increased fuel capacity, 254 built.
Aero Commander 680E
Lightened 560E and 560A type undercarriage, 100 built.
Aero Commander 680F
680E with new undercarriage and supercharged, fuel-injected 380 hp Lycoming IGSO-540 engines and new nacelles, 126 built.
Aero Commander 680FP
Pressurized version modified from 680F, 26 built.
Aero Commander 680FL Grand Commander
680F with stretched fuselage and larger tail, 157 built. After 1967 known as the Courser Commander.
Aero Commander 680FL/P Grand Commander
Pressurized version of 680FL, 37 built.
Aero Commander 680T Turbo Commander
680FL/P with Garrett TPE331-43 turboprop engines, 56 built.
Aero Commander 680V Turbo Commander
680T with increased takeoff weight and slightly improved cargo capacity, 36 built.
Aero Commander 680W Turbo II Commander
680V with pointed nose. squared off fin, one panoramic and two small cabin windows and weather radar, 46 built.
Aero Commander 695A Turbo Commander
Built for the National Oceanic and Atmospheric Administration.
1969 Aero Commander 681
Rockwell 681 Hawk Commander
680W with improved pressurisation, air conditioning system and nose, 43 built.
Rockwell 681B Turbo Commander
Marketing designation for economy version of the 681, 29 built.
Rockwell 685 Commander
690 powered by two 435 hp Continental GTSIO-520K piston engines, 66 built.
Commander 690
681 with new wing centre section and engines moved further outboard, two Garrett AiResearch TPE331-5-251K turboprops, 79 built.
Commander 690A
690 with changed flightdeck layout and increased pressurisation, 245 built.
Commander 690B
690A with improved soundproofing and internal lavatory, 217 built.
690C Jetprop 840
690B with increased wingspan, wet wing fuel tanks and winglets, two 840shp TPE331-5-254K turboprops, 136 built.
690D Jetprop 900
Similar to 690C with internal rear cabin extension, improved pressurisation and five square cabin windows, 42 built.
695 Jetprop 980
Similar to 690C with 735shp TPE331-10-501K engines, 84 built.
695A Jetprop 1000
690D with higher takeoff weight and more powerful TPE331-10-501K engines, 101 built.
695B Jetprop 1000B
695A with minor changes, 6 built.
Aero Commander 720 AltiCruiser
Pressurized version of 680, 13 built.
YL-26 → YU-9A
Aero Commander 520 evaluated by the US Army, 3 built.
YL-26A
Aero Commander 560 evaluated by the US Air Force, 1 built.
L-26B → U-4A
Aero Commander 560A sold to the US Air Force, 14 built.
U-4B
L-26C
L-26B → U-9B
Aero Commander 560A sold to the US Army, 1 built.
L-26C → U-4B
Aero Commander 680 Super sold to the US Air Force, 2 built.
L-26C → U-9C
Aero Commander 680 Super sold to the US Army, 4 built.
RL-26D → RU-9D
Commander 680 for US Army aircraft fitted with SLAR (side looking airborne radar), two built.
NL-26D → NU-9D
One built.

Operators

Military operators

 Argentina
 Benin
 Colombia
 Greece
 Indonesia
 Iran
 Ivory Coast
 Kenya
Laos Kingdom of Laos
 South Korea
 Mexico
 Niger
 Pakistan
 Philippines
 United States

Civilian operators

An Iranian Police Aviation Aero Commander 690 flying over Tehran in 2009
 Iran
 United States

Specifications (Rockwell Aero Commander 500S)

Data from Jane's All The World's Aircraft 1976–77[46]

General characteristics

Performance

See also

References

Notes

  1. 1 2 3 "Rockwell U-9A Aero Commander". March Field Air Museum. Archived from the original on 18 August 2007. Retrieved 1 August 2007.
  2. 1 2 3 4 5 Collman, B.J. (May–June 1973). "The Aero Commander Twins". Air-Britain Digest. 15 (3): 79–86.
  3. 1 2 Nicholis M Williams (Spring 1990). "The Aero Commander 520". AAHS Journal.
  4. ↑ "Feederliner Makes Debut." "Popular Science, August 1948, p. 90, bottom of page. Note: First photos seems to indicate first model was to have fixed landing gear.
  5. ↑ "Shrike Commander". Flying. July 1972. pp. 72–73, 76.
  6. ↑ Collins, Richard L. (January 1999). "Grand Renaissance: The rebirth of the tough bird". Flying. Vol. 126 no. 1. pp. 80–83.
  7. ↑ "none". Sport Aviation: 30. June 2011.
  8. ↑ Archived 17 February 2010 at the Wayback Machine.
  9. 1 2 Harris, Richard. "The Aero Commander Line – A short history". Archived from the original on 13 July 2011. Retrieved 13 August 2011.
  10. 1 2 3 Smith, T. M., "Multiengine Airplane Rating", 2nd Ed., Zweng / Pan American Navigation Service, North Hollywood, California, 1968.
  11. 1 2 "Checkout in a Multiengine Airplane", excerpted from Flight Training Handbook, Advisory Circular 61-21A, Federal Aviation Administration, at website of Aircraft Owners and Pilots Association, retrieved 17 May 2017
  12. 1 2 3 Special Study: "Light Twin-Engine Aircraft Accidents Following Engine Failures, 1972-1976," NTSB-AAS-79-2, 1979, National Transportation Safety Board, Washington, D.C., as retrieved from ERAU Library, 16 May 2017
  13. 1 2 Ibold, Ken, ed., Aviation Consumer's Used Aircraft Guide, 9th Edition, vol. 2, 2001, Belvoir Publications, Greenwich, Connecticut
  14. ↑ Cochrane, Dorothy, "Robert A_ “Bob” Hoover, The Greatest Stick and Rudder Man, is Honored in Hollywood National Air and Space Museum.htm", 20 February 2014, Smithsonian National Air and Space Museum, Washington, D.C., retrieved 16 May 2017
  15. ↑ ["Bob Hoover flies west,"] 25 October 2016, General Aviation News retrieved May, 15, 2017
  16. 1 2 3 Swift, S. J. (1 May 1995), The Aero Commander Chronicle (PDF), Civil Aviation Safety Authority, retrieved 1 August 2007
  17. ↑ "Teddy's Ordeal". Time. 26 June 1964. Retrieved 23 May 2008.
  18. ↑ "The Luck of the Kennedys". Check-Six.com. 8 May 2008. Archived from the original on 1 February 2009. Retrieved 24 February 2009.
  19. ↑ "John F. Kennedy Jr. – Timeline: Misfortunes of a Family". CNN. July 1999. Archived from the original on 23 March 2008. Retrieved 23 May 2008.
  20. ↑ Swidey, Neil (16 February 2009). "Chapter 2: The Youngest Brother: Turbulence and tragedies eclipse early triumphs". The Boston Globe. Archived from the original on 22 February 2009. Retrieved 24 February 2009.
  21. ↑ "Biography for Audie Murphy". IMDb. 1 August 2007. Retrieved 1 August 2007.
  22. ↑ Ray Delgado (12 August 2002). "Galen Rowell 1940-2002". sfgate.com. Hearst Communications Inc. Retrieved 27 November 2016.
  23. ↑ "none". Flying Magazine: 38. August 1954.
  24. ↑ "none". Flying Magazine: 23. November 1962.
  25. ↑ Simpson 1995
  26. ↑ Andrade 1982, p. 12
  27. ↑ Andrade 1982, p. 13
  28. ↑ Andrade 1982, p. 26
  29. ↑ "División de Aviación Asalto Aéreo incorpora nuevo avión Turbo Commander 690D". webinfomil.com. Retrieved 19 December 2016.
  30. ↑ Andrade 1982, p. 94
  31. ↑ Andrade 1982, p. 106
  32. ↑ Andrade 1982, p. 107
  33. ↑ Andrade 1982, p. 109
  34. ↑ Andrade 1982, p. 110
  35. ↑ Andrade 1982, p. 126
  36. ↑ Andrade 1982, p. 141
  37. ↑ "Royal Lao Air Force Aircraft Types". aeroflight.co.uk. Retrieved 19 December 2016.
  38. ↑ Andrade 1982, p. 143
  39. ↑ Andrade 1982, p. 156
  40. ↑ Andrade 1982, p. 167
  41. ↑ Andrade 1982, p. 172
  42. ↑ Andrade 1982, p. 173
  43. ↑ "World Air Forces 2013" (PDF). Flightglobal Insight. 2013. Retrieved 12 March 2013.
  44. 1 2 Andrade 1979, p. 134
  45. ↑ Team, DPS Web. "TxDPS - Aircraft History". www.dps.texas.gov. Retrieved 27 August 2018.
  46. ↑ Taylor 1976, pp. 346–347.

Bibliography

  • Andrade, John (1979). U.S.Military Aircraft Designations and Serials since 1909. Midland Counties Publications. ISBN 0-904597-22-9.
  • Andrade, John (1982). Militair 1982. London: Aviation Press Limited. ISBN 0-907898-01-7.
  • Simpson, R. W. (1995). Airlife's General Aviation. Airlife Publishing. ISBN 1-85310-577-5.
  • Taylor, John W. R. (1976). Jane's All The World's Aircraft 1976–77. London: Jane's Yearbooks. ISBN 0-354-00538-3.

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