Aero Commander 500 family

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Template:Short description Template:Use American English Template:Use dmy dates Template:Infobox aircraft

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 later a division of Rockwell International in 1965. Final production occurred in 1986 under the Gulfstream Aerospace name. The initial production version was the Template:Cvt, 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 Template:Cvt, 11-seat Model 695B/Jetprop 1000B turboprop.[1] As of recent, the Aero Commander is known as the Twin Commander.

Design and development

File:Rockwell YU-9A Aero Commander ‘0-26218’ (26998882710).jpg
The first model, the five-seat 520, was certified in January 1952 with two 260 HP Lycoming GO-435s

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 Template:Convert 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 Template:Convert. 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.Script error: No such module "Unsubst".

Operational history

File:Scott Broo N45RF NOAA.jpg
Special mission cabin for the NOAA

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.

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 National 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.Script error: No such module "Unsubst". This was the smallest "Air Force One", and the first to wear the now-familiar blue-and-white livery.Script error: No such module "Unsubst". This aircraft is now owned by the Commemorative Air Force.[8]

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

A single 560F was operated by the Belgian Air Force as the personal transport of the late king Baudouin of Belgium from 1961 to 1973.[9]

According to the July 1, 1968, Frontier Airlines system timetable, series 500 aircraft were being operated on scheduled passenger flights by Combs Aviation on behalf of Frontier via a contract agreement with service to several smaller communities in Montana and Wyoming at this time.[10][11]

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 Template:Cvt 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. Suburban retired their last 680FLs in the first half of 2024.

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.[12] From approximately 1961 to 1993, 24 aircraft crashed when spar failures caused the loss of the wing in flight.[12] 35 more spars were found cracked during inspections.[12]

Single-engine safety

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.[13][14]

In 1979, the National Transportation Safety Board reviewed light-twin engine-failure accidents, involving the 24 most popular model-groups of light twins between 1972 and 1976. They found that the piston-engined twin-Commanders had averaged slightly over 3.4 engine-failure accidents per hundred-thousand hours, the second worst number of all aircraft under review.[15][16] The most engine failures were suffered by the small-engine versions of the Piper Apache, at 6.9 failures per hundred thousand hours; the third-worst, the Beechcraft Travel Air, averaged 2.9 failures; the average for all models was only 1.6.[15][16]

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, and gliding. Then in his final airshow performance, in a supreme demonstration of conservation of momentum, he did all that, then landed the Shrike Commander dead stick (engines off), coasted the airplane down the runway then from the runway down the taxiway and silently let the craft roll slowly to a full stop right in front of the crowd.[17][18][19]

The turboprop twin-Commanders—with much more powerful engines (and most with longer bodies, allowing greater rudder leverage, critical for single-engine control[14][20]) – 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.[15]

Variants

Type certificate data sheet 6A1[21] and 2A4[22]
model name approved TC engines power MTOW ceiling seats fuel builtTemplate:Efn
L-3805 1
520 1952-01-31 6A1 2× GO-435-C2/C2B 2× 260 5500-5700 5 145 150
560 1954-05-28 6A1 2× GO-480-B/B1C 2× 270 6000 7 145 80
520 with more power, increased weight, swept tail, plus revised wing, landing gear, fuselage, and primary control system
560A 1955-07-01 6A1 2× GO-480-D/C/G 2× 275 6000 7 156
560 with longer fuselage, revised engine installation, wing, landing gear, fuel and oil systems
560E 1957-02-21 6A1 2× GO-480-C/G 2× 295 6500 7 223 93
560A with Larger wings and greater payload, revised engine installation, wing, wheel and brake installation, fuel system with outboard tanks, and landing gear location
560F 1961-02-08 2A4 2× IGO-540-B 2× 350 7500 7 223
680F with normally aspirated engine and reduced gross weight
360 2× 180 4 1
Lightened 560E
500 1958-07-24 6A1 2× O-540-A2B 2× 250 6000 7 156 101
560E with decreased gross weight, powerplants, and 560A landing gear
500A Aero Commander 1960-04-07 6A1 2× IO-470-M 2× 260 6000 7 156 99
500 with new nacelles, fuel injected Continental engines and new landing gear
500B 1960-07-13 6A1 2× IO-540-B/E 2× 290 6750 7 156 217
500A with Lycoming engines and 3-bladed props.
500U Shrike Commander 1964-12-11 6A1 2× IO-540-E 2× 290 6750 7 156 56
500B with pointed nose and squared off tail.
500S Shrike Commander 1968-03-15 6A1 2× IO-540-E 2× 290 6750 7 156 316
500U with minor changes[23]Template:Pn
680 Super L-26C → U-4BTemplate:Efn
L-26C → U-9CTemplate:Efn		 1955-10-14 2A4 2× GSO-480-A1A6 2× 340 7000 7 223 254
supercharged 560ATemplate:Efn
680E 1958-06-19 2A4 2× GSO-480-B1A6 2× 340 7500 7 223 100
680 with Lightened 560E/560A type undercarriageTemplate:Efn, extended wing and increased maximum weight
720 AltiCruiser 1958-12-05 2A4 2× GSO-480-B1A6 2× 340 7500 6 223 13
Pressurized 680-E, structural modifications to the fuselage, extended wing and increased maximum weight
680F 1960-08-23 2A4 2× IGSO-540-B 2× 380 8000 7 223 126
680E with fuel injection engine, new nacelles, new main gear and increased maximum weight
680FP 2× 380 223 26
Pressurized 680FTemplate:Efn
680FL Grand Commander 1963-05-24 2A4 2× IGSO-540-B 2× 380 7000-8500 11 223 157
680F with larger tail, 2 built for the US Army as the RL-26D → RU-9D with SLAR, Courser Commander after 1967;Template:Efn stretched
680FL(P) Grand Commander 1964-10-08 2A4 2× IGSO-540-B1A/B1C 2× 380 8500 11 223 37
pressurized 680FL
680T Turbo Commander 1965-09-15 2A4 2× TPE-331-43 2× 575 8950 25,000 ft 11 286.5 56
680FL/P turbopropTemplate:Efn
680V Turbo Commander 1967-06-13 2A4 2× TPE-331-43 2× 575 9400 25,000 ft 11 286.5 36
680T with slightly improved cargo capacityTemplate:Efn
680W Turbo II Commander 1968-02-05 2A4 2× TPE-331-43BL 2× 575 9400 25,000 ft 11 286.5 46
680V with pointed nose. squared off fin, one panoramic and two small cabin windows and weather radarTemplate:Efn
681 Hawk Commander 1969-03-20 2A4 2× TPE-331-43BL 2× 575 9400 25,000 ft 11 286.5 43
680W with improved pressurisation, air conditioning system and noseTemplate:Efn
681B Turbo Commander 25,000 ft 29
Marketing designation for economy version of the 681Template:Efn
685 Commander 1971-09-17 2A4 2× GTSIO-520-F/K 2× 435 9000 25,000 ft 9 256-322 66
690 powered by piston enginesTemplate:Efn
Template:Visible anchor Commander 690 1971-07-19 2A4 2× TPE-331-5 2× 717.5 10250 25,000 ft 11 384 79
681 with new wing centre section and engines moved further outboardTemplate:Efn
Template:Visible anchor Commander 690A 1973-04-25 2A4 2× TPE-331-5 2× 717.5 10250 31,000 ft 11 384 245
690 with changed flightdeck layout and increased pressurisationTemplate:Efn
Template:Visible anchor Commander 690B 1976-10-05 2A4 2× TPE-331-5 2× 717.5 10325 31,000 ft 10 384 217
690A with improved soundproofing and internal lavatoryTemplate:Efn
690C Jetprop 840 1979-09-07 2A4 2× TPE-331-5 2× 717.5 10325 31,000 ft 11 384 136
690B with increased wingspan, wet wing fuel tanks and wingletsTemplate:Efn
690D Jetprop 900 1981-12-02 2A4 2× TPE 331-5 2× 748 10700 31,000 ft 11 425-474 42
690C with internal rear cabin extension, improved pressurisation and five square cabin windowsTemplate:Efn
695 Jetprop 980 1979-11-01 2A4 2× TPE-331-10 2× 733 10325 31,000 ft 11 425-474 84
more powerful 690CTemplate:Efn
695A Jetprop 1000 1981-04-30 2A4 2× TPE-331-10 2× 820 11200 35,000 ft 11 474 101
more powerful 690D with higher takeoff weight, built for the NOAATemplate:Efn
695B Jetprop 1000B 1984-02-15 2A4 2× TPE-331-10 2× 820 11750 35,000 ft 11 474 6
695A with minor changesTemplate:Efn

Operators

File:An Aero Commander 690A of IRIAA.jpg
Islamic Republic of Iran Army Aviation 690A
File:T-137 Aero Commander 500 Fuerza Aerea Argentina (8164167486).jpg
Argentine Air Force 500U

Government operators

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Military operators

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Civil operators

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Notable accidents

  • On 19 June 1964 Senator Ted Kennedy was a passenger in an Aero Commander 680 airplane flying in bad weather from Washington, D.C., to Massachusetts. It crashed into an apple orchard in the western Massachusetts town of Southampton on the final approach to the Barnes Municipal Airport near Westfield.[25][26] The pilot and Edward Moss, one of Kennedy's aides, were killed.[27] Kennedy suffered a severe back injury, a punctured lung, broken ribs and internal bleeding.[28]
  • 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.[29]
  • On 11 August 2002 photographer Galen Rowell, his wife Barbara Cushman Rowell, pilot Tom Reid and Reid's friend Carol McAffee were killed in an Aero Commander 690 crash near Eastern Sierra Regional Airport in Bishop, California.[30]
  • On Sunday 2 October 1994, an Aero Commander 690 operated by Seaview Air as flight CD111 departed for from Williamtown, NSW, on a flight to Lord Howe Island. Eight passengers, including honeymooners and a family with two children, boarded the single-pilot aircraft. 30 minutes after departure a distress call was made by the pilot with no future communications made. Only some minor wreckage was ever recovered. During the investigation a number of safety breaches by the operator were discovered including regular operations with overweight aircraft, inaccessible safety equipment & illegal regular public transport operations when the operator was only approved to operate charter flights. The incident was a significant one to occur in Australia and led to a $20 million royal commission which resulted in fundamental changes to the governing aviation body in Australia.[31]

Specifications (Rockwell Aero Commander 500S)

3-view line drawing of the Aero Commander L-26B
3-view line drawing of the Aero Commander L-26B

Template:Aircraft specs

See also

References

Notes

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Bibliography

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External links

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Template:Aero Commander aircraft Template:Gulfstream Template:USAF liaison aircraft Template:US utility aircraft Template:Thai civil aircraft designations

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