Aero Commander 500

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Aero Commander 500 Shrike Commander

Aero Commander model 690A, N53RF operated by NOAA
Type	Utility and transport aircraft
Manufacturer	Aero Design and Engineering Company/Aero Commander
Maiden flight	April 23, 1948 (Model L3085)
Primary users	United States Air Force United States Army United States Coast Guard Mexican Air Force

The Aero Commander 500 is the first in a series of light twin-engined aircraft originally built by the Aero Design and Engineering Company in the late 1940s. It later became the Aero Commander division of Rockwell International. The initial production version was the Aero Commander 520. Versions manufactured after 1967 are known as the Shrike Commander.^[1]

1 Design and development
2 Operational history
- 2.1 Safety concerns
  - 2.1.1 Single Engine Safety
  - 2.1.2 Wing Spar Fatigue
3 Variants
4 Operators
- 4.1 Military operators
- 4.2 Civil operators
5 Specifications (Rockwell Aero Commander 500S)
6 References
7 Related content

Design and development

The idea for the type was conceived by two Douglas Aircraft Company workers, who went on to form the Aero company in 1944. The company's first prototype flew on April 23 1948. That aircraft was named the Aero Commander Model L3085. The aircraft accommodated up to five people and was powered by two piston engines.^[1], it was an all-metal high-wing monoplane with retractable undercarriage. The prototype flew successfully and the company obtained finance to build a new factory at Bethany near Oklahoma City to build a production version named the Commander 520. The first production aircraft was rolled out of the new factory in August 1951.

Operational history

In military service, it was initially designated the L-26 though in 1962 this was changed to U-4 for the USAF and U-9 for the US Army. One U-4B became a presidential transport aircraft for Dwight 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]

Safety concerns

Single Engine Safety

In 1950, when the developers were working to satisfy 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.

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.^[2] World War II hero and actor Audie Murphy died in his Aero Commander 680 while flying in a thunderstorm over Roanoke, VA on May 28, 1971. Five others and the pilot were also killed. The cause of this crash is most likely related to the thunderstorm and not to any design defect of the aircraft itself.^[3]

Variants

Aero Commander L.3805: Prototype, one built.
Aero Commander 520: First production version, a developed L.3805 with taller fin and larger cabin with two 290hp Lycoming GO-435-C engines, 150 built.
Aero Commander 560: Model 520 with swept tail, increased take-off weight, seven seats and more powerful engines (two Lycoming GO-480B engines) and refined wing, 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 360: Lightened version of the 560E with four seats and two 180hp engines, one built.
Aero Commander 500: Economy version introduced in 1958, a 560E with 250hp Lycoming GO-450-A engines, 101 built.
Aero Commander 500A: First Aero Commander model - new nacelles to house fuel-injected engines, 99 built.
Aero Commander 500B: 560E with fuel injected engines Lycoming IO-540 engines, 217 built.
Aero Commander 500U/Shrike Commander: 500B with pointed nose and squared off tail, two 290hp Lycoming IO-540 engines, replaced 500A, 500B, 560F and 680F, 56 built.
Aero Commander 680 Super: Development of 560A with supercharged 340hp Lycoming GS-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 fuel-injected Lycoming IGSO-540 engines and new nacelles, 126 built.
Aero Commander 680PF: 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 take off 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.
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 435hp Continental GTSIO-520K piston engines, 66 built.
Commander 690: 681 with new wing centre section and engines moved further outboard, two AirResearch TPE331-5-521 turboporops, 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 Jetprop840: 690B with increased wingspan, wet wing fuel tanks and winglets, two 840shp TPE331-5-254K turboprops, 136 built.
690D Jetprop900: 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 take off weight and more powerfull 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.
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-9D → NU-9D: One aircraft only.