deHavilland Canada EO-5C Dash 7
While deHavilland Canada had produced a series of very successful short takeoff and landing (STOL) "bush" aircraft in the 1960s, such as the DHC-2 Otter and DHC-5 Cairbou, it wanted to break into the commuter aircraft market. The DHC-6 Twin Otter had done very well, but was a smaller aircraft suited to tiny airports or airstrips; it was never meant to compete with the Fokker F.27 Friendship or Hawker-Siddeley HS.748, or replace the aging Douglas DC-3 or Convair 580. deHavilland then hit upon the idea of expanding the DHC-6 into a four-engine aircraft.
In designing the DHC-7--simply referred to as "Dash 7"--deHavilland kept the high wing, high-lift configuration of the Twin Otter, but made the fuselage larger and longer, as well as circular, allowing it to be pressurized. The tail was reconfigured as a T-tail for additional lift, while the wings were expanded to take four engines; by using large propellers, the Dash 7 was also remarkably quiet for a turboprop. It could operate from unimproved airstrips and runways only 2000 feet long--its selling point was that the Dash 7 could operate from airports a F.27 could not think of using.
The DHC-7 entered service in 1978 with Rocky Mountain Airways, which flew their Dash 7s from Denver to Vail, landing on mountain runways and delivering skiiers to resorts served only by smaller aircraft to this point. However, the aircraft proved to be a poor seller. While there was nothing wrong with the design, there was little it could do that a Twin Otter couldn't do as well; often, airports that the Dash 7 could serve didn't bring in many passengers to begin with, and pressurization wasn't a requirement. Most importantly, the Dash 7 was more expensive to operate than the DHC-6 due to having four engines. Somewhat disappointed by lagging sales, deHavilland would rework the DHC-7 into a twin-engined aircraft, becoming the hugely successful DHC-8 Dash 8/Bombardier Q400 series. Only 113 Dash 7s were built.
In the early 1990s, the US Army acquired two (later eight) Dash 7s to be modified into battlefield survelliance aircraft. The First Gulf War had pointed up several flaws in the Army's ability to have real-time battlefield surveillance, allowing Army commanders to track enemy movement of troops and equipment, especially at night; the Iraqi success in keeping their Scud missiles undetected was a continual source of frustration. Two Dash 7s, N566CC and N176RA, were modified as part of the Joint Precision Strike Demonstration (JPSD) program, and referred to as O-5As and RC-7Bs. The modifications on these aircraft remain classified, but likely included synthetic aperature radar, signals intelligence (SIGINT) equipment, real-time datalinks, and high-resolution infrared cameras kept behind shutters on the bottom of the aircraft.
Both N566CC and N176RA were supposedly replaced by later Dash 7s, designated EO-5Bs, and the initial two were redesignated EO-5Cs. However, they were sighted in Afghanistan and in Libya during the Afghanistan War and the Benghazi attack of 2016, as well as Iraq. Whether or not they were still in use as SIGINT aircraft or as operational testbeds is also unknown; they were supposedly based at the Aberdeen Proving Ground in Maryland, but that might have been for administrative purposes.
In any case, both aircraft were retired in 2017, stripped of their equipment, and put in storage at AMARC in Arizona. In 2023, both were moved to the restoration yard at the Pima Air and Space Museum, where they remain as of this writing.
I got this picture of N566CC when I visited Pima in June 2023; neither it nor N176RA (seen across the path from N566CC) were there when I visited in June 2022. I had a feeling these were "black ops" aircraft, but wasn't sure until I did some research. Both have Spraylat preservative on them, and it is unknown if they will be put on display at Pima or used for other purposes.
deHavilland Canada EO-5C Dash 7
While deHavilland Canada had produced a series of very successful short takeoff and landing (STOL) "bush" aircraft in the 1960s, such as the DHC-2 Otter and DHC-5 Cairbou, it wanted to break into the commuter aircraft market. The DHC-6 Twin Otter had done very well, but was a smaller aircraft suited to tiny airports or airstrips; it was never meant to compete with the Fokker F.27 Friendship or Hawker-Siddeley HS.748, or replace the aging Douglas DC-3 or Convair 580. deHavilland then hit upon the idea of expanding the DHC-6 into a four-engine aircraft.
In designing the DHC-7--simply referred to as "Dash 7"--deHavilland kept the high wing, high-lift configuration of the Twin Otter, but made the fuselage larger and longer, as well as circular, allowing it to be pressurized. The tail was reconfigured as a T-tail for additional lift, while the wings were expanded to take four engines; by using large propellers, the Dash 7 was also remarkably quiet for a turboprop. It could operate from unimproved airstrips and runways only 2000 feet long--its selling point was that the Dash 7 could operate from airports a F.27 could not think of using.
The DHC-7 entered service in 1978 with Rocky Mountain Airways, which flew their Dash 7s from Denver to Vail, landing on mountain runways and delivering skiiers to resorts served only by smaller aircraft to this point. However, the aircraft proved to be a poor seller. While there was nothing wrong with the design, there was little it could do that a Twin Otter couldn't do as well; often, airports that the Dash 7 could serve didn't bring in many passengers to begin with, and pressurization wasn't a requirement. Most importantly, the Dash 7 was more expensive to operate than the DHC-6 due to having four engines. Somewhat disappointed by lagging sales, deHavilland would rework the DHC-7 into a twin-engined aircraft, becoming the hugely successful DHC-8 Dash 8/Bombardier Q400 series. Only 113 Dash 7s were built.
In the early 1990s, the US Army acquired two (later eight) Dash 7s to be modified into battlefield survelliance aircraft. The First Gulf War had pointed up several flaws in the Army's ability to have real-time battlefield surveillance, allowing Army commanders to track enemy movement of troops and equipment, especially at night; the Iraqi success in keeping their Scud missiles undetected was a continual source of frustration. Two Dash 7s, N566CC and N176RA, were modified as part of the Joint Precision Strike Demonstration (JPSD) program, and referred to as O-5As and RC-7Bs. The modifications on these aircraft remain classified, but likely included synthetic aperature radar, signals intelligence (SIGINT) equipment, real-time datalinks, and high-resolution infrared cameras kept behind shutters on the bottom of the aircraft.
Both N566CC and N176RA were supposedly replaced by later Dash 7s, designated EO-5Bs, and the initial two were redesignated EO-5Cs. However, they were sighted in Afghanistan and in Libya during the Afghanistan War and the Benghazi attack of 2016, as well as Iraq. Whether or not they were still in use as SIGINT aircraft or as operational testbeds is also unknown; they were supposedly based at the Aberdeen Proving Ground in Maryland, but that might have been for administrative purposes.
In any case, both aircraft were retired in 2017, stripped of their equipment, and put in storage at AMARC in Arizona. In 2023, both were moved to the restoration yard at the Pima Air and Space Museum, where they remain as of this writing.
I got this picture of N566CC when I visited Pima in June 2023; neither it nor N176RA (seen across the path from N566CC) were there when I visited in June 2022. I had a feeling these were "black ops" aircraft, but wasn't sure until I did some research. Both have Spraylat preservative on them, and it is unknown if they will be put on display at Pima or used for other purposes.