Air Certificates come in several forms to fit different types of aircraft, including normal, utility, acrobatic, commuter, transport, manned free balloons and special classes. The DC-7 qualifies as a transport plane.
In order to qualify for the certificate, the plane must meet standardized airframe design, must be in safe operating condition deemed by an FAA inspector, and be under a regular maintenance schedule.
The DC-7 is a quad-propeller transport plane initially built by the Douglas Aircraft Company in 1953. Douglas manufactured 338 airframes during its production period. The planes were used mainly as transport aircraft, with production ending in 1958. The production line ended after only five years due in part to the introduction of the jet engine's popularity over propeller planes. (Boeing merged with McDonnell Douglas in 1997.)
Every aircraft in the sky must be regulated and certified by the FAA. The flight certificate of a DC-7 states that this particular aircraft is worthy of legal flight.
