3 Airworthiness Directives: 2 airplane, 1 rotorcraft.
AD 57-20-01 · published 1957
American Champion Aircraft Corp. Airplanes
AD 57-20-04 · published 1957
Vickers-Armstrongs (Aircraft Limited) Airplanes
AD 57-19-02 · published 1957
Sikorsky Aircraft Corporation Helicopters