(2) The following design features on an aeroplane require a design feature endorsement:
(b) retractable undercarriage;
(c) manual propeller pitch control (piston engine);
(e) multi - engine centre - line thrust;
(3) The following design features on a helicopter require a design feature endorsement:
(b) retractable undercarriage;
Powered - lift aircraft
(3A) The following design features on a powered - lift aircraft require a design feature endorsement:
(a) retractable undercarriage;
(4) The following design features on a gyroplane require a design feature endorsement:
(a) retractable undercarriage;
(5) The following design features on an airship require a design feature endorsement:
(b) gas turbine engine.