A delta-3 hinge is a hinge that is not at a 90-degree angle, it is offset to some degree.
The pitot static system consists of the instruments used for determining aircraft’s speed, altitude, and altitude trend (or change in altitude).
If the pitot tube is clogged, the airspeed indicator will no longer work properly.
If the static port is clogged, all pitot static instruments will provide incorrect readings.
Most piston-powered helicopters have dual magnetos so that if one magneto fails in flight, the engine will still operate.
The most common types of aviation fuel are 100LL [low lead] and Jet A.