PLT470: Rotor System Types And Components
What code PLT470 covers, why the FAA tests it, and how to study Rotor System Types And Components before your checkride.
Recall rotor system - types / components / operating principles / characteristics
What this means for your checkride
The main rotor system consists of a mast, hub, and rotor blades, and systems are classified by how the blades attach and move relative to the hub. A semirigid system, typically two blades, uses a teetering or flapping hinge so the blades flap as a unit, one up as the other flaps down, and also feathers to change pitch. A fully articulated system, found on rotors with more than two blades, lets each blade lead and lag, flap, and feather independently. A rigid rotor system attaches the blade roots firmly to the hub with no flapping or lead lag hinges, so the blades accommodate those motions by bending while still being able to feather.
Knowing the three rotor system types and their motions explains handling differences and susceptibility to hazards like mast bumping.
Semirigid rotors are prone to mast bumping, while rigid rotors are usually not, because rigid hubs are mounted solid to the mast.
Where to study it
A code on your test report is an area of deficiency. An authorized instructor must review it with you and endorse that review before you take the practical test, and the examiner may revisit it during the oral. Study it until you can explain it out loud, not just recognize the answer.