Definition
The condition in which all blades of a helicopter rotor or propeller track through the same plane of rotation, so that each blade follows the identical path as the rotor or propeller turns.
Plain English
When a rotor or propeller is spinning, every blade should travel along exactly the same circle. Blade alignment means the blades are matched up so none of them rides higher or lower than the others.
Context Anchor
Seen in propeller inspection, maintenance records, and discussions of vibration or propeller damage.
Derivation
“Alignment” comes from the idea of placing something “in line.” In this term, it refers to propeller blades being positioned in the correct line or relationship, not just looking neat from the outside.
Why Pilots Care
Misaligned blades create vibration that can damage the aircraft and make flight uncomfortable or unsafe.
Intuition Check
Do not assume blade alignment means the propeller simply looks straight. Here it means the blades are in the correct measured position relative to each other and the hub.
Example Sentence 1
After replacing the rotor blade, the mechanic checked blade alignment to confirm both blades were tracking in the same plane.
Example Sentence 2
After replacing a rotor blade, the technician performed a full blade alignment check before the next flight.