Definition
The variation in blade pitch angle from the root of a propeller blade to its tip. Because each section of the blade travels at a different speed through the air (the tip moves much faster than the part near the hub), the blade is twisted so that every section meets the air at an efficient angle. Pitch distribution describes how that twist is laid out along the length of the blade.
Plain English
It's the way a propeller blade is twisted from the center out to the tip, so that the whole blade -- not just one part of it -- bites the air at a useful angle when the propeller spins.
Context Anchor
Seen in propeller specifications, propeller inspection, propeller repair data, and maintenance discussions about blade shape or blade twist.
Derivation
Pitch' comes from the old idea of how far something would advance in one turn, like a screw threading through wood. 'Distribution' simply means how something is spread out. Together: how the pitch (blade angle) is spread along the length of the blade.
Why Pilots Care
Correct pitch distribution gives the propeller its best thrust and efficiency while reducing stress on the blades.
Analogy
A propeller blade is not shaped like a flat paddle. It is more like a carefully twisted fan blade, with each part set at a slightly different angle so the whole blade can do its job smoothly.
Grounding Statement
Look at a propeller blade end-on and you can see it is twisted -- steeper near the hub, flatter near the tip. That twist is the pitch distribution.
Intuition Check
Do not read “pitch” here as the airplane’s nose-up or nose-down attitude. In this propeller specification, “pitch” means the propeller blade’s angle and effective forward movement, and “pitch distribution” means how that pitch changes along the blade.
Example Sentence 1
The technician checked the blade for any bends or repairs that might have altered its pitch distribution.
Example Sentence 2
A propeller with proper pitch distribution produces even thrust along the entire blade length.