Definition
A lengthwise separation of the wood fibers, running through the piece from one face to the other, caused by the wood being torn apart along the grain. In wooden aircraft structures, a split is a disqualifying defect because it represents a complete loss of fiber continuity at that location.
Plain English
A crack that goes all the way through a piece of wood, splitting it along the grain so the two sides are no longer joined.
Context Anchor
Seen during inspection and repair of wooden aircraft parts, especially when checking wood for defects before deciding whether it is airworthy.
Why Pilots Care
A split reduces the strength of load-bearing wooden parts and can propagate under flight loads, compromising structural integrity.
Intuition Check
Do not read “split” here as simply a piece of wood cut into two parts. In this context, it means a defect: the wood has cracked apart along its grain.
Example Sentence 1
The mechanic rejected the wing rib stock after finding a split running along the grain through the full thickness of the board.
Example Sentence 2
Small splits in non-structural fairings may be filled, but any split in a primary structure requires replacement.