Definition
The state of the landing gear while it is moving between the fully extended (down and locked) and fully retracted (up and locked) positions. During this period, the gear is neither down nor up, and the cockpit position indicator typically shows a transit light or red indication until the gear reaches and locks into its new position.
Plain English
The landing gear is on the move. It has left one position but hasn't finished arriving at the other yet, so it isn't locked anywhere.
Context Anchor
Seen on retractable-gear airplanes when using the landing gear control and checking the landing gear position indicators.
Derivation
"Transit" comes from the Latin transire, meaning "to go across." Here, the gear is going across — moving from one locked position to another.
Why Pilots Care
Pilots must confirm the gear has completed its cycle and is down-and-locked before touchdown; acting on an incomplete cycle can lead to gear collapse or runway contact with the gear only partially extended.
Intuition Check
Do not read gear as general equipment here. In this context, gear means the landing gear, and in transit means it is moving, not already locked.
Example Sentence 1
After selecting the gear handle up, the pilot saw the gear-in-transit light illuminate until all three gear locked into the retracted position.
Example Sentence 2
The pilot waited for the gear in transit light to extinguish before beginning the after-landing checklist.