Definition
VLO is the maximum airspeed at which the landing gear may be safely extended or retracted. Operating the gear above this speed can damage the gear doors, mechanism, or structure due to aerodynamic loads during the transit between up and down positions.
Plain English
The fastest you are allowed to fly while the gear is actually moving up or down. Above this speed, the moving parts and doors can be damaged by the airflow.
Context Anchor
Seen in aircraft performance speed lists, the aircraft flight manual or operating handbook, cockpit placards, and during takeoff or approach when the pilot is moving the landing gear.
Derivation
The 'V' comes from the French vitesse, meaning speed. 'LO' stands for Landing gear Operating. In the V-speed system, the subscript letters tell you which operation the speed limit applies to.
Why Pilots Care
Exceeding VLO while operating the gear may cause structural damage or mechanical failure.
Grounding Statement
As speed increases, the air pushes harder on the landing gear and doors, so the gear must only be moved within its approved speed range.
Intuition Check
VLO is not the same as the maximum speed for flying with the landing gear already down. VLO is the limit for moving the gear; the gear-down speed limit may be different.
Example Sentence 1
On the descent, the pilot slowed below VLO before selecting the gear down.
Example Sentence 2
During the approach, the crew confirmed they were below VLO before retracting the landing gear after a go-around.