Definition
A condition during the takeoff roll in which the pilot's and copilot's airspeed indicators show meaningfully different speeds, indicating that at least one of the two airspeed sensing systems is unreliable. It is treated as a serious anomaly and, in multi-crew operations, is a recognized reason to reject the takeoff if detected before V1.
Plain English
The two airspeed indicators in the cockpit are showing different numbers when they should match. That mismatch tells the crew at least one reading cannot be trusted, which is a problem during a takeoff roll.
Context Anchor
Encountered during the takeoff roll, especially in rejected takeoff discussions and crew briefings about when to stop the airplane before liftoff.
Derivation
‘Split’ here means ‘diverging’ or ‘not in agreement’ — the two indications have parted from each other instead of reading the same value.
Why Pilots Care
Signals unreliable airspeed data that can lead to an incorrect go or no-go decision, requiring an immediate rejected takeoff above certain speeds.
Intuition Check
“Split” does not mean the airspeed is meant to be divided or averaged. Here it means the airplane’s airspeed readings disagree, so the speed information should be treated as suspect.
Example Sentence 1
The captain called for a rejected takeoff after noticing split-airspeed indications between the two primary flight displays during the roll.
Example Sentence 2
The first officer called out split airspeed indications during the takeoff roll, prompting the captain to reject.