Definition
A cognitive tendency in which a pilot perceives, hears, or interprets information as matching what they expected, rather than what was actually presented. It can cause a pilot to read back a clearance incorrectly, mistake a taxiway for the assigned route, or overlook information that conflicts with their assumption.
Plain English
When you expect to see or hear something, your brain can fill in the gap and make you believe that's what happened — even when it didn't. You hear what you thought was said, not what was actually said.
Context Anchor
Encountered during taxiing when a pilot follows taxi instructions, checks airport signs and markings, or confirms position on the airport surface.
Derivation
From 'expectation' (Latin exspectare, 'to look out for') and 'bias' (a leaning or slant). Together, the term names a leaning of perception toward what is anticipated.
Why Pilots Care
It can cause a pilot to miss a critical difference between what is expected and what is real, leading to runway incursions or taxi deviations.
Analogy
It is like reading a familiar sentence and not noticing one changed word because your mind expected the usual version.
Grounding Statement
Expectation bias happens when the situation feels familiar enough that the pilot stops checking it closely.
Intuition Check
Expectation bias is not just carelessness, and bias does not mean an unfair opinion here. It means your attention is tilted toward what you expected, so you must verify what is actually shown or said.
Example Sentence 1
Expecting the same taxi route as the previous day, the pilot turned onto Taxiway B before realizing the controller had actually assigned Taxiway D — a classic case of expectation bias.
Example Sentence 2
The student misheard the clearance as 'taxi via Alpha' because expectation bias made her anticipate the route she had planned on the chart.