Definition
In aviation case study work, the underlying factor or chain of factors most likely responsible for an accident, incident, or operational outcome, identified after examining the available evidence. It is the conclusion an investigator reaches about what most plausibly caused the event, expressed as the primary contributing cause rather than every possible factor.
Plain English
The main reason something most likely happened, based on the evidence available. It is the best-supported explanation, not a guess and not a guaranteed certainty.
Context Anchor
Seen in accident reports, safety discussions, and case studies used in flight training.
Derivation
From Latin probabilis, meaning 'provable' or 'likely to be true,' and causa, meaning 'reason' or 'origin.' Together: the reason that is most likely true based on what can be shown. This is why 'probable cause' means the most supportable explanation, not absolute proof.
Why Pilots Care
Knowing the probable cause of past accidents helps pilots recognize similar risks and make better decisions to prevent them.
Intuition Check
Probable cause does not mean a casual guess. It means the most likely cause supported by the known facts, and it may involve more than one factor.
Example Sentence 1
The instructor asked the class to review the report and identify the probable cause of the runway excursion.
Example Sentence 2
Case studies often highlight how poor weather decisions became the probable cause of controlled flight into terrain.