Definition
In aviation risk assessment, the estimated probability that a hazard will result in an unwanted event during a given flight or operation. It is one of two factors used to assess overall risk, the other being severity (the consequences if the event occurs). Likelihood is typically rated on a scale such as probable, occasional, remote, or improbable.
Plain English
How likely it is that something will actually go wrong. It is a judgment of the chances that a known hazard will turn into a real problem during the flight.
Context Anchor
Used in preflight planning, training discussions, and any decision where a pilot or instructor is judging whether a situation is safe enough to continue.
Derivation
Risk comes from older words connected with danger or possible loss. Likelihood comes from likely, meaning probable or expected. Together, the phrase points to the chance side of risk: the question, “How probable is this problem?”
Why Pilots Care
It helps pilots decide how seriously to treat a hazard and whether mitigation steps are needed before flight.
Grounding Statement
If a fuel cap is loose, the risk likelihood of a fuel leak is higher than it would be with the cap properly secured.
Intuition Check
Do not confuse likelihood with seriousness. A risk can be unlikely but very serious, or likely but less serious.
Example Sentence 1
Given the deteriorating weather and the pilot's limited night experience, the instructor judged the risk likelihood of an unintended IMC encounter as occasional rather than remote.
Example Sentence 2
Reviewing recent reports, the instructor rated the risk likelihood of runway incursions at the airport as moderate.