Definition
In aviation risk management, likelihood is the estimated probability that a hazard will result in an unwanted event such as an incident or accident. It is one of the two factors used to assess risk, the other being severity. Likelihood is typically rated on a scale (for example: probable, occasional, remote, improbable) based on how often the event is expected to occur given the conditions and exposure.
Plain English
How likely it is that something bad will actually happen if a particular hazard is present.
Context Anchor
Used when judging risk before or during a flight, especially when deciding whether a hazard is unlikely, possible, or likely to cause a problem.
Derivation
From Old English 'gelic' meaning 'similar' plus '-hood' meaning 'state or condition.' Originally meant 'the state of being likely or probable.' In risk management it keeps that everyday sense — how probable something is — but applies it to a specific hazard producing a specific outcome.
Why Pilots Care
It directly influences whether a risk is accepted, mitigated, or avoided before flight.
Intuition Check
Likelihood does not mean how bad the outcome would be. It means how much chance there is that the outcome will happen.
Example Sentence 1
Given the forecast thunderstorms along the route, the pilot judged the likelihood of encountering turbulence as high and chose an alternate routing.
Example Sentence 2
After checking the weather, the instructor lowered the likelihood of thunderstorms to remote for the afternoon lesson.