Definition
In risk assessment, the estimated probability that a hazard will actually result in an unsafe event or accident. It is one of the two factors used in a risk matrix, the other being severity. Likelihood is typically rated on a qualitative scale such as probable, occasional, remote, or improbable.
Plain English
How likely it is that something bad will actually happen if you don't do anything about a hazard you've spotted.
Context Anchor
Used when an instructor, student, or pilot rates risk before a flight, training lesson, or maneuver.
Derivation
Likelihood comes from likely, meaning probable or expected. Event comes from a Latin root meaning to happen or come out. Together, the phrase points to the chance that a particular thing will happen, not how serious it would be if it did happen.
Why Pilots Care
It guides whether a risk requires mitigation or can be accepted, directly affecting go/no-go decisions and overall flight safety.
Analogy
Like checking the percent chance of rain before a picnic: a 10 percent chance lets you proceed with light plans, while 80 percent prompts you to change or cancel.
Grounding Statement
A pilot estimates likelihood from weather data, aircraft condition, personal experience, and route factors to place the hazard in the correct cell of the risk matrix.
Intuition Check
Do not confuse likelihood with severity. Likelihood asks, “How probable is it?” Severity asks, “How bad would it be?”
Example Sentence 1
Given the worn tire and the wet runway, the instructor rated the likelihood of a runway excursion as occasional rather than remote.
Example Sentence 2
After reviewing the forecast, the likelihood of encountering icing was judged occasional for the planned altitude.