Definition
A sequence of small individual errors, oversights, or poor decisions that link together and lead to an accident or serious incident. Aviation safety research has shown that accidents are rarely caused by a single failure; they are typically the result of several minor problems that compound. Breaking any one link in the chain is usually enough to prevent the outcome.
Plain English
A series of small mistakes that, on their own, would not cause an accident, but when they stack up one after another, they end in one. Spotting and fixing any one of those small mistakes is usually enough to stop the accident from happening.
Context Anchor
Seen in aeronautical decision-making and risk management discussions, especially when reviewing how accidents develop and how pilots can stop them early.
Derivation
From 'chain' meaning a series of connected links. The image is deliberate: each error is a link, and removing any single link breaks the chain and prevents the final outcome.
Why Pilots Care
Recognizing an error chain early lets a pilot take corrective action to avoid an accident.
Analogy
Like a row of dominoes: if any single domino is stopped from falling, the rest stay upright.
Grounding Statement
A pilot can break an error chain by catching a problem early, slowing down, asking for help, changing the plan, or choosing not to continue.
Intuition Check
An error chain is not usually one dramatic mistake. It is usually several smaller problems connected together, and any one of them may be the chance to stop the accident path.
Example Sentence 1
The pilot recognized that fatigue, a late departure, and worsening weather were the start of an error chain, and chose to delay the flight.
Example Sentence 2
During the debrief the instructor pointed out how fatigue, a rushed checklist, and a late go-around decision had formed an error chain that nearly resulted in a runway excursion.