Definition
In aviation human factors, a sequence of small errors, oversights, or unfavorable conditions that individually appear minor but combine to produce an accident or incident. Accident investigations almost always reveal that no single failure caused the outcome — instead, several links connected in sequence, and breaking any one of them would likely have prevented the accident.
Plain English
A series of small problems that line up, one after another, and together cause an accident. Stopping any one of them usually stops the accident from happening.
Context Anchor
Seen in aviation safety and human behavior discussions, especially when explaining how accidents often develop step by step rather than from one single mistake.
Derivation
The phrase pictures a literal chain — a row of links joined together. Each link is one mistake, distraction, or bad condition. The accident is what happens when enough links connect. Breaking one link breaks the chain.
Why Pilots Care
Recognizing an active chain allows a pilot to intervene at any link and prevent the outcome from becoming an accident.
Analogy
It is like a row of dominoes: if each one knocks over the next, the final result can look sudden, even though it started several steps earlier. Removing one domino can stop the whole sequence.
Intuition Check
Do not assume a chain of events means the accident was unavoidable. In aviation, it usually means there were several links, and breaking one of them could have prevented the outcome.
Example Sentence 1
The instructor reviewed the accident report and pointed out the chain of events: a rushed preflight, a missed weather update, and an unfamiliar airport at night.
Example Sentence 2
Good crew resource management can break a developing chain of events before it leads to an incident.