Definition
A solid chemical oxygen generator used as an emergency oxygen source in aircraft. When ignited, the candle's core of sodium chlorate mixed with iron powder undergoes a controlled chemical reaction that releases breathable oxygen at a steady rate for a fixed duration.
Plain English
A small, sealed canister that produces emergency oxygen by burning a chemical block. Once started, it cannot be shut off and will keep producing oxygen until the chemical is used up.
Context Anchor
Seen in aircraft passenger emergency oxygen systems and in maintenance discussions about chemical oxygen generators.
Derivation
Named for sodium chlorate, the chemical compound that releases oxygen when heated, and 'candle' because the device burns slowly from one end to the other like a wax candle, producing a steady output over a set burn time.
Why Pilots Care
Supplies oxygen to passengers and crew long enough to reach a safe altitude after sudden loss of cabin pressure.
Grounding Statement
Picture a small sealed canister above the passenger area that, once triggered, gets very hot and supplies oxygen to the masks for several minutes.
Intuition Check
Do not think of this as a wax candle used for light. In this term, candle means a solid chemical oxygen source that is consumed after it starts working.
Example Sentence 1
When the cabin lost pressure, the chlorate candles activated and supplied oxygen to the passenger masks for about twelve minutes.
Example Sentence 2
During preflight, the crew verified that none of the chlorate candles had reached their expiration date.