Definition
Small cockpit devices that warn the pilot when carbon monoxide (CO) is present in the cabin air. They range from inexpensive chemical spot cards that change color when CO is detected, to electronic units that sound an audible alarm and display CO concentration in parts per million.
Plain English
Devices that alert you if poisonous exhaust gas is leaking into the cockpit. Some are cheap stickers that change color; others are electronic units that beep and show how much gas is in the air.
Context Anchor
You may see CO detectors in the cockpit or cabin, especially when using cabin heat or when checking for possible exhaust leaks.
Derivation
Carbon monoxide comes from carbon, the element in fuels, and monoxide, meaning one oxygen atom. Detector comes from a word meaning to uncover or find out. Together, the term points to a device that finds carbon monoxide before a person can notice it.
Why Pilots Care
Carbon monoxide is colorless and odorless; even low levels can impair judgment and lead to loss of consciousness in flight.
Analogy
A CO detector is like a smoke alarm for a gas you cannot see or smell. It does not fix the problem, but it alerts you that you need to act.
Grounding Statement
If exhaust gas leaks into the cabin during flight, a CO detector may be the first clear sign that something is wrong.
Intuition Check
Do not assume you will smell or feel carbon monoxide before it becomes dangerous. CO detectors are used because carbon monoxide can affect you before you realize it is there.
Example Sentence 1
During preflight, the pilot checked that the CO detector on the panel was active and showing a normal reading before starting the engine.
Example Sentence 2
When the CO detector alarm sounded at cruise altitude, the pilot immediately opened the cabin air vents.