Definition
A colorless gas (chemical formula NH₃) with a sharp, pungent odor, composed of nitrogen and hydrogen. In aviation, ammonia is used as the working fluid in some absorption-type refrigeration and cooling systems, and historically in certain chemical and manufacturing processes related to aircraft materials. It is highly soluble in water and is toxic and corrosive at higher concentrations.
Plain English
A strong-smelling gas made of nitrogen and hydrogen. It is used in some cooling systems and is harmful to breathe in large amounts.
Context Anchor
Seen in aviation maintenance when reading chemical labels, safety information, cleaning instructions, or equipment servicing notes.
Derivation
The name comes from 'sal ammoniac,' a salt found near the temple of the Egyptian god Amun in ancient Libya. Early chemists noticed the sharp-smelling gas it released, and named the gas after the salt. Knowing this helps explain why an aviation reference book lists ammonia among chemical substances rather than as something specific to flying.
Why Pilots Care
Ammonia is toxic and corrosive. Mechanics and pilots working around systems that contain it must recognize its sharp odor as a warning sign of a leak and avoid prolonged exposure.
Intuition Check
Do not assume ammonia always means the household cleaner. In technical use, ammonia may mean the chemical itself as a gas or the same chemical dissolved in water.
Example Sentence 1
The technician noticed a sharp ammonia smell near the cooling unit and immediately ventilated the hangar.
Example Sentence 2
Any ammonia leak must be handled carefully because the gas is toxic and has a powerful odor.