Definition
A pyrophoric liquid chemical (triethylborane) used as an ignition agent in certain high-performance jet engines, particularly the Pratt & Whitney J58 used in the SR-71. TEB ignites spontaneously on contact with air, producing a brief, intense green flame that lights the engine's main fuel and afterburner under conditions where conventional spark ignition is unreliable.
Plain English
A special chemical that bursts into flame the instant it touches air. It's used to start and re-light certain jet engines, including their afterburners, when a normal spark plug isn't dependable.
Context Anchor
Seen in discussions of specialized turbine engines, rocket engines, and hazardous materials used in engine starting systems.
Derivation
TEB stands for TriEthylBorane. 'Tri-' meaning three, 'ethyl' for the ethyl chemical group, and 'borane' for a boron-hydrogen compound. The name simply identifies the chemical structure of the ignition fluid.
Why Pilots Care
At very high altitudes and during afterburner light-off, ordinary spark ignition can fail. A pyrophoric agent like TEB guarantees a reliable engine start or relight in conditions where the engine would otherwise refuse to fire.
Intuition Check
Do not think of Teb as normal aircraft fuel. It is a special ignition chemical that can catch fire on contact with air.
Example Sentence 1
Each start of the J58 engine consumed a small measured shot of TEB to ignite the fuel.
Example Sentence 2
Without a definition, the teb created unnecessary confusion during preflight review.