A hot start during turbine engine start is most likely caused by

• A. The fuel/air mixture was excessively rich
• B. High ambient temperature
• C. Too high battery voltage
• D. A faulty fuel pump

Answer: (A)

A hot start happens when there’s too much fuel for the amount of air flowing through the engine during start. When the fuel/air mixture is excessively rich, combustion becomes overly energetic, pushing the exhaust gas temperature higher than normal. That rapid, high-heat condition is what characterizes a hot start and can stress the combustor and turbine if it continues.

High ambient temperature can influence engine starts by reducing air density, which can contribute to starting difficulties, but it doesn’t directly define a hot start as clearly as an overly rich mixture does. Too high battery voltage affects electrical systems rather than the fuel/air balance, and a faulty fuel pump tends to cause fuel-starved or unstable starts instead of the hot-start condition.