How is a jet engine started?

Jet engine starting requires rotating the compressor to provide airflow for combustion. Starting methods include: APU (Auxiliary Power Unit) providing bleed air to air turbine starter, Ground cart supplying pneumatic or electrical power, Cross-bleed start using running engine's bleed air, and Electric starter motors. The starting sequence: Starter motors compressor, ignition activated, fuel introduced at ~15-20% N2, light-off occurs and EGT rises, self-sustaining speed reached at ~50-60% N2, starter cuts off. FADEC controls the sequence, protecting against hot starts (excess fuel), hung starts (failure to accelerate), and over-temperature conditions.