What is one advantage of starting the right engine on the ground before the left engine?

• A. The right engine will supply the ECS with bleed air for air conditioning until the left engine is started.
• B. The left engine must be started first to provide bleed air.
• C. There is no advantage; bleed air is the same from both engines.
• D. Only the APU can supply bleed air for ECS before engine starts.

Answer: (A)

Bleed air from engines powers the environmental control system and air conditioning. On the ground, you want conditioned air available even while one engine is still starting. Starting the right engine first makes its bleed air immediately available to the ECS, so the cabin stays cool or heated and the packs keep running until the left engine is up. Once the left engine is started, its bleed air can share the load or take over, but the immediate advantage is uninterrupted ECS operation during the start sequence.