When will the packs auto turn off?

When will the packs auto turn off?

• A. At engine start
• B. At engine shutdown
• C. During flight
• D. On landing

Answer: (A)

Bleed-air management in the environmental control system is being tested here. The packs rely on bleed air from engines or the APU to condition cabin air. When you initiate an engine start, bleed air is needed for starting the engine, so the system automatically prioritizes that demand and shuts the packs off. Once the engine is started and bleed air is available again for conditioning, the packs can come back on to resume cabin conditioning. So the automatic off occurs at engine start, not during flight, landing, or at engine shutdown.

Bleed-air management in the environmental control system is being tested here. The packs rely on bleed air from engines or the APU to condition cabin air. When you initiate an engine start, bleed air is needed for starting the engine, so the system automatically prioritizes that demand and shuts the packs off. Once the engine is started and bleed air is available again for conditioning, the packs can come back on to resume cabin conditioning. So the automatic off occurs at engine start, not during flight, landing, or at engine shutdown.