Which ECAM indicator status is always green during transit?

Which ECAM indicator status is always green during transit?

• A. APU bleed
• B. Engine bleed
• C. Left PACK
• D. Right PACK

Answer: (A)

The main idea is that green on ECAM means normal/available, not faulted. The APU bleed indicator being green in transit reflects that the APU bleed air source is healthy and available as a separate, independent supply. This status is consistent because the APU bleed can provide air without depending on engine operation, so when there are no faults the ECAM shows it as a normal, available source. In contrast, engine bleed status depends on the engines running and their bleed valves, which can vary with thrust, engine start/stop, or faults, so that indicator isn’t guaranteed to be green during transit. Left and right PACK indicators depend on bleed air supply and pack operation, which also can change with flight phase, demand, and source (engine vs APU), so they aren’t consistently green in transit either.

The main idea is that green on ECAM means normal/available, not faulted. The APU bleed indicator being green in transit reflects that the APU bleed air source is healthy and available as a separate, independent supply. This status is consistent because the APU bleed can provide air without depending on engine operation, so when there are no faults the ECAM shows it as a normal, available source.

In contrast, engine bleed status depends on the engines running and their bleed valves, which can vary with thrust, engine start/stop, or faults, so that indicator isn’t guaranteed to be green during transit. Left and right PACK indicators depend on bleed air supply and pack operation, which also can change with flight phase, demand, and source (engine vs APU), so they aren’t consistently green in transit either.