During a bleed duct fault with left or right bleed duct indicated, which action determines the affected side?

• A. ECS synoptic page - SELECT to determine affected side
• B. BLEED SOURCE - SELECT non-affected engine source
• C. ISOL - CLOSED
• D. BLEED VALVES - MANUAL

Answer: (A)

When a bleed duct fault appears with a left or right bleed indicator, the quickest way to identify which side is affected is to use the ECS synoptic page and perform a select action for the bleed source. This diagnostic step prompts the system to display the actual side of the fault, giving you a clear indication of which bleed duct is impacted. Understanding the affected side is crucial so you can isolate or manage the correct duct without guesswork, maintaining proper cabin pressurization and safety.

Other actions don’t provide the side indication. Selecting the bleed source, isolating the duct, or manually operating bleed valves may be part of subsequent operations, but they don’t reveal which side is faulty on the display.