Bleed air leaks are detected by which mechanism?

• A. A protective cover directing leaked air to sensing loops
• B. A bleed line pressure sensor
• C. A cockpit alarm
• D. Visual inspection only

Answer: (D)

Bleed air leaks are identified through visual inspection during maintenance and checks. In this context, there isn’t a dedicated, automatic leak-detection sensor for bleed air; technicians rely on signs observable in the bleed air ducting and components—like frost, oil or residue around connections, hissing sounds, and abnormal pack performance or indications. These visual cues prompt inspection to locate the exact leak source. While alarms may alert to related anomalies, the actual detection mechanism emphasized here is the careful visual examination of the bleed air system.