In the Lavatory, which of the following describes the shut-off valve location?

In the Lavatory, which of the following describes the shut-off valve location?

• A. In the Lavatory Ceiling Panel
• B. Under the Sink, Behind the Access Door, Below the Water Heater
• C. Behind the Lavatory Mirror
• D. Under the Sink, Behind the Access Door, Above the Water Heater

Answer: (B)

The question tests knowledge of where the lavatory shut-off valve is located in the aircraft’s potable water system. The shut-off valve is under the sink, behind the access door, and below the water heater. This placement gives crew easy access through a small, secure access door while keeping the valve out of the heater’s heat zone and in a position that allows proper isolation of the lavatory water supply. The other locations aren’t standard: a ceiling panel isn’t a typical accessible point for shut-off tasks; behind the lavatory mirror isn’t conveniently accessible for maintenance or quick shut-off; and having the valve above the water heater would place it in an incorrect relative position compared to the standard installation.

The question tests knowledge of where the lavatory shut-off valve is located in the aircraft’s potable water system. The shut-off valve is under the sink, behind the access door, and below the water heater. This placement gives crew easy access through a small, secure access door while keeping the valve out of the heater’s heat zone and in a position that allows proper isolation of the lavatory water supply.

The other locations aren’t standard: a ceiling panel isn’t a typical accessible point for shut-off tasks; behind the lavatory mirror isn’t conveniently accessible for maintenance or quick shut-off; and having the valve above the water heater would place it in an incorrect relative position compared to the standard installation.