What amount of usable fuel remains when the L or R FUEL LO annunciator is illuminated?

When the L or R FUEL LO annunciator illuminates, it indicates that the fuel quantity in that respective tank has reached a critical low level. The correct answer reflects that at this point, approximately 110 pounds of usable fuel remain in the tank.

Understanding the significance of this measurement is crucial for safe flight operations. The fuel gauge is designed to provide pilots with an early warning of low fuel conditions, allowing them to manage fuel consumption effectively and plan for a timely diversion or landing if necessary. By knowing that there are still 110 pounds of fuel available, pilots can make informed decisions regarding their flight operations, ensuring they have sufficient fuel reserves to complete their mission or reach an alternate airport if required. This precise knowledge of fuel levels contributes greatly to the safety and management of aircraft operations.