How long is the preflight inspection valid for (BPO)?

The preflight inspection, often referred to in the context of aviation as the BPO (Before Preflight Operations) inspection, is valid for a period of 72 hours. This time frame allows for a comprehensive evaluation of the aircraft’s condition and systems to ensure safety before flight operations. After a BPO inspection has been completed, the validity remains intact for 72 hours, assuming no discrepancies are reported and the aircraft remains in a condition that does not necessitate another inspection.

The rationale behind this 72-hour period is to provide a balance between operational efficiency and safety. It allows for sufficient time between inspections, recognizing that an aircraft may be parked and not in use during that duration. However, it also requires pilots and operators to remain vigilant about any changes in the aircraft's condition that could arise.

In the context of the other choices, the 24-hour, 48-hour, and 96-hour time frames do not align with the established protocols for aircraft inspections and operational standards. Therefore, the 72-hour validity period is the correct response based on the industry standards for preflight inspections, ensuring that any potential issues could be identified and resolved in a timely manner.