What is an essential use of the POH during flight?

The Pilot's Operating Handbook (POH) is a critical document that provides valuable information about the aircraft, including specifications, limitations, and procedures that are essential for safe operation. One of the most vital uses of the POH during flight is to reference emergency procedures. In the event of an in-flight emergency, having immediate access to the correct procedures can significantly enhance the pilot's ability to respond effectively and safely. The POH is designed to guide pilots through various emergency scenarios such as engine failure, electrical malfunctions, or other critical situations that require prompt action to ensure the safety of the flight.

The other options, while potentially relevant to flight operations, do not capture the primary, essential use of the POH in an emergency context. For example, using the POH for holding on during turbulence does not reflect its intended purpose, as it is primarily a reference guide rather than a physical aid. Understanding air traffic communications and calculating flight distances are certainly important aspects of flying, but they do not hold the same urgency as consulting emergency procedures when immediate decisions are required for safety. Therefore, referencing emergency procedures stands out as the essential use of the POH during flight.