What should not be stored in the cockpit overnight if extreme temperatures are expected?

In the context of a cockpit experiencing extreme temperatures, electronic devices should not be stored overnight. High or low temperatures can significantly affect the performance and functionality of electronic devices, such as tablets, smartphones, and navigation equipment. These devices are often sensitive to temperature extremes, which may lead to malfunctions, battery degradation, or even potential hazards if they are subjected to conditions outside their operational temperature range.

When assessing the other options, flight plans are typically paper documents that can withstand fluctuating temperatures without losing their functionality. Food and drinks, while they may spoil or freeze, do not pose the same level of risk to operational safety as electronic devices. Helmets, designed for aviation use, are built to endure a variety of environmental conditions and would not be adversely affected in the same way that sensitive electronic equipment would be. Thus, the focus on safeguarding equipment that relies on stable operating conditions underscores why electronic devices should be kept out of the cockpit under extreme temperature conditions.