What is required prior to take-off concerning altimeter settings?

Prior to take-off, it is essential to ensure that the altimeter is set correctly to the nearest aerodrome setting. This procedure helps pilots obtain an accurate altitude reference for their departure and is vital for maintaining safe separation from terrain and other aircraft. The aerodrome setting is typically provided from local weather information and reflects the atmospheric pressure at the airport's elevation.

Using the nearest aerodrome setting allows pilots to have the most relevant and immediate altitude information, which is crucial for flight safety and compliance with air traffic control instructions. Having an accurate altimeter setting helps in reducing the risks associated with altitude misjudgment, particularly during take-off and landing phases, where elevation changes are most critical.

While setting the altimeter to standard pressure is also important in certain conditions, it is generally used above a certain altitude (usually transition altitude) rather than before take-off. Hence, focusing on the local aerodrome setting just before departure aligns with best practices for airport operations and safety. Setting based on aircraft type or relying solely on ATC for accuracy would not address the immediate need for precise altimeter setting upon departure.