What must be done before starting the engines according to NATOPS Standardization?

Before starting the engines, it is imperative that the wheels are chocked and the parking brake is set. This procedure is in place to ensure the safety of the aircraft and its personnel. By chocking the wheels, you prevent the aircraft from moving unexpectedly, which could lead to accidents or injuries while the engines are starting, particularly given the high thrust and power generated during engine startup.

Having the parking brake set serves the same purpose, providing an additional layer of stability. This is part of standard protocols that ensure adequate precautions are taken to protect both the crew and the aircraft before entering a critical phase of flight operations. Properly securing the aircraft is a fundamental best practice that reduces the risk of incidents during engine start-up, which could occur if the aircraft were to move due to wind, uneven surfaces, or other unforeseen factors.

In contrast to this, while checking fuel levels and ensuring all personnel are clear of the area are important steps in overall aircraft safety and preparation, they do not specifically address the necessity to secure the aircraft before engine start.