Before climbing a three-section extension ladder, firefighters must ensure which sections are locked?

The necessity for ensuring that both sections of the ladder are locked before climbing is crucial for maintaining safety and stability when using a three-section extension ladder. The locking mechanism is designed to prevent the ladder sections from sliding, which could lead to dangerous situations if a firefighter were to climb while any part of the ladder was not securely locked in place.

When both the upper and lower sections are locked, it ensures that the ladder maintains its structural integrity and does not collapse or slide down while being used. This adds an extra layer of safety for the firefighter, allowing them to concentrate on their tasks rather than worrying about potential falling hazards.

In the context of safety practices and procedures, the caution of locking the ladder represents the best practice to avoid accidents and ensure that the ladder can support the firefighter's weight properly while they are at height. It reinforces the importance of thorough checks before undertaking potentially dangerous operations, aligning with the overall safety protocols that are critical in firefighting.