Which of the following factors does NOT influence a stall?

A stall occurs when the airflow over the wing reaches a critical angle, causing a significant loss of lift. The factors that influence a stall primarily relate to the aerodynamics and operational characteristics of the aircraft.

The weight of the aircraft is crucial because it affects the stall speed. A heavier aircraft requires a higher speed to maintain lift at any given angle of attack, meaning that as weight increases, the stall speed increases as well.

The angle of attack is vital in determining when a stall will occur. As the angle of attack increases beyond the wing's critical angle, the airflow can no longer adhere to the wing surface, resulting in a stall.

Airflow over the wing is also integral to stall dynamics. Smooth, laminar flow is necessary for optimal lift, and any disruption to this airflow (due to turbulence, for instance) can lead to a stall.

In contrast, the type of fuel used does not have a direct effect on the stall characteristics of the aircraft. While fuel type can influence weight due to differences in density or energy content, it does not alter the aerodynamic principles that govern stall behavior. Thus, it is the least relevant factor in the context of what influences a stall.