If a pilot suspects vapor lock, what procedure might be helpful?

When a pilot suspects vapor lock, turning on the auxiliary fuel pump can be helpful in alleviating the issue. Vapor lock occurs when the fuel in the lines vaporizes due to high temperatures or low pressure, preventing liquid fuel from reaching the engine. By activating the auxiliary fuel pump, the pilot can increase fuel pressure in the lines, helping to push any vaporized fuel back to the tank and restore a steady fuel flow to the engine.

This procedure is beneficial because the auxiliary fuel pump is designed to maintain fuel delivery under adverse conditions. Turning on the pump adds redundancy to the fuel delivery system, allowing it to function more effectively in situations where fuel vapor might hinder engine operation.

Other procedures, such as turning off the auxiliary fuel pump, would not help address vapor lock as they would decrease fuel pressure and potentially exacerbate the problem. Changing the fuel mixture setting might not directly resolve the vapor lock situation, though it does play a role in engine operation under normal circumstances. Increasing engine RPM could lead to faster fuel circulation, but it might also cause more vaporization depending on engine temperatures and conditions. Therefore, the most direct and effective response to a suspected vapor lock is to turn on the auxiliary fuel pump.