When inspecting a removable rigid fuel tank for leaks, what procedure should be followed?

When inspecting a removable rigid fuel tank for leaks, the preferred procedure involves pressurizing the tank with air and then applying soapy water to the tank's surface. This method is effective because the air pressure inside the tank forces any air leak outwards, while the soapy water creates bubbles at the site of any escaping air, making leaks easily visible.

This technique is not intrusive and can be performed quickly, which is useful in many maintenance scenarios. By using soapy water, you can identify small leaks that might be missed with other methods. If bubbles form while applying soapy water, it indicates a leak, allowing for proper reparative actions to be taken.

The other methods while effective in certain contexts, could provide less efficient means of leak detection. Submerging a pressurized tank in water may not provide all the clarity needed, especially if the tank is large. Filling the tank with water adds unnecessary complexity and weight and could be impractical in certain situations. Ultrasonic testing, while a highly accurate method, may not always be readily available or suitable for every scenario, particularly if a straightforward visual inspection with soapy water can suffice. Thus, the combination of air pressure and soapy water is a practical and efficient approach for leak