Aviation Safety Letter 1/2005
Fuel Systems Modifications: Think Twice
Your lifeline to a safe flight rests, among other things, on the proper management of your aircraft fuel system. Without an ample fuel supply available, your flight will not last very long! Countless accidents occur annually because pilots fail to ensure an adequate supply of fuel to the engine or because of the use of poor quality fuel. Who's at fault? One doesn't have to look very far for the answer, but inevitably, lives are lost, damages are incurred and the pilot community suffers considerably for the amateurish way some pilots view their responsibilities.
The number of aircraft owners who choose to modify their aircraft fuel system without due care or consideration for established practices is scary. A very famous folk and country music singer, John Denver, died because a modification was made to the fuel selector of the aircraft that he had purchased several weeks before. As he was flying at low altitude over the Pacific coast, one of his fuel tanks ran dry and it is believed that, as he pivoted to try and reach the fuel selector located aft of his right-hand shoulder, he exerted pressure on the left rudder and the aircraft dove into the sea.
Modifications to fuel supply systems are not restricted to fuel selectors, as fuel tank location, size, fuel line diameters and pattern, material and connections, all manufacturers too, spend countless hours designing, testing, and compiling data on their fuel system to ensure the best design possible under the conditions chosen for the type of aircraft and engine configuration. When aircraft owners choose to modify it without consulting the proper authorities and experts (e.g. the aircraft manufacturer, a Transport Canada qualified design engineering representative (DER), or someone else who is qualified), they are very likely risking the lives of whomever is going to fly in their aircraft. Some aircraft owners modify the fuel lines improperly, in a way that any water present in the fuel can accumulate at various points in the lines. Others install drains and filters that do not allow for the removal of all of the water that may be present and may cause an engine failure at the most critical moment of flight, the takeoff. Some add a collector or header tank but do not add draining capabilities at the lowest point in the reservoir. Water then collects in sufficient amounts and can clog the fuel filter entirely while in flight.
In short, if you are allowed to do your own maintenance (according to the category of aircraft you own), and you consider making modifications to your aircraft fuel system, it is highly recommended that you seek professional advice, as this consists in a major modification, which can greatly affect the safety of flight. If in doubt, consult with your regional Transport Canada inspectors; they will be glad to provide guidance.
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