The importance of checking the fuel before flight in pilot basic training

In pilot basic training, one of the essential tasks during pre-flight is checking the fuel to ensure its quality and detect any contaminants. This process involves several steps to ensure a thorough inspection. First, a fuel cup is used to draw a sample from each fuel drain or sump. The color of the fuel is checked, with 100 LL aviation gasoline typically appearing blue. Additionally, pilots need to examine the fuel for water and other contaminants that may be present.

While checking the fuel using the fuel drains or sumps is a common method, it may not always detect certain issues. For example, in aircraft with rubber bladder-lined tanks like the Cessna 182, water can get trapped due to wrinkles in the bladder, preventing it from reaching the sump. Similarly, humid air trapped in partially full tanks can condense on the tank's walls and not reach the fuel lines until after takeoff. To address these potential issues, it is recommended to gently rock the wings at the start of the preflight to help dislodge any trapped water and sump the tanks at the end of the inspection.

To prevent misfueling, which is a significant concern in aviation, pilots should supervise the fueling process. There are simple tests that can be conducted to ensure the correct fuel type is used. One method is the touch test, where a small amount of fuel is poured on the finger. Avgas (aviation gasoline) evaporates quickly, causing a cool feeling, while water evaporates more slowly. Jet fuel, on the other hand, hardly evaporates and leaves an oily residue. Another test involves placing a few drops of fuel on a piece of plain white paper. If jet fuel is present, it leaves an oily ring after the avgas evaporates. Additionally, checking the fuel by pouring a small amount on dry pavement can help identify the presence of water. Water will bead up due to surface tension, while avgas will continue to spread.

Another useful approach to checking the fuel is through odor. Jet fuel has a distinct kerosene-like smell, while avgas has its characteristic odor. If no avgas odor is detected, the entire sample may be water. However, it's important to be cautious because water can carry a slight avgas odor if it has been in contact with avgas.

Understanding the importance of preflight procedures and knowing what to check and why are crucial aspects of pilot training. Preflight inspections should not be performed mechanically but rather with an understanding of the purpose behind each check. A thorough preflight involves attention to detail and organization. Following the aircraft's written checklist and paying attention to even small switches can make a significant difference in ensuring safety. It is also recommended to double-check everything if the airplane has recently undergone maintenance. During the initial visual inspection from a distance, potential issues such as flat tires, bent or damaged wings, and other visible damages can be identified.

The use of fuel testers or fuel sumpers is common in pre-flight inspections. These devices help pilots check the type of fuel and ensure it is free from contaminants. For example, in the case of light aircraft, the most common fuel is 100 octane leaded gasoline (100LL). The fuel's color can be examined by holding a sample against a light-colored background, as 100LL is tinted blue. Additionally, the smell of the fuel can provide a clue. Jet fuel smells like kerosene, while 100LL has a distinct smell similar to premium gasoline.

Contaminants, such as water and debris, are also critical factors to consider during fuel inspections. Water, being heavier than fuel, settles at the low points of the fuel system. By sumping the tanks, any water present should be detected and drained. Water droplets may appear as beads or a distinct line in the fuel tester. Debris can come from various sources, such as dirty fuel nozzles or deteriorating tank components. Sumping can help identify the presence of debris, which may be expelled during the process.

In summary, checking the fuel before flight in pilot basic training involves using a fuel cup to draw samples from fuel drains or sumps. This process includes checking the color of the fuel, examining it for water and contaminants, and performing additional tests to ensure the correct fuel type is used. Understanding the purpose behind each check, conducting a visual inspection, and utilizing fuel testers are all part of a comprehensive pre-flight procedure to ensure a safe and successful flight.