At all Phillips 66 and many other FBOs, line technicians must first complete a line technician training course before handling or fueling aircraft. At many FBOs, video training programs are offered, ranging in subjects from refueling piston and jet aircraft to customer service and safety. After each video, line personnel take written and hands-on tests. (At Phillips, upon passing all training segments, technicians receive a "line service specialist" certification.)
A quality control and fire safety seminar acts a refresher course to reinforce the basics learned during the video training. For example, seminar attendees are reintroduced to the five major tests that should be conducted at the FBO to ensure fuel quality. They are:
The White Bucket Test — a visual test to determine the possible presence of surfactants, water, and/or solids in jet fuel. The fuel sample is taken from the filter vessel sump drains, tank bottoms, and compartments of the transport truck when accepting fuel and from the dispensing nozzle.
The Filter Membrane Test. The purpose of the (colorimetric) test is to evaluate the performance of the filter/separator (F/S) unit in removing particulate from the fuel. The F/S unit is the major component for providing clean, dry jet fuel. If the F/S is performing properly, the color rating method should indicate a reduction in rating as compared to a sample taken before the F/S. For the line technician this is a quantitative test — it indicates color in fuel and quantifies if a high concentration of particulate is present. Further testing such as a gravimetric test may be required.
Free (condensed) Water Test. "Dry" fuel is a must for flight safety. The presence of condensed water in aviation fuels can cause engine flameout or ice crystal formation. All tank and filter sumps should be checked daily to determine if any free water is present downstream of the Filter/Separator and if any free water found should be sumped out. The free water test should include a check for undissolved (or suspended) water using a test system similar to the Hydrokit.
API Gravity Test. Equally important to line personnel is identifying if avgas is contaminated with other fuel. Each fuel shipment to an FBO will have an API gravity value measured at the terminal and listed on shipment receiving documents. If the API gravity at the FBO differs from the API gravity record at the terminal, the shipment may have been contaminated.
On proper handling of avgas, for example, Phillips 66 explains that less than a half-gallon of jet fuel contamination in a piston-engine fuel tank could be enough to bring an aircraft down. Even worse, the engine will likely run well until after liftoff, since it takes some time for the jet-A contaminant to move from the lowest point in the sump through the fuel system to the cylinders.
Despite these potentially deadly consequences, FBO line technicians may be unable to tell if avgas has been contaminated with jet-A unless they conduct an API Gravity Test.
The Jet Fuel Additive Test. All Phillips 66 branded jet fuel is pre-blended with an additive package. The jet fuel additive test determines whether the proper amount of additive is present in the fuel.
AREAS OF CONCERN FOR LINE TECHNICIANS
Potential for Misfueling an Aircraft. Misfueling an aircraft with jet fuel when it requires avgas, or vice versa, can happen. The FAA requires that all jet-A hoses are fitted with a wide-mouth nozzle (duck bill) to prevent line personnel from accidentally fueling piston aircraft with jet fuel. The duck bill is wider than the mouth of any piston aircraft fuel tank so it is nearly impossible to fuel one with it.
However, incidents have occurred as a result of some helicopter refueling. After the line technician has fueled a helicopter correctly with jet-A by taking the duck bill nozzle off (paradoxically, the nozzle does not fit the fueling orifice of a helicopter — even though it should), he or she can forget to put it back on, which could lead to the subsequent misfueling of piston aircraft with jet fuel.
Properly Grounding The Aircraft When Refueling. Grounding an aircraft to protect against static sparks should be a by-the-book procedure. But fires have started when a line technician has taken off the fueling nozzle clip because it’s a nuisance or it slows down the jet plane refueling process.
The National Fire Prevention Association (NFPA) and the FAA require that all overwing jet refueling use nozzle grounding clips which can be attached to the plane or the fuel tank. This avoids creating sparks which can lead to fires.
Proper Application of Anti-Icing Addi-tive. Providing an aircraft with anti-icing protection is crucial to the aircraft but can be completed impro-perly by the line technician when the FBO does not use preblended fuel. In this case, the line technician must individually blend the additive into the refueler. When administering the additive, "splash blending", atomizing the additive with the fuel, or spraying are methods not recommended since they are imprecise and can render the anti-icing agent ineffective.
For best results, line technicians should use an injector to meter out the additive in the proper proportions — or use preblended fuel.
Ultimately, it is the responsibility of the pilot to ensure his aircraft has been safely and properly fueled. Even though oil companies and FBOs spend a lot of effort and money ensuring aviation fuel quality, it is the pilot who is the most important and final link in the quality control chain.
Pilots are advised not to leave final responsibility entirely with the line technician. Every pilot should watch the fueling procedure to ensure it’s handled properly — and should sump the tanks before taking off.
Tell-tale signs that an FBO has quality fuel include: cleanliness of the facility and the fueling equipment; knowledgeable line personnel; and branded fuel. An extremely low-priced fuel can be a sign the pilot is not getting a quality product.
When all these steps are taken by the fuels supplier, FBO and pilot, the risk of human error in aviation fueling is drastically reduced and that means safer flying for everyone.
Detecting Microbial Growth - The ’X’ Inspection
Any fuel delivery system can become contaminated without pre-treated
fuel. Microbial build-up can rapidly occur inside refuelers and
may present a quality control problem. Microbial particles, already
saturated in the fuel, can flow into the closed environment of an
aircraft’s fuel tank. Once in the aircraft’s tanks, the
growth can continue unless the fuel is properly treated.
How can a line technician know if the FBO’s fuel is contaminated with microbial growth? One suggestion is to try an old military method called the "X" inspection.
A clean rag is tied to the bottom of a pole to protect the inside of the tank and is then inserted, rag-end first, into the refueler’s tank where the technician "draws" an X into whatever sediment may exist at the bottom of the tank. If the "X" mark remains visible through the fuel after the pole has been removed, this an indication of heavy microbial growth.