Fuel Contamination in Aircraft
One of Soar Aviation’s senior management team, Vernon is as passionate about flying as he is about biltong. Since starting his career with British Overseas Airways Corporation (BOAC) 1969 followed by British Airways Vernon has ridden many waves of change in the world of aviation, contributing his knowledge and expertise along the way to help shape the future of flight. When he has time to remove his management hat you’ll find Vernon exploring the world’s airwaves as a radio amateur (ham) radio operator.
On two occasions I, recall prior to fuel being loaded, that contamination was located, fuelling a jet aircraft using Jet fuel was loaded with avgas this could have caused a major disaster with the aircraft failing to climb.
The other occasion was in Johannesburg where the entire fuel farm was contaminated “Fuel contamination at Johannesburg’s main airport had left 7 million litres of their stock unfit for usage, sparking fears of flight delays at Africa’s busiest airport, a consortium supplying fuel to the hub detected the contamination reducing stock levels from four to one day’s supply a delivery of lower standard, more volatile fuel contaminated existing stocks.”
How often are we told that aviation fuels are superior to other fuels as they must meet one common, exacting worldwide standard, are produced with more stringent controls, are transported, stored, filtered and dispensed from dedicated equipment? Given these tough requirements, one would expect contamination or misfueling to be near impossible, yet it does happen. Here are three different incidences from recent years:
The Australian Transport Safety Bureau describes an incident on Christmas in 1999 involving contaminated avgas: “The avgas contamination event that happened over Christmas 1999 caught everyone by surprise. It had not been seriously considered as a potential hazard to aviation anywhere in the world, therefore the consequences had not been considered. The reasons behind why the fuel became contaminated were unexpected….No one was hurt as a result of contaminated aviation fuel, and there were no accidents that could be attributed to a loss of power caused by fuel contamination. At the time of the crisis the fuel refiner responded immediately and recalled all avgas that had been manufactured at the refinery, and CASA grounded all avgas-powered aircraft that could have been contaminated until it was known that they were safe to fly….The investigation followed the grounding in January 2000 of thousands of piston engine aircraft across eastern Australia when a black gunk was found in fuel systems. The investigation found that a very small amount of an anti-corrosion chemical [ethylene diamine] that was not removed in Mobil’s avgas refining process in late 1999, and not detected by the usual tests, led to the safety problem.”
The Canadian Transportation Safety Board reported on Jet fuel being pumped into three piston engine-powered Robinson R44 helicopters: “On 1 March 2011, the Robinson R44 Raven II helicopter (C-FNZO) was accompanied by two other Robinson R44 II helicopters for a trip from Port-Menier, Quebec, to Quebec City, with two people on board and two refuelling stopovers planned. On their way back from the trip, all three helicopters stopped in Forestville to refuel. The refueller was asked to refuel the helicopters and none of the pilots noticed that the incorrect Jet fuel fuel was used instead of the required avgas 100LL. During takeoff, the fuel gauges were showing less than full. After a few radio exchanges among the three helicopters, and at approximately 1,000 feet above ground level, the pilots concluded that the wrong fuel had been used. C-FNZO lost engine power and the pilot made a forced landing in a residential neighbourhood in Forestville. Both people on board had minor injuries and were taken to hospital. The helicopter was substantially damaged. The other two helicopters landed near C-FNZO and sustained no damage.”
Most recently, Trenton NJ times reported- that either avgas or jet fuel was being pumped into cars at three New Jersey gas stations, which casts doubts over claims of dedicated aviation fuel transporters delivering solely to airports: “Three gas stations in Mercer County unwittingly received and pumped aviation gasoline or jet fuel over the weekend, filling some drivers’ cars with a product that can damage automobile engines. The gas was mistakenly delivered over the weekend to several stations around the state, including locations in Hamilton and Lawrence, which were subsequently closed for inspection, Mercer County spokeswoman said. Automobile engines filled with jet fuel can stall almost immediately. In Monmouth County, several customers’ cars stalled on Friday when two gas stations in Keyport and Manasquan unknowingly pumped them with the fuel. The state Division of Consumer Affairs, which oversees weights and measures issues, was unable to provide any information on the mistaken gas delivery, such as the name of the gasoline supplier, when the fuel was delivered, and whether the substance was aviation gasoline or jet fuel, which are different products.”
Many users obtain their fuel from retail sellers and know to test fuel for the presence of ethanol, water or sediment, and assure that its octane (AKI) rating meets or exceeds the requirements for the aircraft’s engine. As these three incidents show, however, even when sold at airports, fuel can include contaminants, and ground personnel can make mistakes when fuelling aircraft.
The best means to prevent problems is to go back to what we learnt in ground school: After fuelling a plane, allow the fuel to settle for 5-10 minutes, then take several samples from each sump. Check the fuel for the correct colour and odour, and keep dumping it until there is no evidence of sediment or water. Avgas should be light blue and has an almost sweet smell; Jet fuel known as Jet A1 will be a straw to beige colour and smells like its cousin, kerosene; mogas can vary in colour from nearly clear to light brown and generally has the strongest oil smell of the three fuels. If anything appears odd, contact line personnel, the FBO manager or call the help number usually found on or near the airport’s fuel system.
If your aircraft has been outdoors in moisture, you might be seeing a cup full of water when you first sump the tanks if there are any leaks in the fuel system. An easy way to determine this is by smell and by touch — a wet finger held in the air will smell of fuel and will cool quickly due to the more rapid evaporation compared to water. A cup full of water might even have some of the colouration of the fuel in your tank — just enough to fool you.
As we have seen, fuel problems can happen. Just because our fuel comes out of a shiny tank does not mean that it is immune to contamination. While this is very rare, a few simple precautions can prevent serious issues, which according to Murphy’s Law always occur just as we’ve reached an altitude sufficient to kill ourselves.
It does not matter whether you have fuelled your air plane yourself or have allowed line personnel to do this for you; “Trust but verify” — make sure you double-check what fuel is really in your tanks before flying, keep the copy of the fuel receipt very important and please always make sure you have your aircraft well grounded via a static line before any fuelling operations, even if you self-fuel a few gallons into your tank on your Fox Bat for a short flight around the patch at dusk. “Trust but verify”.