SAFETY & TRAINING DEF Contamination YES, it is that serious! By Michael France W e’ve all heard the expression “planes fly on paperwork,” and while our regulatory envi- ronment makes that adage nearly true, it’s the fuel in those planes that literally keeps our industry flying. Without clean, dry, on-specification fuel, airport and flight operations can come to a screeching, and sometimes disastrous, halt. Those of us who’ve spent any time managing aviation fuel storage and delivery to aircraft are keenly aware of the contamination dangers that lurk in the corners. Things like water, particulates, surfactants, microorgan- isms, and especially misfueling all top the list of usual suspects. There have been stories of water making its way into aircraft fuel tanks, and several documented cases of jet fuel being loaded onto aircraft requiring Avgas that have ended in tragedy and cost people their lives. As an industry, we have spent countless hours drilling into our teams the importance of aviation fuel quality control and the process of grade verification prior to refueling, and our industry is the safer for it. However, we are now seeing the arrival of a startling new threat to aviation fuel quality and flight safety, both in terms of frequency and severity. The threat is Diesel Exhaust Fluid, or DEF, and in the past 18 months there have been three separate DEF contamination events that have led to multiple in-flight engine failures and at least one dead stick landing. Miraculously, none of these DEF contami- nation events led to an aircraft crash, but make no mis- take, if we do not take immediate action, OUR LUCK WILL NOT LAST. Preventing DEF contamination is not difficult, and in the following Q&A we’ll cover the information and action items necessary to help our industry prevent another DEF contamination event. What is DEF? DEF is a urea and water-based fluid that is required by federal regulations to be used in the emission reduc- tion systems of modern diesel engine vehicles. DEF is NOT a fuel additive, aviation or otherwise. It is a clear liquid, stored in a specialized tank on the chassis of diesel engine vehicles, that is injected into the engine exhaust to promote reduction of noxious emissions. How is DEF getting into Jet Fuel? The apparent contamination pathway involves line service personnel mistaking DEF for Fuel System Icing Inhibitor (FSII, PRIST, DiEGME) and adding DEF to the FSII storage tanks on mobile refuel- ers. DEF and FSII are both clear, colorless liquids, and if DEF is mistakenly added to a FSII storage tank, con- tamination can be very difficult, if not impos- sible, to detect. Continued on page 13 Aviation Business Journal | Summer 2019 11
