May 24, 2019

A recently reported third case in which business aircraft received fuel contaminated with diesel exhaust fluid (DEF) highlights the urgent need for education and awareness to mitigate such incidents, including resources now being developed by NBAA and other industry stakeholders in coordination with the FAA.

According to the agency, earlier this month two Cessna Citation 550 business jets each received more than 400 gallons of Jet A contaminated with DEF at Florida’s Punta Gorda Airport (PGD). Both aircraft then flew to Naples, FL (APF), where they took on more fuel before departing on separate flights to different destinations.

It was on those flights when both aircraft suffered single-engine flameouts while at cruising altitude. One of the twinjets diverted to Louisville, KY (SDF), where it made a one-engine inoperative emergency landing, while the other Citation later lost its second engine while descending through 8,000 feet on approach to Savannah/Hilton Head International Airport (SAV), where it successfully glided to the runway. No injuries were reported in either incident.

DEF is similar in appearance to fuel system icing inhibitor additive (FSII, also known as Prist), but when mixed with Jet A, the solution forms non-soluble crystals that can clog aircraft fuel systems. The Environmental Protection Agency mandated the urea-based additive to lower noxious emissions from diesel-powered ground vehicles operated on public roads.

Last August, after several aircraft were serviced with DEF contaminated jet fuel, a Dassault Falcon 900EX was forced to return to Miami-Opa Locka Executive Airport (OPF) when one of the trijet’s engines failed and a second became unresponsive to throttle inputs. In November 2017, seven aircraft were fueled with DEF-contaminated Jet A at Eppley Airport (OMA) in Omaha, NE while another six received fuel from equipment previously exposed to the contaminated fuel.

“This third known incident of DEF contamination highlights a very pressing concern,” said NBAA President and CEO Ed Bolen. “Unfortunately, these incidents have not been isolated occurrences, and FBOs and flight crews alike should closely examine methods to mitigate and eliminate this potential hazard in their operations.”

The FAA issued special airworthiness information bulletins about DEF contamination following the OMA and OPF incidents.

Bolen noted that NBAA is also among a coalition of industry stakeholders – including the National Air Transportation Association, Aircraft Owners and Pilots Association and General Aviation Manufacturers Association – working with the FAA to develop educational resources and mitigation strategies to avoid DEF fuel contamination incidents.

“While it’s imperative that FBOs work to reduce the probability of contamination, resolving this issue relies also on the vigilance of aircraft refuelers and flight crews monitoring the fueling process,” Bolen emphasized. “There must not be any confusion over what is going into aircraft fuel.”

The DEF education resource is expected to be published in the coming weeks.