Diesel Exhaust Fluid (DEF) Contamination Risk Alert

The issue of Diesel Exhaust Fluid (DEF) contamination of jet fuel has proven to be a very serious threat to the safety of flight. There have been several incidents where DEF was accidentally injected into jet fuel instead of Fuel System Icing Inhibitor (FSII). These incidents have led to inflight emergencies, including both partial and complete engine failures, nine emergency landings, and at least one aircraft deadstick landing – narrowly avoiding a tragic outcome.

NATA urges its members and all refueling operators that utilize DEF and FSII (DiEGME, PRIST®, DICE®) to review their storage, handling, and personnel training procedures to prevent DEF contamination of jet fuel. The Federal Aviation Administration (FAA) has released a Special Airworthiness Information Bulletin (SAIB) that addresses the dangers of DEF contaminated aviation fuel.

In December of 2017, NATA released a DEF Contamination Prevention training course which is provided free of charge to anyone currently using the Legacy Safety 1st online training program. NATA is also bringing an updated version of this training to the Safety 1st Training Center and www.preventmisfueling.com, where NATA offers a free misfueling prevention program.

For questions regarding DEF Contamination Prevention or any of the resources described in this alert, please contact safety1st@nata.aero.


NATA Safety 1st Alert
OBP DEF Handling and Contamination Prevention
Misfueling Prevention Training 
NTSB Alert
Aircraft Diesel Exhaust Fluid Contamination Working Group Report & Recommendations
Safety Risk Management DEF Report - August 30, 2019