AD FAA-2020-0579

The FAA is adopting a new airworthiness directive (AD) for certain The Boeing Company Model 737-8 and 737-9 (737 MAX) airplanes. This AD requires removing Kathon FP 1.5 biocide from the fuel tanks and engines, installing a fuel limitation placard, and revising the existing airplane flight manual (AFM) to prohibit operation of the airplane with Kathon FP 1.5 biocide in a fuel tank or engine. This AD was prompted by a report indicating that Kathon FP 1.5 biocide added to fuel and running through the engines can lead to significant engine anomalies. The FAA is issuing this AD to address the unsafe condition on these products.