EASA SIB 2007-01R1: Use of Automotive Gasoline (Mogas) containing Bio-Ethanol

What to do

Operators should verify whether their aircraft are approved to use Mogas containing methanol or ethanol and avoid using fuels with these alcohols if not approved. They should obtain certification from fuel suppliers or conduct tests to confirm fuel composition. For aircraft approved to use such fuels, operators must consider the impact on fuel quantity readings and consult type certificate or STC holders for proper calibration and maintenance procedures. No mandatory compliance deadline is specified.

Summary

EASA Safety Information Bulletin SIB No. 2007-01R1 provides guidance on the use of automotive gasoline (Mogas) containing bio-ethanol in piston-engine aircraft certificated under CS-VLA, CS-22, CS-23, or CS-27 and approved for Mogas operation. It addresses concerns related to the presence of low-molecular weight alcohols such as methanol and ethanol in Mogas fuels and their potential effects on engine performance and fuel system integrity. The bulletin is relevant for aircraft with spark-ignited piston engines approved by type certificate holders or through Supplemental Type Certificates (STC).

What changed

This bulletin revises the earlier Safety Information Notice 2007-01 dated 05 January 2007, updating information on the risks associated with bio-ethanol and methanol content in Mogas fuels. It reflects changes in European fuel standards and the increased use of biofuels following Directive 2003/30/EC. The revision clarifies the potential operational issues and provides updated recommendations for operators.

Why it matters

The presence of methanol or ethanol in Mogas can cause engine in-flight shutdowns, fires, vapor lock, material incompatibility, phase separation, and inaccurate fuel quantity readings, which are critical safety concerns for operators and maintenance personnel. Understanding these risks helps ensure safe fuel use and proper maintenance of fuel quantity indication systems, especially in aircraft with capacitive gauging. Compliance with these recommendations supports continued airworthiness and operational safety.