A primary concern for all parties to the search for a single unleaded avgas is safety—particularly the safety of end-users: the pilot and passengers, fuel handlers, and others in the aircraft operating environment.
Question: What are the key avgas safety issues related to aircraft and engine performance?
Answer: There are two major categories of safety concerns that every pilot faces: achieving rated power for the aircraft engine without detonation and ensuring materials compatibility. For rated power issues, it is critical that a new fuel meet aircraft performance specifications in the pilot’s operating handbook. Consider such vital issues as rated power on takeoff and climb, range, and performance at high altitude. On materials compatibility, fuel tank and fuel system integrity is at stake—water absorption and possible corrosive effects on tank seals, bladders, fuel lines, and carburetor parts are major concerns. For example, the corrosive effects of ethanol blends of auto fuel are now well-documented.
Question: Are there other “sleeper issues” related to avgas and aircraft safety?
Answer: Avgas weight vs. energy content. While some blends of high-octane fuels have shown to be heavier than current 100LL, they may also have higher energy convert which could potentially negate the weight concern. But operationally, this must be considered so that ultimately pilots have the accurate information for preflight planning purposes.
Question: While getting the lead out of avgas in pursuit of health benefits, is it possible that future avgas solutions could pose new and as-yet-unforeseen health and safety concerns?
Answer: One of the many factors that potential fuel solutions must take into consideration is their emissions. Each will need to address concerns about emissions (carbon dioxide and nitrogen oxide levels and known carcinogens) and meet requirements for safe handling (toxicity and water solubility).