Should You Use Lead-Reducing Fuel Additives?

A FLYING reader asks our A&P author if using these fuel treatments will help their aircraft.

Richard Scarbrough

Wednesday, June 22, 2022 at 08:31 AM ET

Verified

An Aeronca 7AC Champ aircraft. [FLYING Archive]

Key Takeaways:

Lead in 100LL is harmful and contributes to engine deposits, with unleaded alternatives demonstrating significantly cleaner engine operation.
Lead-reducing additives like Alcor's TCP (tricresyl phosphate) act as effective tetraethyl lead scavengers, designed to reduce deposits and prevent plug fouling.
Using lead-reducing additives proactively, even without current plug fouling issues, can be a beneficial interim measure until widespread unleaded avgas is approved and available.

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Q: I fly a Champ with a Continental C-85 engine, and I am confused about the benefits of fuel treatments like TCP that reduce lead deposits from 100LL. My spark plugs look clean. Is it just a good idea to use lead-reducing fuel additives anyway?

A: There is no secret about the harmful effects of lead. I recently spoke with George Braly of General Aviation Modifications Inc. (GAMI), who is currently running tests for their unleaded avgas alternative G100UL. Initial teardowns of the tested powerplant showed cleanliness far superior to that of leaded 100LL. Lead is a dirty business, a foul element (no pun intended), and better left to history.

Aircraft Spruce & Specialty carries a wide range of lead-reducing additives, including TCP. While we cannot review each one individually, one key indicator to look for when choosing an aircraft product is FAA approval. It is always a good idea to stay in line with the feds.