POSITION REPORT March 2022

AS I WRITE, THE RUSSIAN INVASION of the Ukraine has plunged world markets into chaos. Gold is heading through US$2000 an ounce and the prices of commodities, which includes oil, are peaking.

This is naturally bad news for the already battered general aviation industry in South Africa. Eight years ago, the price of Avgas breached R20 per litre and then mercifully dropped back. The pain of that spike prompted us to launch a page to bring our readers the best Avgas prices in the country. And we still publish the table of fuel prices each month, such is the sensitivity of the industry to fuel prices.

For the past few years Avgas has been steadily climbing on the back of rising oil prices. There is a real chance the Ukraine war is likely to push it through R30 a litre. Will this hasten the demise of Avgas?

The basic facts are well known: Avgas is the last fuel to still contain Tetraethyl Lead (TEL) and there is an ongoing campaign to ban TEL. As early as the 1960s there was a push to remove lead from mogas based on the theory that lead is bad, so ban it.

There were a number of studies done to prove the health hazard of leaded fuel, but none proved conclusive. They collected blood samples from New York taxi drivers who worked in exhaust fumes all day was compared the samples to blood from people living in parts of the world where there were no cars at all. There was no difference in lead levels between the two groups.

They nonetheless succeeded in removing lead from car fuel but it has persisted in aviation fuel, largely due to the primitive nature of our engines which still do not have electronic ignition with knock sensors to catch pre-ignition and detonation.

But the pressure has continued. Lead was supposed to have been removed by 2017. On 23 February outgoing FAA head Steve Dickson unveiled an industry-government initiative to eliminate the use of leaded aviation fuel by piston-engined aircraft by 2030. Called Eliminate Aviation Gasoline Lead Emissions (EAGLE), the initiative requires industry to accomplish the replacement of Avgas with unleaded fuel.

The reality is – if the fuel industry is forced to provide unleaded Avgas, it will not work for many aircraft. A key challenge is exhaust valve recession. The by-products of lead combustion coat the exhaust valves and seats. This prevents the valve from grinding into the valve seat and recessing into the head. Without lead, exhaust valves recess into the head until valve burning occurs.

And Mogas is just not an option for low wing fuel injected planes which are vulnerable to fuel cavitation from vapour lock – often at the worst possible moment after takeoff. So the situation is in flux – but in the meanwhile we will just have to swallow the exorbitant fuel price and hope it comes down again.

Guy Leitch