When it comes to flight operations, jet fuel is probably the most important item on the list. Commercial and private aircraft typically use two types of fuels-jet fuel and AVGAS. Which fuel works best for a plane depends on the type of engine the plane has.
Jet fuel is a colorless kerosene-based fuel and is generally used for jet engines and turboprops. The second type of fuel is called aviation gas or AVGAS. This is used for small piston-engine planes and propeller aircraft.
More often than not, these are used by some of the best private jet companies. It is also used by flying clubs and for flight training purposes.
AVGAS is made of small amounts of tetraethyl lead as an additive. There are two types of AVGAS still in use in the aviation industry-AVGAS 100 and AVGAS 100LL. The former has more lead content than the latter.
It stops the engine from detonation which can avoid engine failures, but when humans absorb or inhale it, tetraethyl lead can be toxic. And because of that, the Federal Aviation Authority (FAA) and the US Environment Protection Agency (EPA) are working on eliminating it from AVGAS.
The number 100 that is common to both these AVGAS types indicates the fuel's octane rating. But there are a few differences too.
● The percentage of tetraethyl lead is not the same in both AVGAS types.
● AVGAS 100LL is low lead when compared to AVGAS 100.
● AVGAS 100LL is blue in color whereas AVGAS 100 is green.
Aviation fuel is one of the biggest sources of lead emission in the US. While lead is no longer added to automobile fuel, it is still being used by the aviation industry and efforts are being made to rectify this problem.
Now, this is not used in commercial aircraft which are the majority of the planes. But the smaller planes that do use AVGAS cause half of all the lead pollution in the air. So, this is a problem when it comes to maintaining air quality.
Being exposed to lead repeatedly can cause several health problems to the kidneys, red blood cells, central nervous system, the heart and cause immunity problems too. In children, it can lead to learning disabilities and lower IQ levels.
In 2008, the EPA set newer, tougher standards for the amount of lead that was safe to be in the air. In 2010, they said that 16 regions in the country did not meet those standards and all of those regions either had or were close to an airport where AVGAS was used.
Despite all this evidence, there is no restriction on the usage of leaded AVGAS which is conspicuous considering there is access to unleaded AVGAS.
70 percent of these small planes could use unleaded gas but they don't. Some clubs are trying to shift to unleaded AVGAS but it is their own initiative. The plan of action from the government or the EPA looks bleak at best.