Stakeholders Call for FAA-led Process on AvGas Replacement
June 23, 2010 — A coalition of industry groups are calling on the FAA to establish and lead a public-private partnership for finding an unleaded replacement for 100LL or avgas. Fuels research has been underway for years to develop a "drop-in" replacement for the 100 octane leaded avgas, but to date no such fuel has been proven to fully satisfy the needs of the existing fleet of aircraft.
The coalition, which includes representatives from the EAA, the Aircraft Owners and Pilots Association (AOPA), the American Petroleum Institute (API), the General Aviation Manufacturers Association (GAMA), the National Air Transportation Association (NATA), the National Business Aviation Association (NBAA), and the National Petrochemical and Refiners Association (NPRA), is seeking an organized process to evaluate all of the available data on high octane fuel development and engine technologies. The goal is the best possible outcome for the existing fleet and future production aircraft.
The process would consider aircraft performance and safety, and cost/availability factors affecting any future fuel. Over the past 20 years, more than 200 candidate fuels have been tested in the laboratory. Of that group, 45 of the most promising fuels have undergone full-scale engine testing. To date, none of those fuels would fully replace 100LL without other compromises. Several new fuels in early development stages have shown promising results in engine tests, but the range of data necessary to evaluate them fully is still in development.
Since the 1940s, aircraft engines have been designed to run on AvGas, whose properties and performance is deeply understood. The future of leaded avgas is uncertain due to a combination of regulatory and economic factors. The Environmental Protection Agency (EPA) is in the early stages of a rulemaking process that could phase out the use of lead in AvGas. But even in the absence of that regulatory action the security of leaded avgas availability remains in question.
There is only one remaining supplier of the lead additive tetraethyl Lead (TEL) in the world. After 2012, aviation gasoline which is produced in extremely low volumes compared to other transportation fuels, will be the sole marketplace for the additive, calling into question the likelihood that TEL would be available for the long term. Any replacement fuel would need to be able to power the full range of aircraft engines found in the existing fleet of aircraft, from a Cessna 120 to a Navajo Chieftain or a T-28.
“It’s a very difficult problem and despite two decades of research and development no answer has been found yet.” said Doug Macnair of the EAA. “We are trying to find a safe, economical, producible and stable fuel product that will support our community into the future and most importantly, satisfy the existing fleet of aircraft.”
EAA agrees with the coalition’s support of every group conducting fuels research. Those innovations and research are welcome and important steps toward finding the best solution. As each of those fuels is developed, however, it must attempt to meet the same criteria that has made 100 low-lead such a versatile fuel for aviation. Those qualifications should include: anti-knock/detonation properties, energy density, weight, water separation and freeze point, materials compatibility, hot, cold and high altitude starting ability, vapor pressure, corrosion, conductivity, materials compatibility, and storage stability, among many others. Octane is a heavily weighted criteria because it determines the ability for the existing fleet to use the fuel but it is but one of many properties of a success and safe aviation gasoline.
The coalition, which includes aviation advocacy groups, aircraft manufacturers, and fuel producers say they are supportive of all who are conducting fuels research. However they argue that any new fuel should be evaluated by a process that will ensure that it provides: An appropriate level of safety; Ability to be consistently produced; Performance across a wide range of environmental extremes; Specifications that can be produced by refiners and widely distributed in the marketplace.
One of the key components of aviation fuel is octane. 100 octane has been the standard for years; but 70 percent of today’s general aviation fleet would be able to perform with an acceptable margin of safety burning a fuel with a lower octane. The remaining 30 percent of GA aircraft employ high-performance piston engines that need higher octane for anti-detonation protection. While these engines represent about 30 percent of the fleet, they burn a majority of the fuel consumed by general aviation aircraft each year.
Some have advocated a multi-fuel solution similar to that used by the automotive industry during its transition away from leaded gasoline in the 1970's and early 1980's. A few airports today make available both 100LL and MoGas (equivalent to approximately 82 motor octane, the scale used in aviation gasolines). But the broad availability of auto fuel or a similar aviation standard called 82UL at airports has been hindered by the economics associated with needing a second distribution, storage, quality assurance, and dispensing network for a fuel that represents about 30 percent of the already low avgas consumption.
As a near-term solution to help states comply with the dramatically lower EPA ambient air quality standards for lead, the industry is researching the possibility of lowering the maximum lead content in 100LL while still retaining the essential qualities of the fuel. This would be an interim step while an FAA-led integrated fuel research, approval and certification program is undertaken to implement the best possible unleaded alternative over a longer period of time. In the mean time the coalition would work to ensure that 100LL, or a reduced lead version of 100LL, would continue to be available to power the existing fleet.
Presently the AvGas stakeholders group is working with the FAA, EPA and Congress to “Create a path forward for fuels development,” said Doug Macnair. “We are trying to set forth the path to studying the problem, gather and review all of the available data, determine where additional data is required and arrive at the best possible solution for the entire general aviation community. This is a long and difficult project that will take years of dedication and industry and government commitment. 100LL is not going away overnight and the fleet is not at risk of being imminently grounded. We have time to work the problem but we need to move forward in a coordinated and steady manner to address the potential loss of tetraethyl lead in our fuel in the years to come. ”
Meanwhile, the Environmental Protection Agency (EPA) has granted a 60-day extension to the comment period for its advance notice of proposed rulemaking on lead emissions from piston aircraft with comments now due on August 27, 2010.