Regulatory and Certification Policy

Regulatory Brief

General Aviation, Air Quality, and Leaded Aviation Fuel

The Issue

The Environmental Protection Agency (EPA) announced on Wednesday October 15, 2008, that it had strengthened the national ambient air quality standards (NAAQs) for lead for the first time since 1978. Following up on a notice of proposed rulemaking issued earlier in the year, the EPA lowered the NAAQS for lead by a factor of 10.  This change sets into motion a multi-year effort requiring state and local governments to ensure they meet new standards by 2017.

In a separate action the EPA opened a rulemaking petition for comment titled “Petition Requesting Rulemaking to Limit Lead Emissions from General Aviation Aircraft.” This EPA rulemaking petition was issued in response to a petition submitted to the EPA by the environmental organization Friends of the Earth.  To date the EPA has not issued a final rule.

Background

In June 2008, AOPA testified to the importance of leaded aviation fuel at a public hearing hosted by the EPA.  AOPA testified that changes to the NAAQS for lead could impact the amount or type of fuel used in general aviation aircraft. AOPA also testified on the safety implications of changing the aviation fuel standard stating that any change in the aviation fuel standard would have a direct impact on the safety of flight and the future of light aircraft in this country.  Also, in 2008 AOPA filed official comments to the EPA “Petition Requesting Rulemaking to Limit Lead Emissions from General Aviation Aircraft.”

Three-fourths of the U.S. fleet—167,000 of the 220,000 aircraft—are piston-powered aircraft certified to fly on leaded fuel. 100LL contains up to 2.2 grams of lead per gallon. Lead boosts the octane of the fuel used in piston-powered aircraft, thus protecting aircraft engines against detonation, which can cause an engine to literally tear itself apart during operation. Additionally, 100LL protects engine pistons and cylinders from wear, and burns cleaner than lower octane fuels. At present there is no commercially available replacement for 100LL.  Outside of general aviation leaded fuel is rarely used.

While past airport air quality studies show that the lead levels around airports are under the limit set by the NAAQs, changes to the NAAQs standard highlight the important of industry’s research into a suitable replacement fuel.  The EPA is in the process of expanding on an earlier air quality study done in 2005 at the Santa Monica airport. The current study will focus on air and soil lead levels around the airport. Data collection is projected to be complete by July 2009.

Why It’s Important

General aviation piston aircraft are reliant upon 100LL, a “specialty fuel” that is produced in small quantities when compared with other fuels. Optimistically speaking, 100LL will continue to be more expensive relative to other petroleum and energy products and, at worst, could be unavailable altogether. Currently, there is no single replacement for 100LL that is economical, requires only minor or no aircraft modification or recertification, and does not offer a penalty in aircraft performance.

Most general aviation piston aircraft rely on the use of 100-octane leaded aviation gasoline, or 100LL.  Currently, there is no unleaded alternative for 100LL that can be used as a substitute or replacement fuel for all piston-powered general aviation aircraft.

AOPA’s Position

A suitable unleaded replacement fuel would be a single-source fuel that could be used in all existing and new piston-powered general aviation aircraft. For a small percentage of aircraft transition to an unleaded fuel may require engine and airframe modifications.

In the FAA’s 2009 Flight Plan the FAA highlighted its commitment to researching alternative fuels for general aviation. While draft versions of the Flight Plan did not include a commitment to pursue finding an avgas replacement, the final document indicated the FAA’s commitment by promising to “continue working with the general aviation community to test, adopt, and certify a new aviation gasoline fuel standard.”  AOPA welcomes the FAA’s commitment to finding an unleaded fuel that meets the safety and operational needs of the general aviation fleet.