Just got an email from the FAA saying that ASTM has developed a standard for 100VLL fuel.
I wonder how this will affect performance and engine operation for the older engines?
SAIB: NE-11-55
SUBJ: Grade 100VLL Aviation Gasoline Date: September 14, 2011
This is information only. Recommendations aren’t mandatory.
Introduction
This Special Airworthiness Information Bulletin (SAIB) advises aircraft operators, Fixed Base
Operators (FBOs), FAA repair stations and Flight Standards District Offices, and Foreign Civil
Aviation Authorities that grade 100VLL aviation gasoline meeting the American Society for Testing
and Materials (ASTM) fuel specification D910 is acceptable for use on aircraft and engines
certificated for operation with D910 grades 80, 91, 100, and 100LL aviation gasolines. Grade
100VLL meets all the performance requirements of grades 80, 91, 100, and 100LL and therefore
meets the approved operating limitations for aircraft and engines certificated to operate with these
other grades of aviation gasoline.
Background
The FAA relies on ASTM International to develop fuel specifications that applicants may designate
as operating limitations for their approved products. These aviation fuel operating limitations may be
listed in the product’s Type Certificate Data Sheet (TCDS), Installation Manual, service instructions,
or as limitations associated with a Supplemental Type Certificate (STC).
Grade 100VLL aviation gasoline (avgas) was developed by ASTM International to provide a lowerlead
alternative to 100LL in response to impending environmental regulations. Grade 100VLL is
identical to 100LL in all aspects, except that the maximum lead content is reduced by about 19%.
The specification criteria for lead content is expressed as only a maximum value, because avgas
producers routinely tradeoff lead content with other fuel compositional changes to meet the
specification criteria for Motor Octane Number (MON). FAA survey data has shown that the lead
content can vary by up to 39% from the maximum lead value listed in the specification while still
meeting the MON minimum requirement. Consequently, and most importantly, grade 100VLL has
the same minimum octane rating and will provide the same level of anti-knock performance as
100LL and 100 avgas grades.
The FAA collaborated with industry on the ASTM International task force that evaluated data
supporting the incorporation of grade 100VLL into specification D910. The FAA determined that
grade 100 VLL meets all of the performance requirements of grades 80, 91, 100, and 100LL and will
perform identically in existing aircraft and engines.
Recommendations
Because grade 100VLL avgas that meets ASTM specification D910 is identical to grade 100LL
avgas, the following recommendations apply:
1. Grade 100VLL avgas is acceptable for use on those aircraft and engines that are approved to
operate with grades 80, 91, 100, or 100LL avgas.
2
2. ASTM International standard D910 specifies blue coloration for both grade 100VLL avgas
and grade 100LL avgas, and, therefore, these fuels are visually indistinguishable from each
other.
3. Operating limitations in Aircraft Flight Manuals, Pilot Operating Instructions, or TCDSs that
specify grades 80, 91, 100, or 100LL avgas fuel are acceptable for use with grade 100VLL
avgas.
4. Current aircraft placards that specify grades 80, 91, 100, or 100LL avgas are acceptable for
use with grade 100VLL avgas.
5. Operating, maintenance, or other service documents, for aircraft and engines that are
approved to operate with grades 80, 91, 100, or 100LL avgas, are acceptable for use when
operating with grade 100VLL avgas.
For Further Information Contact
Mark Rumizen, Aerospace Engineer, FAA, Engine & Propeller Directorate, 12 New England
Executive Park, Burlington, MA 01803; phone: (781) 238-7113; fax: (781) 238-7199;
email:
mark.rumizen@faa.gov.