In November, the FAA published its latest “Reciprocating Engine Aircraft Fleet Fuel Distribution Report” DOT/FAA/AR-TN11/22. As described in the report’s abstract, “The purpose of the data analysis was to establish a baseline of aviation fuels currently in use by all reciprocating engine-powered aircraft to quantitatively assess the effect of first reducing and, eventually, eliminating the tetraethyl lead content on the population of aircraft currently certificated by the FAA.”
Incredibly, the report states that “Only 0.4% of the aircraft are approved to use unleaded fuel.” On further study, the report reveals that its authors were allowed to report only on fuels specified in aircraft Type Certificates, completely ignoring the fact that some 60,000 Supplemental Type Certificates (STCs) have been issued for lead-free autogas since 1982.
Furthermore, the report misses over 2,200+ new S-LSA aircraft that are best operated on autogas. Since LSAs are issued a Special Airworthiness Certificate as opposed to a Type Certificate, they were not counted, although they qualify as reciprocating engine-powered aircraft.
None of the estimated 30,000+ homebuilt aircraft that have been registered in the E-AB category appear in this report, and it is known that many are operated regularly on lead-free autogas. The report also makes no mention of an array of new, autogas-burning aircraft engines that power these LSAs, as well as higher performance aircraft, including the latest generation of products from Continental and Lycoming.
At best, this report is deeply flawed; at worse it was intended to create a skewed baseline to justify continued use of 100LL/100VLL longer than is necessary, given that — in reality — between 70%-80% of all piston engine aircraft are capable of operating on 91 AKI lead-free, ethanol-free autogas, an FAA-approved aviation fuel since 1982.
We strongly recommend that the FAA revise this report to include all reciprocating engine-powered aircraft, including TC’d, STC’d, E-AB, ULs, LSAs, rotorcraft, motorgliders, etc. Otherwise it is essentially worthless in its current form.
The GAfuels Blog is written by two private pilots concerned about the future availability of fuels for piston-engine aircraft: Dean Billing, Sisters, Ore., an expert on autogas and ethanol, and Kent Misegades, Cary, N.C., an aerospace engineer, aviation sales rep for U-Fuel, and president of EAA1114.