The U.S. aircraft register, updated daily
Fuels · Aviation gasoline · data as of November 2, 2026

UL91 unleaded avgas

An unleaded 91-octane aviation gasoline for engines that do not need 100 octane, sold mainly in Europe. Rotax and other low-compression engines are approved for it.

The fuel

Class
Aviation gasoline
Specification
ASTM D7547
Status
in use
FAA airport-file code
UL91
16,606
aircraft are approved for it by their engine's maker
20 engine series
5
airports and fields sell it
in 4 states

Who burns it engine series on the register

Approved for it by the engine's maker as an alternative to 100LL (16,606 aircraft):

Rotax 912ULS series 3,382Rotax all models (one FAA code) 2,584Rotax 582 series 1,193Rotax 912 IS 878Rotax 582DCDI 578Rotax 503 DCDI 561Jabiru 3300 475Rotax 503 series 449Rotax 912UL series 402Rotax 915 IS 393Volkswagen (converted) CONVERSION 374Subaru (converted) ALL MDLS A/B 348Rotax 912S 335Rotax 914UL 305Rotax 912 241Rotax 914 series 228Rotax 912ULS2 208Rotax 912UL2 186Jabiru 3300A 161HKS 700E 155

An engine's fuel follows from its FAA type: piston engines burn aviation gasoline, turbines burn jet fuel, the diesel pistons burn jet fuel, electric motors charge from the grid. Each series' page lists the models and aircraft that carry it.

Approvals the FAA's supplemental type certificates for this fuel · the owner buys the certificate once

CertificateHeld byWhat it approvesModel families namedEngine series namedDate
SA01831WIPetersen Aviation INCTo allow the use of UL91 (minimum) grade aviation fuel 90—July 27, 2020

Model families the certificates name · 90, by aircraft on the register

Cessna 172 Skyhawk 20,681Piper PA-28 Cherokee, Warrior, Archer and Arrow 18,637Piper PA-32 Cherokee Six, Lance and Saratoga 3,916Piper PA-24 Comanche 2,428Piper PA-23 Apache and Aztec 1,315Piper PA-12 Super Cruiser 1,247Diamond Aircraft DA 40 Diamond Star 1,018Boeing A75 Stearman Kaydet 978Piper PA-30 Twin Comanche 880Cessna R182 Skylane RG 706Piper PA-44 Seminole 602Piper PA-25 Pawnee 455Piper PA-38 Tomahawk 442Aeronca 65 Chief and Super Chief 377Diamond Aircraft DA20 Katana and Eclipse 364Maule M-5 364Beechcraft A23 329Bellanca 14 282Maule M-7 275Dehavilland DHC-2 255Fairchild 24 242Maule M-4 207Rockwell International 112 207Daher (Socata) TB-20 200Maule MX-7 193Waco UPF-7 189Fairchild M-62 186Great Lakes 2 168Piper PA-15 165Douglas DC-3 155Costruzioni Aeronautiche Tecna P2010 139Maule MXT-7 134Taylorcraft BL-65 134Ryan Aeronautical ST3 117Interstate S-1 104Commander Aircraft Co 114 103Piper PA-14 100Mooney M-18 98Howard Aircraft DGA-15 97Piper PA-17 Vagabond 97Piper PA-39 Twin Comanche C/R 82Maule M-6 81Maule MT-7 76Monocoupe 90 63Britten-Norman BN-2 54Daher (Socata) TB 10 53Daher (Socata) TB 9 34Cub Crafters CC18 33Porterfield LP-65 27S.O.C.A.T.A. MS894 27Omf OMF-100 25Stinson HW75 23Cessna C-165 21Waco YKS-7 21Found Acft Canada Inc FBA-2 19Porterfield CP-65 19Helio H-395 17Siai-Marchetti F.260C 17Stinson SR-10 17Helio H-391 16S.O.C.A.T.A. RALLYE 235 16Taylorcraft BL12 16Consolidated Aeronautics Inc. LAKE LA-4 15Estumkeda Ltd Dba Micco Acft MAC-145 15Symphony Aircraft Ind Inc SA 160 15Waco YKS-6 15Indus Aviation Inc T-211 14Meyers MAC-145 14Varga Aircraft Corp. 2180 14Pilatus Britten-Norman Ltd. BN-2 13Boeing IB75 12Waco VKS-7 12Agusta Spa F.260D 11Helio H-250 11S.O.C.A.T.A. RALLYE 150 10Consolidated Vultee 28 9Consolidated Vultee BT-15 8Dornier DO 27 8Dornier DO28 7Porterfield FP-65 7Ryan Aeronautical SCW-145 7Siai-Marchetti F.260 7Waco ZQC-6 7Aeronca S-65 6Curtiss Wright TRAVEL AIR D-4000 5Howard Aircraft DGA-11 5Northwestern PORTERFIELD 35 5Thurston TSC-1 5Waco YQC-6 5Waco ZKS-7 5

The families and series are those the FAA's certificate listing names; a certificate written for "all spark-ignition engines" names none and covers them all. Whether one aircraft is covered depends on its exact model and engine, which the certificate's approved model list settles; the aircraft's own page says what applies to it.

Where it is sold 5 airports and fields in 4 states

Wisconsin 2Minnesota 1Indiana 1South Dakota 1
AirportWhereBased aircraftSays who
Capitol Drive AirportBrookfield, Wisconsin116 the FAA's airport file
Little Falls/Morrison County-Lindbergh FieldLittle Falls, Minnesota25 the FAA's airport file
Price CountyPhillips, Wisconsin15 the FAA's airport file
Walker/Rowe Waterloo AirportWaterloo, Indiana— the FAA's airport file
Lake Cochrane Seaplane BaseGary, South Dakota— the FAA's airport file

Connections how this fuel links to the rest of the register

Also approved for it, by the maker
Approved for it under an STC
The approvals
Sold at
Other aviation gasoline
More

The whole map of how records connect · these connections as data: /graph/fuel/ul91.json.

Sources: FAA Civil Aviation Registry (November 2, 2026) for the engines and aircraft; the FAA airport master file for fuel sold; the FAA's supplemental type certificate listings for the approvals; SAFxCHANGE's record for the plants, deals and the airports named in the news; the sellers' own websites where named. Specifications as published by ASTM International and the U.S. military. The fuel makers' own pages say where their fuel is sold this month; this page is as current as those records.