What happened
The FAA’s narrative, in sentence case. The FAA writes it in capitals and removes private details.
On April 28th, 2024, at 1415 local time the pilot in command (PIC) of a part 91 banner towing operation conducted an emergency off-field landing in Fresno, CA. The PIC stated they lost engine power during their approach to their intended landing destination of sierra sky park (E79). The PIC said they switched the fuel selector to the left tank and attempted two restarts of the engine, which were unsuccessful and due to their low altitude, they switched their focus to conducting the landing. The PIC landed the aircraft with the banner still attached and only sustained minor aircraft damage to the right wing, which struck a tree, and the landing gear (wheel pants), which contacted a curb. The aircraft was towed to sierra sky park and during the towing evolution to the airport it was heavily damaged when the left wing struck a tree.
During the investigation of this incident, it was identified that the aircraft had roughly 10-12 gallons of total fuel remaining between the right and left fuel tanks. Holding the majority in the left fuel tank. The aircraft was towing a banner for a total in-flight time of about 4 hours with every turn being a left-hand turn. There was one flight prior to the one in which the incident occurred, adding to a total in-flight time of roughly 4 hours and 15 minutes since the aircraft received fuel. Due to a combination of in-flight factors, such as power settings, angle of attack, in-flight time, fuel consumption rates and drag from both the aircraft flap position and banner being towed, it has been determined there is a high likelihood the engine was not receiving the proper fuel flow to maintain normal engine operation.
An exact cause can’t be pinpointed, however, after careful consideration of all the factors fuel starvation is the most likely cause. The aircraft flight manual supplement for the modified O-360 A4M engine and propellor notes an expected increase in fuel consumption and reduced range. The supplement does not have an updated exact useable fuel limit included. The aircraft was not in level flight conditions, and only had an estimated 4-8 gallons left of usable fuel which may have mostly been in the left tank. The aircraft just came out of a series of left turns around an event center and the fuel system may have been unable to supply enough fuel to the engine to maintain stable flight conditions, causing the loss of power.
As the FAA filed it
ON APRIL 28TH, 2024, AT 1415 LOCAL TIME THE PILOT IN COMMAND (PIC) OF A PART 91 BANNER TOWING OPERATION CONDUCTED AN EMERGENCY OFF-FIELD LANDING IN FRESNO, CA. THE PIC STATED THEY LOST ENGINE POWER DURING THEIR APPROACH TO THEIR INTENDED LANDING DESTINATION OF SIERRA SKY PARK (E79). THE PIC SAID THEY SWITCHED THE FUEL SELECTOR TO THE LEFT TANK AND ATTEMPTED TWO RESTARTS OF THE ENGINE, WHICH WERE UNSUCCESSFUL AND DUE TO THEIR LOW ALTITUDE, THEY SWITCHED THEIR FOCUS TO CONDUCTING THE LANDING. THE PIC LANDED THE AIRCRAFT WITH THE BANNER STILL ATTACHED AND ONLY SUSTAINED MINOR AIRCRAFT DAMAGE TO THE RIGHT WING, WHICH STRUCK A TREE, AND THE LANDING GEAR (WHEEL PANTS), WHICH CONTACTED A CURB. THE AIRCRAFT WAS TOWED TO SIERRA SKY PARK AND DURING THE TOWING EVOLUTION TO THE AIRPORT IT WAS HEAVILY DAMAGED WHEN THE LEFT WING STRUCK A TREE.
DURING THE INVESTIGATION OF THIS INCIDENT, IT WAS IDENTIFIED THAT THE AIRCRAFT HAD ROUGHLY 10-12 GALLONS OF TOTAL FUEL REMAINING BETWEEN THE RIGHT AND LEFT FUEL TANKS. HOLDING THE MAJORITY IN THE LEFT FUEL TANK. THE AIRCRAFT WAS TOWING A BANNER FOR A TOTAL IN-FLIGHT TIME OF ABOUT 4 HOURS WITH EVERY TURN BEING A LEFT-HAND TURN. THERE WAS ONE FLIGHT PRIOR TO THE ONE IN WHICH THE INCIDENT OCCURRED, ADDING TO A TOTAL IN-FLIGHT TIME OF ROUGHLY 4 HOURS AND 15 MINUTES SINCE THE AIRCRAFT RECEIVED FUEL. DUE TO A COMBINATION OF IN-FLIGHT FACTORS, SUCH AS POWER SETTINGS, ANGLE OF ATTACK, IN-FLIGHT TIME, FUEL CONSUMPTION RATES AND DRAG FROM BOTH THE AIRCRAFT FLAP POSITION AND BANNER BEING TOWED, IT HAS BEEN DETERMINED THERE IS A HIGH LIKELIHOOD THE ENGINE WAS NOT RECEIVING THE PROPER FUEL FLOW TO MAINTAIN NORMAL ENGINE OPERATION.
AN EXACT CAUSE CAN’T BE PINPOINTED, HOWEVER, AFTER CAREFUL CONSIDERATION OF ALL THE FACTORS FUEL STARVATION IS THE MOST LIKELY CAUSE. THE AIRCRAFT FLIGHT MANUAL SUPPLEMENT FOR THE MODIFIED O-360 A4M ENGINE AND PROPELLOR NOTES AN EXPECTED INCREASE IN FUEL CONSUMPTION AND REDUCED RANGE. THE SUPPLEMENT DOES NOT HAVE AN UPDATED EXACT USEABLE FUEL LIMIT INCLUDED. THE AIRCRAFT WAS NOT IN LEVEL FLIGHT CONDITIONS, AND ONLY HAD AN ESTIMATED 4-8 GALLONS LEFT OF USABLE FUEL WHICH MAY HAVE MOSTLY BEEN IN THE LEFT TANK. THE AIRCRAFT JUST CAME OUT OF A SERIES OF LEFT TURNS AROUND AN EVENT CENTER AND THE FUEL SYSTEM MAY HAVE BEEN UNABLE TO SUPPLY ENOUGH FUEL TO THE ENGINE TO MAINTAIN STABLE FLIGHT CONDITIONS, CAUSING THE LOSS OF POWER.