Amateur/Home Built/Experimental
Flight Crew Private
Flight Crew Last 90 Days 40; Flight Crew Total 2750; Flight Crew Type 450
Troubleshooting
Aircraft Equipment Problem Critical; Inflight Event / Encounter Fuel Issue
Flight Crew Took Evasive Action; Flight Crew Landed in Emergency Condition; General Maintenance Action
Aircraft
I was flying along the highway at 1;500 feet AGL with the mountains to my north and the ocean to my south. I took the plane on a personal flight out to Location. I was returning to my home base airport ZZZ and was 5 miles out when the engine started to cough/quit very erratic. It was apparent that I needed to land immediately as the plane would not be able to hold altitude. My landing options at 1;500 feet in this area were limited. The tide was in so there were no beach options along the ocean and the mountains were cliffs down to the road. I landed the aircraft on the highway with the motor still coughing. After safely landing the plane with no damage to aircraft or risk to other traffic on the road I shut down the motor and pushed it off on a shoulder. It appeared to me that I was having a fuel delivery issue and that was causing my motor to choke. I had 12 gallons of fuel in the plane and was operating with 1.25 hours remaining. I sumped the fuel and was unable to find contaminates at the time. I poured 3 each 5 gallon travel bags of fuel into the wings and sumped the fuel again. After 40 minutes of inspection; I started the motor up again; It ran rough for short period of time and then came back to full power and normal operation condition. I departed right after traffic was momentarily stopped on either end and returned to my home airport without further issue. I have scheduled a full mechanical inspection of the fuel tank plumbing system. I suspect the vent caps and/or vent lines for the new fuel tanks are not venting as fast as the motor is sucking fuel when the tanks get down to 12 gallons remaining.This is an experimental aircraft which received a new wing and fuel tank system and I have only flown the new wing for approximately 60 hours. We will also retest each tank to verify usable fuel in each tank and make determination if fuel indicating lines need to be re-placarded for usable. Plane will not be returned to service until root cause has been identified with mechanic.
Experimental aircraft pilot reported engine problems developed during cruise; resulting in an off-airport landing. Pilot suspected that the fuel supply system was not working properly.