Bonanza 35
Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine
Flight Crew Last 90 Days 67; Flight Crew Total 4500; Flight Crew Type 321
Troubleshooting
Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter Fuel Issue
Flight Crew Overcame Equipment Problem
Procedure; Aircraft
While en-route to ZZZ I experienced an engine fuel starvation event. I have a Beech V35B with two main tanks and Osborne Tip Tanks. The tip tank design is a direct feed system where the fuel from the tip tanks is fed directly to the engine via a 5 position fuel selector. The positions are off; left; right; right tip and left tip. The fuel tanks can both feed at the same time via a crossfeed valve that is open only while using fuel from the tips and closed in normal operations while feeding from the main tanks. I usually plan on burning 20 gallons from the left main and then using the tip tanks because the fuel system while using the tip tanks will return the extra fuel to the left main fuel tank. The engine driven fuel pump will return about 10-11 gallons/hour to the left main fuel tank. I have a known problem of sometime the tip tank fuel line from the tip to the fuel selector will not be 'primed' and the engine will stutter as the fuel flow is reduced as I start to feed from the tip tanks. I also had a time where even with the cross feed open the tanks did not symmetrically feed. So my SOP is to burn a gallon from the right tip and a gallon from the left tip and then open the crossfeed. This will ensure that both lines are primed and will prevent an imbalance.On this day I burned the 20 gallons from the left main and began my tip tank procedures. 1 gallon from the left and 1 gallon from the right. When I selected the left tank the engine stumbled a little and the fuel flow decreased a bit and recovered after about 10 seconds. After 1 gallon was burned from the left tip I switched to the right tip and it ran ok for a while and I relaxed. Then it ran rough for a second and then all power was lost. I had a good headset on and was listening to music so I didn't even realize the engine stopped. The prop was still turning and the oil pressure was still good. The autopilot was on and I saw the pitch trim wheel going up and the airspeed rapidly decaying. I looked at the engine monitor which shows digital EGT and CHT they were both zero. I knew I had an engine failure so I clicked off the autopilot and since I was below best glide and slowing I pushed over and trimmed for best glide. I was directly over an airport so I knew I had an out. I switched tanks to the right main since that is the closest position on the fuel selector to a main tank. I slightly enriched the mixture since I was lean of peak at cruise. I knew there was air in the lines and our engine driven fuel pumps don't work well as suction pumps - I turned on the electric fuel boost pump for a second and the engine started.I was at 10;000 feet so I had a lot of time to glide there was no panic except for a delayed response the engine fuel starvation occurred and I should have switched tanks when the fuel flow fluctuated too much.I lost about 500 feet during this process. I was IFR and ATC (ZZZ Center) called me to ask if I had a problem. There was traffic below me which I saw on ADSB and was called out to me by ATC. I reported to ATC that I had an engine problem and that I had restarted the engine and was climbing back to 10000 feet. ATC was very helpful because as soon as I said I had an engine problem they provided the bearing and range to an airport. Luckily it was right under me. Some lessons learned. I will prime the tip tanks lines on the ground by selecting that tip tank on the ground and using the fuel strainer on the fuel selector to draw fuel in the line from the tip to the fuel selector. This should ensure there is no air in the lines when I go to use the tip tanks in flight.
Bonanza pilot reported difficulties with fuel crossfeed while using tip tank fuel resulting in a temporary engine failure due to fuel starvation.