This is an excerpt from a report made to the Aviation Safety Reporting System. The narrative is written by the pilot, rather than FAA or NTSB officials. To maintain anonymity, many details, such as aircraft model or airport, are often scrubbed from the reports.
During cruise in my Velocity XL, one tank was consuming fuel faster than the other, even though they are interconnected.
Right tank reading empty, but there was almost over an hour in the left tank.
Cruise on left tank was sufficient for nearly 15 minutes.
During last part of descent into ZZZ, engine sputtered and fuel pressure warning occurred (even though there was still almost 1 hour of fuel in left tank).
Fuel boost pump on low seemed to resolve the issue but because I wasn’t sure if the engine would stay on at idle throttle settings, and because ZZZ1 was directly in front of me with a large runway, I chose to divert there.
Because it is a PPR (Prior Permission Required) airport, the only way to get that diversion was to request priority handling (which given the night conditions I sure felt it was appropriate).
Landing was without incident, but turning off the boost pump on the ground resulted in sputtering engine.
After talking with my local A&P, and a fuel system inspection, he believes the root of the unbalanced fuel consumption was a poorly seated and older fuel cap. It has since been replaced with new fuel caps.
In general I was happy with my decision making during the event, although it may have been a bit overly conservative since the boost pump resolved the issue.
In hindsight, it may have been prudent to divert earlier when I noticed the unbalanced fuel consumption between the tanks.
I believe with the inspection from my A&P, and the testing of the fuel system (including venting and caps), this issue should be resolved.
Primary Problem: Aircraft
ACN: 2020113
If there ball is a mot center neither is the fuel flow. Both just means the fuel will flow tank to tank.
I had a similar situation in my C-182T. On a long flight with the fuel selector valve on both, I observed the fuel level in my left tank decreasing faster than on the right. I selected the right tank, but the level in the left tank continued to drop. Eventually the gauges reported minimum fuel on the left, but 1/2 full on the right. Faced with crossing a large body of water at night, I did a 180 to the nearest airport with fuel, which was ~30 minutes away. On final, the left tank showed red, zero, but thankfully the engine continued running. On the ground, I immediately used the tube fuel gauge in both wings. I found the left tank bone dry and half a tank of fuel on the right, in agreement with the gauges. I moved the fuel selector to both for 30 minutes before fueling. Measuring again, I found that the fuel on the right had redistributed to 1/4 in each tank as expected. So, they cross fed on the ground, but not in the air, on that day. My A&P has puzzled over this. The fuel cap gasket looks fine. He repositioned the vents which are mostly behind the struts beneath the tanks to where he thinks they should be, but this has not resolved the problem. I continue to fly without a clear resolution, but with heightened vigilance, and carrying more fuel than I did in the past. Fortunately my fuel gauges are reasonably accurate. On most flights, the tanks feed almost equally as expected. Sometimes the left tank feeds faster. When it does, switching to right does not solve the problem, leaving me with inaccessible fuel. Fuel levels do always balance on the ground with the fuel selector in the both position. I’m interested in hearing if anyone has experience resolving this problem in a C-182T or similar.
When I first got my Ercoupe several years ago, one wing tank always took more fuel than the other wing even though the simple system has fuel flowing from both wings to header tank at all times.
I decided it was a venting isuue. Ising compressed air, I blew out the vents in all fuel caps. There was definitely some debris in all of them but the left side was worse. That solved the problem.
I like those cheap and simple solutions.