Fuel System OverPressure 912IS
in 912iS Technical Questions
7 years ago
First significant post after purchasing an S7 w 912iS (N52LR) a few months ago. I have been putting some good flight time in and getting comfortable with the plane. Love it so far. I have been flying since 79 with time in many planes, but primarily an SR22 I sold a few months ago. I really like this kind of flying.
A couple of weeks ago shortly after takeoff I got a fuel high pressure warning. At the time I had the main pump running and full power. I throttled back and it bumped up to the red and the Lane A light came on solid. Shortly after the Dynon suggested to land the plane. I was not far from the runway and landed without incident.
I was able to communicate with the builder and review the fuel system. The filter system is relatively new based on the recommendation from Kitfox/Rotax. It was installed in March of this year and has somewhere near 30 hrs on it.
I found what looked like an oil drip coming from the fuel pressure sensor. I was able to pull both fuel filters. It was kind of a mess, could not figure out how to drain the system to keep everything from leaking when disconnected. I let the large post pump filter drain as best I could and captured the fuel. There was some very fine particles suspended in the fuel. I lightly blew in the end and it held pressure for a couple of seconds then gave way. It seemed clear after that. I could not see a way to open the filter. When pulling the pre-pump filter it looked pretty clear.
I put everything back together and checked the pumps. Everything seemed to be fine. The pressure holds around 44-45. I did a full power start / roll out and pulled the cowl. No leaks. Then took it up in the pattern for 20 minutes. All good.
Last Saturday I changed the oil, filter and the fuel filter. I had purchased 3 replacement fuel filters. The original filter seemed to be working OK, but it had a problem prior, so just to be safe (maintenance induced problem coming) I replaced it. The pressure on pump 1 was in the 45 range. Seemed a little high, but in the green. The 2nd pump would put the system in yellow. I flew the plane for a while, running on the single pump one. It ran fine.
Last week I took my wife to Fredricksburg for lunch. All was well on the outbound trip. But 10 minutes in to the return the fuel pressure was in and out of yellow. Then it went red and Lane A light and the "land the plane" warning came on. I had to continually back off of the throttle to keep the RPM's down. I was close enough to my home airport to press on while keeping safety airports in range. I was able to land without a problem and on the ground turned the engine off and back on. The fault had cleared and the fuel pressure was back down to 44.5 or so. I noticed that using the pump 2 rather than 1 brought the pressure down to the middle range. Both pumps on would hit the yellow.
So... I am thinking the filter I had originally been running in the plane may have failed allowing the pressure to go down. The new one seems to just be too fine to allow proper flow. Yes, I could have accumulated trash in that short of time (1hr). But considering I effectively flushed the system multiple times by taking it apart, does not seem likely.
I could just run on pump 2 at the lower pressure and likely be OK. But this just does not seem to be working right. As a safety measure the fuel filter seems to be causing in-flight problems more than solving them. Any one else seeing anything like this? Suggestions?
Thanks in advance for any help and support.
A couple of weeks ago shortly after takeoff I got a fuel high pressure warning. At the time I had the main pump running and full power. I throttled back and it bumped up to the red and the Lane A light came on solid. Shortly after the Dynon suggested to land the plane. I was not far from the runway and landed without incident.
I was able to communicate with the builder and review the fuel system. The filter system is relatively new based on the recommendation from Kitfox/Rotax. It was installed in March of this year and has somewhere near 30 hrs on it.
I found what looked like an oil drip coming from the fuel pressure sensor. I was able to pull both fuel filters. It was kind of a mess, could not figure out how to drain the system to keep everything from leaking when disconnected. I let the large post pump filter drain as best I could and captured the fuel. There was some very fine particles suspended in the fuel. I lightly blew in the end and it held pressure for a couple of seconds then gave way. It seemed clear after that. I could not see a way to open the filter. When pulling the pre-pump filter it looked pretty clear.
I put everything back together and checked the pumps. Everything seemed to be fine. The pressure holds around 44-45. I did a full power start / roll out and pulled the cowl. No leaks. Then took it up in the pattern for 20 minutes. All good.
Last Saturday I changed the oil, filter and the fuel filter. I had purchased 3 replacement fuel filters. The original filter seemed to be working OK, but it had a problem prior, so just to be safe (maintenance induced problem coming) I replaced it. The pressure on pump 1 was in the 45 range. Seemed a little high, but in the green. The 2nd pump would put the system in yellow. I flew the plane for a while, running on the single pump one. It ran fine.
Last week I took my wife to Fredricksburg for lunch. All was well on the outbound trip. But 10 minutes in to the return the fuel pressure was in and out of yellow. Then it went red and Lane A light and the "land the plane" warning came on. I had to continually back off of the throttle to keep the RPM's down. I was close enough to my home airport to press on while keeping safety airports in range. I was able to land without a problem and on the ground turned the engine off and back on. The fault had cleared and the fuel pressure was back down to 44.5 or so. I noticed that using the pump 2 rather than 1 brought the pressure down to the middle range. Both pumps on would hit the yellow.
So... I am thinking the filter I had originally been running in the plane may have failed allowing the pressure to go down. The new one seems to just be too fine to allow proper flow. Yes, I could have accumulated trash in that short of time (1hr). But considering I effectively flushed the system multiple times by taking it apart, does not seem likely.
I could just run on pump 2 at the lower pressure and likely be OK. But this just does not seem to be working right. As a safety measure the fuel filter seems to be causing in-flight problems more than solving them. Any one else seeing anything like this? Suggestions?
Thanks in advance for any help and support.
