Howdy, Scotty.
Welcome to the group. I'm new too.
You asked about fuel management systems:
As youalready know, there isnt a whole lot out there that is certified for the 337 (seems the rest of the world is resistant to acknowledginging our awsomeness).
We just made a "Spare no expense" upgrade to our panel (cant wait to show it off..its a doozy)
As part of our re-fit, I shopped around for fuel LEVEL indicators which would give me more accurate info than the mechanical OEM needle.
I found a few that seemed just right...until I called and found them unavailable for the 337.
Side note- I'm under the San Antonio FSDO "Iron Curtain" so getting field approvals is litterally an acto of congress.
I eventually landed on the Aerospace Logic FL-100 Digital fuel LEVEL indicator.
Its cool. You get digital, color coded bar-graph indications of both fuel tank LEVELS and you also get a digital numeric indication of tank level, calibrated to 1-gallon accuracy.
Sounds perfect.
It aint.
Although at $500, (aviation terms thats almost free) the installation was reasonably easy...about another $500.
But here is the problem. The tanks have to be filled for the initial calibration mark. Then the tanks have to be drained and re-filled at 1 gallon incriments.
Fuel aint cheap....and once drained, FAA says it cant be re-used.
The calibration process took 7 HOURS.
Best of all...the gauge didnt hold the calibration data...so we did it ALL again.
Still no good despite hours on the phone with tech support.
Sent the gauge back to Canada for eval. After the obligatory Customs delays, we received a replacement gauge 10 days later....and recalibrated...again. More fuel...more time...more money....
We even upgraded and recalibrated the penny-cap fuel level sending units.
The Gauge still doesnt work exactly as it is advertised...but its pretty good.
Owen installed a switch for me that allows me to switch back and forth between factory and digital fuel LEVEL instrumentation so I can always abate my fuel paranoia.
You'll see that I keep emphasizing LEVEL. that is because I've found the decision-making tree on fuel instrumentation is divided into three significant branches: Level, pressure, and flow.
"X-Ray" had a Shaden fuel computer when we got it...gives real-time digital fuel FLOW info and is VERY helpful. It also has fuel remaining indications which takes your manual input of how much fuel you have then subtracts the computed fuel flow, to give you fuel remaining....VERY nice instrument.
And we kept the factory fuel PRESSURE instuments (for now).
Flow and pressure are great....if the fuel only goes to the engine.
If you have a leak, or if its being siphoned from the top of the wing....you wont know.
Both of the skymaster schools I've gonoe to say that the skymasters factory needle gauge is remarkably accurate (compared to other aircraft).
Bill, at RTC in Illinoise points out that the fuel level indication on the mechanical needle gauge is so sensitive that you can watch alterations in fuel density as the OAT changes through the altitudes.
I've rambled on long enough, and dont want to loose track of the question: Yes, I have had experience with a few Fuel Management Systems. I love Shaden. I despise Aerospace Logic....it works...but I make sure I have a redundant indicator.
However....
.... I've been keeping in close contact with JPI reguarding their EDM-960 systems monitor. Its been approved for other twins for some time, but the 337 wasnt on the Approved Model List. Yesterday, they submitted the documentation to change that and we should have it available to us in about 3 months!!!!!!!!!
That'll give us computerized ALL of our engine, fuel (level, pressure, AND flow), electrical and vacuum instrumentation...in one package....with audio and visual alarms!!!!!
And its from JPI...an increadibly reputable company.
I initially researched and opted for the Xerion Auricle 2120 systems monitor...it seemed great on paper, but numerous issues with their past and current company caused me to pull the order before it shipped.
If you're thinking of upgrading....you might want to install a used Factory gauge until the JPI system is available.
If you're happy with the factory needle....It'll do a good job.
There's my 2-cents. Sorry for dragging it out so long, but I figure giving too many details up front was better than not enough.
Cole