Sure, after you pay an initial membership fee of $500K.

Mike C.

Membership Fee for the C340 is $1500. Perhaps we can meet in the middle??

I suspect this is backwards. The light should go ON when the transfer is DONE.

Or your airplane is different than the other twin Cessnas with nacelle tanks.

Mike C.

Nice.

When you you are getting close to empty and turbulence causes the fuel to unport briefly, then does it drop off and you still had some fuel left? You could restart it, of course, but this could get old after a while. Maybe it has a timer built in so that it takes, say, 60 seconds of no fuel before it drops off?

The other possible issue is that the pressure sensor can fail so it won't latch on. Now you have to hold the switch manually to get the pump to run to get to the fuel in that tank.

Or it can fail that it won't turn off. Can you force the pump off if that occurs?

I think all these failure modes is why the factory way is a simple switch to turn pump on, light to show pressure.


The light means "pilot, fuel is done, shut off the pump".

If it goes out when done, that is harder for the pilot to notice and you don't want a pump running with no indication.


If the pressure switch fails, and you need that fuel, holding the switch will get tiring.

I've seen pressure switches fail due to cold temperatures, some water freezes on them.


The outer tanks are similar to twin Cessna factory operation, switch to turn on pump, light when pressure drops.

The later models have an automatic system that does tips, then outers without pilot involvement. Sensor failures mean there are overrides and other associated complexities. My plane doesn't have that.

The engines always draw fuel from the center tank, so "switching" is merely pumping fuel into the tank from other tanks, doesn't change the plumbing to the engine.

Mike C.

Nice.

When you you are getting close to empty and turbulence causes the fuel to unport briefly, then does it drop off and you still had some fuel left? You could restart it, of course, but this could get old after a while. Maybe it has a timer built in so that it takes, say, 60 seconds of no fuel before it drops off?

The other possible issue is that the pressure sensor can fail so it won't latch on. Now you have to hold the switch manually to get the pump to run to get to the fuel in that tank.

Or it can fail that it won't turn off. Can you force the pump off if that occurs?

I think all these failure modes is why the factory way is a simple switch to turn pump on, light to show pressure.


The light means "pilot, fuel is done, shut off the pump".

If it goes out when done, that is harder for the pilot to notice and you don't want a pump running with no indication.


If the pressure switch fails, and you need that fuel, holding the switch will get tiring.

I've seen pressure switches fail due to cold temperatures, some water freezes on them.


The outer tanks are similar to twin Cessna factory operation, switch to turn on pump, light when pressure drops.

The later models have an automatic system that does tips, then outers without pilot involvement. Sensor failures mean there are overrides and other associated complexities. My plane doesn't have that.

The engines always draw fuel from the center tank, so "switching" is merely pumping fuel into the tank from other tanks, doesn't change the plumbing to the engine.

Mike C.

That's the way the 421C works. Light comes on when transfer DONE so you can turn off pumps.

You are supposed to only turn on the nacelles when you have the room in the mains.

Mike C.

You already know this as an experienced pilot. The problem is not with complexity of the aircraft (C340A), it is that there is no carry over knowledge from flying the Seneca. So, if you are flying the 340A every few months, you will forget this and that, not remember speeds, not remember the sight picture for landing. That's if everything is working. Those trips in the 340A that you want to go on will come with family involvement and additional distractions.

Where it gets interesting is when things don't work. The craziest little things fade from memory after not flying an airplane for awhile. Its' those little things that matter.

If something real happens then the "mental tank" is totally empty on trouble shooting because the brain is already at maximum capacity just trying to remember the little stuff. You end up burying your head in the POH while trying to fly. No good.

In short, I don't recommend it. One or the other. YMMV.

If you notice.

If you don't, because you don't have to normally, might be facing a damaged pump from being dry.

The manual systems have the same problem if the pilot fails to notice the end of transfer light and leaves the pump on. But then the light being on is abnormal and attracts attention. Mine are big red ones.


MU2: no. A float valve only lets in fuel if there is room in the main tank. There is no way a pilot can make fuel vent overboard with the controls.

340/A, 414, 421/A/B: yes. No float valve, excess fuel vents. If running from aux, can vent if not enough room in main tank due to fuel pump return flow.

414A, 421C: yes. No float valve, excess fuel vents.


The factory Cessna way is a simple system that the pilot controls. The sensor does not control the pump and vice versa.

The O&N way connects those together which introduces new failure modes. They can be overcome with pilot action.

Every time something becomes more automatic, it reduces pilot workload whens things work and it increases pilot workload when it doesn't.


True in all cases, but a sensor failure in your case potentially requires you hold a switch for 30-40 minutes. A sensor failure in an MU2, 421 factory setup doesn't require that, the pump will run without sensor operation.

Mike C.

Yes, but I will gladly take a sensor failure over a pump failure across the board. The pump failure leaves almost all of us with unusable fuel to some degree or another.

That's the way the 421C works. Light comes on when transfer DONE so you can turn off pumps.

You are supposed to only turn on the nacelles when you have the room in the mains.

How long does it take you to transfer? I am burning at almost the same amount as I transfer, so any overflow would be very minimal.

Find 2 members, and you got a deal.

Mike C.

I flew a C421 once where the nacelle on one side annunciated when transfer was complete and the other side annunciated when transfer was in progress.

These are 40+ year-old airplanes with all sorts of modifications. You get what you get.

I flew a C421 once where the nacelle on one side annunciated when transfer was complete and the other side annunciated when transfer was in progress.

These are 40+ year-old airplanes with all sorts of modifications. You get what you get.

Mine has factory nacelle on the Left, light OUT while transfer in progress; and an O&N on the right, light ON while transferring.

I use the nacelle gas first- because I've had the vents ice up and not transfer (broken heater wire on the vent). after that, I use stall heat nearly 100% of the time.

Love the carbon fiber panel Doug! wish my transfer lights were in the annunciator panel (I've got one in it, and one on a sub-panel).