With the Synaptic A220 set to release soon, I've been studying the FCOM and came across something I found really interesting and intriguing: the fuel system. I certainly didn't know this, so l'll share what I found.

There are so many ways the A220 transfers fuel in flight!

Most are auto-managed, like Auto Crossfeed and Gravity Crossflow, but it also features true tank-to-tank transfer that is manually controlled.

The A220 can even transfer fuel back from the wing tanks to the center!

I put together a quick visual breakdown with the schematics if anyone wants to see how the overhead controls and synoptic pages behave for the different modes of fuel transfer.

I found this unusual because, in my flight sim experience, the only passenger planes I know of that do this are the Concorde, Douglas DC-8, DC-10, and MD-11.

I believe the tank-to-tank transfer on the MD-11 significantly increased the complexity and maintenance of its fuel system. This is probably why the 777 uses passive crossfeeding and boost pump manipulation for balancing.

The process is quite simple, actually: you turn the rotary selector to the tank you want to transfer fuel to. Only 180 kg is allowed to be transferred at any one time between wing tanks

There are some quirks too, like when to use AUTO and ON in these transfers. I also found out that suction feed (motive flow) is the primary means of engine feed -not the AC boost pumps.

For anyone who has flown or studied the A220 in real life: what was the engineering rationale behind keeping active tank-to-tank transfer as well as simple crossfeeding?

Great video!

looking forward to seeing the first ezy123 on vatsim flying LHR-LGW in it.