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Does anyone have any feedback on flying the DA62 in very cold temperatures? Specifically, I have a flight planned tomorrow and right now the forecast is for -37C at departure. I'm aware of the fuel restriction of being warmer than -30C at engine start but it's in a heated hangar so that shouldn't be an issue. I've heard things about some of the avionics not working well in older airplanes but nothing on the G1000. Also I've seen a post on the forum about flying a DA42 at -35C w/o issues.

I'm doing my preflight tonight in the hangar.

Thanks!

--Ron

Lots of electronic devices have lower temp limits of -20 Deg C, which isn't all that cold. It seems to be some kind of magic number. Worth checking into that for everyone's magic boxes if you're subject to this current cold blast (I'm not, nyah, nyah ).

rdrobson wrote: ↑Tue Jan 29, 2019 7:03 pm Does anyone have any feedback on flying the DA62 in very cold temperatures? Specifically, I have a flight planned tomorrow and right now the forecast is for -37C at departure. I'm aware of the fuel restriction of being warmer than -30C at engine start but it's in a heated hangar so that shouldn't be an issue. I've heard things about some of the avionics not working well in older airplanes but nothing on the G1000. Also I've seen a post on the forum about flying a DA42 at -35C w/o issues.

I'm doing my preflight tonight in the hangar.

Thanks!

--Ron

Jet A (common in the US) has a freezing point of -40 C. Are your fuel tanks heated? (As they are on many turbine aircraft).

Erik wrote: ↑Tue Jan 29, 2019 10:12 pmJet A (common in the US) has a freezing point of -40 C. Are your fuel tanks heated? (As they are on many turbine aircraft).

Yes, the AFM requires engine start with fuel at -30C or higher. After start, the engines recirculate warm fuel to the tanks so that should keep it above -30C from then on.

rdrobson wrote: ↑Tue Jan 29, 2019 10:19 pm

Erik wrote: ↑Tue Jan 29, 2019 10:12 pmJet A (common in the US) has a freezing point of -40 C. Are your fuel tanks heated? (As they are on many turbine aircraft).

Yes, the AFM requires engine start with fuel at -30C or higher. After start, the engines recirculate warm fuel to the tanks so that should keep it above -30C from then on.

That's good. That is how turbine's work, or at least the one SET I am aware of - the Piper. But it still has a freezing point - if I remember correctly that warm fuel recirculating system is stated to raise fuel temps by 7C - but more than that and your fuel still freezes in flight. Then there are additives like the temp is lower for A1.

rdrobson wrote: ↑Tue Jan 29, 2019 7:03 pm Does anyone have any feedback on flying the DA62 in very cold temperatures? Specifically, I have a flight planned tomorrow and right now the forecast is for -37C at departure. I'm aware of the fuel restriction of being warmer than -30C at engine start but it's in a heated hangar so that shouldn't be an issue. I've heard things about some of the avionics not working well in older airplanes but nothing on the G1000. Also I've seen a post on the forum about flying a DA42 at -35C w/o issues.

I have been at ESNQ at -32 Celsius. It was also a heated hangar. No issues with a DA42NG.

robert63 wrote: ↑Wed Jan 30, 2019 6:35 am I have been at ESNQ at -32 Celsius. It was also a heated hangar. No issues with a DA42NG.

Same here. Only it was outside parking at -35C or so at BGSF. The displays did not like the cold and showed a red-ish tint, but the aircraft flew just fine. Heating up the engines to get started and de-icing with TKS was all it took.

OK, mission accomplished. Here's a little PIREP regarding the trip.

At departure, temp was -36C. I flew for about an hour and landed at -33C. It's important to note, this flight was in sunlight and that makes a big difference. On our return the temp was warmer but the sun was setting and the cockpit felt colder.

There was some frost on the right side windshield and co-pilot side window but all of the other windows were clear throughout the flight. After about 45 minutes, the frost on the right side dissipated. (See photo) The defrosting vents are heavily biased towards the left side.

Comfort wise, there were no issues but I was wearing a winter jacket but no hat or gloves. It was a little cool around my thighs but that was it. The one problem was that the throttles became very cold and I didn't realize how cold until I was getting ready to land and was gripping them firmly. On the next leg I made sure to put a glove on before landing. I could have easily flown all day long with these temperatures.

The only problem I encountered was that one of the fuel caps froze shut. I had to leave it in a heated hangar until it thawed out so we could refuel it. Also, the OAT gauge isn't calibrated very well at those temps. The lowest it ever read was -28C but METAR at both fields was several degrees colder.

Interestingly, the aux temps seem to hold their temp from the warm hangar very well. After about 20 minutes into the flight I transferred 3 gallons into each main tank. The fuel temperature actually rose from -5C to -2C during the transfer.

The ground crews did a great job in very difficult weather. Frozen doors, stuck tugs, it was a mess.

--Ron

Great PIREP Ron!

Looks like the defroster vents in the 62 have a bias to the "correct" side at least. In our 40 the co-pilot's side defrosts nicely, while I can't see anything on the pilot's side.

Just out of curiosity, how is the 62 heated? does it use an automotive style heater core in the liquid cooling setup?