GFC 700 upgraded TDI question

[cttime]

I recently started flying a TDI which has had an SBAS / GFC 700 upgrade. The AFM for this aircraft is interesting because the limiting speeds are all changed from the TDI speeds (Flaps, Gear, VNO, VLO, VNE).

Does anyone have more insight into why the speeds have changed?
Interestingly I noticed one of the placards (VE/Loe / VLR) was missed, it still had the original TDI speeds placarded (194/156 kts).

[meowmeow]

If the engines are still the same as before the upgrade then the v-speeds shouldn't have changed, but if the upgrade was to NG (i.e. including CD-->Austro) then some minor v-speed changes are possible/likely. In any case, the gear-related speed placards should obviously be in sync with the updated documentation.

[ememic99]

I recently started flying a TDI which has had an SBAS / GFC 700 upgrade. The AFM for this aircraft is interesting because the limiting speeds are all changed from the TDI speeds (Flaps, Gear, VNO, VLO, VNE).

Does anyone have more insight into why the speeds have changed?
Interestingly I noticed one of the placards (VE/Loe / VLR) was missed, it still had the original TDI speeds placarded (194/156 kts).

Original reply deleted on OP request due to revealing personal data. Here's modified reply:

If that's the aircraft that used to be listed in your profile, than it's not DA42 TDI but upgraded DA42 NG, originally built 2005 as TDI and then upgraded to NG. That means the engines were changed to Austro and that explains speed changes comparing to original POH.

[cttime]

So sorry for the confusion Ememic99 but it is not that aircraft. The aircraft in question is still a TDI (so still continental engines, 1785kg MTOM, etc.) but with an upgrade to GFC 700. I would understand if it had undergone the NG upgrade but apparently, the TDI's with GFC700 (DA42 GFC700 AFM available on Diamond site) speeds have been changed over a normal TDI.

Here you see normal speeds for a TDI with GFC 700

and here are normal speeds for a TDI

[ememic99]

I don't understand what A/P has to do with speeds.

This is what original POH specifies for CD-135 engines (and KAP140):

And this is specified for CD-155 engines (Supplement S07 doesn't have reference to autopilot):

[ememic99]

DA42NG

DA42-VI

[ememic99]

All in all, I think those POHs suffer from some inconsistencies. I tried to point out this to DAI few years ago but I've never received any reply.

[cttime]

I don't understand what A/P has to do with speeds.

Me neither. It's confusing, but actually simplifies our operations manual by having very similar speeds as the NG since we have an NG as well.

[ememic99]

Pay attention on one detail which is totally illogical (I believe it's error in POH): CD-155 Vr (flaps UP) is 72 kts and Vr (flaps APP) is 76 kts. All other specifications where rotate is allowed with flaps in APP position have (logically and correctly) lower speed with flaps APP then flaps UP.

Rotating TDI at 76 kts doesn't make sense, in any flaps position and with any A/P. The same way approach speed of 82 kts with flaps in LDG position is simply too fast for TDI and lead to quite long landing. DAI should definitely check these numbers.

[Ed McDonald]

Could you guys provide me with a summary of the issues and as the official Diamond Pilots Association liaison withe DAI I will ask them for clarification. PM me and I will try to get some answers.