Yesterday I went flying with a friend in a C172 equipped with a Garmin GTN 750. The 750 was new to both of us, as it was a recent upgrade to this aircraft, which is a club plane. While the map looks great I found the touchscreen very difficult to use. There was only light turbulence, but both of us (I was flying right seat) struggled not to hit the wrong keys and in fact repeatedly did so. I cannot imagine having to use this in more pronounced turbulence, such as descending over the mountains into the L.A. basin, where you often have a frequency change every two minutes (and more often if you’re unlucky) and turbulence is a fact of life. Anyone having more experience with this kind of interface? Thoughts?
I’m using the GTN now for a little more than four years. It is working very well with the touch screen for me. I’m flying IR most of the time and also in bad weather itis working fine. In the beginning it took some days to become familiar with the new interface, but then you will feel comfortable.
BTW: As far as I habe seen Garmin offers now the possibilty to send voice commands to the GTN. This might be worth a closer look.
The bezel of the Garmin stuff is designed that you can brace a finger on it so turbulence doesn’t move the other one. I’ve flown a few hours with a friend who has a Garmin touchscreen box in her Grumman Tiger, and if you use the bezel to steady your fingers, it works just fine.
Same experience as the previous two when I flew in a DA40 with a GTN650, if you try to hold your arm in the air it’s impossible, but I quickly rested my middle finger or thumb on the bezel and typed with the index finger, and then it was fine. I did really enjoy the responsiveness of the interface (unlike in our old GNS430), so even if you type wrong it’s really quick and easy to correct.
Yes but it is worth remembering that in the Cessna jets using G3000 with full touchscreen functionality, Cessna required a separate knob and button on glareshield above PFDs to enable non touchscreen inputs.
Arne wrote:
but I quickly rested my middle finger or thumb on the bezel and typed with the index finger, and then it was fine.
We both tried that, but that didn’t work for the simple reason that the screen of the 750 is too big. Same issue people have with these super-sized smartphones, which you cannot hold and type with one hand. Moreover, this may work somewhat better sitting in the left seat (assuming you are right-handed), but doesn’t work at all from the right seat. I am right-handed and tried this, then tried it with my left hand to much the same outcome. I also find the bezels on the 750 to me far too small (only 3-4 mm or so). Again, perhaps it’s mostly a matter of getting used to it, but IMHO not a very satisfactory way to input info.
From demos I have seen, this is a big advantage of the Avidyne IFD540 over the Garmin GTN750. The former is very usable with knobs, not least due to very good predictive behaviour when entering waypoint names.
An IFD540 has just been fitted into N20TB and one of the main reasons for choosing it over a 750, was the ability to use the knobs in turbulence. There are a couple of Gotcha’s though.
Setting up the RS232 (Aviation) data out of the unit caused a few headaches. I needed the unit to output on 4 channels to, EI CGR-30P, Golze 110B, KT74 Txpdr, and ACK-04 ELT. No problem then as there are 6 channels on the unit to do this. Wrong. The present software release (10.1.3.0) currently only supports RS232 Aviation data out on 1 channel, although the next software release of 10.2 is supposed to resolve this.
Another annoying issue is that the CGR and IFD540 don’t communicate with each in a normal sense. I’ll explain. The CGR is powered up by the Master Switch to record fuel used at engine start up. With the engine running the Avionics Master is then switched on to power up the IFD540. The CGR won’t send fuel data to the IFD540. To resolve this you have to switch off the CGR (pull circuit breaker) and then reset after a few seconds. Fuel data then appears on the IFD540. Apparently there is some sort of initial data packet transmitted when the CGR is initially powered up that the IFD540 needs to open the communication. It seems odd that the 2 units can only establish communication at initial power up.
Flown with the IFD540 a couple of times now (VFR only) and it really is fantastic, although I have never flown with a 750. Next stop Cherbourg and Alderney to try the LPV approaches.
I have an Avidyne 540/440 combo and I wouldn’t want to miss it. The keyboard can be shown on the 440 so not to interfere with the 540 map. Resting the finger on the bezel of the box doesn’t in my case in turbulence so I am more than happy to have the traditional knobs or the portable real keyboard that comes with the Avidynes. The new software release will enable all keys and functions.
In my case I had no problems with the communications to the TAS1000 from Insight which is both an airdata computer as well as a fuel flow totalizer.
172driver wrote:
We both tried that, but that didn’t work for the simple reason that the screen of the 750 is too big.I made this reflection to myself as I pressed “submit” earlier, maybe the 750 is just too big. You need to get a 650 too to act as keyboard! ;-)
