I am flying the TBM and most all of my flights are longer since I am flying my second WWT.
Not being tied to my chair while I fly means that I need to know my local time when I should sit back down and take control of the plane after I do some honey-dos…
So, in my Google Spreadsheet I created some columns that do some calculations and redisplay the current UTC time too. The UTC time in the spreadsheet should “basically” match the UTC time that is displayed in the MDF window of the TBM (Current flight: ETA: 20:06UTC).
Here are two screen prints of my spreadsheet. The second image has the calculation field for UTC in the top-left of the image. My time zone is -5 UTC so that is why the value in my spreadsheet is shown in the top-left as:
=J18 + 5/24
J18 is my calculated time using Duration and Local Start time.
This is matching my current flight to the minute and now I can see my time and the UTC time at a glance. 
Calculation:
You spreadsheet Gods probably have an easier way to do it, but this is currently working for me and I thought I would share it.