Groundspeed in flight log - mach makes no sense

Hi guys,
I’ve been trying to get used to the new way of displaying groundspeed with multiple columns. Came to the conclusion that a couple things would make tons of sense.

  1. Display in either KTS or MPH but not both. Let user click column header to switch between the two. This would greatly ease the data overload of the display.

  2. Groundspeed in mach makes no sense. Mach is only a true airspeed concept. I would take it out of the groundspeed column altogether (thus also getting rid of more clutter that doesn’t make sense).

Now, #2 leads to a feature request… A display of current winds aloft would be great. Then you could tell how fast the aircraft was travelling in KTAS (is that plane you are considering buying a fast or slow example…). Or, using the indicated altitude and temperature probably back into KIAS and therefore the Mach number, though the precision and accuracy of winds and temperatures aloft would still make this merely a ballpark.

Thanks!

-Jon C.

Addendum… As long as I’m being picky about the flight log display…

I would change “Heading” to “Track” to more accurately identify what it is.

Also, I would greatly shrink the size of the “Direction” column and use the 1-2 letter abbreviations (e.g. NW, SE, etc), which would be just visually easier to scan.

-Jon

Thanks for the feedback. I agree we should only display knots or mph according to the user’s account preference. The Mach number is an approximation that gives users a feel of how fast it is, a turboprop at 0.50 vs a jet at 0.80 despite the effects of wind.

Thanks for listening!

The Mach number is an approximation that gives users a feel of how fast it is, a turboprop at 0.50 vs a jet at 0.80 despite the effects of wind.

How does that differ than displaying kts? 400 kts is pretty clearly faster than 300 kts. Besides, a jet going 400 kts into the wind may only make 300 kts ground speed, whereas the turboprop going with the wind may make the same 300 kts ground speed. But in this case they’d both display the same mach number (neither of which is meaningful at all…).

The only thing one can get a feel for using groundspeed is, well, groundspeed (in the absence of wind data). Displaying it as kts, mph, km/h, or mach doesn’t really change that. And mach is particularly meaningless when speaking of groundspeed.

IMHO. :slight_smile:

Couldn’t agree more… Mach number is a function of the airplane’s ambient pressure altitude, temperature, and true airspeed and is meaningless and erroneous as a groundspeed.