On Saturday, July 21, 2018 at 4:34:58 PM UTC+2, jfitch wrote:
On Saturday, July 21, 2018 at 2:15:40 AM UTC-7, wrote:
I would have interpreted the mention of 48 knots as being a descent rate shown on the data recorder file (= around 880ft/11seconds).

The report clearly says airspeed not descent rate. Default Flarm setting is 4 second fixes so 11 seconds represents at most 3 fixes. 11 seconds from normal flight to impact indicates a very low altitude no matter how you interpret it.

FLARM does -not- report or calculate airspeed. The device only calculates positions from GPS fixes and has a pressure sensor to enhance that information, but any airspeed or groundspeed calculations are only speculative approximations from the GPS data in the logs. From the GPS fixes of itself and those transmitted from nearby aircraft it then calculates threat levels and warns you appropriately if necessary.