.
"...The aircraft was fitted with two Garmin 128 marine-type GPS units that provided aircraft tracking and groundspeed information..."
... the aircraft had
two GPS units and yet the report mentions the
"pilot’s attention was diverted to the task of selecting the GPS unit OFF"
A miss-print perhaps? Methinks if the pilot were actually turning both units off he would be a fairly distracted chap - not what you want on short final at night.
Running this by an experienced instructer the question was asked where were these boating GPS's mounted ? - No idea as theres no picture or schematic of the aircraft panel layout.
Thinkin about it, due to the full avionics fitout posibly limiting space mid panel there is a posibility that one GPS were mounted on the control colum with the other top of the dash of perhaps right side panel. If this were the case then the pilot would need to look down to aquire the off button on the possibly well lite (temperally affecting night vision) colum mounted GPS. I'm thinking that to look down at a control colum and press a button would probably induce a slight increase in descent profile. Then to look right side panel...
All this is conjecture on my part as the factual report notes -
"...The investigation could not establish the extent to which that selection, if made..."
.