[Seems like this site does not respect BB Codes so I'll revert to posting an image]
For what it is worth I have done some calculations on the data given in the interim report, Table 1. These give the ground speed and track between the Lat/Long positions over time. There are a number of wind estimates given in the report, I have used a wind of 15kt/025 to calculate the airspeed and heading from the ground speed and track.
The error terms are based on the photo time resolution of one second. So a gap of, say, 10 seconds between photographs will actually be somewhere between 9 and 11 seconds. There will be other uncertainties as well, not accounted for here.
The first column is the photograph number pairs given in the interim report, Table 1. Numbers 409 and 411 are missing from the sequence.
Image as [code] is not rendered properly on this site.
I don't know anything about DHC-2 operations but perhaps someone here could elaborate on whether these speeds and
rates of climb are typical, and at what power settings, given the aircraft was at, or very close to, MTOW.