If you sieve out the data points where nothing changes you can certainly see it was a bumpy night and there was very little straight and level flight going on - he seems to have been trying to maintain about 3500' and a SSWesterly heading but there are some significant variations in height from a fraction under 4000' down to 2400' and changes in vertical speed of almost +/- 2000'/min at times.
The last few data points though are significantly different.