An expert witness at the impaired driving trial of Pembroke dentist Christy Natsis says he doesn't know if police followed certain protocols when removing evidence from Natsis's car following a fatal crash.

Natsis faces charges of impaired driving causing death, dangerous driving causing death and exceeding the legal blood-alcohol limit in a 2011 crash that killed Ottawa father Bryan Casey.

Jim Engle

Ford automotive engineer Jim Engle testified that none of the data from the power control module in the key moments before impact was lost. (CBC)

Ford automotive engineer Jim Engle, who analyzed information from the power control module of Natsis's Ford Expedition, was questioned for the second day in a row about the reliability of that information.

Engle had previously testified the recorder did not show any indication Natsis touched her brake in the seconds leading up to the collision, and that Natsis was travelling at about 88 km/h at the moment of impact.

On Monday defence lawyer Vincent Clifford tried to cast doubt on the reliability of Engle's evidence, questioning why the module sat on the engineer's desk for over a year before the data was analyzed.

Engle said it took that long because an outside agency had to design software to download the data.

On Tuesday Clifford asked Engle if the Ontario Provincial Police followed Ford's own procedures to remove the SUV's black box so as not to damage the data.

Engle said he didn't have any knowledge of how the police extracted the box from the SUV.

Clifford asked if in hindsight he should have asked police how they removed the black box and whether it was damaged.

Engle said the protocol should be followed but maintained the data retrieved was intact.

The point that Natsis's vehicle hit the pick-up truck was captured without any corruption, said Engle.

The day's testimony ended after the cross-examination. On Wednesday, the Crown is expected to call OPP crash investigator Jeff Hewitt.