The witness accepted that the pilot had met Pacific Blue's required cloud ceiling limit of 1500ft and visual segment of 10km.
The crosswinds were not officially known to the court because the pilot had used his assessment of a windsock prior to take-off, something the prosecution has criticised.
The pilot had also used a Pacific Blue Boeing chart to calculate the aircraft's ability to reach the required 3600ft at tollgate 6, a key airspace marker, and Mr Douglas said this was something he also would have done.
"If I were in the position I would have done the same thing. He cannot in my opinion be criticised for basing his calculations on it."
"It [his methodology] was conservative and it was cautious, it was reasonable and prudent."
Mr Douglas said the pilot, who has over 16,000 hours flying experience, was best qualified to assess the weather conditions at the time and his eventual decision to depart was "correct."
"Even if the crosswind was above limitation it would not have posed a risk, particularly in regard to the captain's experience."
"I am satisfied the pilot accurately identified issues in accordance with conditions and departed appropriately."
He said a cancellation of the flight would not have been a good decision, but ultimately this was up to the captain of the plane.
Mr Douglas had sat through the entire three and a half week court hearing and concluded the captain had taken the safest option.
He said any diversion the pilot had taken on the departure, such as the lowering in altitude over the Kelvin Heights golf course were "legal, safe and simple".
The pilot had received cockpit warning of bank angle and don't sink at this very point of the departure.