A colleague, identified as “Dieter,” told Europe1 that Sonderheimer was a trusted pilot, saying:
He was someone very reliable, he was one of the best pilots we had. I am 100 percent sure they did the best they could. That’s what I think because I knew him very well, he was one of the best, he had a lot of experience, he had more than 6,000 flight hours behind him.
Winn said U.S. air safety regulations are generally followed worldwide because of airline alliances and the airlines’ desire to have regulatory harmony across borders.
The Germanwings flight would appear to have violated the safety protocols in place at Lufthansa, which is Germanwings’ parent company. In addition, the pilot’s need for a bathroom trip on a short flight is in itself unusual, Winn said, noting that pilots “are normally pre-prepared themselves for not having to go to the lavatory on a short trip.”
From the link - I wouldn’t think sounding “curt” in his responses could be considered “normal” conversation..Perhaps he was always “curt?”
“”According to the Times, there were normal conversations heard on the cockpit audio recorder prior to the captain leaving. Robin said the co-pilot’s responses sounded “curt” during a discussion about the planned landing of the plane in Dusseldorf.””