So he worked for the airline for 18 months and accrued only 630 flight hours? Maybe I’m wrong but that doesn’t seem like much flying time. That’s less than 10 hours a week. I realize that pilots have workload restrictions but still that doesn’t sound like a lot of cockpit time. Maybe he was a problem employee.
Interesting point. He did spend several months or possibly more in the US (in Arizona, I believe) qualifying for some other certificate, so perhaps he came and went on his job. That is, he may have had long education leaves that would have meant he accumulated fewer flying hours.
BTW, in the US, he learned to fly gliders and other very simple aircraft. Don’t know if this is relevant, but essentially he did a glide into the mountainside.