The instructor of the 20-year-old co-pilot on the doomed Learjet, Nathalia Gadelha Filgueiras, says Filgueiras was the "most naturally gifted pilot [he had] ever taught."In a tribute post for Filgueiras on Facebook, Chris Kirk, a long-time pilot instructor, reminisces over his time teaching the young co-pilot, while adding a selfie of the two smiling happily in the cockpit of a plane.He recalls he was Filgueiras' first instructor and mentor, and she was most definitely a pleasure to teach."She was without a doubt the most naturally gifted pilot I have ever taught, and I have been teaching for 40 years!!" wrote Kirk..Kirk says that Filgueiras aced both the Lear type training and the Pilot-in-Command (PIC) type rating, both certifying co-pilots to operate on specific aircraft, in this case a Learjet."When she did her Lear type rating, she had less than 1,100 hours and she absolutely aced the PIC type rating and the examiner thought she had about 5,000 hours!" Kirk recalls.He also remembers he gave her many opportunities to fly different aircraft, and he was always taken with her passion to fly."I am saddened because so many of the pilots in training today never wanted to become pilots and only want to become airline pilots!" Kirk wrote.."As I did check rides, I saw this time and time again!""They had no passion for flying.""They only wanted to get to the airlines to make the big money…"What distinguished Filgueiras, who received her pilot's license when she was just 17, he says, was that she was "PASSIONATE about flying!!!"."She was a 100% natural born pilot!!!""I pray that she continues to fly amongst the clouds in heaven," he states in the post.Filgueiras was the first to be identified on the Learjet, as air traffic control audio from the crash of the Learjet in West Palm Beach, Florida, recorded her narrating the sharp decline of the plane.Her grieving mother, Camila, who originally confirmed Filgueiras was a co-pilot on the flight, says she "wanted her [Filgueiras] to live her dream, but I knew that her dream was going to be the thing that would take her away from me."I knew that a plane was gonna take her away from me. I always knew it, but I was so proud of her. I know she was living her dream," she told the New York Post..Federal investigators have yet to determine what caused the crash of the Learjet 60 flying from Austin, Texas, to the Bahamas before it entered a nosedive, descending at 20,000 ft per minute and smashing into the ground.According to the National Transportation Safety Board (NTSB) on Monday, the plane was traveling through temperatures of -46°C, while starting to pick up ice and hit heavy turbulence.The NTSB also says the plane began breaking apart before impact, scattering debris over a half-mile radius.