A glider which crashed in a field in Oxfordshire, killing the pilot, came down after its wings fell off at about 1,000 feet (305m), her family said.
Bruce Duncan, boyfriend of pilot Amy Barsby, from Lancashire, watched as the small aircraft fell apart in the air above a field in Bicester on Sunday.
Her mother Helen said the family was in shock, describing her 25-year-old daughter as "dedicated and wonderful".
The Air Accident Investigation Branch (AAIB) said it was investigating.
The experienced glider pilot, who had been flying for more than a decade, had been researching into possible causes of cancer at Queen's University in Belfast.
She and her boyfriend Bruce Duncan, a gliding instructor, had just bought a house in Edinburgh where they had both attended university.
Speaking from the family home in Longridge, Lancashire, to the BBC, Mrs Barsby, 55, said: "We have received so many lovely and beautiful comments from so many people, from those we didn't even know knew her.
"She was so popular and well-loved.
"She may have crammed so much into her short life, but she still had so much to give."
The structure of the Foka 4 glider, which is believed to be about 30 years old, has been sent away for investigation. Miss Barsby regularly borrowed it from a friend in Edinburgh.
"We do not know why the wings suddenly fell off, there is no way that Amy would have flown it if she had been concerned about her safety," her mother said.
"She was always so cautious and safety-conscious. She had flown it earlier on in the day and had no problem with it.
"We just keep on hoping that we will wake up from this nightmare to find out it never happened."
Miss Barsby was pronounced dead at the scene, South Central Ambulance Service confirmed.