The Icarus Case (The Blind Sleuth Mysteries Book 16‪)‬

While Daisy and Darren roamed the countryside around Bottomleigh House in their faithful little car, they chanced upon a small airfield called Gremian Hill, which caught their fancy at once. They were told by members of the local parachuting club that a blind person or a paraplegic too could skydive, and they became regulars to find out more.
But soon tragedy struck, a parachute failed to open and one of their new friends fell to her death under suspicious circumstances. What's more, the chutes were kept under lock and key in a special shed, so sabotage seemed impossible.
Time for our blind sleuth to tackle this locked-room mystery, and when another member of the Icarus Skydiving Club fell to her death and the press started talking about a serial killer, it became even more urgent to uncover the truth.