The crash on Aug. 18 near New Castle Airport killed the pilot, 52-year-old Terrence Daniels, and flight instructor Albert Dohrig, who was 79.
The NTSB says after the plane took off, the pilot told the controller that they needed to return to the runway but didn't mention a reason and didn't declare an emergency. The report said the controller tried four times to reach the pilot, but got no response.