According to the Air Force, the remains were found in the landing gear compartment of a C-17 aircraft, which was surrounded by hundreds of people on the runway at the Kabul airport.
The remains were found already at the Al-Udeid airbase in Qatar.
In a press release, the BBC said investigators will study videos and media publications, as well as the remains.
On the morning of August 16, AFP, citing eyewitnesses, reported that the US military began firing warning shots into the air after a large crowd broke into the airfield at Kabul airport.
The media also reported that three people fell from a plane taking off from the airport in the Afghan capital.
The network published footage from the Kabul airport, in which dozens of people climb onto the landing gear and fuselage, while the aircraft does not reduce speed.