On Monday, October 1, 2018 at 12:42:15 AM UTC-7, krasw wrote:
After almost all accidents pilots start to speculate about technical issues, weather, turbulence etc. as a main reason for accident. Statistics show that glider accidents cause by technical reasons are extremely rare, which is logical as glider has basically less moving parts that modern bicycle and reinforced plastic structure is pretty foolproof. Heartbreakingly most accidents are caused by various reasons categorized as pilot error.

Loose objects don't necessarily need to be under the seat. Loose objects in the cockpit can also obstruct the control stick. If the loose object caused a stick jam in the cockpit of the non-flying pilot, it would not be seen by the flying pilot, and the non-flying pilot may not understand that the stick has been jammed.