27/09
The cause of the rudder jam remains uncertain. The pilot vividly described the onset of the jam feeling like he went over a tennis ball (not in the literal sense).
The possibility of a jam via the passenger's foot was a potential possibility. Regrettably the footwear he wore was destroyed before inspection was possible.
Another possibility was the passenger's SLR camera, on which the last image was a rear facing selfie of passenger and pilot taken by the passenger while taxiing - note, no photos once airborne.
Notably, despite no mention of this in the AAIB report. The broken camera lens and battery pack were spotted by the Defence team in the accident scene photos in the immediate vicinity of the rudder pedals within the wreckage.