I saw a very similar incident circa '89, runway 36 at FAGM (now rwy 35- or other way round ). One instructor(FO initials) + student in an arrow4. Engine was shut down and stopped perfect unside down"Y" (ZS-KTA - I think). Student was put in the aft section of the plane and a firmish landing on the mains popped the nose gear out! The fault was caused by an 'O' ring not fitted correctly! All the cameras were there and not a scratch on the plane.
Anyway, nice job guys - just interested to hear what the cause may have been?