On initial touchdown the pilot detected an abnormality with the landing gear. An immediate go around was carried out and the pilot of another aircraft reported that the left main gear was sloping rearwards of its normal alignment. The pilot was committed to a landing with the gear in this position and the gear leg subsequently collapsed at about 60 knots. Initial investigation indicated that the failure of a slotted pin allowed the trunnion forward pivot pin to work itself free, with consequent misalignment of the gear leg. The pivot pin showed evidence of grinding, apparently carried out during maintenance in order to facilitate the fitting of the pin into its appropriate socket. However, the grinding also resulted in excessive free play, which allowed the pivot pin to apply bending loads to the slotted retaining pin and which resulted in the eventual failure of this pin.
