On the smaller side (OP question) there was the Augusta A109A II which failed to extend its landing gear at Redhill, with David Cameron on board.
Press "sensational" report and
AAIB report; the handle came off which eliminated both the main system and the back-up system.
Last edited by John R81; 11th Jan 2017 at 12:18.
Reason: Newspaper link inoperative