The Bf 109's automatic leading-edge slats popped out of the wing when the Bf 109 was flown at slow speed – making a clanging noise so loud that pilots could hear it above the roar of the engine. The slats increased lift and drag but were not for the faint of heart. Oberleutnant Erwin Leykauf said, 'For us, the more experienced pilots, real manoeuvring only started when the slats were out.'1 Less experienced pilots could put a Bf 109 into a stall and spin when the slats deployed on one wing and not the other in a tight turn. When slats deployed unevenly in tight turns, they would disrupt the airflow, causing the ailerons to 'snatch' enough to shake a Bf 109, spoiling the pilot's aim.