Jumping through the `Whitley Hole' then became the norm, but even this method had serious disadvantages for the hole was nearly three feet deep and unless a perfectly upright and rigid position was maintained the parachutist's face would strike the inside of the hole - known as "ringing the bell"- with very painful consequences. The first live drops of trainees were made at Tatton Park on 14July through the floor aperture of a converted Whitley bomber. LAC Oakes was first, followed by six others, with just one injury. By 25 July, 135 drops had been made when Driver R Evans RASC, of No.2 Commando, plummeted to the ground as his parachute failed to open properly. This was the first fatality to be sustained but reserve parachutes were not issued to British airborne services until 1955.

The most common impediment to a safe descent was twisted rigging lines. This meant that the front and back sets of the rigging lines were interwoven above the lift webs in two strands like a thick rope. As the full development canopy was thus retarded so the rate of fall was increased and adequate flight control was impossible until the body revolved through 360° and the twists eliminated. The blown periphery or `thrown line' was much more dangerous. This abnormality was formed when part of the periphery was firstly blown inwards and then outwards through the rigging lines producing a second inverted canopy. Another kind of blown periphery was experienced when a portion of the canopy blew between the two rigging lines and the tendency followed for the canopy to roll up at the skirt. A `streamer was the name given to a canopy that paid out but failed to develop until the last moment. The 'roman candle' , the key to the door of Heaven's gate, was the type of `streamer' which failed to open at all.