UK investigators believe two Cessna 208 turboprops were just 5 seconds from an almost certain mid-air collision on final approach, after each aircraft joined a landing circuit without visual contact with the other.
The collision was averted only by “the narrowest margin”, according to the UK Airprox Board, after the air-ground communication service operator realised the two aircraft were simultaneously descending towards the runway with one stacked above the other.
Neither pilot was aware of the other’s presence and the communication service operator ordered the higher aircraft to execute a go-around.
One of the 208s had been carrying out a parachute drop from Sibson airfield outside Peterborough, and was returning for an approach to runway 06 on 18 April. The other aircraft, operated by the same company, was undertaking pilot training and performing a circuit.
The parachute aircraft had joined final approach but the training aircraft also turned into the approach from below.
Both parachute-drop pilots involved in the incident agreed that skydiving operations are safer if the airport stops other traffic at the circuit for the time between dropping and landing.