The US National Transportation Safety Board (NTSB) has found that errors by air traffic controllers were the probable causes of three recent near-misses, according to final reports on the events.

An early afternoon 21 July incident at Chicago O'Hare International Airport resulted in an arriving Learjet 60 business jet passing 99m (325ft) above and slightly behind an American Eagle ERJ145 on departure from an different runway. The NTSB says the controller failed "to ensure the appropriate separation between two airplanes operating on runways where flight paths intersect".

A 28 August night-time near-miss at Fresno, California occurred when a tower controller failed "to ensure the runway was clear" after a six-passenger Piper Malibu private aircraft landed before allowing a Skywest CRJ200 to land. Compounding the situation was the Malibu pilot's unfamiliarity with the airport layout.

The Skywest pilot told investigators he was forced to steer to the right side of the runway as the CRJ decelerated under braking and full reverse-thrust in order to avoid the Malibu, which had failed to leave the runway on a left-side taxiway.

In a similar 19 September night-time incident at the Lehigh Valley International Airport in Pennsylvania, a Mesa Airlines CRJ700 on takeoff narrowly avoided a Cessna 172 that had landed previously and not turned off the runway as rapidly as controllers had intended.

The Mesa crew estimated that the two aircraft missed one another by approximately 3m as the CRJ decelerated through 40kt after aborting the takeoff.

NTSB puts primary responsibility for the near miss on both tower controllers, who failed to "maintain awareness of the position of (the Cessna) and ensure that the aircraft was clear of the runway before issuing a takeoff clearance to the (CRJ)".

Source: Air Transport Intelligence news