An Ottawa tower controller’s use of nonstandard phraseology at a critical moment was mostly responsible for a June 2014 runway incursion at Ottawa MacDonald-Cartier International Airport, according to a report on the accident from the Transportation Safety Board (TSB) of Canada. At about 8:48 a.m. that morning, a medevac AgustaWestland AW139 ready to depart on an IFR flight taxied into a runway protection zone for Runway 25 at the same moment a FedEx A300 was landing on the same runway. The Airbus was, however, able to stop without further incident.
The investigation discovered the issue as they listened closely to a last-minute routing change delivered to the helicopter pilot on the tower frequency. “LF 4 Medevac,” the tower controller said, “while we wait, amend your Ottawa 39 for a right turn heading 290 degrees, balance unchanged.” The pilot heard “while we wait” and apparently thought the controller had cleared him to “line up and wait,” on Runway 25 and began hover-taxiing toward the active. The other helicopter pilot and the tower controller both saw the movement and halted the helicopter, but not before it entered into the runway’s protected zone.
The TSB said another contributor to the incident was the Ottawa tower controller’s failure to tell the helicopter pilot about the Airbus landing on Runway 25.