The Transportation Safety Board of Canada (TSB) is investigating a close call at the Hamilton International Airport.
The agency says there was what it calls a "runway incursion" at the airport between a plane and two snowplows on Tuesday.
Two TSB investigators have been assigned to investigate what caused the near-collision, the agency said.
The incident involved a Boeing 727 operated by Kelowna Flightcraft, the TSB said. Kelowna Flightcraft provides air cargo services for Purolator Courier Ltd. and Canada Post.
Kelowna Flightcraft operates out of Hamilton and Kelowna, B.C.
The airport is also investigating.
"We are working in full co-operation with the Transportation Safety Board, as well as conducting an internal investigation," Frank Scremin, chief executive of John C. Munro Hamilton International Airport, said in a statement.
The incident in Hamilton comes just days after an Air Canada flight narrowly missed hitting a driverless van that rolled onto a runway at Toronto's Pearson International Airport.
According to the TSB, there were 4,100 runway incursions from 2001 to 2009 at Canadian airports, where millions of flights take off and land each year.
That number is high enough that runway incursions are listed as an issue on the TSB watchlist.