Canadian Forces officials are trying to figure out what caused a fighter jet to lose a piece of its wing during a flyby over Toronto on Sunday.

The CF-18 jet was one of two participating in the kickoff to the Molson Indy auto race, flying over tens of thousands of spectators.

Luckily, the metre-long piece splashed into Lake Ontario. Although the lake was dotted with boaters, no one was hurt.

CF- 18 (CP file photo)
CF- 18 (CP file photo)

The part, identified as the nose door to a luggage pod under the wing, was recovered by the Toronto police marine unit.

It appears the incident was caused by a mechanical malfunction, said Captain Julie Roberge of Canadian Forces Base Bagotville in Saguenay, Que., where the fighter is based. A flight safety investigation has been called.

The incident didn't ground the jet, since the piece isn't critical to the aircraft's performance. The pilots flew the jets back to Quebec yesterday afternoon to be examined.

While it may seem strange for a fighter jet to carry luggage, pilots on ceremonial duties like to take along some luggage as there is no room in the single-seat cockpit, Roberge said.

The oblong pod on the underside of the jet's wing would not likely be flown into combat; it can be replaced with bombs or a fuel tank for long missions.

The jet is one of the oldest of Canada's 104 operational CF-18s; it was among the first batch to be delivered in 1982.

It was unclear if any luggage was lost in the incident, which Roberge called "quite unusual."

A year ago, a CF-18 on approach to Yellowknife airport dropped a missile on the driving range of a local golf course. The missile was live, but the safety mechanism was on.