Twice within the span of two weeks, an Air Canada plane's crew was warned by air traffic controllers that it was flying too low while approaching New York's LaGuardia airport.

On Dec. 9, Air Canada Flight 730 left Toronto's Pearson airport bound for LaGuardia. The plane, an Embraer 175 with 72 people on board, was on autopilot, nearing the airport and about to make its final approach to runway 4.

That's when air traffic controllers noticed the plane was coming in below the minimum approach height of 1,400 feet. After air traffic control alerted the flight crew, the plane climbed to 1,500 feet before continuing its approach and landing safely.

The incident was similar to an event a little over a week earlier, with the same type of aircraft. In that case, an Embraer 175 with 40 people on board flying from Montreal to LaGuardia. In that case, too, the plane was on autopilot when it became apparent it was making its approach well under the minimum approach height. The flight crew abandoned their first landing attempt before another approach and landing, without incident.

"We are studying these two cases," Air Canada spokesman Peter Fitzpatrick said. "During both approaches, the crew followed all standard operating procedures and all path corrections were completed well above the alerting thresholds."

"At no time were the passengers and crew in any danger," Fitzpatrick said. "Flight crews have been instructed to no longer use this type of approach in LGA and there have been no other such instances. We are also following up with Embraer and Honeywell," the company that makes the plane's electronics, he said.