An air traffic controller had to alert the pilots of an Air Canada flight after they descended too low during a bad weather approach to New York’s La Guardia airport.
The airline has launched an internal probe into the Nov. 27 incident involving Air Canada Flight 748, which happened as the twin-engine Embraer 170 jet was arriving from Montreal.
The pilots were using electronic aids to guide the aircraft through the low clouds, rain and late-day darkness to a landing on Runway 4 and had been told by air traffic control not to descend below 520 metres until passing an approach fix.
But with autopilot engaged for the approach, the Embraer jet started down to the runway too soon, busting the altitude restriction issued by the controller, according to a preliminary report prepared by Transport Canada.
The jet — still enveloped in cloud — continued down and was just 300 metres above the borough of Queens when the controller sounded the alarm about the premature descent.
“The aircraft was one mile outside the (fix) when it reached 1,000 ft. and (air traffic control) issued an Altitude Alert,” the report said.
The pilots quickly aborted their faulty approach, circled around and made a successful landing at the busy airport on their second try.
The Transportation Safety Board of Canada conducted a preliminary investigation into the incident but has handed the file over to the airline to pursue internally, a spokesperson said Thursday.
Airline spokeswoman Isabelle Arthur said the controller told the crew that there “appeared to be a discrepancy with the aircraft altitude indication.”
“As per operating procedures the crew did a go around and landed without incident,” Arthur told the Star in an email. “These types of events are extremely isolated and we always conduct internal reviews to ensure we maintain the highest levels of safety standards and operations.”
Arthur did not say whether the discrepancy had been attributed to human error or a mechanical problem.