A look at safety aboard Boeing 737-700 jets

CTV National News: Search for clues Investigators say metal fatigue may be the cause of a midair explosion on a Southwest flight that killed a passenger. Melanie Nagy reports.

The plane involved in an engine explosion on a Southwest Airlines flight, which killed one passenger, was a Boeing 737-700, one of the most commonly-used aircraft in the aviation industry.

And according to global safety records, technical problems with the plane are rare.

The Aviation Safety Network collects incidents involving plane malfunctions. Since 2000, there have been 17 incidents involving Boeing 737-700 planes, eight of which involved Southwest Airlines flights. No Canadian flights made the list.

It’s a tiny number compared to the number of Boeing 737-700 planes in use. According to Flight Aware, a live flight-tracking site, there are hundreds of the jets in the sky at any particular point.

Initial findings into Tuesday’s fatal flight suggest that a fan blade snapped off as the Southwest Airlines jet flew at cruising altitude. Investigators say there is evidence of “metal fatigue,” tiny cracks that can suddenly burst open, where the blade separated.

Metal fatigue was also blamed in a 2016 engine failure in Florida.

Since then, the European Aviation Safety Authority (EASA) issued a directive requiring operators of the planes to inspect specific fan blades on the CFM56-7, an engine used in some Boeing 737-700 planes, by the end of 2019.

In Canada, WestJet owns and operates a fleet of Boeing 737-700 jets.

Based on Tuesday’s deadly incident, WestJet plans to speed up the required inspections on its own fleet, a spokesperson told CTVNews.ca.

“WestJet is in compliance with this directive and based on the incident yesterday, has an immediate plan to accelerate these inspections,” said spokesperson Lauren Stewart in a statement.

Stewart said only a “small portion” of WestJet’s aircraft have the fan blades that were scrutinized by American investigators. Regardless, WestJet plans to inspect the planes promptly.

“All WestJet aircraft have regularly scheduled maintenance checks that are compliant with regulations and completed based on time and usage,” Stewart said, adding that safety is the airline’s “top priority.”

WestJet also expressed its “deepest sympathies to all of those affected by yesterday's tragic event.”

The Transportation Safety Board of Canada only has three aviation investigation reports concerning Boeing 737-700 jets. In two cases, the planes overrun the runway, and one case involved a wing making contact with the runway during landing.

No passengers or crew were injured in any of those incidents. None of the reports found any technical problems with the aircraft. In the Enerjet incident, pilot fatigue was found to be a factor.

Boeing 737-700 jets typically seat 134 people. They have a cruise speed of 850 kilometres per hour and can reach a max altitude of 41,000 feet.

Southwest Airlines owns more than 500 737-700 jets, which make up the majority of its 700 planes.

Passenger Jennifer Riordan sustained fatal injuries in the Albuquerque-bound flight. She was travelling home from a business trip in New York City when, according to U.S. federal investigators, a hole was blown in the plane.

Riordan was partially sucked out of the shattered window, but fellow passengers rescued her. She later died of her injuries.

With files from The Associated Press