Nervous flyers with active imaginations can always imagine the worst when it comes to plane malfunctions. But for those who are familiar with the workings of aviation, there is one particular piece of kit whose failure would be scariest of all: the landing gear.

Endeavor Air Flight 4819 descended quickly while landing at Toronto's Pearson International Airport on Feb. 17, and its right main landing gear collapsed when it contacted the runway, Canadian investigators said.

A preliminary report into the Delta Air Lines flight that flipped upside down in a crash landing at Toronto's Pearson International Airport last month shows the plane had been descending at a high rate of speed. Twenty-one people were injured in the botched landing on Feb. 17.