Pilot explains the ‘vanishingly rare' risk of a plane flipping over

Telegraph

18-02-2025

A Delta Airlines plane has flipped onto its back after coming into land at Toronto Airport.
Extraordinary footage shows the commercial jet lying upside down on the icy runway with one of its wings snapped off. There were no fatalities in the incident, although at least 18 people were injured, three critically.
The details of the Toronto crash are still unclear, so we cannot yet build a definitive picture of how exactly this happened. Delta said in a statement that the airline's chief executive Jim Graham and other members of the leadership team are en route to Toronto to 'ensure full cooperation with investigators'.
Brian Smith, a pilot with decades of experience flying for cargo and major commercial airlines, has analysed the videos, the photographs and the available flight data. This is his take on what may have occurred on the icy runway at Toronto Airport on Monday.
New footage emerges of the Delta plane crash at Toronto Pearson Airport last night. It's a miracle anyone survived! 👀
The aircraft had 80 people on board, with 18 injured, including 3 in critical condition. pic.twitter.com/EXWJCoP3gH
— Volcaholic 🌋 (@volcaholic1) February 18, 2025
Has anything like this happened before?
'Fortunately, events like this where the aircraft is turned over are vanishingly rare. They are almost always related to the severity of the impact with the ground and the attitude [the position of wings and nose in relation to the horizon] of the aircraft,' says Smith.
'A previous and very noteworthy case was United Airlines flight 232, a DC10, which crashed at Sioux City in July 1989. This aircraft, however, had already suffered a catastrophic engine failure, which resulted in total hydraulic failure of flight control surfaces and the crew had to rely on differential thrust on the remaining two engines to attempt to control the aircraft flight path. As it touched down, the aircraft cart wheeled, causing a fireball and the break up of the fuselage.'
Of the 296 people on board, 112 died in the accident.
What exactly causes a plane to flip upside down?
'The aircraft in this case does appear to have suffered a very heavy landing, a landing in which the manufacturer's limit for rate of descent has been exceeded,' Smith says, admitting that this is speculative while we await more information. 'Usually this is more than about 650 to 700 feet per minute, or a G-force exceeding about 2.6. The result is that the left wing has snapped and 'folded' up, immediately followed by an explosion and a large pall of black smoke, which obscures the subsequent overturning moment. The undercarriage appears to have been broken off, at least partially.'
What causes a hard landing?
Smith says: 'Hard landings are often the result of an unstable approach, which in simple terms means that one or more parameters are outside of acceptable limits: either speed, rate of descent or power setting being the most likely. In the videos I have seen, there also doesn't seem to be any 'flare', the point just above the runway, where the aircraft is pitched up slightly, as the thrust is reduced, to arrest the rate of descent and enable a softer landing.'
Did the weather conditions play a part?
'Weather conditions were 'sporty' but not insurmountable: strong winds at 28 knots with gusts to 35 knots (32 to 40mph), with the wind approximately 40 degrees off the landing runway,' says Smith. 'The runway surface was partially covered in snow, but was otherwise free of contaminant.'
Have you encountered a scenario like this before?
Smith says: 'I have never come close to encountering this scenario. Crosswind landings are treated with caution, because there is a higher risk of striking the tail or a wing tip but pilots are trained extensively in the techniques during their twice-yearly simulator sessions. I would point out that once an aircraft suffers such a catastrophic ground contact, there is no possibility of control from the flight deck; it is in the hands of inertia and physics until it comes to rest.'