Nervous fliers need not worry...this tragedy is likely to be an aberration
Questions still surround the tragic incident on the Southwest Airlines Boeing 737-700, the first fatal US airline accident since 2009, and the first ever for Southwest. What went wrong? Were safety regulations breached and could this happen to any plane at any moment?
Full answers may not be revealed until the National Transportation Safety Board (NTSB) has concluded its report – a process that could take more than a year. However early inquiries are understood to be focused on the possibility of metal fatigue on the engine blades: where stress over time inevitably weakens the component.
So far, it is not clear – in public at least – how the blade came free, but it is likely that its high-velocity impact, particularly at that altitude, caused the CFM56-7 engine casing to blow apart. Parts were jettisoned with enough speed to strike the fuselage and break the window, causing depressurisation.
Even a fragment the size of a penny slamming into a plane at cruise height would have a massive impact.
It is not known whether or not the victim was wearing a seat belt when the window next to her smashed, nor whether it could have saved her. The force of the depressurisation would be far too immense for the scenario to be recreated on the ground.
Southwest is the world’s largest operator of the Boeing 737 with a fleet of about 700, including more than 500 737-700s like the one involved in Tuesday’s incident.
So, should passengers be concerned? In short, no. Incidents like this are so rare, quantifying it is pointless. When you consider that a 737 takes off or lands somewhere in
‘This engine is widely used across the globe, accounting for some tens of millions of flight hours each year’
the world every 1.8 seconds, this event is likely to be a one-off aberration.
CFM International, who exclusively make engines for the 737 are, in my view, the best in the world at making them, and the CFM56-7 model that powers the 737 Next Generation family is arguably the very pinnacle of engine design – with a unique record of safety and robustness. It is used widely across the globe, accounting for some tens of millions of flight hours each year without a single incident of any magnitude occurring.
That there were not more injuries in this event, and that the damage was largely contained during the emergency descent, speaks to the excellency of Boeing’s design too.
Engineers will be poring over the flight data and engine characteristics to understand why this uncontained failure happened, but ultimately, any nervous fliers should remember that air travel remains the single safest method of transportation in the world.