Did the increasingly popular and eco-friendly use of “gliding” or “straight in” descents by airliners cause the BA crash landing at London Heathrow on 17 January?

The Boeing 777 involved was making an (almost) continuous descent approach to the airport after a 12-hour flight at high altitude from Beijing. During this descent its engines remained at an idle setting until intersecting the normal instrument landing system glide slope for the final approach to the runway.

At that point the engines should have responded to the auto-throttle system to produce the extra power needed to complete the descent.

But they didn’t. Fortunately no-one died when it flopped onto grass short of the runway.

Rewind to a normal descent, in which jets descend in a series of steps, each of them involving short periods of increased engine thrust as the aircraft briefly levels out before resuming the approach.

“Normal” descents waste time and fuel. But they work the engines harder and hotter. The current discussion among pilots is whether the multiple changes in engine thrust involved in the standard approaches might also avoid a significant risk of icing interfering with the capacity of some engines to respond to commands for more power from an auto-throttle system, and subsequent urgent pilot input, which happened in the final moments of the BA flight.

It might be a problem with the data the engine control systems get, rather than the engines themselves. No-one knows, but the suspicion is that an external factor came into play to disrupt at the same instant two engines that have entirely separate control systems.

This is a complex accident investigation that may take some time to identify causes and remedies.

But it’s also tightly reasoned speculation which is relevant in Australia. Qantas is a pioneer of continuous descent approaches and they have been extensively trialed and are in regular use by itself and other airlines at Sydney, Auckland and a rising number of international airports including Heathrow.

However Qantas doesn’t fly 777s, for which Boeing has in the past reminded operators of the need to select engine de-icing as “on” in some atmospheric conditions.

Nor is anyone suggesting so-called “gliding” approaches should be banned. Tweaked perhaps, but the reductions in fuel burn and noise they bring are compelling reasons for keeping them.

All of which is very technical. For those seeking comic relief we offer this link to an overnight expose of how British Airways pilots cope with stress.