The circumstance doesn’t have to be that dramatic to be abnormal.
Landing after a merely unstable approach, too many significant changes too close to landing, increases risk.
Landing too fast may result in overrunning the end of the runway, pilot induced oscillation, or loss of control. Energy being proportional to the square of velocity means the margin doesn’t have to be huge to pose significant danger. Landing too slow risks an aerodynamic stall or worse a spin, which at low altitude is nearly certain to be fatal.
Landing safely with a crosswind requires technique changes. Too much crosswind or “running out of rudder” is extremely dangerous.
Landing after accumulating airframe icing is triply bad because the ice reduces the control surfaces’ aerodynamic effectiveness, makes the airplane heavier, and requires a faster landing.
As the article already states, there is a well known phenomenon in aviation called automation-induced complacency. So, yes, if you automate landing to the extent that human pilots no longer pay attention to abnormal signals that indicate something is wrong, or no longer feel the need to train or stay vigilant, it can make things more dangerous. There is plenty of research on this, but here's the first that came up in a cursory search:
A more recent example is the Boeing 737-Max where there was a focus on automating trim control. In that case, the automation made the system more complex, to the detriment of a pilot understanding and reacting to an abnormal operation.
We should also be careful that we don't create a false dichotomy between "all automated or no automation", or an expectation that more automation is always better. The goal should be the right balance that increases reliability/safety.
> A more recent example is the Boeing 737-Max where there was a focus on automating trim control. In that case, the automation made the system more complex, to the detriment of a pilot understanding and reacting to an abnormal operation
To be fair this is not entirely accurate: a focus was made on stall prevention in a very specific mode of flight given the variant's increased susceptibility to the pitch-power couple. It did not make the system any more complex per se than other airliners - see e.g. Airbus aircraft which do actually have autotrim in normal flight. The actual kicker was that the existence of MCAS was hidden to avoid the need for lengthy re-training of pilots if the 737 MAX was deemed sufficiently different from its predecessor variants (on top of MCAS being rather poorly implemented in its first iteration).
Fair enough. The “hidden” aspect is what I was alluding to…ie, control that exists but isn’t apparent to the pilots (and worse, intermittent). In the human factors world, it was more complex than the pilots assumed, but you’re right that it’s probably not the best description.
(As an aside, the hazard being mitigated, ie stall, has little bearing on whether or not it’s autonomous or complex, although it does impact whether its safety critical)
The fact that the autopilot will loudly disengage if there is a serious enough control surface failure to cause an upset is more than enough support IMO.
Landing after a merely unstable approach, too many significant changes too close to landing, increases risk.
Landing too fast may result in overrunning the end of the runway, pilot induced oscillation, or loss of control. Energy being proportional to the square of velocity means the margin doesn’t have to be huge to pose significant danger. Landing too slow risks an aerodynamic stall or worse a spin, which at low altitude is nearly certain to be fatal.
Landing safely with a crosswind requires technique changes. Too much crosswind or “running out of rudder” is extremely dangerous.
Landing after accumulating airframe icing is triply bad because the ice reduces the control surfaces’ aerodynamic effectiveness, makes the airplane heavier, and requires a faster landing.