Hi Paul,

Thanks for picking that up, and thank you also for your kind words about Bob. He certainly was a legend, and we are doing our best to keep the material as clear and accurate as he would have wanted.

This is one of CASA’s favourite Human Factors questions because they can turn it around in several different ways, and it causes confusion for a lot of students. The key is to separate what the pilot sees from how the pilot reacts.

Correct summary — air and runway lights

Clear air / very bright runway lights
These can make the runway or lights appear closer than they really are.
The pilot may feel that the aircraft is too low or closer to the runway than it actually is, and may therefore tend to fly a higher approach, risking an overshoot.

Haze, smoke, poor visibility / dim runway lights
These can make the runway or lights appear further away than they really are.
The pilot may feel that the aircraft is too high, and may therefore tend to fly a lower approach, risking an undershoot.

So, in plain English:

Bright and clear = looks closer = pilot may fly too high.
Dim, hazy or smoky = looks further away = pilot may fly too low.

The summary section should not imply that dim runway lights belong in the “pilot thinks they are too low” group. Dimmer lights/poor visibility are more correctly associated with the runway appearing further away, which can lead the pilot to think they are too high and then descend too much.

Thanks again for bringing it to our attention. We’ll add that to the correction list so the next update is clearer.

@bobtaitsadmin Thank you….much appreciated.