Jenni, thanks for that link, that is a great video. Carol, don't be too worried, as he explains in many of his other videos, in most instances there are numerous redundant systems that are designed to keep us safe. In this case, even though the controller set the lights to night level , which actually decreased the popi lights instead of increasing them, the pilot flying went below the 3,000 foot minimum without visual confirmation of the runway, and the pilot monitoring ( the captain ) failed to notice they had an unstabilized approach and that their rate of descent was too high, ( if he noticed either at that point he should have called a go around at 1,000 feet, one of those systems - EGPWS - did kick in and told the pilot flying to pull up.