The LED is measurably the least bright of the three
That statement seems astonishing to me, given these pics. The LEDs are vastly brighter than the normal lamps. I wonder how AC did those tests.
However I have not yet had a chance to test them by taxiing at night.
I don’t have experience either with LED or HID in aviation but I have years of experience using these lights in technical and cave diving. Last 10 or so years divers use HID lights in demanding environments both for lighting and communication purposes. LED started to enter this arena few years ago with more and more success. The brightness is still on HID side at least when we consider mainstream products. But LED development is huge and it will surely become dominant in following years. Recently, I was part of cave diving exploration project which included filming. The lighting used was LED (custom made, still not available commercially) and it was by far stronger than anything I had ever seen. Sometimes (in narrow cave passages and when the walls were pure white limestone) it was too bright and had to be dimmed. So, my conlusion is that LED is way to go.
