Originally Posted by
Centaurus
That comment brought back a memory of watching a MD80 (stretched DC9) landing on the 5600 ft length runway on Nauru atoll, Central Pacific around 1984. I was a B737 pilot at the time and had operated out of Nauru many times. There are no overruns at the end of the only runway 12/30 - only massive rocks which would tear open any aircraft.
The MD 80 seemed quite high over the fence compared to a 737 approach using T-VASIS. There was a long float after initial touch down which was well into the runway. The aircraft stopped at the extreme end after heavy braking. It was a close thing.
I later talked to the captain of the MD80 which was on a Good-Will flight around the world. Neil Armstrong the astronaut was on the aircraft.
The captain said he used the HUD for landings. Certainly in this case, the HUD nearly pranged him and I saw no value in using a HUD on a sunny day on a short runway where there were ample visual cues and a T-VASIS for glide slope guidance
While I can understand that today's HUDS are much more sophisticated than in 1984, I still question it's use when it is simply an aid to landing but yet has its limitations. Like the Fly Dubai 737 go-around accident where I believe there was evidence the PF was locked on his HUD. In following its guidance for the go-around at night the PF flew the 737 into a spiral dive from a steep go-around climb. I understand the HUD was not designed for such an extreme manoeuvre but the company demanded its crews use the HUD for all landings.
I remember the MD-80 HUD quite well. For approach there was an ILS mode, which gave the same guidance as the FD, albeit with a dot to aim for rather than needles. Using this and Autoland we could fly Cat111 to 20ft RA min, as the GA mode counted as a backup for the AP channel.
Then there was a visual mode. I never really liked it. You aimed an element in the display at the desired touchdown point and when around 50ft RA it gave you a flare to a very soft landing. While concentrating on the guidance it was easy to stop concentrating on the visual landing clues. I could imagine folk might use it to give a VIP a soft touchdown but I preferred to use the Mk1 eyeball and get down at the right spot.