2 ms·

I guess that sounds good, though it might sound less good after a mass casualty collision. Wonder if we couldn't have "ground strobes" visible only to viewers

I guess that sounds good, though it might sound less good after a mass casualty collision. Wonder if we couldn't have "ground strobes" visible only to viewers looking downward at a significant angle.

captain_perl 8y ago
No, because when there's fog, the strobe gets reflected within the cloud everywhere. This is SFO after all.
- sokoloff 8y ago
  In the case of fog or other low clouds though, airplanes are overwhelmingly likely to be following a localizer or GPS/RNAV approach, making this type of incident much less likely.
  - throwaway5250 8y ago
    Hmm. So why not use that technique _all_ of the time?
    - sokoloff 8y ago
      Well, AC759 should have been doing so, even on the visual approach to 28R. On this particular approach (in contrast to literally every other approach in the FMS's database), a manual tuning step was required and skipped.-[0] If there were another approach that required manual tuning and it was not a visual approach, the crew would detect they didn't have a localizer/equivalent to follow and would identify the missed step, because that's the only way they could navigate to the airport/runway. It's a specific combination of visual approach and the only approach that required manual tuning (and not having another aircraft to follow visually) that setup this possible outcome. Then, the crew visually acquires the wrong bit of pavement and there's no safety mechanism inside the airplane remaining unless/until the pilots see that they're lined up wrong or get a go-around call from ATC/another aircrew. [0] - Quote from the NTSB report: The FMS Bridge visual approach to runway 28R was the only approach in Air Canada’s Airbus A320 database that required manual tuning for a navigational aid, so the manual tuning of the ILS frequency was not a usual procedure for the flight crew.

2 ms·

I guess that sounds good, though it might sound less good after a mass casualty collision. Wonder if we couldn't have "ground strobes" visible only to viewers

by throwaway5250 8y ago

I guess that sounds good, though it might sound less good after a mass casualty collision. Wonder if we couldn't have "ground strobes" visible only to viewers looking downward at a significant angle.

captain_perl 8y ago
No, because when there's fog, the strobe gets reflected within the cloud everywhere. This is SFO after all.
- sokoloff 8y ago
  In the case of fog or other low clouds though, airplanes are overwhelmingly likely to be following a localizer or GPS/RNAV approach, making this type of incident much less likely.
  - throwaway5250 8y ago
    Hmm. So why not use that technique _all_ of the time?
    - sokoloff 8y ago
      Well, AC759 should have been doing so, even on the visual approach to 28R. On this particular approach (in contrast to literally every other approach in the FMS's database), a manual tuning step was required and skipped.-[0] If there were another approach that required manual tuning and it was not a visual approach, the crew would detect they didn't have a localizer/equivalent to follow and would identify the missed step, because that's the only way they could navigate to the airport/runway. It's a specific combination of visual approach and the only approach that required manual tuning (and not having another aircraft to follow visually) that setup this possible outcome. Then, the crew visually acquires the wrong bit of pavement and there's no safety mechanism inside the airplane remaining unless/until the pilots see that they're lined up wrong or get a go-around call from ATC/another aircrew. [0] - Quote from the NTSB report: The FMS Bridge visual approach to runway 28R was the only approach in Air Canada’s Airbus A320 database that required manual tuning for a navigational aid, so the manual tuning of the ILS frequency was not a usual procedure for the flight crew.