4 ms·

Windows for Warships

10 points by bane 3y ago

SenHeng 3y ago
(2007)
netsharc 3y ago
> a software bug in the F-22 Raptor stealth fighter. It seems that the computer systems had problems flying West across the International Date Line. Does it have a database of timezones and their borders, why would it care what time it is "locally"/they're in? But if it crashes when it goes from -179°59'59" (179°59'59" degrees West) to 179°59'59" East it'd be sort of understandable... Maybe some programmer botch-coded a speed indicator or a plot of the flight using the lat/longs...
- simonblack 3y ago
  But if it crashes when it goes from -179°59'59" (179°59'59" degrees West) to 179°59'59" East it'd be sort of understandable... Apparently one of the early 737 series of crashes back around the 1970s had an 8-bit rudder variable as 000 being full-left and 255 as full-right (or maybe it was vice-versa). The problem being that if the rudder was full-right at 255 and the system allowed any increase in right-rudder, it would immediately overflow back to 000 or full-left-rudder.That caused several 737s to fall out of the sky before the cause was discovered.
  - yial 3y ago
    I think you’re referencing https://en.wikipedia.org/wiki/United_Airlines_Flight_585 https://en.wikipedia.org/wiki/United_Airlines_Flight_585 “The National Transportation Safety Board determines that the probable cause of the United Airlines flight 585 accident was a loss of control of the airplane resulting from the movement of the rudder surface to its blowdown limit. The rudder surface most likely deflected in a direction opposite to that commanded by the pilots as a result of a jam of the main rudder power control unit servo valve secondary slide to the servo valve housing offset from its neutral position and overtravel of the primary slide”
    - simonblack 3y ago
      When I was a pilot, we used to get Air Safety publications which told of air crashes and their causes. Extremely good educational material. Probably why I'm still alive today.
simonblack 3y ago
The Government should make 'Windows for Warships' mandatory for all Navy ships.

10 points by bane 3y ago

(2007)

> a software bug in the F-22 Raptor stealth fighter. It seems that the computer systems had problems flying West across the International Date Line. Does it have a database of timezones and their borders, why would it care what time it is "locally"/they're in? But if it crashes when it goes from -179°59'59" (179°59'59" degrees West) to 179°59'59" East it'd be sort of understandable... Maybe some programmer botch-coded a speed indicator or a plot of the flight using the lat/longs...

simonblack 3y ago
But if it crashes when it goes from -179°59'59" (179°59'59" degrees West) to 179°59'59" East it'd be sort of understandable... Apparently one of the early 737 series of crashes back around the 1970s had an 8-bit rudder variable as 000 being full-left and 255 as full-right (or maybe it was vice-versa). The problem being that if the rudder was full-right at 255 and the system allowed any increase in right-rudder, it would immediately overflow back to 000 or full-left-rudder.That caused several 737s to fall out of the sky before the cause was discovered.
- yial 3y ago
  I think you’re referencing https://en.wikipedia.org/wiki/United_Airlines_Flight_585 https://en.wikipedia.org/wiki/United_Airlines_Flight_585 “The National Transportation Safety Board determines that the probable cause of the United Airlines flight 585 accident was a loss of control of the airplane resulting from the movement of the rudder surface to its blowdown limit. The rudder surface most likely deflected in a direction opposite to that commanded by the pilots as a result of a jam of the main rudder power control unit servo valve secondary slide to the servo valve housing offset from its neutral position and overtravel of the primary slide”
  - simonblack 3y ago
    When I was a pilot, we used to get Air Safety publications which told of air crashes and their causes. Extremely good educational material. Probably why I'm still alive today.

simonblack 3y ago

The Government should make 'Windows for Warships' mandatory for all Navy ships.