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How does this happen? Shouldn’t the pilots see the approaching aircraft on radar (and assuming 3nm visibility) also see the approaching aircraft. This feels lik

How does this happen? Shouldn’t the pilots see the approaching aircraft on radar (and assuming 3nm visibility) also see the approaching aircraft. This feels like a situation where a lot of things went wrong with multiple crews.

version_five 5y ago
From one of the videos posted, it's an uncontrolled airport, so it seems like it was just an error that resulted due to the missing coordination
- jonas21 5y ago
  I had no idea commercial airliners took off from or landed at uncontrolled airports. Sounds scary!
  - geoffeg 5y ago
    It's quite common, at least in the US (where I have most of my experience). It's generally not scary, pilots coordinate with each other on the radio, announcing their intentions. There are, however, some pilots who seem to not make more than the bare minimum number of calls or don't seem interested in listening to the other pilots near the airport. Additionally, there are guidelines for how to enter the airspace of an uncontrolled airport to reduce congestion and the chance of a collision. There are a few exceptions, one of them being an approach during poor weather, which appears to have been the case in the incident mentioned here. In those situations, the approach controller usually coordinates arriving and departing aircraft to use appropriate runways. I'm not sure why that didn't happen in this case, but I haven't gone and looked for the ATC archives.
  - gambiting 5y ago
    Boeing used to sell a protection kit for a 773 to allow it to land and take off from unpaved airports: http://www.b737.org.uk/unpavedstripkit.htm http://www.b737.org.uk/unpavedstripkit.htm
mlyle 5y ago
Non-tactical aircraft don't really have radars like this to spot other planes. TCAS exists and can provide collision warnings and some degree of information on where other aircraft are using secondary radar data, but it's very much a last line of defense. Both planes are expected to see each other, and they're also expected to hear each other on the radio.
- jdavis703 5y ago
  I was just on a 12-seater Cessna Caravan that had some sort of collision warning system, because I heard it alarm. It also had a graphic of the approaching aircraft’s relative position. Would an A320 not have a similar system? Likewise, both pilots physically moved their heads to scan both directions of the runway for hazards. I’m just confused why the big boys wouldn’t be more sophisticated than this.
  - mlyle 5y ago
    > I was just on a 12-seater Cessna Caravan that had some sort of collision warning system, because I heard it alarm. It also had a graphic of the approaching aircraft’s relative position. Yes, it's called TCAS / TCAS II (mentioned). Or portable systems called PCAS for the smallest planes. Alerts are generally disabled on the ground, and .. there's a lot of technical factors that limit its usefulness in this scenario. > Likewise, both pilots physically moved their heads to scan both directions of the runway for hazards. I’m just confused why the big boys wouldn’t be more sophisticated than this. A careful, visual scan is essential. But when you have oncoming fast aircraft, convergence rates are fast. They were 8-9nm apart, at night, when the A320 started its takeoff roll. There's basically 3 defenses against this scenario at an untowered airport: - Weakest: hopefully both aircraft pick the same runway direction. There's a "calm wind" runway for this reason. But when winds are 0 and not quite calm, do they agree? - Stronger, but problematic-- unicom: aircraft are supposed to announce their intents and listen on a common frequency. If someone has the wrong frequency tuned, that won't work. - Strongest: visual avoidance. That happened late here, and triggered an overreaction in this case.
- GekkePrutser 5y ago
smdyc1 5y ago
I think ATC has a big question to answer here. Why the hell would you vector a plane to land in the opposite direction of a departing aircraft on the same runway? At any rate, TCAS also has a big part to play in collision avoidance. It's not just up to the pilots scanning visually or manually looking at a radar screen. I wonder if the A350 got an RA or something and pulled up a bit too much in response. EDIT Just read it was an uncontrolled airport as i posted this, so i guess ATC is out of the picture.
- raverbashing 5y ago
  It does not have TWR it doesn't mean the rest of ATC is unaware, and as the Avherald mentions they have a UNICOM. An interesting tidbit from wikipedia: "Straight-in approaches are discouraged at non-towered airports in the United States"
breckenedge 5y ago
Yes they definitely should have seen and heard each other, but then again when the Airbus started it’s takeoff roll, they would have been maybe 6 miles apart? I would have expected both to have their anti-collision lights on. My bet is one of these aircraft was on the wrong frequency. I’ve done that once before and nearly had the same result.
thetinguy 5y ago
Commercial airplanes have weather radar not for seeing planes.
- chinathrow 5y ago
  But commercial airplanes also have TCAS [1]. If both transponders are working fine, this gives a simulated radar view on who is where. [1] https://en.wikipedia.org/wiki/Traffic_collision_avoidance_system https://en.wikipedia.org/wiki/Traffic_collision_avoidance_sy...
FL410 5y ago
It was almost definitely on their TCAS but that’s not usually something you’re looking at when barreling down the runway about to take off
- GekkePrutser 5y ago
  Does TCAS work on the ground? At least the alerts wouldn't I guess as most of them ask the pilot to ascend or descend
  - FL410 5y ago
    tbh I don't know on transport class planes. The GA aircraft I fly won't STFU about traffic on the ground though, quite annoying. I still would have missed it in this case as I'm used to tuning it out on the ground.
    - GekkePrutser 5y ago
      Wow I didn't even know GA aircraft had it! I've never seen it on a Single engine piston one (which is all I've flown).

version_five 5y ago

From one of the videos posted, it's an uncontrolled airport, so it seems like it was just an error that resulted due to the missing coordination

jonas21 5y ago
I had no idea commercial airliners took off from or landed at uncontrolled airports. Sounds scary!
- geoffeg 5y ago
  It's quite common, at least in the US (where I have most of my experience). It's generally not scary, pilots coordinate with each other on the radio, announcing their intentions. There are, however, some pilots who seem to not make more than the bare minimum number of calls or don't seem interested in listening to the other pilots near the airport. Additionally, there are guidelines for how to enter the airspace of an uncontrolled airport to reduce congestion and the chance of a collision. There are a few exceptions, one of them being an approach during poor weather, which appears to have been the case in the incident mentioned here. In those situations, the approach controller usually coordinates arriving and departing aircraft to use appropriate runways. I'm not sure why that didn't happen in this case, but I haven't gone and looked for the ATC archives.
- gambiting 5y ago
  Boeing used to sell a protection kit for a 773 to allow it to land and take off from unpaved airports: http://www.b737.org.uk/unpavedstripkit.htm http://www.b737.org.uk/unpavedstripkit.htm

mlyle 5y ago

Non-tactical aircraft don't really have radars like this to spot other planes. TCAS exists and can provide collision warnings and some degree of information on where other aircraft are using secondary radar data, but it's very much a last line of defense. Both planes are expected to see each other, and they're also expected to hear each other on the radio.

jdavis703 5y ago
I was just on a 12-seater Cessna Caravan that had some sort of collision warning system, because I heard it alarm. It also had a graphic of the approaching aircraft’s relative position. Would an A320 not have a similar system? Likewise, both pilots physically moved their heads to scan both directions of the runway for hazards. I’m just confused why the big boys wouldn’t be more sophisticated than this.
- mlyle 5y ago
  > I was just on a 12-seater Cessna Caravan that had some sort of collision warning system, because I heard it alarm. It also had a graphic of the approaching aircraft’s relative position. Yes, it's called TCAS / TCAS II (mentioned). Or portable systems called PCAS for the smallest planes. Alerts are generally disabled on the ground, and .. there's a lot of technical factors that limit its usefulness in this scenario. > Likewise, both pilots physically moved their heads to scan both directions of the runway for hazards. I’m just confused why the big boys wouldn’t be more sophisticated than this. A careful, visual scan is essential. But when you have oncoming fast aircraft, convergence rates are fast. They were 8-9nm apart, at night, when the A320 started its takeoff roll. There's basically 3 defenses against this scenario at an untowered airport: - Weakest: hopefully both aircraft pick the same runway direction. There's a "calm wind" runway for this reason. But when winds are 0 and not quite calm, do they agree? - Stronger, but problematic-- unicom: aircraft are supposed to announce their intents and listen on a common frequency. If someone has the wrong frequency tuned, that won't work. - Strongest: visual avoidance. That happened late here, and triggered an overreaction in this case.
GekkePrutser 5y ago

smdyc1 5y ago

I think ATC has a big question to answer here. Why the hell would you vector a plane to land in the opposite direction of a departing aircraft on the same runway? At any rate, TCAS also has a big part to play in collision avoidance. It's not just up to the pilots scanning visually or manually looking at a radar screen. I wonder if the A350 got an RA or something and pulled up a bit too much in response. EDIT Just read it was an uncontrolled airport as i posted this, so i guess ATC is out of the picture.

raverbashing 5y ago
It does not have TWR it doesn't mean the rest of ATC is unaware, and as the Avherald mentions they have a UNICOM. An interesting tidbit from wikipedia: "Straight-in approaches are discouraged at non-towered airports in the United States"

breckenedge 5y ago

Yes they definitely should have seen and heard each other, but then again when the Airbus started it’s takeoff roll, they would have been maybe 6 miles apart? I would have expected both to have their anti-collision lights on. My bet is one of these aircraft was on the wrong frequency. I’ve done that once before and nearly had the same result.

thetinguy 5y ago

Commercial airplanes have weather radar not for seeing planes.

chinathrow 5y ago
But commercial airplanes also have TCAS [1]. If both transponders are working fine, this gives a simulated radar view on who is where. [1] https://en.wikipedia.org/wiki/Traffic_collision_avoidance_system https://en.wikipedia.org/wiki/Traffic_collision_avoidance_sy...

FL410 5y ago

It was almost definitely on their TCAS but that’s not usually something you’re looking at when barreling down the runway about to take off

GekkePrutser 5y ago
Does TCAS work on the ground? At least the alerts wouldn't I guess as most of them ask the pilot to ascend or descend
- FL410 5y ago
  tbh I don't know on transport class planes. The GA aircraft I fly won't STFU about traffic on the ground though, quite annoying. I still would have missed it in this case as I'm used to tuning it out on the ground.
  - GekkePrutser 5y ago
    Wow I didn't even know GA aircraft had it! I've never seen it on a Single engine piston one (which is all I've flown).