10 ms·

Not good. Less than 3nm separation and headed straight for each other, Beech pilots at 900ft AGL and descending. This was about as close to disaster as it gets.

Not good. Less than 3nm separation and headed straight for each other, Beech pilots at 900ft AGL and descending. This was about as close to disaster as it gets. Nice of the Beech pilots to relay the tail strike to Center, that would have been quite the fireworks show.

jdavis703 5y ago
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).
mlyle 5y ago
Also not good is the fact that they climbed to altitude (before knowing about the tailstrike?). There's been a few accidents from tailstrike damage causing rear bulkhead failure and catastrophic depressurization.
- hugh-avherald 5y ago
  I don't think there have been any where the tailstrike and decompression occurred on the same flight.
  - mlyle 5y ago
    All the ones I'm aware of were on subsequent flights after improper repair. But, still, the QRH says to avoid altitude and not pressurize the plane for a reason...
- TylerE 5y ago
  Did they? This is Colorado...the runway is at ~6600ft ASL, and there are mountains above 12k in close proximity.
  - mlyle 5y ago
    They reached FL300. https://flightaware.com/live/flight/N760JB https://flightaware.com/live/flight/N760JB
deleted 5y ago
[deleted]
joe-collins 5y ago
Because I was at a loss, nm is this context is nautical mile, not the obviously absurd nanometer.
- justsomehnguy 5y ago
  Or a frightening small nautical meter.
- FabHK 5y ago
  The use of imperial units in aviation is lamentable. AFAIK, Russia and China use metric, the rest of the world uses a wild mix (feet for altitude, nautical miles for horizontal distance, statute miles for visibility, metres for runway visible range, etc.) Quite obviously, switching units is complicated, but the current patchwork is a nightmare, and has lead to accidents (like the famous Gimli glider, where kg/pound confusion lead to insufficient fuel). https://en.wikipedia.org/wiki/Gimli_Glider https://en.wikipedia.org/wiki/Gimli_Glider
- worewood 5y ago
  Well on most molecules a 3nm separation is not a separation anymore =D
geocrasher 5y ago
To put it in perspective: The A320 rotates at about 150kts, the B350 approaches at about 140kts. Their combined speed was around 290kts, or 333mph. With 3nm separation, that's about 30 seconds before impact. They were half a minute from absolute disaster. Scary stuff.

jdavis703 5y ago

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).

mlyle 5y ago

Also not good is the fact that they climbed to altitude (before knowing about the tailstrike?). There's been a few accidents from tailstrike damage causing rear bulkhead failure and catastrophic depressurization.

hugh-avherald 5y ago
I don't think there have been any where the tailstrike and decompression occurred on the same flight.
- mlyle 5y ago
  All the ones I'm aware of were on subsequent flights after improper repair. But, still, the QRH says to avoid altitude and not pressurize the plane for a reason...
TylerE 5y ago
Did they? This is Colorado...the runway is at ~6600ft ASL, and there are mountains above 12k in close proximity.
- mlyle 5y ago
  They reached FL300. https://flightaware.com/live/flight/N760JB https://flightaware.com/live/flight/N760JB

deleted 5y ago

[deleted]

joe-collins 5y ago

Because I was at a loss, nm is this context is nautical mile, not the obviously absurd nanometer.

justsomehnguy 5y ago
Or a frightening small nautical meter.
FabHK 5y ago
The use of imperial units in aviation is lamentable. AFAIK, Russia and China use metric, the rest of the world uses a wild mix (feet for altitude, nautical miles for horizontal distance, statute miles for visibility, metres for runway visible range, etc.) Quite obviously, switching units is complicated, but the current patchwork is a nightmare, and has lead to accidents (like the famous Gimli glider, where kg/pound confusion lead to insufficient fuel). https://en.wikipedia.org/wiki/Gimli_Glider https://en.wikipedia.org/wiki/Gimli_Glider
worewood 5y ago
Well on most molecules a 3nm separation is not a separation anymore =D

geocrasher 5y ago

To put it in perspective: The A320 rotates at about 150kts, the B350 approaches at about 140kts. Their combined speed was around 290kts, or 333mph. With 3nm separation, that's about 30 seconds before impact. They were half a minute from absolute disaster. Scary stuff.