9 ms·

AA A321 takes off after smashing ground sign at JFK

116 points by howard941 8y ago

deleted 8y ago
[deleted]
tyingq 8y ago
Scroll down to these pictures: https://www.pprune.org/rumours-news/620410-aa-a321-takes-off-after-smashing-ground-sign-3.html#post10450077 https://www.pprune.org/rumours-news/620410-aa-a321-takes-off... Youch. It took quite a bit of that sign with it.
userbinator 8y ago
This is the AVherald article about it, with more details: http://avherald.com/h?article=4c68c5a8&opt=0 http://avherald.com/h?article=4c68c5a8&opt=0
- dang 8y ago
  Ok, we've changed to that from https://www.pprune.org/rumours-news/620410-aa-a321-takes-off-after-smashing-ground-sign.html https://www.pprune.org/rumours-news/620410-aa-a321-takes-off....
cmurf 8y ago
The avherald reporting is better. And has photos of the damage. Currently they're calling this an accident, not an incident, and per 49 CFR 830.2 that's because of the substantial damage to the wing. http://avherald.com/h?article=4c68c5a8&opt=0 http://avherald.com/h?article=4c68c5a8&opt=0 A passenger, who they confirmed was on the flight, says the pilot announced "a major computer failure". The runway heading and wind conditions mean a crosswind takeoff. The plane would have a natural inclination to weather vane toward the wind (yaw right) and the right wing to have more lift (roll left). Proper crosswind takeoff counteracts this with right aileron and left rudder and slightly higher rotation speed. The left wing should have lifted sooner, not later, the idea being to bank into the crosswind to keep the airplane from drifting; and as the plane lifts off immediately establish a crab into the wind which then permits wings level flight and climb out while compensating for the cross wind in order to maintain a runway heading ground track. Anyway, the exact opposite happened. I'm not sure which surprises me more, pilot error or computer error. Both seem incredible to me, and this report is eyebrow raising. Dragging a wing on takeoff is extremely dangerous, regardless of the frangibility of airport signage.
- mc32 8y ago
  It looks like another plane’s jet blast from a 90 degree angle could be a possibility causing it to veer while taking off. [Speculation by poster Trixie on avherald]
  - cmurf 8y ago
    From where? Takeoff runway is 31L, reportedly from intersection KE, therefore 04L isn't a factor, and it puts rotation around intersection PA. No one is going to be at takeoff power over there and not on a runway. Idle power wouldn't do this. If there's an uncommanded roll before V1, I'd expect aborted takeoff. So it's more plausible this happened after V1, and before Vr, which means the instigator was present for some distance.
    - FPGAhacker 8y ago
      From a comment on avherald: > It is being discussed at American that as the aircraft was at rotation, JFK Ground had cleared a heavy jet into the ramp and he used a great deal of power to get moving. His jetblast, coming from a 90 degree angle to flight 300 on takeoff, is being considered a factor in the roll of the Airbus as it lifted off causing the displacement from the runway and the wingtip drag. > Powerful taxi thrust could most certainly be an factor. Many years ago I witnessed a DC-10 literally blow a small aircraft up and onto its nose, then onto its back during landing with the thrust of those DC-10 engines powered up while exiting the runway and turning 180 degrees.
- tyingq 8y ago
  "The avherald reporting is better. And has photos of the damage." The damage pics in the pprune thread are better. You do have to scroll a bit. Here's a direct link to the detailed pics: https://www.pprune.org/rumours-news/620410-aa-a321-takes-off-after-smashing-ground-sign-3.html#post10450077 https://www.pprune.org/rumours-news/620410-aa-a321-takes-off...
jrockway 8y ago
First they employed software engineers to put an end to 20 years of unprecedented aviation safety. They fired those guys and now the pilots just drive the plane into objects on the ground, like the good old days.
pascalxus 8y ago
I'm confused as to why there would be a sign anywhere near the flight path of an airplane.
- tyingq 8y ago
  It's a runway marker sign. They are pretty low, and in the grass, and have breakaway mounts. This sort of thing: https://blog.klm.com/assets/uploads/2015/08/Signs_7.jpg https://blog.klm.com/assets/uploads/2015/08/Signs_7.jpg The aircraft would have been way off center of the runway, with the left wing literally dragging the ground. JFK runway 31L is 200 feet wide, an A321 has a wingspan of 112 feet. The wings are 12 feet from the ground at the fuselage, and maybe two feet higher than that at the wingtips. The photos[1] show heavy abrasion under the left wingtip, presumably it was dragging the ground. [1] https://imgur.com/a/rKu8cUC https://imgur.com/a/rKu8cUC
  - mveety 8y ago
    Also if there’s wind and the gas in the shocks is a bit low you can easily hit them.
    - deleted 8y ago
      [deleted]
- zhte415 8y ago
  Fron TFA, it was taxiing when it hit the sign. Edit: Disregard this, AV Herald links provide more info.
  - zaroth 8y ago
    This appears to be incorrect. Reports state damage was sustained during takeoff.
- cmurf 8y ago
  Not the normal flight path of an airplane, anyway. I don't know which kind they hit. But based on what's on the left side of runway 31L, I suspect it was a runway remaining distance sign, those are all black, and around 5' tall, and vaguely resembles the passenger photo of something black embedded in the wing. Edit: Comment #77 in this forum thread is interesting if a true account. https://www.airliners.net/forum/viewtopic.php?f=3&t=1420137&start=50#p21285555 https://www.airliners.net/forum/viewtopic.php?f=3&t=1420137&...
lvs 8y ago
The NTSB seems to get a lot of work. https://twitter.com/NTSB_Newsroom https://twitter.com/NTSB_Newsroom
- consumer451 8y ago
  Thanks for that well of information. This highway crash[0] makes me feel like it's crazy that we still haven't created, and mandated, forward collision avoidance for all tractor-trailer sized vehicles. The people in the SUV never had a chance. [0] https://www.ntsb.gov/investigations/AccidentReports/Reports/HWY18FH015-preliminary-report.pdf https://www.ntsb.gov/investigations/AccidentReports/Reports/...
  - jdsully 8y ago
    Trucks are cut off in traffic extremely frequently. Some trucks do have auto braking and it getting triggered all the time from jerks on the road is a frequent complaint. That said the NTSB has recommended it be mandatory.
    - consumer451 8y ago
      > Trucks are cut off in traffic extremely frequently. Some trucks do have auto braking and it getting triggered all the time from jerks on the road is a frequent complaint. Yeah, false positives would be a giant source of friction. Do you know what types of sensors the existing systems use?
      - jdsully 8y ago
        Nope no specific knowledge, just a decent amount of trucker griping. The stopping distance of trucks is much longer so the triggering distance on these devices must be correspondingly longer as well. A lot of cars don't even realize they cut off the truck because they can stop so much faster. A trucker can assume that a car cutting them off with open road in the front won't slam their brakes. These devices can't.
deleted 8y ago
[deleted]
kerng 8y ago
Does this mean the plane "rolled" slightly to the left while still on runway, and hence the left wing was able to hit that sign? Did the pilot use the ailerons while on runway?
- cmurf 8y ago
  Unverified video taken on the ground after landing. https://www.airliners.net/forum/viewtopic.php?f=3&t=1420137#p21273103 https://www.airliners.net/forum/viewtopic.php?f=3&t=1420137#... It looks similar to other photos, and if authentic yes it suggests a significant roll to the left. From the available information I can't assess whether the plane was on the ground or airborne, either are possible. Aileron is normally used for crosswind takeoffs, to lift the leeward wing sooner in order to "lean" the plane into the crosswind to keep the plane from drifting from runway centerline. Essentially the opposite happened in this case. The airplane must have both drifted to the left of the runway center line (not out of the ordinary, in particular if it's gusty) as well as left wing dipped. It's possible this was a suddenly gusty takeoff. I'm not sure to what degree A320 series can do auto takeoff or computer assisted takeoffs, and what crosswind limits they presumably have where a pilot has to do the takeoff manually instead. Maybe the pilot's suggestion of a computer problem is related to that, and they subsequently took manual control.
  - danaliv 8y ago
    Aileron is normally used for crosswind takeoff Airbus crosswind takeoff recommendation is no lateral stick input. The sidestick is a rate controller, so a lateral deflection commands a roll, not a specific control surface position like on non-fly-by-wire aircraft. And you run the risk of deploying spoilers.
    - cmurf 8y ago
      The original article article URL before the change to avherald contains a post that addresses this: https://www.pprune.org/showthread.php?p=10450572 https://www.pprune.org/showthread.php?p=10450572 Obviously we'll have to wait and see what the actual story is, whether this is really old bad tribal knowledge, and if the operating manual contradicts that, and whether pilots are getting the proper training and consistently applying it in practice. I'm an opinionated and biased pilot and former flight instructor, but not an aerodynamic engineer. Spoiler extension does not increase the effective angle of attack of the wing, whereas a dropping aileron does. And therefore off hand, and without benefit of an Airbus type rating, I don't really care if the actual control surface is a bit of right spoiler instead of left (down) aileron, all I care about is that the windward wing does NOT lift off first because that will foul up the ground track on takeoff, and that's simply not proper technique.
deleted 8y ago
[deleted]
leemailll 8y ago
Found this first on vasaviation (https://www.youtube.com/watch?v=Ca-0Bi2lZhg https://www.youtube.com/watch?v=Ca-0Bi2lZhg), which focus on atc communications. It looks like the pilots took 5 mins to report to atc for emergency landing request.
- cmurf 8y ago
  From other reporting it sounds like they didn't know they hit something until left side passenger(s) reported wing damage to flight attendants, who then reported to pilots. Also it wasn't an emergency landing request: no mayday, no pan-pan, their only request was for a particular runway presumably because it was the longer one, and they explicitly denied needing ground assistance.
  - jetrink 8y ago
    How can an incident require turning back immediately (and requesting a specific runway!), but not require declaring an emergency? Here's an incident[1] from yesterday where an American Airlines flight declared an emergency after a tire blew. Meanwhile, this aircraft has visible damage to the wing. 1. https://vancouversun.com/news/local-news/flight-from-vancouver-to-chicago-makes-emergency-landing-in-seattle https://vancouversun.com/news/local-news/flight-from-vancouv...
    - mchristen 8y ago
      Just because it looks bad doesn't mean it actually is bad. A blown tire has many more ways of causing a plane to fail during landing then a wing that isn't operating at 100%. As long as all the flight controls are operational and there is no leaking fuel I don't see why it would be considered an emergency.
    - akira2501 8y ago
      > but not require declaring an emergency? Having an emergency condition and declaring one on frequency are two entirely different things. By declaring an emergency you're more or less taking control of all surrounding airspace and doing whatever is necessary to achieve a safe resolution of your flight, the tower and ATC both become bound by your declarations as an emergency flight. If your flight controls aren't damaged, you have enough fuel and/or aren't leaking any, and you're capable of flying the standard arrival pattern it may not be necessary to declare the emergency to gain the privileges above.
throw03172019 8y ago
Expensive accident. Glad everyone is safe!
snazzycalynx 8y ago
Right crosswind: the rudder, during the take off run, tends to veer the plane to the right, so left rudder inputs must be applied by the pilot. At rotation, if that input is not relieved, left rudder will produce left bank. It all depends on where the plane was positioned at rotation in relation to the runway axis... The preliminary report will surely make things clearer, let's be patient

116 points by howard941 8y ago

deleted 8y ago

[deleted]

Scroll down to these pictures: https://www.pprune.org/rumours-news/620410-aa-a321-takes-off-after-smashing-ground-sign-3.html#post10450077 https://www.pprune.org/rumours-news/620410-aa-a321-takes-off... Youch. It took quite a bit of that sign with it.

userbinator 8y ago

This is the AVherald article about it, with more details: http://avherald.com/h?article=4c68c5a8&opt=0 http://avherald.com/h?article=4c68c5a8&opt=0

dang 8y ago
Ok, we've changed to that from https://www.pprune.org/rumours-news/620410-aa-a321-takes-off-after-smashing-ground-sign.html https://www.pprune.org/rumours-news/620410-aa-a321-takes-off....

cmurf 8y ago

The avherald reporting is better. And has photos of the damage. Currently they're calling this an accident, not an incident, and per 49 CFR 830.2 that's because of the substantial damage to the wing. http://avherald.com/h?article=4c68c5a8&opt=0 http://avherald.com/h?article=4c68c5a8&opt=0 A passenger, who they confirmed was on the flight, says the pilot announced "a major computer failure". The runway heading and wind conditions mean a crosswind takeoff. The plane would have a natural inclination to weather vane toward the wind (yaw right) and the right wing to have more lift (roll left). Proper crosswind takeoff counteracts this with right aileron and left rudder and slightly higher rotation speed. The left wing should have lifted sooner, not later, the idea being to bank into the crosswind to keep the airplane from drifting; and as the plane lifts off immediately establish a crab into the wind which then permits wings level flight and climb out while compensating for the cross wind in order to maintain a runway heading ground track. Anyway, the exact opposite happened. I'm not sure which surprises me more, pilot error or computer error. Both seem incredible to me, and this report is eyebrow raising. Dragging a wing on takeoff is extremely dangerous, regardless of the frangibility of airport signage.

mc32 8y ago
It looks like another plane’s jet blast from a 90 degree angle could be a possibility causing it to veer while taking off. [Speculation by poster Trixie on avherald]
- cmurf 8y ago
  From where? Takeoff runway is 31L, reportedly from intersection KE, therefore 04L isn't a factor, and it puts rotation around intersection PA. No one is going to be at takeoff power over there and not on a runway. Idle power wouldn't do this. If there's an uncommanded roll before V1, I'd expect aborted takeoff. So it's more plausible this happened after V1, and before Vr, which means the instigator was present for some distance.
  - FPGAhacker 8y ago
    From a comment on avherald: > It is being discussed at American that as the aircraft was at rotation, JFK Ground had cleared a heavy jet into the ramp and he used a great deal of power to get moving. His jetblast, coming from a 90 degree angle to flight 300 on takeoff, is being considered a factor in the roll of the Airbus as it lifted off causing the displacement from the runway and the wingtip drag. > Powerful taxi thrust could most certainly be an factor. Many years ago I witnessed a DC-10 literally blow a small aircraft up and onto its nose, then onto its back during landing with the thrust of those DC-10 engines powered up while exiting the runway and turning 180 degrees.
tyingq 8y ago
"The avherald reporting is better. And has photos of the damage." The damage pics in the pprune thread are better. You do have to scroll a bit. Here's a direct link to the detailed pics: https://www.pprune.org/rumours-news/620410-aa-a321-takes-off-after-smashing-ground-sign-3.html#post10450077 https://www.pprune.org/rumours-news/620410-aa-a321-takes-off...

jrockway 8y ago

First they employed software engineers to put an end to 20 years of unprecedented aviation safety. They fired those guys and now the pilots just drive the plane into objects on the ground, like the good old days.

pascalxus 8y ago

I'm confused as to why there would be a sign anywhere near the flight path of an airplane.

tyingq 8y ago
It's a runway marker sign. They are pretty low, and in the grass, and have breakaway mounts. This sort of thing: https://blog.klm.com/assets/uploads/2015/08/Signs_7.jpg https://blog.klm.com/assets/uploads/2015/08/Signs_7.jpg The aircraft would have been way off center of the runway, with the left wing literally dragging the ground. JFK runway 31L is 200 feet wide, an A321 has a wingspan of 112 feet. The wings are 12 feet from the ground at the fuselage, and maybe two feet higher than that at the wingtips. The photos[1] show heavy abrasion under the left wingtip, presumably it was dragging the ground. [1] https://imgur.com/a/rKu8cUC https://imgur.com/a/rKu8cUC
- mveety 8y ago
  Also if there’s wind and the gas in the shocks is a bit low you can easily hit them.
  - deleted 8y ago
    [deleted]
zhte415 8y ago
Fron TFA, it was taxiing when it hit the sign. Edit: Disregard this, AV Herald links provide more info.
- zaroth 8y ago
  This appears to be incorrect. Reports state damage was sustained during takeoff.
cmurf 8y ago
Not the normal flight path of an airplane, anyway. I don't know which kind they hit. But based on what's on the left side of runway 31L, I suspect it was a runway remaining distance sign, those are all black, and around 5' tall, and vaguely resembles the passenger photo of something black embedded in the wing. Edit: Comment #77 in this forum thread is interesting if a true account. https://www.airliners.net/forum/viewtopic.php?f=3&t=1420137&start=50#p21285555 https://www.airliners.net/forum/viewtopic.php?f=3&t=1420137&...

lvs 8y ago

The NTSB seems to get a lot of work. https://twitter.com/NTSB_Newsroom https://twitter.com/NTSB_Newsroom

consumer451 8y ago
Thanks for that well of information. This highway crash[0] makes me feel like it's crazy that we still haven't created, and mandated, forward collision avoidance for all tractor-trailer sized vehicles. The people in the SUV never had a chance. [0] https://www.ntsb.gov/investigations/AccidentReports/Reports/HWY18FH015-preliminary-report.pdf https://www.ntsb.gov/investigations/AccidentReports/Reports/...
- jdsully 8y ago
  Trucks are cut off in traffic extremely frequently. Some trucks do have auto braking and it getting triggered all the time from jerks on the road is a frequent complaint. That said the NTSB has recommended it be mandatory.
  - consumer451 8y ago
    > Trucks are cut off in traffic extremely frequently. Some trucks do have auto braking and it getting triggered all the time from jerks on the road is a frequent complaint. Yeah, false positives would be a giant source of friction. Do you know what types of sensors the existing systems use?
    - jdsully 8y ago
      Nope no specific knowledge, just a decent amount of trucker griping. The stopping distance of trucks is much longer so the triggering distance on these devices must be correspondingly longer as well. A lot of cars don't even realize they cut off the truck because they can stop so much faster. A trucker can assume that a car cutting them off with open road in the front won't slam their brakes. These devices can't.

deleted 8y ago

[deleted]

kerng 8y ago

Does this mean the plane "rolled" slightly to the left while still on runway, and hence the left wing was able to hit that sign? Did the pilot use the ailerons while on runway?

cmurf 8y ago
Unverified video taken on the ground after landing. https://www.airliners.net/forum/viewtopic.php?f=3&t=1420137#p21273103 https://www.airliners.net/forum/viewtopic.php?f=3&t=1420137#... It looks similar to other photos, and if authentic yes it suggests a significant roll to the left. From the available information I can't assess whether the plane was on the ground or airborne, either are possible. Aileron is normally used for crosswind takeoffs, to lift the leeward wing sooner in order to "lean" the plane into the crosswind to keep the plane from drifting from runway centerline. Essentially the opposite happened in this case. The airplane must have both drifted to the left of the runway center line (not out of the ordinary, in particular if it's gusty) as well as left wing dipped. It's possible this was a suddenly gusty takeoff. I'm not sure to what degree A320 series can do auto takeoff or computer assisted takeoffs, and what crosswind limits they presumably have where a pilot has to do the takeoff manually instead. Maybe the pilot's suggestion of a computer problem is related to that, and they subsequently took manual control.
- danaliv 8y ago
  Aileron is normally used for crosswind takeoff Airbus crosswind takeoff recommendation is no lateral stick input. The sidestick is a rate controller, so a lateral deflection commands a roll, not a specific control surface position like on non-fly-by-wire aircraft. And you run the risk of deploying spoilers.
  - cmurf 8y ago
    The original article article URL before the change to avherald contains a post that addresses this: https://www.pprune.org/showthread.php?p=10450572 https://www.pprune.org/showthread.php?p=10450572 Obviously we'll have to wait and see what the actual story is, whether this is really old bad tribal knowledge, and if the operating manual contradicts that, and whether pilots are getting the proper training and consistently applying it in practice. I'm an opinionated and biased pilot and former flight instructor, but not an aerodynamic engineer. Spoiler extension does not increase the effective angle of attack of the wing, whereas a dropping aileron does. And therefore off hand, and without benefit of an Airbus type rating, I don't really care if the actual control surface is a bit of right spoiler instead of left (down) aileron, all I care about is that the windward wing does NOT lift off first because that will foul up the ground track on takeoff, and that's simply not proper technique.

deleted 8y ago

[deleted]

leemailll 8y ago

Found this first on vasaviation (https://www.youtube.com/watch?v=Ca-0Bi2lZhg https://www.youtube.com/watch?v=Ca-0Bi2lZhg), which focus on atc communications. It looks like the pilots took 5 mins to report to atc for emergency landing request.

cmurf 8y ago
From other reporting it sounds like they didn't know they hit something until left side passenger(s) reported wing damage to flight attendants, who then reported to pilots. Also it wasn't an emergency landing request: no mayday, no pan-pan, their only request was for a particular runway presumably because it was the longer one, and they explicitly denied needing ground assistance.
- jetrink 8y ago
  How can an incident require turning back immediately (and requesting a specific runway!), but not require declaring an emergency? Here's an incident[1] from yesterday where an American Airlines flight declared an emergency after a tire blew. Meanwhile, this aircraft has visible damage to the wing. 1. https://vancouversun.com/news/local-news/flight-from-vancouver-to-chicago-makes-emergency-landing-in-seattle https://vancouversun.com/news/local-news/flight-from-vancouv...
  - mchristen 8y ago
    Just because it looks bad doesn't mean it actually is bad. A blown tire has many more ways of causing a plane to fail during landing then a wing that isn't operating at 100%. As long as all the flight controls are operational and there is no leaking fuel I don't see why it would be considered an emergency.
  - akira2501 8y ago
    > but not require declaring an emergency? Having an emergency condition and declaring one on frequency are two entirely different things. By declaring an emergency you're more or less taking control of all surrounding airspace and doing whatever is necessary to achieve a safe resolution of your flight, the tower and ATC both become bound by your declarations as an emergency flight. If your flight controls aren't damaged, you have enough fuel and/or aren't leaking any, and you're capable of flying the standard arrival pattern it may not be necessary to declare the emergency to gain the privileges above.

throw03172019 8y ago

Expensive accident. Glad everyone is safe!

snazzycalynx 8y ago

Right crosswind: the rudder, during the take off run, tends to veer the plane to the right, so left rudder inputs must be applied by the pilot. At rotation, if that input is not relieved, left rudder will produce left bank. It all depends on where the plane was positioned at rotation in relation to the runway axis... The preliminary report will surely make things clearer, let's be patient