AA A321 takes off after smashing ground sign at JFK
avherald.com
avherald.com
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.
[Speculation by poster Trixie on avherald]
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.
> 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.
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...
https://www.pprune.org/rumours-news/620410-aa-a321-takes-off...
Youch. It took quite a bit of that sign with it.
1. https://vancouversun.com/news/local-news/flight-from-vancouv...
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.
Pilot language in the radio audio suggests the turn around is precautionary, there are too many examples of return to departure airport that are not emergencies. Also, they were offered both 4L and 4R, so it's not like they requested a runway that was not in use.
If there are no control problems, no system warnings, and the pilot sees no damage - on what basis do they declare an emergency? Very different from a blown nose gear tire which is a fire hazard on landing, might grind down the wheel, and some risk of nose gear collapse as well.
US ATC can declare an emergency and handle a flight as an emergency in the absence of a declaration from the pilot.
Source - FAA Administration Order JO 7110.65X, section 10. (and conversations with controllers over the years and a flight where I did not declare an emergency, but was handled in every regard as one, including asking souls and fuel on board [an unambiguous indicator])
> on what basis do [the pilots] declare an emergency?
FAR 91.3 gives them incredibly broad discretion and declared emergencies are, despite the name, fairly routine. No pilot would be violated for declaring an emergency under this circumstance.
Dinking a wingtip is not an emergency. The damage looks alarming, but it's nowhere near anything vital. You want to get on the ground ASAP simply as a precaution, but you've still got full control of the aircraft and the capacity to land normally.
Blowing a tire is definitely an emergency, because your landing could go catastrophically wrong. You need to declare an emergency, because you may need a major response on the ground.
Daytime only would still be a huge improvement.
Aviate. Navigate. Communicate. In that order.
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/...
That said the NTSB has recommended it be mandatory.
Yeah, false positives would be a giant source of friction. Do you know what types of sensors the existing systems use?
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.
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.
Edit: Disregard this, AV Herald links provide more info.
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&...
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.
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.
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.