AA flight hits object. Returns to airport

[A930Rocket]

AA flight hits sign on takeoff.

Sign says...PULL UP NOW! 🤪

https://www.cnn.com/2019/04/11/us/american-airlines-hit-sign/index.html

An American Airlines flight returned to JFK after hitting a sign during takeoff


(CNN) — An American Airlines flight returned to the airport Wednesday night after hitting a sign during takeoff.

Flight 300 was departing New York's John F. Kennedy International Airport on its way to Los Angeles International Airport when the plane hit a sign adjacent to the runway, Port Authority spokesman Steve Coleman told CNN.

The sign "directs pilots as they're going down the runway," Coleman said. The plane hit the sign because it was slightly off center during takeoff, Coleman said.

The flight took off at 8:40 p.m., but was back at JFK by 9:09 p.m. and taxied to the gate, American Airlines said in a statement. There were 101 passengers and eight crew members on board, and no injuries were reported, the airline said.

"American is swapping flight 300 to a new aircraft, as our team reviews the incident and inspects the aircraft," American Airlines said. "We never want to disrupt our customers' travel plans and we are sorry for the inconvenience."

[wildthing]

I'm not a pilot, so... is this his/her first time on that runway, first time on that aircraft, honest misjudgement of the size and position?

[seafeye]

First time at the airport for a takeoff should have zero to do with hitting a sign. What probably happened is that then the pilot advanced the thrust the aircraft veered off centerline. It is company procedure to advance the thrust on the GE engines to approx 1/3 takeoff power. In some cases the engines do not spool up evenly and it is difficult to keep on the center line if one engine lags behind the other. If a pilot goes from idle to takeoff power then I’d say it would be near impossible to keep on the centerline with the rudders. One engine will lag behind the other.
If the aircraft had the IAE engines then the advancement to takeoff power is slightly different. There is a no go zone in the rpm spectrum. Because of vibration causing wear. In any event most pilots advance the IAE engines slowly to prevent being pushed to one side of the runway.
I’m Sure the data will be pulled and we will know exactly what happened. But this would be my guess.

[Neilk]

Originally Posted by A930Rocket

AA flight hits sign on takeoff.

Sign says...PULL UP NOW! 🤪

https://www.cnn.com/2019/04/11/us/american-airlines-hit-sign/index.html

An American Airlines flight returned to JFK after hitting a sign during takeoff


The sign "directs pilots as they're going down the runway," Coleman said. The plane hit the sign because it was slightly off center during takeoff, Coleman said.
."

I just checked flightaware and it was an Airbus A321 that hit the sign. Those aren't big planes, so I would question their description that it was "slightly off center", sound more like they almost ran off the side of the run way.

[GH85Carrera]

Originally Posted by wildthing

I'm not a pilot, so... is this his/her first time on that runway, first time on that aircraft, honest misjudgement of the size and position?

Airport taxiways and runways all have a center line that the pilot is supposed to try to keep the center of the airplane over. Most airplanes that means the nose wheel. Some airplanes, it is the tail wheel. Whatever, the stripe is a guide to the center of the runway, and the safest place to be.

[Nate2046]

Originally Posted by seafeye

What probably happened is that then the pilot advanced the thrust the aircraft veered off centerline.

I dunno, seems unlikely. If you had that much of an asymmetry on initial spool up that it caused you to veer off the runway and hit a sign, you’d reject the takeoff. If I had to guess, I’d say improper crosswind technique on rotation. That wingtip isn’t hitting a sign unless the aircraft is in a pretty good bank.

[vash]

For sure. That’s IRONY!

[seafeye]

Originally Posted by Nate2046

I dunno, seems unlikely. If you had that much of an asymmetry on initial spool up that it caused you to veer off the runway and hit a sign, you’d reject the takeoff. If I had to guess, I’d say improper crosswind technique on rotation. That wingtip isn’t hitting a sign unless the aircraft is in a pretty good bank.

Crosswind is a good theory. There has been instances of aircraft nearly going off the runway because of asymmetry. Yes they usually abort the takeoff.
The Airbus is also a funny airplane. It doesn’t have the typical ailerons. It has spoilerons. So they only go up. Not down. Crosswind landings are never pretty in an airbus. And on takeoff it can be challenging to keep the nosewheel on the centerline. You basically are treating the airplane like a Tailwheel airplane. Working the rudders. And in the airbus you are Not putting in aileron. Took a long time to get used to that.
The 321 holds 197 people. Not a Heavy. But still a fair size airplane. Climbs like a pig.

[seafeye]

Here is Airbus‘ recommendation on aileron use during takeoff.....

“The traditional use of upwind aileron is not recommended. In strong crosswind
conditions, small lateral control sidestick input may be used to maintain wings level.

Excessive lateral input causes spoiler deployment, which increases the aircraft’s tendency
to weathervane and increases drag.

If some lateral control has been applied on the ground, center the sidestick during rotation
so that the aircraft becomes airborne with a zero roll rate demand."

[Zeke]

Originally Posted by seafeye

Here is Airbus‘ recommendation on aileron use during takeoff.....

“The traditional use of upwind aileron is not recommended. In strong crosswind
conditions, small lateral control sidestick input may be used to maintain wings level.

Excessive lateral input causes spoiler deployment, which increases the aircraft’s tendency
to weathervane and increases drag.

If some lateral control has been applied on the ground, center the sidestick during rotation
so that the aircraft becomes airborne with a zero roll rate demand."

Sounds good to me...


...now, what's that in English?

[seafeye]

Basically you can add wind correction during the takeoff roll but you should remove it when you rotate.

The aircraft that hit the sign may or may not have had crosswind correction. It could have been just really bad luck that at the point he rotated they got a gust and the wing dropped and hit the sign.

I’m sure they have already reviewed the FDR (Flight Data Recorder) so they will know exactly what control inputs were made. The whole aircraft is fly by wire and everything is recorded.

[rcooled]

[bkreigsr]

Also not a pilot, but, FWIW, wind gusting to 70 mph yesterday. Lots of power outages and trees down in our neck of the woods.
Bill K