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That Runway Incursion at JFK: What Went Wrong and Right
One more illustration of calm, quick competence under pressure.
The purpose of this post is to provide a clearer guide to what happened on Friday at John F. Kennedy airport in New York, where controllers had to intervene at the last second in a potentially catastrophic situation.
As with everything in aviation, it takes a while for the facts to be known and the right lessons to be learned. (Update: since posting this, I’ve learned that the initial part of one plane’s taxi path might be different from what I lay out here—a counter-clockwise rather than clockwise course. The fundamentals of the story remain the same.1) But here is what seems knowable at the moment, based mainly on air-traffic control tapes that I have found through this Twitter link, which includes an animation of aircraft positions via Flight Radar 24.
Below I’ve quoted what’s available in radio transmissions among several controllers and several pilots. Again, you can listen to the audio for yourself here. The controllers are from “Kennedy Ground,” which gives pilots taxi instructions, and “Kennedy Tower,” which gives them clearance to take off. The pilots are from “American 106 Heavy,” which was bound for London, and "Delta 1943,” headed to the Caribbean.
The annotated transcript will refer to the Kennedy Airport taxiway chart, below. The background chart is from the invaluable Foreflight, of which I’m a longtime subscriber and user. The annotations are from me.
Here’s what you’re looking for:
The American plane starts out near the top of the image, at the “Tango Alpha” intersection, which is marked at “TA” on the chart.
The taxi route it’s supposed to follow, to its position for take off, is the light green line, circling around in a big right-hand turn. [Please see footnote below for an update, about whether instead it made a big left-hand turn.] That whole line follows the circular “Taxiway Bravo,” marked as “B,” at JFK. Eventually the plane is supposed to take off in the direction shown by the magenta arrow, on Runway 4 Left. The magenta arrow is the path of the Delta plane that had been cleared to depart.
The place where several arrows intersect is where the American plane turned left, and went across Runway 4 Left, as opposed to going from taxiway Bravo to taxiway Kilo (K). It did so just as the Delta plane was beginning its takeoff roll.
That’s the problem.
Let’s go to the tapes.
Here is my transcription of what is initially available from ATC. Two very important caveats.
-One is that these are clearly not in real time. In reality it would have taken the American plane several minutes from first being cleared to taxi, to getting the clearance to “Cross Runway 31 Left.” On the tape, these transmissions come back-to-back.
-The other is that we don’t know what’s not in these tapes, and what else might have happened. But here is what they contain, with my notations in brackets and itals [like this]. I’ve assumed who the speaker is in each case but could have missed some.
Now, the ATC transcript and the notes.
American pilot #1: Ground, American 106 Heavy, Tango Alpha for taxi.
[This is standard formula when a plane is ready to taxi toward the takeoff area. The pilot identifies her plane with its flight number, including “heavy” for the largest airliners, like this Boeing 777. “Tango Alpha,” shown as TA on the chart, is where the plane is starting.
I’m listing the American pilots separately because a different one weighed in later.]
Ground controller: 106 Heavy, Kennedy Ground, Runway 4 Left, Taxi Bravo, hold short of Kilo. [These again are familiar instructions, boiled down to their terse minimum because it’s such a busy airport. The controller is saying that the plane should taxi to Runway 4 Left; that it should taxi along taxiway Bravo; and that it should stop — “hold short” — and await further clearance before proceeding onto the Kilo taxiway. ]
American pilot #1: Hold short of Kilo, American 106. [As a safeguard against runway incursions, pilots are required to “read back” — repeat to the controller — all “hold short” instructions. The pilot is not required to read back the rest of the instructions. Though in the circumstances it probably would have helped if she had read back “Runway 4 Left.”]
Kennedy Ground; American 106 Heavy, cross Runway 31 Left at Kilo.
[In real time, this message would have come a few minutes later. What the controller intended here is again routine. As shown in the image above and the small portion below, the idea was for the American plane to keep going along the green line, toward the takeoff end of Runway 4 Left, as the taxiways changed from Bravo to Kilo. This would involve crossing one end of another runway, 31 Left. The controller was confirming clearance to cross that runway and proceed.
The full tapes will make clear where the American plane was when it got this instruction. But what happened next was that rather than proceeding onto Kilo, American 106 turned onto taxiway Juliet (J), which took it across the active runway, 4 Left.]
American pilot #1: Cross 31 Left at Kilo, American 106 Heavy. [Note that American confirmed a clearance to cross Runway 31 Left, as intended. But in fact it turned and crossed Runway 4 Left. ]
Kennedy Tower controller. Delta 1943, wind 350 at 18 gust 24, Runway 4 Left cleared for takeoff. [Now we’re hearing from another controller, one who clears planes for takeoff and landing. This all is routine: Giving the plane’s identifier, giving a wind reading, naming the runway for takeoff, and issuing the clearance.]
Delta pilot: Cleared for takeoff, runway 4 Left, Delta 1943.
Voices of many controllers, all at once: S^*%!!! F&#)!! [The controllers are seeing, with their eyes and on their screens, that the American plane is crossing the runway in front of the departing Delta flight.]
Kennedy controller, urgently: American 106 Heavy—American 106 Heavy, hold position!!! American 106 Heavy, HOLD POSITION. [This is probably a ground controller, still in touch with American, and wanting them to stop moving.]
Kennedy controller, also urgently: Delta 1943, cancel takeoff clearance! Delta 1943, CANCEL TAKEOFF CLEARANCE! [This is probably a tower controller. The Delta pilots are pushing the throttles forward for full takeoff power. There comes a point when a plane cannot safely abort a takeoff. It’s going too fast; there’s not enough runway ahead. The controllers are judging that it’s still early enough to order them to stop—as they in fact did safely.]
Delta pilot; Rejecting. [That is all he says, using the aviation lingo to confirm that he is cutting the power and aborting the takeoff. If he had wanted to say instead that it was too late to comply, he would have said “Unable.” The two Delta pilots are going through a “rejected takeoff” drill they review as part of the pre-takeoff briefing for every flight. But in real life it doesn’t happen very often, and they have a lot to handle.]
[I am omitting here follow-up discussions between the Delta crew and the controllers, about their needing to return to a gate.]
Kennedy controller: American 106 Heavy.
American pilot #1: 106 Heavy, go ahead.
Kennedy controller: American 106 Heavy, possible pilot deviation, I have a number for you. Advise ready to copy. [The controller says this very calmly, but in the aviation world these are consequential words. “Possible pilot deviation” means possible violation of FAA rules, with real implications for professional pilots. “I have a number for you” is a sentence you never want to hear.]
American pilot #1: Ready to copy.
American pilot #2: Tower, American 106 Heavy. [This is a different voice from the American cockpit, presumably the other pilot This pilot is saying that he wants to ask the controller a question.]
Kennedy controller: American 106 Heavy. [This means, “go ahead.”]
American pilot #2: The last clearance we were given, we were cleared to cross, is that correct? [This pilot is clearly registering the news about “possible pilot deviation,” and confirming that they had just been cleared to cross a runway. Unfortunately, it was a different runway.]
Kennedy Controller: American 106 Heavy, we’re departing runway 4 Left. I guess we’ll listen to the tapes. But you were supposed to depart 4 Left. You’re currently holding short of runway 31 Left. [What he is saying is, “You crossed the wrong runway and are in the wrong place.” But it is as matter-of-fact as imaginable. “I guess we’ll listen to the tapes” reflects the awareness of everyone in the air-traffic world that whatever they say and do is on the “permanent record” and will be reviewed.]
American pilot #2: Roger, American 106 Heavy. [He is realizing what happened.]
There is still a large amount we don’t know. About what was happening in that American cockpit, and how a two-pilot team missed the taxi instructions and mixed up which runway was which. About what was happening among the Kennedy control team, and when exactly they realized where the errant plane was heading. About what practices and safeguards will be revised, to reduce the chance of this ever happening again. Because we know that the aviation world is ruthless about learning from its mistakes. And the stakes are high: the highest-fatality airplane disaster in history involved a similar confusion about runway clearances.
I think we do know that the Delta crew responded skillfully under life-and-death pressure. And so did the Kennedy controllers when they recognized what was about to occur.
Since taxiway Bravo is circular, some reports indicate that the plane took the opposite, counter-clockwise route to the departure area, as shown below. This would alter the angle at which the plane approached the fateful Bravo/Kilo intersection, but it does not change the fact of a profound mistake.
Whichever way they approached on the green path of the Bravo taxiway, this is what they would have seen immediately in front of them, after receiving the clearance to “Cross Runway 31 Left.” This is a screenshot of the actual JFK intersection from Google Earth. It shows the familiar red marking that means YOU ARE ABOUT TO CROSS A RUNWAY, and it shows that they were about to enter “Runway 22 Right / 4 Left.”
Each runway has two names, depending which direction you’re going. They always differ by 180 compass degrees, shortened to a difference of 18 in the runway number. Thus an east-west runway will be “Runway 09 / 27.” A north-south one will be “Runway 18/36” and so on. Right and Left, or sometimes Center, are added when there are parallel runways, as in this case.
This sign showed they were about to cross Runway 4 Left (22 Right), which is not the one they had been cleared for.