Near-collision at JFK 1/13 brief

[foggydogg]

Juan Braun is a 777 pilot for American, but is careful to never mention the company in his postings. He also flies the London route.

[abscate]

I thought taxiing airplane on wrong route when I first heard this, there is no way an aircraft is going to roll Runway 4L at JFK before clearance. Looks like that was the case.

End of someone’s career rise for a few years at least

[foggydogg]

I thought taxiing airplane on wrong route when I first heard this, there is no way an aircraft is going to roll Runway 4L at JFK before clearance. Looks like that was the case.

End of someone’s career rise for a few years at least

Delta cockpit crew looks like they were right on top of it; when ATC cancels takeoff clearance, the reaction should be automatic. The same thing is true when enroute Center tells a pilot to make a course change "immediately" it means cessation of all thought, push the appropriate rudder pedal, bank that direction, and ask questions later.
Mr. Braun gives a good explanation of the rejected takeoff braking system.
Once the turbines spooled down from takeoff power they would have had reverse thrust (Beta means something different in the jet aircraft world ), unless they were going fast enough that the squat switches in the landing gear had unweighted.
1,000 feet travelling at 120 in a loaded 737 would take 5.7 seconds by my calculation. Rotation would likely have been at around 135, and they would have been committed to fly at that point.

[BlackBart]

This brings to mind the Tenerife collision of two 747s. Fog, bad visibility, no ground radar, overcrowded, unfamiliar small airport. They let two different 747s taxi down the only runway as the taxiway was clogged with waiting planes. The first one was to turn 180 at the end and wait for takeoff clearance, the second one was to turn off the runway onto a taxiway and make it's way to the end of the runway to go next. The lead plane thought they had clearance to take off, or were impatient and jumped the gun. The trailing plane was confused in the fog and missed their taxiway. The first plane started their run and in the fog plowed right into the side of the second plane as it was turning to get off the runway. 583 fatalities.

https://en.wikipedia.org/wiki/Tenerife_airport_disaster

Tenerife-diagram.jpg (343.09 KiB) Viewed 589 times

Primary causes were the pilot taking off without verifying clearance, poor radio communications, inaccurate radio language, and no visibility.

[abscate]

You won’t find runways being used as taxiways in US airports. You land, you get the hell off.

Mr. Braun gives a good explanation of the rejected takeoff braking system.

I learned cool stuff about RTO there.

The comms were cool.

ATC: “ Delta cancel takeoff clearance”

Delta: Rejected


That Tenerife diasaster left it’s mark on us, even today , in several ways.

The use of OK or Roger as acknowledgement of transmissions was stopped.

Old way

United 777 Heavy, taxi to end of Runway 4K, hold for takeoff

United hears “ taxi to end if Runway****** takeoff

“ OK”

The word “ takeoff is only used for actual clearance or cancellation , the word departure is used instead.

So

Tower : “United 777. , taxi to Runway 4l and hold for departure.”

United has to respond :” Taxi 4L and hold, United 777”

Or else the Tower repeats.

Delta gets a pass on the” rejected “ above”

[BlackBart]

So many mistakes, assumptions, misunderstandings.

"The chain of events which led to the crash turned out be absurdly long. Neither plane was supposed to be on Tenerife in the first place; they diverted there after the closure of Gran Canaria. The way the KLM plane was parked prevented the Pan Am jet from taxiing past, even though they were ready to leave much earlier. The efforts to find all the KLM passengers and take on more fuel delayed the departure of both planes until after the arrival of the island’s notorious fog, which restricted visibility and forced all parties to rely on radio communications to coordinate their movements. And then a long series of misunderstandings occurred, as the Pan Am crew, convinced that they would not be ordered onto a taxiway too narrow for a 747, missed their expected exit, and the KLM captain, apparently mishearing a clearance, initiated his takeoff without permission. Two simultaneous warnings that could have revealed his mistake cancelled each other out, causing him to hear neither. That was what happened, but explaining why it happened would prove to be a much more difficult and controversial endeavor."

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