Understanding the Near-Collision at JFK

An air traffic controller saw the potential conflict and said, according to ATC recordings, "Shit! Delta 1493 cancel takeoff clearance." The Delta pilot, who might have seen the AAL 777 milliseconds prior to the controller's call, was quick to pull back the power and get on the brakes. The 737 stopped a reported 1,000 feet before where the AAL 777 was situated. Would the planes have collided had action not been taken? It's a frightening and very real possibility.

Why the great concern when no collision took place? The FAA refers to such mistakes as "runway incursions." The agency has gone to great lengths in recent years to combat this kind of potentially catastrophic ground conflict---in the old days, a majority of the responsibility was on the pilots, by following taxi clearances to the letter. While that's all well and good, mistakes were being made, so the FAA has wisely instituted new methods to help prevent mistakes from happening. Today, in addition to controllers issuing mandatory taxiing, takeoff, and landing orders to the airplanes they are overseeing, the FAA has also instituted new runway and taxiway markings, put traffic light-like signals at some problematic runway intersections and changed the way that controllers talk to pilots, all to mitigate confusion in what is arguably the riskiest part of any airline flight, that when the airplane is still on the ground. 

It can be truly perplexing. At these biggest airports, the multitude of runways and taxiways can confuse even the most experienced crews, and if they taxi onto an active runway without clearance, as appears to be the case with last Friday's near-collision, it is considered an error of the highest magnitude.

And the FAA's concern is well founded. The deadliest crash in aviation history was just such a runway mishap when a pair of 747s at Tenerife in March of 1977 collided in the fog as one was taxiing on the runway and the other was taking off in the opposite direction. In that horrifying crash, 583 people lost their lives.

When jets take off, they need to accelerate to high speeds, and when they are heavily loaded with passengers, cargo and fuel, that number is even higher. It's a double whammy, as the heavier the plane is, the longer it takes for it to stop on the runway, too. Split seconds can mean the difference between hundreds of lives lost or none. The fast action of the controller and the Delta pilot very possibly averted just such a tragedy.

Video: Boeing 757 goes off runway in Costa Rica, breaks apart