- Air Canada Flight 759 attempted to land on a taxiway at SFO.
- The incident could have been a major aviation disaster.
- Smith explains how the Air Canada pilots could have made such a mistake.
Editor's note: Patrick Smith is a commercial airline pilot who currently flies Boeing 757 and 767 aircraft. Smith also runs the blog AskThePilot.com and is the author of the book "Cockpit Confidential."
On July 7, an Air Canada jet nearly landed on a busy taxiway at San Francisco International Airport, apparently mistaking the taxiway for runway 28R. Taxiway C, as it’s designated (“Charlie,” pilots would call it, using the phonetic alphabet), runs parallel to the runway on its north side.
At least four other planes were on the taxiway at the time. At the last minute, the pilots of flight AC759, an Airbus A320 with 140 people aboard, broke off the approach and climbed away.
This could easily have been disastrous — something akin to the USAir crash in Los Angeles in 1991. Luckily the Air Canada crew, aided in part by startled pilots on the taxiway, realized in time that they were lined up incorrectly.
What happened in 1991 was an air traffic controller’s deadly mistake. What happened the other night in SFO appears to be straightforward crew error, the million-dollar question being how the pilots got into this situation in the first place. Runway 28R is equipped with the standard electronic landing aid (ILS) and fancy approach lighting found on most major runways. The aiming point should have been pretty obvious.
That said, San Francisco has its quirks. Only about 300 feet separate runway 28R from taxiway C, and approaches into SFO are often busy and very high-workload. Also, non-precision approaches to this runway are common, and sometimes the ILS isn’t used. I land on runway 28R all the time, and the most common approach is something called an “RNAV visual,” a hybrid procedure in which the final segment is flown visually, with no runway-specific guidance from the instruments. You can transition to the ILS in those final seconds, but this isn’t always done. And, it was midnight. Maybe fatigue played a role.
Another factor is that the parallel runway, 28L, was closed that evening, with its approach lights turned off. Pilots landing at SFO normally expect to see a pair of runways, laid more or less next to one another. Perhaps they mistook 28R for 28L, which would have been dark, and saw taxiway C as 28R.
I landed on runway 28R two nights ago, right about at dusk. Runway lighting and taxiway lighting are very different, and this, among other things, should have been a huge clue For Air Canada. They should have broken off the approach a lot sooner. But as we descended toward the threshold, I couldn’t help thinking: taxiway C does indeed resemble a runway!
Those aren’t excuses, but under the right set of circumstances, what happened isn’t totally beyond the pale. And there had to be some external contributing factors aside from pure recklessness on the part of the pilots.
How close a call was it? That would mostly depend on how far out the A320 was — distance from the threshold and altitude — when the crew began the go-around maneuver. Early on, reports said the plane never got lower than 350 feet above the ground. That’s the height of a 30-story building and would represent fairly adequate clearance. The voices on the recordings, meanwhile, show concern, as well they should, but remained measured and calm, suggesting a catastrophe was never imminent.
However, investigators are now saying the Air Canada crew flew a full quarter of a mile along the taxiway before beginning a climb, and came within 55 feet of a taxiing United jet’s tail. If so, that’s downright alarming, and about as close a call as you can have. How and why the crew got to that point, and why air traffic control didn’t notice their mistake and alert them sooner, is unclear.
Also unclear is why air traffic control didn’t notice the pilots’ mistake and alert them sooner. In the controllers’ defense, however, the taxiway and the runway are close together, and they would’ve been watching from a considerable angle, throwing off the perspective. I’m not sure their radar would have shown anything too worrying either, at least until the final seconds. Planes sometimes zig and zag a bit on final approach. And, after a clearing a crew to land, you more or less take it for granted they will know the difference between a runway and a taxiway.
As they approached the airport, the pilots queried air traffic control about traffic on the runway. They saw something that concerned them. The tower’s reply, that the runway was clear, may have given them a false sense of security and encouraged them to continue. They should not have gotten as close as they did, but it can be very difficult to see other aircraft on the ground at night, even when those aircraft have all of their appropriate lighting on. Just ask the USAir crew than ;landed on top of that plane at LAX.
Runway numbers correspond to the strip’s magnetic orientation. Just add a zero. Runway 28 is aligned 280 degrees — just a smidgen north of due west. The opposite end would be runway 10, pointing 100 degrees. Runways laid in parallel also carry a left or right — “L” or “R” — suffix. SFO’s runway 28L was the one on which an Asiana Airlines 777 crash-landed on July 6, 2013 — four years before Air Canada, almost to the day.
