May 2, 2011
Air traffic controllers have been in the news several times in the past month. First came the “asleep in the tower” stories at Washington National Airport and Reno, Nevada. Then the First Lady’s airplane had to go around at Andrews AFB because it was too close to other traffic. The 24-hour news monster has already moved on to the next “shiny object” (the Royal wedding), but I thought I’d share my thoughts anyway.
I was as surprised as anyone about the traffic controllers; I always assumed there was more than one guy in the tower at all times. Still, the comments I heard from the pundits on TV and radio had me shaking my head. There seemed to be a worry that pilots had to land without the security blanket of ATC, and I heard the phrase “landing blind” more than once.
The tower controller (aka Local Control) has jurisdiction over the runways at the airport. He or she clears planes to take off, land or cross any active runway. It’s important, especially at busy airports, but there are hundreds of airports in the country that are not served by a control tower, and pilots manage to sequence themselves for takeoff and landing just fine. In the wee hours (the period during which the DC and Reno controllers were asleep), there is very little traffic, and the danger posed by “do it yourself” is minimal.
At uncontrolled fields, pilots approaching the airport announce their position and intentions on a VHF frequency set aside for that purpose. It might be a Unicom frequency serving several small airports in the area, or a specific frequency for that airport called a CTAF (Common Traffic Advisory Frequency). The airlines don’t fly into many uncontrolled fields, but they do exist. When I worked for United Express, two uncontrolled fields I routinely flew into were State College, Pennsylvania and Shenandoah Valley Regional airport in Virginia.
I’m not trying to minimize the seriousness of falling asleep at the switch, but it just wasn’t as dire or life-threatening as some reports led you to believe.
The second story was even less serious, and shouldn’t even have made the news. Michelle Obama was on a plane coming into Andrews AFB, just outside Washington, and had to execute a go-around because her plane was too close to the plane in front of it.
First of all, “too close” doesn’t mean there was danger of them exchanging paint. It just means that someone was concerned that the first plane wouldn’t be clear of the runway before the second plane touched down. The rule is only one plane on the runway at a time.
I would be surprised if you could find any pilot who hasn’t had to go around at some point. It doesn’t happen to the airlines very often (or to planes carrying the First Lady, I’m sure) because the controllers and the pilots try hard to avoid it. But it does happen every day, at airports all across the country.
There are a few possible scenarios that typically lead to a go-around. The first is when the controller is a little overzealous in trying to squeeze in arrivals. I’ve seen it on a handful of occasions where a controller, trying to keep the arrival rate up, vectors a plane in too close behind another one. Again, not dangerously close, but close enough that it becomes obvious at some point that it’s just not going to work out. Result: go around.
Other times, it’s strictly the pilot’s fault. A controller will often point out preceding traffic to us, and if we call it in sight we are likely to receive the following clearance: “Maintain visual separation from that traffic, cleared for the visual approach to Runway 31L.” If we accept that clearance, the burden is now on us to maintain adequate distance from the preceding plane so that it can land and clear the runway before we touch down. If we get too close, the controller will tell us to go around.
The pilot of the first plane can also mess things up by slowing unexpectedly during the approach. At busy airports, the controller issues exact speeds for the planes to maintain, and anyone who deviates from these speeds can ruin the flow. The approach clearance will often contain a final speed restriction, like “Cleared for the visual approach to three one left, maintain a hundred eighty knots to MEALS.” (MEALS is an intersection 5.4 miles from the end of the runway at JFK airport.) Occasionally we’ll get someone who slows to final approach speed too early, and, you guessed it: another go-around for the following traffic.
The last possibility is that the preceding traffic just doesn’t clear the runway expeditiously. At busy airports, the controllers are very sharp, and they expect the pilots to be on their game too. They know our capabilities and how much runway we need to land, slow and exit the runway. Occasionally a pilot surprises them by rolling out to the end of the runway, throwing a wrench in the beautiful arrival flow the controller has established. Some unlucky innocent on final approach has to go around.
I don’t know what happened with Mrs. Obama’s plane, but I’m pretty sure she was safe the whole time. A go-around is inconvenient, but it’s also routine.