Brainlock

I was all set to get a new blog up, early this morning. It finally rained last night so I didn’t have to water my flowers. But I made the mistake of checking the news first and I ran into an editorial from Mary Peters -- Secretary of Transportation. Go ahead and read it if you like.

End Gridlock on the Runway

Between writing a comment for it at The Times and playing Mr. Mom, I’m running behind as usual.

As my readers would suspect, Ms. Peter’s editorial is more of the same deregulated, “free market” ideology from the Bush Administration. It’s the same kind of thinking that has led to the financial disaster in the banking industry. It’s not enough that we’ll be bailing out Bear Stearns, IndyMac, Freddie Mac, Fannie Mae and whoever else collapses. We’ll be bailing out the airline industry too. Or should I say, again ? (Hint: That link is interesting in more ways than one.)

I’ve been over this ground before but I guess it’s time to do it again. I’ve been trying to write a coherent piece that is 650 words or less but until I do, you’ll just have to put up with the blog equivalent of thinking out loud.

Slot controls work. History has proven it over and over again. Just like any other policy, they need to be well thought out and and administered effectively. The current slot restrictions at the New York area airports (EWR, LGA and JFK) aren’t doing the job because they are not restrictive enough.

I hate math but it all boils down to the math so let’s run the numbers. I’ll use JFK (Kennedy International at New York) for an example but the equation works for any airport.

JFK’s arrival rate fluctuates anywhere between 68 arrivals per hour all the way down to 17 per hour. Actually, it can go all the way down to zero per hour if the weather is bad enough. Therein lies the key to understanding the concept. Basing the number of arrival slots on the absolute worst weather imaginable is just as dumb as basing the number of arrivals slots on perfect weather. We need to think in terms of variable weather and what the average airport arrival rate is over the long term. If you would like to make it complicated, you can adjust the average arrival rate by seasons. Assuming winter weather is worse than summer weather (for airplanes, not for people) we could adjust “the number” seasonally. The fundamental principle remains the same -- limit the number of arrival slots to a sustainable rate in variable weather conditions.

Just to add to the confusion factor, the FAA uses two different terms when talking about slot restrictions. There’s the arrival rate per hour and then there is the number of operations per hour. It’s simple to handle if you’ll just keep in mind that an arrival -- sooner or later -- will become a departure. Each -- an arrival or departure -- takes up time on the runway. Each takes up a slot.

Currently, JFK is limited to 81 operations per hour. If we just pick the first number from the JFK arrival rate chart you’ll see that the IFR arrival rate is 38 and the VFR arrival rate is 49. In simple terms, IFR means bad weather and VFR means good weather.

Remembering that arrivals + departures = operations, we get the following numbers.

IFR: 38 + 38 = 76

VFR: 49 + 49 = 98

If the weather is good (VFR) JFK will have 17 unused slots. 98 (VFR slots) minus 81 (actual slot restrictions) equals 17 unused slots. This makes the airlines and the airport operators crazy. That is 17 airplanes per hour that could have been carrying paying passengers and 8 and 1/2 airport landing fees per hour that the airport operator (The Port Authority of New York and New Jersey in the case of JFK) didn’t get to collect. It’s 8 and 1/2 cities that don’t get hourly service to JFK. As I hope you can readily see, this is where the pressure to increase landing slots comes from. Think of the unused capacity lost. The sheer inefficiency of it. The lost profits. The Horror !

Now that we have the dramatics out of the way, let’s look at the other side of the equation. If the weather is bad (IFR) you have 81 operations per hour scheduled at an airport that can only handle 76 operations -- or less. 81 minus 76 leaves us with 5 airplanes waiting to take off. I know what you’re thinking. You’re thinking that there are actually 2 and 1/2 airplanes trying to land and 2 and 1/2 waiting to take off. But you would be wrong. Airplanes running out of gas -- while airborne -- is bad for business. Arrivals take precedence over departures and if push come to shove (and it always does), the departures will wait while the arrivals use the slots.

But I want to fair about all this. I want to be more than fair. Let’s say we keep 2 arrivals circling in a holding pattern while we use 2 of the 5 slots for departures. Now we’ve got 2 arrivals waiting in the air and 3 departures waiting on the ground. No problem, we’ll just put them in the next hour’s slots. Surely they have enough fuel to hold for an hour or less. The only problem you have is that 81 more operations are scheduled in the next hour for your now-76-operations-per-hour airport. Don’t worry, we’ll get the 2 previously holding in the air on the ground. But at the end of the hour we now have 4 arrivals in the holding pattern -- at best. And if something doesn’t change it will grow to 6 in the next hour, 8 in the next and on and on and on. Not to mention the ( 3+3+3+3 =) 12 departures waiting to take off.

For those that do like math, go back to that JFK arrival rate chart and start running the numbers for all the different runway configurations. Consider the fact that last year the airlines were scheduling over 100 operations per hour during certain periods of time at JFK. Plug that number into the equation and then consider how many passengers were left stranded, the lost productivity and the impact on safety. Then you’ll understand why people in aviation were using the term meltdown. Air traffic controllers had airplanes stacked up in holding patterns like cordwood and the taxiways looked like parking lots. Meanwhile, passengers waited for hours in airplanes with no food, no water and overflowing toilets -- looking for a slot that disappeared into a cloud, a thunderstorm or a fog bank.

Running the numbers is the simple part of the real equation -- the real question. Do you want stable, reliable air service or do you want gridlock ? More airplanes per hour means less reliability. Less airplanes per hour means more of our cities won’t have any service at all. More airplanes per hour means cheaper tickets. Less airplanes means more expensive tickets. It’s a decision that must be weighed and measured. And it must be made.

I know which side I’m on. Safety tips the scale for me every time. Limit operations to the average sustainable IFR rate and accept that we lose some capacity. It keeps the system predictable, it minimizes delays and it enhances safety. It also raises ticket prices. I can accept that. I believe it will help stabilize airline profits. That should help raise the wages of airline employees, and in my book, that’s a good thing. If you’ll think it through, there are a lot of good things that can come from a stable and profitable air transportation system.

Oh, by the way, in case you forgot ? Ms. Peters’ slot auction scheme ? That is what happens when you try to twist the facts to fit your ideology -- you get brainlock.

Don Brown
July 22, 2008