PlasticPilot.net

The recent accidents involving British Airways Boeing 777 in London and Kalitta Air Boeing 747 in Brussels both occurred really closed to the airport perimeter. One was landing, and the other was taking-off, but both were close to crash outside the airport. The Kalitta one is probably even slightly out, and the nearby railway had to be temporarily closed.

The pictures below show how close to off-airports accidents these cases are.

Each accident raises an endless list of “what if ?” questions. In these two cases, there was a special focus on “what if it had been longer / shorter”. Thanks to Google Earth, it’s rather easy to answer these questions. I measured the distance from the runway threshold or runway end to the next building (roads, parkings and railways excluded).

In Brussels, the first building in the axis of runway 20 is as 1.2 kilometers, and in Heathrow the last building before landing is at 1.0 kilometer. On standard ILS approaches, planes descend by 52 meters for each kilometer flown. Climb rates are much higher, and strongly variable, depending on aircraft type, load, and weather.

Both Heathrow and Burssels are in relatively dense areas. To compare, I measured the same distances for various airports and runways:

This little survey is not a safety benchmark, but is intended to show the how varied are airport implantations throughout Europe. Tempelhof (which is about to be closed) and Madrid are certainly exceptions. An airport like Madrid with nothing around might seem better, but this has its counterpart: even with a taxi, a transfer to city center takes 30 minutes.

If you want to measure distances between your home and the landing point, do it to threshold, or to the touchdown zone. Many runways have displaced thresholds - planes can’t land at begin of runway, but only after the numbers.

This is to make sure they come in high enough if they are roads or other things to protect before landing, to avoid things like what happened to this Iberia plane.

Geneva runway 05 threshold is displaced by 330 meters. The part of runway which I highlighted in red can be used to take-off run only. This ensures that approaching planes fly with sufficient height over the public road highlighted in blue.

So next time you’re on an airliner and wonder why your pilot did not landed at runway begin, you’ll know why. Ok, sometimes they also just land loooooooong by mistake.

I can’t finish this post on landing distances and what’s shortly before the airport fence without mentioning the famous Princess Juliana airport, in St-Marteen. This is where some of the most famous airplane photos have been taken, picturing Boeing 747s approaching low over the beach. There’s displaced threshold as well, it’s anyway impressive. I have to go there one day…

If you have kids, you know how important (and hard) it is to explain them to cross roads at the zebra-crossing only. What has this to do with aviation ? It’s all about runway markings, kids, and Toulouse Airport…

Someone working for the french ATC told me this story a couple of years ago. A group of kids living east of Toulouse Blagnac airport (home of Airbus) had to walk daily to their school, west of the airport. A rather long walk so when they found a hole in the airport perimeter fence, they were quite happy.

After a couple of days, they got caught by the security service, and were severely sermoned by the guys in charge. To plead their cause, the kids told that they were really careful, and always crossed the runway at the zebra. If you’re a pilot you probably already got it, if not you’re may be a bit lost.

There are several markings on runways, to guide pilots. The centerline (where the nose-wheel is supposed to be…), the touch-down zone (where the main wheels should normally get in contact with the ground… softly), and the threshold (from where the runway is usable for landing).

The picture below shows the threshold of runway 32 Right in Toulouse - the one the kids were crossing. According to ICAO requirements, the threshold is materialized by a series of parallel markings across the runway. One must admit that it seriously looks like a Zebra crossing.

The hole in the fence got fixed, and the kids had to walk around again… For this time, the “I crossed at the zebra” excuse did not worked. Sorry kids.