Reducing Runway Incursions

Making Airport Diagrams (10-9 page) Usable. Some of the low hanging fruit of Aviation Safety.

Left is the Current chart, right is the proposed chart.

One powerful way to reduce runway incursions is to keep airline captains focused outside the cockpit while moving. That means minimizing attention spent inside the cockpit such as reading charts. One dramatic improvement with my airline was requiring the after start checklist be completed prior to taxiing.

One area remains, though, that pilots have to look at while taxiing—the airport diagram. For most airlines that is Jeppesen's 10-9 page. And it could use a lot of improvement. The airline doesn't produce these charts but, as a major customer, it should push for improvements.

The goal must be to minimize how long pilots must look at the chart to decipher instructions. A number of visual tools can be employed that have been incorporated in the modified example. It's a given that pilots should try to understand taxi instructions before moving, but sometimes instructions are given, or must be verified, while moving.

To the right, on top, is the current FLL 10-9 page and below that is a modified one. Look at the two diagrams and see which one is quicker to understand the sample instructions. Remember, except for the initial call, a captain may be taxiing the airplane while getting instructions.

Southwest flight 1 is parked on the far east side at terminal one. A crew is getting ready to taxi and gets this:

“Southwest 1, taxi to runway 9L via T, T5, S, hold short of taxiway Q”.

Consider also this one. The flight just landed on runway 13. The crew will most certainly be moving when this instruction comes in.

Southwest 1, turn left when able, left on Delta. Taxi to your gate using Sierra, Bravo, enter the ramp at T2.

Look at both charts to see which are easier to use. Of the pilots I've showed these charts to the answer has been immediately that the second one is.

The pilot is going to take much less time looking at the modified chart to figure (or re-figure if given new instructions while moving) his route. Given the FAA's appropriate emphasis on minimizing runway incursions, that is an important outcome. 

Other elements that could improve usability.

1. Increase the airport diagram size by eliminating surrounding airport features. How many pilots use these charts to know about items such as trees, roads, etc., near the airport? The answer is very few (none that I've talked to). We use them to taxi. The current full chart  gives up 20% of it's width to airport surroundings—valuable chart real estate. Bordering information may be valuable for studying the chart beforehand, but gives up clarity in its primary function, understanding taxi routings especially in a dimly lit cockpit.

2. Use visual icons for the most common taxiway notes. Icons can be overused but, in this case, they can help. The max wingspan notes are the best example since pilots will recognize quicker the need to check if they can use a taxiway. The most common values are max weight and max wingspan (or aircraft model). There's never a minimum wingspan so, if the pilot sees a wing icon with 112' in it, he knows immediately whether or not the note applies to him and can go on to read the rest of it. Importantly, this reduces clutter, too.

3. Further reduce clutter by putting runway numbers in the runway and terminal descriptions in the terminal using white on black.

4. Further reduce clutter by avoiding word descriptions of obvious things wherever possible such as VOR's. Every pilot knows the standard VOR symbol so the word "VOR" is superfluous and adds to clutter. Clarity is improved by having secondary information, such as buildings in a lighter shade of gray.

It's true that charts fall outside the control of the airline but we are, after all, the customer. And we pay dearly for this service—we can have some input. In all likelihood, Jeppesen (Boeing) wants to have a good product but they are like any other business, not wanting to spend money on changes unless the customer really wants them to.

Thanks for listening.

Jeff Goin
Captain, 737

Benefits: Taxiways are much easier to find and follow. Tower and ground frequencies are easy to find. Relevant maximum sizes for taxiways are rapidly found or, just as important, ignored.


Taxiway Design Principles

Design principles for readable taxiway markings.

1. The letters themselves should indicate the direction of the taxiway by their alignment. There is a lot of value to quickly seeing that taxiway Bravo goes East/West because of how the B's are placed. Letters should be as evenly spaced as possible--humans pick up quickly on patterns.

2. The letter should be on the taxiway as much as possible. It's too easy to confuse one with another when they are off to the side, primarily when other taxiways are nearby.

3. If the angle is less than about 30° to horizontal, then the letter should be angled with the taxiway. This angling, on its own, helps determine quickly which taxiway the letter applies to. Taxiways that angle more than 45° should have their letters be aligned vertically to the page but follow principle 1. In between those angles, other factors must be considered—a design element that takes a good human eyeball.

4. You should not have to hunt for a taxiway designator when clearing any runway. They should be obvious and large.

5. Make the taxiway letters larger. They are the most important element, we should be able to see them clearly and quickly. Seeing the designators is much more important than seeing the roadways that surround the airport.


© 2016 Jeff Goin & Tim Kaiser   Remember: If there's air there, it should be flown in!