Smart pilots review the runway lengths before visiting an airport to see if the runways are long enough for their planned operation. Early in flight training performance considerations come up and one that is big on the written exam as well as the oral exam is the question of is the runway long enough to land and then take off from again? But, equally as important to consider is the width of a runway.
There may not be a performance chart with curved/sloping lines to follow to come up with a figure of takeoff distance but knowing the width of available runways is important for a variety of reasons:
1. Runway illusions
Runway illusions include narrow versus wide runways in addition to the more commonly discussed, up sloping and down sloping conditions.
Let’s say for the sake of argument that you learn to fly at an airport with a 75′ wide runway. This is what is comfortable to you and what you know. This environment is what your mental sight picture is based upon after approach and approach during training. Next thing you know your instructor takes you to an airport with a 50′ wide runway and you’ll find your palms getting a littl sweaty with so little wiggle room! Similarly, of you are taking a friend flying and want to impress them by visiting a ‘big’ airport, like somewhere that airliners fly you’re likely to encounter a 100′ or 150′ wide runway ,or maybe even larger. That’s twice the width of what you’re used to. What do you do? One option is to just use the left half of the runway, using the left side and the center line of the runway as your mental guides, thus making the runway 75′ wide… obviously that’s not the right answer!
When flying into a runway that is wider than you are used to, you’re prone to thinking you are lower than you actually are. When there is so much runway filling your perifiery, you assume you’re just about to touch down. This causes pilots to flare too high and you guessed it, pancake-slam it onto the runway. The landing gear aren’t going to like that, just a word to the wise.
Conversely, if you’re visiting a runway that is more narrow than you’re used to then you’ll face the opposite and think you’re higher than you really are. As you’re waiting for more runway to fill the windscreen you’ll be nose-wheel landing thinking you’re getting ready to flare… how do you over come those? You have to ‘feel’ it. Use other reference, buildings, trees, the windsock to gauge you’re altitude. Know the file elevation and plan your stabilized approach and planned round out ahead of time. Mentally prepare yourself for these illusions so you don’t fall prey to them…
When I did my flight review earlier this year, I hadn’t flown in quite a while and most of my recent flying prior to that was out of had two runways, both 150′ wide. When the instructor told me we’d be landing at an airport with a long but narrow runway in a crosswind for the first one I was a little apprehensive. the length, about 4000′ combined with the width of only 60′ made for a very odd looking runway surface while I was on final, the runway appeared to be miles long but narrow. You can imagine my delight when our smooth-as-baby’s bottom touch-and-go was in the books. The confidence surge was great too.
2. Crosswind conditions
We always line up with and aim for the centerline of the runway while on final approach. That’s why the centerline is there, for orientation, other wise we’d just have grey slabs of pavement or concrete… Runway width can be thought of as a buffer for crosswind conditions. Proper technique calls for landing on the centerline and sticking it, but often even the best pilots drift a little bit in the wind. Knowing the runway width is very valuable when planning a landing, a stiff crosswind and a narrow runway can make for a bad situation even with the best skills and intentions.
An older pilot, who had done a lot of flying and seen a lot of things once taught me a trick. In heavy crosswind conditions he would line up ina side slip or crab for the upwind runway edge. As he approached to land he would use the conditions to his advantage. As he came out of the crab or lessened the side slip he would allow the wind to ever so gently slide in to the center line for a touchdown on the centerline. Now this shouldn’t be done without practice, but I utilized the technique and it worked quite well. Generally I would line up just upwind of the centerline though so that if I got pushed it wasn’t very far. Too much drift and you’ll find yourself fighting the wind to stay over or on the runways and that wouldn’t be a good situation. Remember to consult a flight instructor before trying that one and practice with a qualified instructor who is comfortable with the plan.
3. Minimum required
For the majority of general aviation aircraft there is no runway width limitation. In fact for a lot of commercial aircraft there isn’t a limitation either but for insurance purposes and to maintain company (operatpr) standards many operating handbooks and manuals for large aircraft require a minimum runway width. This often has to do with having the ability to swing a turn around on a runway,.. if you fly long enough and move to larger aircraft this is certainly a factor you could face and one it’s good to be ready for.
As you can see there are a variety of reasons that knowing a runway width is important. My last tip on this topic is to be careful, not everything is as it appears. Runway width can be determined by a pilot on an approach by counting the number of threshold markings (commonly referred to as piano keys). This information is published in the Aeronautical Information Manual (AIM) and should be known by pilots.
Runways that are served by a precision or non-percision approach are required to have threshold markings. Additionally, runways that serve approach category C or D aircraft and/or international commercial air transport operations are required to have the threshold markings.
Let’s take a look at a couple runways and see how we do… how wide is this runway?
If you guessed 100′ wide you’re correct, 8 “boxes” before the number. These markings line centerline stripes can be solid of striated, as is the case on this runway. The striations promote heating and snow melt during the winter, and also increase operating cost when it comes to pajamas ting due to the detail. The funds saved in paint is often spent on the labor time it takes to line everything up and apply the paint…
How about another runway?
If you counter 12 bars and guessed that Runway 23 is 150′ wide, then you’d be correct. Pictured is Runway 23 at New Bedford Regional Airport.
Let’s try another one, how wide is this runway?
If you guessed 100′ again, sadly you are incorrect. Runway 32 at Mansfield, MA is only 75′ wide. Why then is it marked for 100′ width? Well, I’m not really sure. I suppose because it always has been. The last time the runway was painted, not including cracksealing and touch up painting, the incorrect number of threshold stripes was applied. Airports that do not hold a Part 139 certificate, meaning they do not have scheduled air service, aren’t required to be upheld to the highest standard. While the airport’s are inspected regularly, the airport is not required to fix this. Next time the runway is repainted, I’m sure it will be corrected, until then pilots better be doing their homework and checking the Airport/Facility Dirctory prior to takeoff!
It’s also important to remember that not every runway has the “piano keys”, they are utilized on runways served by instrument approaches.
Remember not everything is as it seems, so do your flight planning homework and be ready for nonstandard situations to present themselves. In all of my time flying I have never faced a traffic avoidance “close call” as described with the right-of-way rules in the FAR/AIM, it’s always a little bit different and nonstandard. That’s why pilots need to be prepared to make good, quick decisions.
If you’re interested in learning more about the specifics of markings, take a look at the guidance the FAA provides to airports. The FAA Southern Region produces a comprehensive guide, available HERE.
-Fly Safe, @MTElia1B9