All posts tagged 'runway conditions'

Do You Know Your Runway Markings?

Runway Markings

Flight training magazine and AOPA discussed runway markings recently because after your private, and maybe a few times in instrument training, it's not really discussed in depth again. Sometimes if you didn't get the best luck of the draw with your instructor it may not be discussed well at all.

Whatever the case is, let's talk about runway markings!

Displaced Threshold

I think this one is most often missed in training. The basic information taught about a displaced is "you can taxi and takeoff there but don't land." BUT WHY?!?! 

The short unprofessional answer for this is because you'll hit something. The better answer is it's there to protect you. If you aim for it as a landing spot, your glide path will become too low and again...you'll hit something. This could be power lines, trees, hills, etc. depending on the airport environment so it is designed specifically to avoid the dangers. Don't aim to touchdown until the threshold to be safe.

Threshold

As previously mentioned, the threshold now marks the beginning of available landing distance on the runway. Thresholds also have a coding system to tell you how wide the runway is. I think the coding system for the threshold is pretty neat. Here's a picture as it's described in the AIM of how the width is depicted:

Threshold Stripes

When it comes to instrument flying, the threshold can also tell you what type of approach the runway has: visual, precision, or nonprecision. On a visual runway with no approaches, it will just start at the beginning of the paved area, but for approaches, you'll see long, bold white stripes between the start of the runway and the edge of the numbers called your threshold markings. 

Designation Markings

Believe it or not, this is the official term used for runway numbers. They indicate the approximate magnetic orientation of that runway. Over time as the earth's magnetic fields change, however, the number has to be changed. A runway might be 17 for 10 years and then have to be changed to say 18 (this blew my mind as a private student!).

Side note: make a good habit as early as you can of saying "runway verified" or "I see 17 (insert correct runway number)" whenever you enter a runway and see the designation markings. It'll save you on that one leg in the middle of the night where you're exhausted and accidentally enter the wrong runway. You never know!

Touchdown Zone 

500 feet down the first stripe of runways with a precision approach is what is known as the touchdown zone. This is the line where football players must reach to score a goal against their opponent.

Just checking to see if you're still reading! These stripes are most useful in helping you know how much runway you've already eaten up in case you're pushing landing distance factors. 

Aiming Point

You might recognize these as they're most commonly called: the 1000 foot markers or captains bars! Similar to the purpose of the touchdown zone, these also help to show how much runway you've used. And if you're a commercial student, these are much better to use to aim for on power off 180's than the numbers!

Side-stripe Markings

These are the solid continuous white stripes that signify the edge of the runway to help provide a visual contrast from the terrain off the side of the pavement. Something similar to this is the yellow runway shoulder marking, cueing a non-taxi area. 

Centerline

Lastly demonstrated on the picture is centerline, perhaps one of the most important! One of its functions is keeping you on the center of the runway, protecting the wings from hazards off the side of the runway like windsocks, terrain, and worst of all aviation YouTubers.

The stripes also help mark the distance you've used. According to the AIM, each stripe is 120 feet long with 80 feet in between each of them. The stripes can be between one and three feet wide depending on the size of the runway. 

Hopefully this was a good refresher for runway markings for you! Remember to work for centerline and don't forget to flare!

Questions or comments? Let us know below!

That Frigid FICON NOTAM


I don’t know about you, but we’ve had a few snow and ice storms this winter in our neck of the woods. As a flight instructor, bad weather offers the opportunity to teach students about runway condition and braking action, among other things, and it’s a good time to reinforce the importance of checking NOTAMs before heading to the airport.

During a recent winter storm, we were snowed in for three days. We were all getting antsy, wanting to get out of the house and fly. So after the clouds cleared, a student and I scheduled a flight for the first VFR day after the snowstorm. The weather looked fantastic - clear below 12,000, light winds and sunshine. Everything looked great… except for just this one thing:

!TTA 01/015 TTA RWY 03/21 FICON ICE BA POOR OBSERVED AT 1601241330. 1602241405-1602241900.

What does all that mean? In short, it means that there was still ice on the runway, and braking action was poor. This is a NOTAM(D) for runway condition, and yet another good reason to always check NOTAMs! While the weather outside was great VFR flying weather, we were still stuck on the ground. Here’s a breakdown of this NOTAM:



A NOTAM for field condition - what we call FICON - can be issued for any of the following runway conditions:

  • Snow
  • Ice
  • Snow and Ice
  • Slush
  • Water
  • Drifting or drifted snow
  • Plowed/Swept
  • Sanded/De-iced
  • Snow banks
  • Mud
  • Frost
  • Frost Heave
  • Cracks, Ruts, Soft Edges

Here are two more examples:

!MIV MIV RWY 10/28 FICON 1/4 IN LSR WEF 1112201200

NOTAM for Millville Municipal Airport (MIV), runway 10/28 is covered in ¼ inch loose snow, observed December 20, 2011 at 1200 UTC.

!ENA 5HO RWY 16/34 FICON THN PSR WEF 1109131520

NOTAM issued by Kenai for Hope Airport (5HO), thin layer of packed snow on runway 16/34, observed at 1520 UTC on September 13, 2011.

But what does that really mean? Can you - or should you - land under these conditions? For pilots, there are a few things to consider when taking off or landing on runways with any type of contamination. FICON NOTAMs will often include braking action reports, given as GOOD, FAIR, POOR or NIL, like in the example above. These values are often reported by pilots as they land.

Sometimes, braking action is reported as a MU value. MU is the mathematical term for the coefficient of friction, and its value is determined by a friction measuring device at airports. A value of 40 or above would mean braking action is good. A value of below 40 MU can mean a significant reduction in braking action.

Landing on any runway with less than GOOD braking action can be hazardous. It’s always best to avoid landing on runways covered in snow and ice. Even water can decrease braking action significantly. If you must land on an icy or snowy runway, use extreme caution, make a normal, stabilized approach use aerodynamic braking as much as possible before touching down. Try to keep the nose wheel straight during the landing rollout to prevent skidding. And remember that the taxiways are often in worse condition than the runways - even if the runway has been cleared, there’s a good chance the parking area hasn’t been.

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