To: (Separate email addresses with commas)
From: (Your email address)
Message: (Optional)
Send
Cancel

Thanks!

Close

Landing On A Snowy Runway This Winter? Here's How To Know The Braking Conditions.

Boldmethod

We're deep into winter and with snow/ice covering many runways around the country, it's time to do a little review on how runway condition codes work and what you should do if you're landing on a contaminated runway.

Student And Instructor Slide Off The Runway

We pulled the following report from the NASA ASRS database. It's a good example of how, even with proper planning, you may find yourself in a situation where loss of control can sneak up on you...

Student and instructor were coming back from an instrument practice lesson. Approaching the airport and entering the downwind, the crew briefed the landing and made a special note for landing on the contaminated surface and what exactly could happen. It was made clear that the student would have control and the instructor would shadow along for safety. The approach, flare, and touchdown were all controlled and stable. A straight roll-out path remained for about 2-3 seconds after touchdown before the airplane veered left of centerline. The instructor took control to correct, and the roll-out path straightened back up. Airplane again started veering left no matter how much rudder and braking action was applied to the right. The aircraft left the runway surface into the snow at a very slow speed. No injuries were noted.

A thorough weather briefing, indicating runway MU values in the mid-high 20s was obtained prior to launching. ATIS was obtained prior to entering BTL airspace. At the time, runway conditions were thin dry snow over ice with MU values in the mid-20s. The MU values below 40 indicated less than ideal braking, but not impossible landing conditions. The crew believed the contaminated runway to be an acceptable risk. A better understanding of braking action reports, aircraft landing performance on, and different landing procedures for contaminated runways could be gathered and applied to conditions such as these to help determine the likelihood of conducting a safe flight.

How Did The Crew Get Runway Condition Information?

So how can you figure out what the runway conditions are like before you arrive at your destination?

When airports conduct a braking action test, they issue a NOTAM for the braking action. You can find the NOTAMs in ForeFlight, like the example below:

ForeFlight

What Do The Numbers Mean?

Every year, dozens of aircraft go sliding off of slick runways. Sometimes it's off the end of the runway, and sometimes it's off the side. And one factor the FAA has identified with countless accidents is confusion of what braking action reports actually mean, and how a pilot should use them.

The FAA previously used the "MU" scale to relay braking conditions. It was based on a 0 to 100 scale, with 0 being no braking, and 100 being perfect braking. When there are frozen contaminants on the runway, an MU value of 40 or less means that aircraft braking performance deteriorates, and directional control becomes less responsive. In the mid-20s, the runway in the report above was quite slippery for this crew to land on.

NASA.gov

Today, the FAA has changed the way braking reports and delivered. The 0 to 100 MU scale was too confusing, so now it's a much more simple 0 to 6 scale. 0 is bad. 6 is good. The numbers are issued for each third of the runway: touchdown, midpoint, and rollout. So when you're picking up ATIS, you're going to hear something like this: braking action 5/4/2.

Now for the terminology. When you used to talk to ATC, they referred to braking action as good, fair, poor, or nil. But "fair" has been tossed out the window, and you'll now hear "good, medium, poor, and nil", or a couple combinations of those words.

If You're Flying Into A Towered Airport...

When a braking action NOTAM is issued at a towered airport, they'll include it in ATIS. But keep in mind, even if a runway condition report is NOTAM'd for the airport, the tower is not required to give you a conditions report over the radio.

It's not because they don't want to be helpful, it's because they're often times very busy. If conditions are rapidly changing and the ATIS isn't representative of the true runway conditions, tower may give you updated runway information directly. But if you have a question about the runway condition after listening to ATIS, it's always best to ask.

If You're Flying Into A Non-Towered Airport...

We spoke to Kreg Anderson, who runs the non-towered Alexandria Municipal Airport in Minnesota (KAXN) to find out more. As a side note, Kreg started as the youngest airport director in the country at just 23 years old last year, and we think that's pretty awesome!

When you're flying into a non-towered airport, there may or may not be a NOTAM issued for runway conditions. And even if there is a NOTAM, it might not have the same FAA braking action codes due to a lack of airport operations personnel, equipment, or a general lack of aviation knowledge by city-appointed airport managers. This is why you'll sometimes find public-use, non-towered airports with snow or ice covered runways and no winter weather NOTAMs. On the other hand, some airport managers use a software called the "Runway Condition Matrix" to determine braking reports, which is a great tool for smaller airports! When we're talking smaller general aviation airports, it all comes down to each airport's individual funding, staffing, and plowing equipment.

Preparing For Touchdown

When you touch down on a contaminated runway too fast, you can significantly increase your landing distance. Trying to compensate by over-braking only makes thing worse.

On slick surfaces, your brakes are much less effective, and they can quickly get you in trouble. Initially after touchdown, use little to no brakes. Then, gently press them to feel their effectiveness. It's easy to get anxious and jam on the brakes, but that can lock up your wheels. And when that happens, your braking effectiveness decreases, and you can start sliding. The more gentle you are on the brakes, the easier it is to maintain directional control on the runway.

CDN Aviator

When All Else Fails: Go-Around

If you have enough runway, and braking/directional control is clearly a problem, going around even after touchdown may be an option.

During your go-around, adding power increases airflow over your tail, and you'll most likely have better directional control on the ground with the rudder (even considering left-turning tendencies). If you do go-around, lift off, and take time to think through your Plan-B. That might be making another attempt at the airport, but it might also mean flying to another airport with better runway conditions.

Preparing To Land In Less-Than-Ideal Conditions

Next time you fly, pay attention to the runway conditions. We're deep into the season for slick runways, and if you're not prepared, you can find yourself in a lot of trouble in almost no time at all.

Know the runway condition codes, give yourself enough plenty of runway to stop, be gentle on the brakes, and fly your airplane all the way to the taxi turnoff.

Tell us about your experience with slick runways in the comments below.

Swayne Martin

Swayne is an editor at Boldmethod, certified flight instructor, and an Embraer 145 First Officer for a regional airline. He graduated as an aviation major from the University of North Dakota in 2018, holds a PIC Type Rating for Cessna Citation Jets (CE-525), and is a former pilot for Mokulele Airlines. He's the author of articles, quizzes and lists on Boldmethod every week. You can reach Swayne at swayne@boldmethod.com, and follow his flying adventures on his YouTube Channel.

Images Courtesy:

Recommended Stories

Latest Stories

    Load More
    Share on Facebook Share on Twitter Share via Email