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In July, the Federal Aviation Administration (FAA) released a draft Advisory Circular (AC) entitled Airport Field Condition Assessments and Winter Operations Safety. Essentially, this draft AC cancels the previous AC 150/5200-30C, Airport Winter Safety and Operations from December of 2008.
Changing ACs, regulations, etc., is no small task – this AC changes how conditions on the airfield are reported. RCAM, or Runway Condition Assessment Matrix, is going to look a lot different than what pilots are expecting to see. Today’s article will strive to shed some light on a new reporting system as we are now well into winter.
The Old Way
You might remember way back in your Private Pilot Ground School learning about Braking Action Reports (BARs for today’s purposes). BARs included two correlating pieces of information:
1) Pilot Weather Reports (PIREPS) – Pilots are expected to provide a PIREP to Air Traffic Control (ATC) if the braking action is less than “Good” (more on what consists of “Good” later).
2) Runway Friction Mu Reports – These are often referred to as “Mu values”. These numbers are typically shown as whole in the United Sates (U.S.) and as decimal values round to two places in the International Civil Aviation Organization (ICAO).
a. 0 would be the lowest friction value, while 100 is the highest.
b. These values are given as an average of every third of the runway to generate a Mu value for the entire runway.
c. In addition to Mu values, there will be a contaminant conditions for each corresponding section of the runway (e.g., snow, slush, deicing chemicals, etc.).
Lastly, pilots (at least in General Aviation) tend to pay attention to the words used to describe the runway conditions. The following words have an attached meaning (AC91-79, Appendix 1):
a. Good – the braking deceleration is normal for the effort applied and directional control is normal (Mu is 40 and above).
b. Medium (Fair) – the braking deceleration is not as good and is more noticeable; directional control may be less (Mu is 35 to 30).
c. Poor – braking is significantly reduced, as well as the potential for hydroplaning; directional control may be significantly reduced (Mu is 25 to 21).
d. Nil – braking is minimal to nonexistent and directional control ability is uncertain (Mu of 20 and below).
As pilots, we most likely just were given a word or ATC telling us “Braking action is Fair”. We did not often know the background behind what these values stand for. Hopefully, this informs the average user a little more. Next, I will discuss what the new system entails and how that is different for pilots.
The New Way
As of October 1st, 2016, under RCAM the braking action codes remain mostly the same with words such as “Good”, “Poor”, etc. The biggest change is the replacement of “Fair” with “Medium” – they mean the same thing, however, the FAA decided to simply change the word. The graphic below shows visually what the airport will use versus what a pilot will use.
As you will notice, the pilot still uses the word descriptors, while the airport is now using a numbering system that ranges from zero to six. Zero is the “Nil” end while six is “Good”. Zero can also be thought of as ice and six as completely clear.
It is important to note that the Runway Condition Codes (RCCs) are given for every third of the runway. An example would be the following: 4/3/3. Each third represents the parts of the runway: Touchdown, Midpoint, and Rollout. These RCCs correlate with the Mu values that are measured by the friction tester, if the airport employs one. These RCCs helps a pilot to properly visualize what conditions are affecting what points of the runway.
As the descriptors of the conditions are somewhat lengthy, I will not go into detail in this post to describe each condition. However, I would recommend that all pilots reference the FAA’s website as well as their home airport’s Notice to Airmen (NOTAMs) in addition to any field condition reports that might be issued as well.
Hopefully this blog has shed some light on an interesting and somewhat confusing new regulation. While pilots may see some slightly new wording in reports from airports, this rule affects many commercial airports especially when it comes to major snow events. As this is the first winter that the new rule has been affect, it remains to be seen how airports are handling this new regulation. Hopefully, it will be a safe winter season for all the hard-working Airport Operations personnel!
Have a comment on experiencing RCAM at your local airport? Leave it below!
Images courtesy of Google.com.