The FAA has completely overhauled the method that Pilots, Airport Operators, ATC (Air Traffic Control), and Aircraft Manufacturers use to report and interpret braking action during inclement weather. The catalyst for the overhaul was a runway excursion that occurred at Chicago Midway in 2005. According to the NTSB Safety Board Press Release, the aircraft at Midway was given "mixed braking action reports". Due to misinformation of the actual runway conditions along with other contributing factors, the Southwest Boeing 737 departed the runway, went through two fences, and ended up on a roadway where it struck a vehicle. The accident resulted in one fatality and 22 people with injuries. The FAA then determined that the current system of notifying pilots of runway surface conditions was inadequate. Thus the formation of TALPA (Takeoff and Landing Performance Assessment) and RCAM (Runway Condition Assessment Matrix).
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| Courtesy of DIA |
The goals of the FAA in this endeavor are summed up nicely on the FAA website in the aim of mitigating the possibility of runway excursions in the future:
"The goal of the Takeoff and Landing Performance Assessment initiatives, or TALPA, is to standardize terminology and an aircraft's performance data given actual surface conditions. The cornerstone of this voluntary effort is the Runway Condition Assessment Matrix (RCAM). The RCAM seeks to tie together runway contaminant descriptions, braking action, and airplane performance data by utilizing codes 0 through 6."
The RCAM Table developed by the FAA is pictured below:
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| From (AC) 150/5200-30D |
The RCAM table will go into effect on October 1, 2016, which is also when the NOTAM system will change over to the new way of reporting runway surface conditions. Let's break the table down a bit to make sense of it.
- The description column is categorized based temperature,type, and depth of contaminant.
- There are 7 Runway Condition Codes (RwyCC) that will be used to understand the surface conditions (0-6), with 6 being better than good and 0 being the worst condition resulting "Nil" braking action.
- The RwyCC will be ascertained by the airport operator and used by pilots to help determine braking action performance.
- RwyCC are only reported when greater than 25% of the runway is contaminated. When less than 25% is contaminated, only the type of contamination for each third of the runway is reported.
- The computer NOTAM systems actually assign the RwyCC for each third of the runway based on the contaminant information the airport operator enters into the system. The airport operator then makes sure that the RwyCCs accurately represent the runway condition.
- Mu values will no longer be reported to aircraft operators. The Mu friction values listed are approximate ranges and can be used to degrade the RwyCC, but not upgrade the code unless the actual surfaces are not as slippery as the ascertained code. In this case a higher condition code no greater than 3 can be assigned for each third of the runway that measures a Mu greater than .40 and this changed code must be supported by other observed conditions. Additionally, if the code is upgraded, the surface conditions must be closely monitored for degradation of conditions (More information about this in the AC).
- The condition descriptions can be used for reference on all airport surfaces.
- The term "Fair" for braking action has been changed to "Medium" (which is what Europe already uses)
Advisory Circular (AC) 150/5200-30D, for Airport Winter Safety and Operations, was just updated on July 29, 2016. The biggest updates to the AC include the RCAM as seen above and the change in the way NOTAMs (Notices to Airmen) for precipitation conditions will be formatted, since it needs to correlate to the RCAM.
This was the first installment on this topic. Next time, we'll go over more information about how the NOTAMs will look and how to translate them.
This was the first installment on this topic. Next time, we'll go over more information about how the NOTAMs will look and how to translate them.
Resources:
http://www.airtech.tc.faa.gov/Safety/Downloads/TC-TN13-22.pdf
http://runwayexcursions.faa.gov/
Catalyst for RCAM:
http://www.ntsb.gov/news/press-releases/Pages/Safety_Board_Determines_Cause_of_Runway_Overrun_at_Chicago_Midway.aspx
https://www.faa.gov/about/initiatives/talpa/media/Airport-Operators-TALPA-FAQS.pdf
This article was written by the creator of Everything Airport, Jessica.
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