NTSB urges FAA runway review

Why it matters

The National Transportation Safety Board on May 26 told the Federal Aviation Administration to revise the system pilots and airports use to judge runway conditions in heavy rain, saying current assumptions can understate stopping risk. The board issued three recommendations tied to the FAA’s Runway Condition Assessment Matrix, or RCAM, which is used to calculate landing distances on wet runways. The move followed an NTSB review of 11 runway overrun accidents and incidents from 2008 through 2019. In eight of those events, low runway friction was cited as a cause or contributing factor. ### Why is the NTSB targeting the runway matrix now? The NTSB said the current matrix does not adequately account for the way braking friction drops as rainfall intensity rises. In its recommendation A-26-61, the board told the FAA to update wet-runway condition codes so they reflect the “progressive decrease” in wheel braking friction as rain gets heavier. A second recommendation, A-26-62, asked the FAA to add more rainfall-intensity descriptors to aviation weather reports for storms that exceed the current heavy-rain threshold of 0.3 inches per hour. (ntsb.gov) The agency’s concern is rooted in measured performance, not only reporting language. The NTSB said that in all but one of the 11 overruns it studied, the braking friction achieved during landing was substantially lower than the friction level associated with a “wet runway” in the FAA matrix. In nine of the 11 events, the board said the shortfall most likely resulted from moderate-to-heavy rainfall and the greater water depths that formed on the runway surface. (ntsb.gov) ### Which accidents pushed this issue to the front? A May 3, 2019 overrun in Jacksonville, Florida, was one of the events cited in the NTSB’s announcement. FlightGlobal, citing the NTSB, reported that a Miami Air Boeing 737-800 overran the runway there after landing in rain falling at rates up to eight times the FAA’s threshold for “heavy” rainfall. (ntsb.gov) The broader set of 11 events spans 2008 to 2019, according to the NTSB. Reuters reported that the board’s recommendations came after those investigations raised concern that airplanes can skid off runways when rain intensity, water depth and pavement conditions combine in ways the current framework does not capture well. (ntsb.gov) ### What does the FAA system do today? The FAA’s Takeoff and Landing Performance Assessment program standardizes how airports report runway conditions when pavement is not dry. Under that system, airport operators use the RCAM to assign runway condition codes based on contaminants and observations, and those codes feed the landing-performance information pilots use. (srnnews.com) FAA guidance already warns that wet-runway braking can deteriorate in moderate to heavy rain. In Safety Alert for Operators 19003, the agency said overruns on grooved and smooth runways in such conditions showed friction significantly lower than expected and that 30% to 40% more stopping distance might be needed if a runway shifts from wet to contaminated. (faa.gov) ### What is the NTSB saying the FAA still misses? The NTSB’s third recommendation, A-26-63, told the FAA to revise airport pavement hydraulic and skid-resistance evaluations so they better account for heavy-rain operating conditions. The board said the current framework does not sufficiently capture how drainage, water accumulation and pavement characteristics affect braking during intense short-duration storms. (faa.gov) FAA research has already identified rainfall intensity, pavement texture and grooving, tire pressure and speed as variables that affect aircraft braking and runway friction. The NTSB is now asking the regulator to translate that knowledge into the operational matrix and airport evaluation methods used in day-to-day landing decisions. That is an inference from the recommendations and the FAA’s own research agenda. (ntsb.gov) ### What happens next at the FAA? The FAA is the addressee for all three recommendations and will decide whether to accept, reject or modify them through the NTSB recommendation process. The recommendations are publicly listed in NTSB report DCA25SR002 and were announced in press release NR20260526 on May 26. (ntsb.gov) (faa.gov)

Key numbers

• The National Transportation Safety Board on May 26 urged the Federal Aviation Administration to change how it rates runway conditions in heavy rain.
• An NTSB study of 11 overruns found 9 cases where moderate-to-heavy rain likely reduced braking friction below FAA wet-runway assumptions.
• The recommendations are in NTSB safety report AIR-26/04 and press release NR20260526, both issued on May 26.
• The National Transportation Safety Board on May 26 told the Federal Aviation Administration to revise the system pilots and airports use to judge runway conditions in heavy rain, saying current assumptions can understate stopping risk.

What happens next

• The National Transportation Safety Board on May 26 told the Federal Aviation Administration to revise the system pilots and airports use to judge runway conditions in heavy rain, saying current assumptions can understate stopping risk.
• A May 3, 2019 overrun in Jacksonville, Florida, was one of the events cited in the NTSB’s announcement.
• (ntsb.gov) What happens next at the FAA?

Sources

• ntsb.gov
• ntsb.gov
• ntsb.gov
• srnnews.com
• faa.gov
• faa.gov
• faa.gov

Quick answers