Originally Posted by
B888
“ The problem with heavy rain at Leeds, is that even if you can land comfortably in the 115% Factored LD, the technique for recovery from loss of directional control creates a huge decision problem: “
Not judging here but :
Part of the FAA SAFO 19003 States :-
Subject: Turbojet Braking Performance on Wet Runways.
Purpose: This SAFO cancels and replaces SAFO 15009 and warns airplane operators and pilots that the
advisory data for wet runway landings may not provide a safe stopping margin especially in conditions of
Moderate or Heavy Rain.
Background: Landing overruns that occur on wet runways typically involve multiple contributing factors
such as long touchdown, improper use of deceleration devices, tailwind and less available friction than
expected. Several recent runway-landing incidents/accidents have raised concerns with wet runway
stopping performance assumptions. Analysis of the stopping data from these incidents/accidents indicates
the braking coefficient of friction in each case was significantly lower than expected for a wet runway as
defined by Title 14 of the Code of Federal Regulations (14 CFR) part 25 § Section 25.109 and Advisory
Circular (AC) 25-7D methods.
These incidents/accidents occurred on both grooved and un-grooved runways. The data indicates that
applying a 15% safety margin to wet runway time-of-arrival advisory data, as recommended by
SAFO 19001 (or current guidance), may be inadequate in certain wet runway conditions. Takeoff and
Landing Performance Assessment (TALPA) procedures implemented by the FAA on October 1, 2016,
added new insight as to how flightcrews can evaluate runway braking performance prior to landing.
TALPA defines WET as “Includes damp and 1/8-inch depth or less of water,” while CONTAMINATED is
“greater than 1/8-inch of water.
”
Discussion: These overruns have occurred on grooved and smooth runways during periods of moderate to
heavy rain. Analysis of these incidents/accidents indicates that the braking coefficient of friction in each
case was significantly lower than expected, and that 30 to 40 percent of additional stopping distance may
be required if the runway transitions from wet to contaminated based on the rainfall intensity or reported
water contamination (greater than 1/8-inch depth). For the operational in-flight landing assessment,
determining whether the runway is wet or potentially contaminated is the pilot’s responsibility.
The FAA recommends that airports report “Wet” conditions. However, airports are not required to report
when a runway is only wet. Further, an airport may not be able to generate a Field Condition NOTAM
(FICON) for sudden rain showers that result in water on the runway more than 1/8 of an inch in depth
(contaminated). Rainfall intensity may be the only indication available to the pilot that the water depth
present on the runway may be excessive. The 1/8-inch threshold that separates a wet runway with a
RWYCC of 5 from runway contaminated with water depth greater than 1/8-inch a RWYCC of 2 is based
on possibility of dynamic hydroplaning. This can be especially true in moderate rain if the runway is not
properly crowned, grooved, constructed with a porous friction course (PFC) overlay, or when water run-
off becomes overwhelmed. During heavy rain events, this may be true even on a properly maintained
grooved or PFC runway.
The TALPA RCAM recommends using landing performance data associated with medium to poor
braking or RwyCC of 2, if greater than 1/8-inch of water is anticipated to be on the runway. When
planning to land on a smooth runway under conditions of moderate or heavy rain, or when landing on a
grooved or PFC runway under heavy rain, pilots should consider that the surface may be contaminated
with water at depth greater than 1/8 inch and adjust their landing distance assessment accordingly.
Pilots should use all available resources to determine what condition they may expect upon landing to
include Air Traffic Control (ATC), FICONs (as some airports do report Wet conditions), flight
visibility, and/or onboard weather radar.
sorry, but what does FAA stand for?