Honeywell EGPWS MK VII - Runway Field Clearance Floor

Mark V and Mark VII EGPWS Pilot’s Guide
System Description 060-4241-000
28 Rev H, August 2011
Runway
Field
Clearance
Floor
In -210-210 and later versions, a Runway Field Clearance
Floor feature is included. This is similar to the TCF feature
except that RFCF is based on the current aircraft position and
height above the destination runway, using Geometric
Altitude (in lieu of Radio Altitude). This provides improved
protec
tion at locations where the runway is significantly
higher than the surrounding terrain as illustrated below.
With version -218-218 and later models, the RFCF envelope
is moved from 1nm to 1/2nm if runway and position data is of
high integrity.
(1.5 + Krf) nm
Minimum Runway Field Clearance, ft
RFCF Ceiling (300 ft above field)
Krf
RFCF
Alert Area
Runway
End
Field
Elevation
5.0 nm
(Outer Limit)
(No Lower Limit)
RFCF Alert Envelope
5500
5000
4500
4000
3500
3000
2500
2000
1500
-2 -1 0 1 2 3 4 5 6 7
Distance to Center of Runway (nm)
Altitude / Elevation (ft)
RFCF Alert Envelope
TCF Alert Envelope
RWY
TCF and RFCF alerts result in illumination of the EGPWS
caution lights and the aural message
“TOO LOW
TERRAIN”
. The audio message is provided once when
initial envelope penetration o
ccurs and again only for
additional 20% decreases in Radio Altitude. The EGPWS
caution lights will remain on until the TCF and RFCF
envelopes are exited.