Mark V and Mark VII EGPWS Pilot's Guide
In -210-210 and later versions, the TCF alert envelope and
Envelope Bias Factor are improved. The alert envelope is
limited to a minimum of 245 feet AGL adjacent to the runway
as illustrated in the following diagrams. The Envelope Bias
Factor is reduced (moved closer to the runway) when higher
accuracy aircraft position and runway position information is
This is typically 1/3 to 1 nm providing greater protection
against landing short events. With version -218-218 and later
models, the envelope bias factor is reduced to 1/4 nm if
runway and position data is of high integrity.
Also in -210-210 and later versions, runway selection logic is
Comprehensive aircraft position and navigation information is
used to evaluate proximate runways and determine the most
likely destination runway for all alerting purposes.
Rev H, August 2011
*245 foot curve expansion on runway
sides only applicable to -210-210 and on.
to better identify the
ENVELOPE BIAS FACTOR