The RAAS uses aircraft inputs from the EGPWS such as GPS
position, heading, groundspeed and a runway database to
generate the runway awareness aural advisories. Note that
GPS availability is a requirement for the operation of RAAS.
Aircraft position is referenced to the GPS antenna position.
RAAS does not have knowledge of taxiways, ATIS &
NOTAM information, other traffic, pilot intent, ATC
clearance, ground markings and signage. Crews should be
cognizant of the prevailing ATIS and any NOTAMs.
(Similarly, data on newly constructed runways or changes to
length of existing runways may not necessarily be included in
the RAAS runway database). RAAS operates automatically,
without any action required from the flight crew.
The RAAS advisories are presented below for the relevant
flight phases. Note that all RAAS advisories have a lower
priority than any existing EGPWS alert, including radio
Taxiway Take-Off Advisory
A Honeywell runway incursion study indicates that 7% of
incidents during takeoffs and landings were from/onto a
taxiway. The purpose of the Taxiway Take-Off Advisory is to
enhance crew awareness of excessive taxi speeds or a take-off
on a taxiway.
This advisory is provided for each of the following
• Inadvertent taxiway take-off or excessive taxi speeds; and
• Approved take-off operations on a taxiway (e.g., at airports
• Groundspeed of the aircraft exceeds 40 Kts; and
• Aircraft is on a surface other than a runway.
Note: RAAS functions are based on a database of runway
locations. The system does not have knowledge of the
location of taxiways, ramp areas, grass surfaces, etc.
If groundspeed reduces below 40 knots after an advisory is
provided (i.e., corrective pilot action taken), the system will
generate a single advisory again if the conditions above are
with a single runway that is closed for surface repairs).
"On Taxiway! On Taxiway!" is provided once if:
Mark V and Mark VII EGPWS Pilot's Guide
Rev H, August 2011