Garmin GNS 430 Pilot's Manual And Reference page 215

ETA (estimated time of arrival) - The
estimated time at which the aircraft will reach the
destination waypoint, based upon current speed
and track.
ETE (estimated time enroute) - The time it
will take to reach the destination waypoint, from
present position, based upon current ground
speed.
FF (fuel flow) - The fuel flow rate, expressed in
fuel units per time (e.g., gallons per hour).
FOB (fuel on board) - The total amount of
usable fuel on board the aircraft.
GS (ground speed) - The velocity the aircraft is
travelling relative to a ground position.
HDG (heading) - The direction an aircraft is
pointed, based upon indications from a magnetic
compass or a properly set directional gyro.
IND (indicated) - Information provided by
properly calibrated and set instrumentation in the
aircraft panel (e.g., 'indicated altitude').
LFOB (left-over fuel onboard) - The amount of
fuel remaining on board after the completion of a
one or more legs of a flight plan (or a direct-to).
LRES (left-over fuel reserve) - The amount of
fuel remaining on board after the completion of a
one or more legs of a flight plan (or a direct-to),
expressed in time and based upon a known fuel
consumption (flow) rate.
MSA (minimum safe altitude) - Uses Grid
Minimum Off-route Altitudes (Grid MORAs) to
determine a safe altitude within ten miles of the
present position. Grid MORAs are one degree
latitude by one degree longitude in size and clear
all reference points within the grid by 1000 feet in
areas where the highest reference point is 5000
feet MSL or lower. If the highest reference point
is above 5000 feet, the Grid MORA will clear the
highest reference point by 2000 feet.
TKE (track angle error) - The angle difference
between the desired track and the current track.
An arrow indicates the proper direction to turn to
reduce TKE to zero.
TRK (track) - The direction of movement relative
to a ground position. Also referred to as 'ground
track'.
VSR (vertical speed required) - The vertical
speed necessary to descend/climb from current
position and altitude to a defined target position
and altitude, based upon the current ground
speed.
XTK (crosstrack error) - The distance the
aircraft is off a desired course in either direction,
left or right.
GNS 430 Pilot's Guide and Reference
SECTION 13 – MESSAGES,
ABBREVIATIONS, & NAV TERMS
13-13