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5 - PROCEDURES
112
190-00356-00 Rev E
Flying the LP Approach
Flying the LP Approach
LP approach capability is available for units with SW
Version 3.30, or later.
AnLPapproachisownthesameasanLPV
approach, except that vertical guidance is not provided.
Angular scaling is similar to a localizer approach. Most
LP approaches have step down altitudes associated with
them.
1. Within 30 nautical miles of the destination, the
400W-series unit switches from en route mode
to terminal mode and the CDI scale transitions
from 2.0 to 1.0 nautical miles, full scale deflec-
tion.
2. As you approach the IAF, a turn direction mes-
sage appears on the bottom of the screen.
3. As the distance (DIST) to the IAF approaches
zero, the message is replaced by a time to turn
advisory that counts down 10 seconds prior to
the turn.
4. As you approach the FAF, the 400W-series
unit will begin to automatically rescale in an
angular fashion. This will allow the LP approach
to be flown in the same fashion as a standard
localizer approach. At 2.0 nautical miles from
the FAF, CDI scaling is tightened from up to
either 2° or 0.3 nautical miles, full scale deflec-
tion, whichever is smaller.
5. Sixty seconds prior to reaching the FAF, the
400W-series unit will check the required
Horizontal Alarm Limit (HAL) to ensure the GPS
position integrity is within limits to complete
the LP non-precision approach. In the event
the HAL limits are exceeded, the approach will
be downgraded, when available, indicated by
“LNAV” on the moving map, otherwise the
approach will be aborted. A message will note
that the approach is downgraded and the NAV
indicator will be flagged. You may continue the
approach using LNAV non-precision minimums
if there are LNAV minimums for this approach.
In the rare event the GPS HAL limits cannot
meet non-precision limits, the 400W-series unit
will notify the pilot with a message to abort the
approach. The 400W-series unit will revert to
terminal limits of 1.0 NM to support navigation
to the missed approach.
6. As you cross the FAF, the destination sequences
to the MAP. With the needle on the external CDI
(or HSI) centered, fly toward the MAP, observing
the altitude minimums dictated by the approach
plate.
7. When viewing the Map Page, you’ll note that
the final course segment is displayed in ma-
genta (the active leg of the flight plan always
appears in magenta).
8. As you approach the MAP, a waypoint message
(“Arriving at Waypoint”) appears on the bottom
of the screen.
9. At the MAP initiate the missed approach, if
necessary. Once the 400W-series unit crosses
the MAP sequencing will be suspended. Prepare
the aircraft for missed approach operation.
Press the OBS key to sequence to the Missed
Approach procedure.
NOTE: For missed approaches with heading legs,
fly manually until the first active course leg is
reached, as described in earlier sections.
10. Fly the guidance provided by the 400W-series
unit to the MAHP and hold.