vertical navigation

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vertical navigation (VNAV)

A function of area navigation (RNAV) equipment that calculates, displays, and provides vertical guidance to a profile or path. Vertical navigation descent information appears in the profile view of selected non-precision approaches with charts printed after December 3, 1999. The information indicates the geometric descent path with a descent angle from the final approach fix to the threshold-crossing height at the approach end of the runway. The inclusion of the VNAV descent does not change or modify existing non-precision approach requirements, and the usage of the MDA (minimum decision altitude) and the MAP (missed approach point) remains unchanged. This implies that a descent below the MDA cannot be continued unless required visual references are available. Similarly, the prescribed missed approach procedure should not be initiated until the aircraft has reached the published MAP.
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References in periodicals archive ?
A vertical navigation (VNV) mode in some installations let the autopilot fly an entire sequence of courses and altitudes from an IFR arrival through all the step-downs on an approach.
The new bridge has a 81-meter main channel span, one of the largest in North Carolina, as well as 65 feet of vertical navigation channel clearance.
The latest software update for Garmin's GTN navigators outputs vertical navigation information for SIDS, STARS and approach stepdowns, and Garmin's GFC 600 VNAV mode can follow those or manual crossing restrictions you enter.
To use an MDA as a DA when using vertical navigation, operators " must be authorized with a Letter of Authorization (LOA) C073 in order to use an MDA as a DA with VNAV." In Notice NOTC6369, the FAA recommends that operators wishing to implement such a change review paragraph C073 to determine if the aircraft is capable of using MDA as DA, assess whether the required procedures are acceptable and, if so, request LOA C073 from their local Flight Standard District Office.
The accident investigation determined that among the probable causes of the accident were, "The lack of situational awareness of the flight crew regarding vertical navigation, proximity to terrain, and the relative location of critical radio aids." In other words, the crew did not monitor the position of the aircraft.
"Pilots cleared for vertical navigation using the phraseology 'descend/climb via' must inform ATC upon initial contact with a new frequency, of the altitude leaving, 'descending via (procedure name),' the runway transition or landing direction if assigned"--if on a STAR--"and any assigned restrictions not published on the procedure." In its many forms, pilot's discretion is a great tool that helps both pilots and controllers relax a bit when ATC operations aren't at their highest pressure point.
We dealt with all that by programming the Flight Management System (FMS) to provide vertical navigation to the runway.
If your GPS is WAAS-certiffed, you'll use another set of minimums, LNAV/VNAV, the "VNAV" signifying approved vertical navigation. This is flown like an ILS to DA.