GPS NAVIGATION

VERTICAL NAVIGATION (VNV)

NOTE: Refer to the Appendices for VNV Flight Planning definitions, abbreviations, and acronyms.

The G1000 System can use altitude constraints associated with lateral waypoints to give guidance for vertical navigation. These altitudes are, depending on the specific instance, entered by the pilot or retrieved from the published altitudes in the navigation database.

The navigation database only contains altitudes for procedures that call for “Cross at” altitudes. If the procedure states “Expect to cross at,” then the altitude will not be in the database. In this case the altitude may be entered manually.

When activating or loading an arrival or approach procedure into an active flight plan, the VNV ‘ALT’ fields will be populated with any altitudes that can be retrieved from the navigation database.

To help interpret the meanings of how the altitudes are presented, keep the following points in mind:

•When the altitude is displayed in light blue, the system is using that altitude to determine vertical speed and deviation guidance.

•When the altitude is displayed in white, it is not being used by the system to determine the vertical speed and deviation guidance.

•An altitude displayed as small text is an altitude that is published in the navigation database.

•Altitudes displayed as a light blue halftone cannot be used in the current vertical navigation calculations.

Refer to Figure 5-81 and Table 5-2 for more detail regarding the significance of text size and color.

						Large
		White Text
					Large Light
						Blue Text
				Small Light
					Blue Text
					Small Light Blue
						HalftoneText
					Small White
						Text with
Figure 5-81 VNV Altitudes						Altitude
		Restriction Bar

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		White Text	Light Blue Text	Light Blue Halftone Text
		Altitude calculated by the	Altitude has been entered by the
		system estimating the altitude of
			pilot. Altitude is being used by
		the aircraft as it passes over the	the system for vertical speed and	The system cannot use this
	Large Text	navigation point. This altitude	deviation guidance. Altitude does	altitude in determining vertical
		is provided as a reference and	not match the published altitude	speed and deviation guidance.
		is not being used by the system
			in navigation database or no
		to determine vertical speed and
			published altitude exists.
		deviation guidance.
		Altitude is not being used to	Altitude is being used by the
			system for vertical speed and
		determine vertical speed and
			deviation guidance. Altitude
		deviation guidance. Altitude		The system cannot use this
			has been retrieved from the
	Small Text	has been retrieved from the		altitude in determining vertical
			navigation database or has been
		navigation database and is		speed and deviation guidance.
			entered by the pilot and matches
		provided as a reference.
			a published altitude in the
			navigation database.
		Table 5-2 VNV Altitude Text Size and Color

Some altitudes retrieved from the database have associated restrictions indicating to stay ‘At’, ‘At or Above’, or ‘At or Below’ a specific altitude. These restrictions are indicated using a ‘bar’ above and/or below the appropriate altitude as shown in Figure 5-82.

Stay AT or ABOVE 5,000 ft

Stay AT 2,300 ft

Stay AT or BELOW 3,000 ft

Figure 5-82 Altitude Restrictions

Note:Vertical constraints and along track offset waypoints are not retained in stored flight plans.

Enabling/Cancelling VNV guidance:

1)Select the Active Flight Plan Page.

2)Press the CNCLVNV Softkey. CancelingVNV results inVNV outputsV DEV (vertical deviation),VS REQ (vertical speed required),andTIMETOTOD/BOD (time to top of descent/bottom of descent) going invalid. As a result the non-numeric vertical deviation and VS REQ indicators on the PFD are removed. Additionally the V DEV,VS REQ, and TIME TO TOD displayed in the Current VNV Profile box on the Active Flight Plan Page is dashed.

Once cancelled, VNV will remain disabled until manually enabled or a direct-to waypoint is entered while in reversionary mode. When cancelled the CNCL VNV Softkey will change to ENBL VNV. VNV can be enabled by pressing the ENBL VNV Softkey causing a VNV waypoint to be selected (if possible) and vertical navigation to resume.

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ALTITUDE CONSTRAINTS

The G1000 provides a means to enter altitude constraints associated with waypoints in the active flight plan so long as the waypoint is not the final approach fix, a waypoint after the FAF, or part of an unsupported lateral leg type.

Altitude constraints are displayed and entered in mean sea level (MSL) values to the nearest hundreth. An altitude constraint in above ground level (AGL) format is supported for airports. To convert the value to AGL, turn the FMS Knob when MSL is highlighted and press the ENT Key. When a database altitude restriction is displayed, the G1000 allows user entry of a different altitude when creating a waypoint, effectively overriding the database restriction (only before the FAF). The G1000 allows activation of a displayed database altitude restriction by highlighting the database constraint and selecting the ENT Key. When a database altitude restriction of type “AT or ABOVE” or “AT or BELOW” is activated, the G1000 uses the “AT” portion of the restriction to define the vertical profile.

The G1000 annunciates all constraints that cannot be used to calculate vertical guidance by displaying the value in halftone, light blue text. The following conditions constitute an invalid altitude constraint:

•Meeting the constraint requires the aircraft to climb

•Meeting the constraint requires the maximum flight path angle to be exceeded

•Meeting the constraint requires the maximum vertical speed to be exceeded

•The altitude constraint results in a TOD behind the aircraft present position

•The constraint is within a leg type for which altitude constraints are not supported

•The pilot is attempting to add an altitude constraint to the FAF or a waypoint past the FAF of an approach that provides vertical guidance (i.e. ILS or GPS WAAS approach)

•The pilot is attempting to add an altitude constraint to any waypoint past the FAF of an approach that does not provide vertical guidance (i.e. not an ILS or GPS WAAS approach).

To enter altitudes as a flight level, enter an “F” in the most significant digit by rotating the inner FMS Knob counter-clockwise past zero or clockwise past 9, the system will automatically change to show units of Flight Level.

NOTE: Vertical constraints and Along Track offset waypoints are not retained in stored flight plans.

NOTE: When an altitude constraint is subdued it means that the user has selected a vertical profile that cannot be flown. The computed FPA for adjacent vertical constraints is too steep.

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Entering an altitude constraint:

1)Select the Active Flight Plan Page.

2)Highlight the desired waypoint altitude field (Figure 5-83).

3)Enter an alt constraint value using the FMS Knob or the Control Unit number keys.

4)Press the ENT Key to accept the VNV altitude constraint.

VNV ALT Field

Figure 5-83 Entering an Altitude Constraint

ALTITUDE CONSTRAINT MODIFICATION

The pilot can modify or delete any altitude constraint. An altitude constraint is deleted by highlighting the altitude and pressing the CLR then ENT Key. In the event an altitude constraint is deleted and the navigation database contains an altitude restriction for the lateral waypoint, the G1000 displays the altitude restriction from the database provided no predicted altitude can be provided.

Changing an altitude constraint:

1.Select the Active Flight Plan Page.

2.Highlight the desired altitude constraint.

3.Use the FMS Knob or control unit number keys to change the altitude constraint value.

4.Press the ENT Key to confirm the change.

Deleting an altitude constraint:

1.Select the Active Flight Plan Page.

2.Highlight the desired altitude constraint.

3.Press the CLR Key.

4.Press the ENT Key.

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ALONG TRACK OFFSETS

NOTE: An along track offset waypoint cannot be created if it is not adjacent to its parent waypoint

The pilot can enter a waypoint having an “along track offset” distance from an existing waypoint. Offset distances can be entered from 1 to 99 nautical miles in increments of 1 nautical mile before the offset waypoint (shown as a negative value) or after the offset waypoint (shown as a positive value).

A waypoint is allowed as long as the along track offset places the waypoint adjacent to its parent waypoint in the lateral flight plan.

An along track offset that places a waypoint after the final approach fix of an approach is not allowed. Along track offset waypoints lie along the great circle path of the existing lateral flight plan. Assigning an along track offset to a leg with indeterminate length is not permitted.

Entering a negative offset distance results in an along track offset waypoint inserted before the selected lateral waypoint, whereas entering a positive offset distance results in an along track offset waypoint inserted after the selected lateral waypoint. The creation of multiple along track offset waypoints is allowed.

NOTE: If the CLR Key is pressed prior to completing the definition of the along track offset waypoint, the along track offset waypoint will be removed.

NOTE: An along track offset distance cannot be modified once entered. If the along track offset distance must be changed, the pilot must delete the existing along track offset waypoint and create a new one with the corrected offset distance.

Entering an along track offset distance:

1)Select the Active Flight Plan Page.

2)Select the desired lateral waypoint.

3)Press the OFST Softkey.

4)Enter a positive or negative offset distance in the range of +/- 1 to 99 nautical miles (Figure 5-84). NOTE:The offset also cannot exceed the distance to the next or previous lateral non-ATK offset waypoint.

Along Track Offset

Distance

Figure 5-84 Along Track Offset Distance

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Active VNV Waypoint

Altitude

Target Vertical									Flight Path Angle
Speed
								Time To Bottom of
Required Vertical Speed
Vertical Deviation									Descent

Figure 5-85 VNV Profile

VNV PROFILE

The VNV profile can be changed by one of the following means:

•Changing the Flight Path Angle (FPA) for the descent segment

•Changing the target vertical speed for the descent segment

ChangestotheVNVprofileapplytothecurrentactivewaypointonly. TheVNVprofileisnotmodifiable if there is no active waypoint. An invalid entry results in the previous value being restored. The VNV profile modification is invalid if it results in any of the following conditions:

•The maximum allowed FPA is exceeded

•The calculated target vertical speed exceeds the maximum allowed

•The TOD point is now located behind the aircraft’s present position or an s-turn would be required to capture the modified vertical profile

•Modifying the vertical speed target for the current waypoint

The VS TGT will be computed using the FPA and current ground speed and updated on the display periodically. If there is an active waypoint with a vertical component, a valid ground speed, and the system determines the aircraft is airborne, the pilot can select and modify the VS TGT. Updates to the field will cease when the field is selected for modification.

The VS TGT may be changed using the following sequence of actions:

Modifying the VS TGT:

1)Press the VNV PROF Softkey.

2)Use the small FMS Knob, or enter the desired value or to modify the value.

3)Press the VNV PROF Softkey again when finished or press the FMS Knob to remove the cursor from the VNV Profile (NOTE:VS TGT must be negative and cannot be less than the configured minimum value).

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Upon completion of entering a new VS TGT the G1000:

•Periodically computes a new FPA using the selected VS TGT and current ground speed until the TOD is reached

•Uses the newly computed FPA for the active waypoint with a vertical component

•Resumes periodic updates of the VS TGT using the new FPA and current ground speed. VNV profile changes apply to the active waypoint only.

The active waypoint with a vertical component and its FPA is shown in the current VNV profile information box. The pilot can change the FPA.

Modifying the flight path angle:

1)Select the FPA by pressing the VNV PROF Softkey followed by a clockwise turn of the large FMS Knob. It can also be selected by scrolling past the end of the active flight plan waypoint list.

2)Modify the value using the small FMS Knob. The FPA must be negative and cannot be less than the configured minimum value.

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