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THIS IS A WORK IN PROGRESS


Checklist

[AFM, §02-05-40]

  1. POF . . . ARRIVAL

  2. Altimeters . . . Set / Cross-check

  3. PFD / SFD . . . Set / Displayed

  4. Glareshield Visor . . . As required

  5. Flight Observer Seat Position . . . Check

  6. Interior Doors . . . Verify Open

Programming an Approach

images

Photo: Perf init descent modes and arrival speed limit, G500 Ground and Flight Operations, fig. 56

Click photo for a larger image

[G500 Ground and Flight Operations, pp. 117]

Vertical Modes for Descent

    The FMS menu, Perf lnit tab is used to set up the initial planned descent mode. The pilot can select a descent speed (knots/Mach combination) and the planned descent angle for path construction from top of descent (TOD) through approach and landing. There are standard descent mode selections, as seen in the graphic above, or the pilot can manually specify the descent speed (CAS/Mach) and angle.

  1. Altitude Select {ASEL) - IAS or MACH A/T Mode -ASEL GP Vertical Mode

    • The altitude select mode, or ASEL, is used in conjunction with the other vertical modes. While the other vertical modes are used to fly the aircraft toward the selected altitude, ASEL is a transition mode designed to capture and level off the aircraft at the selected altitude, ultimately transitioning to the altitude hold or ALT mode.

    • At altitude capture, ASEL becomes the active vertical mode replacing the active vertical mode that was used to the fly aircraft towards the selected altitude. The text "ASEL" replaces the "VS", "FPA", "IAS/MACH", "VIAS/VMACH" or "VPATH" in the vertical mode window of the FMA at altitude capture.

    • Altitude capture in the descent for the FPA and VS modes begins when the flight guidance system determines that the flight director will have to command a continuous 1.05 g capture curve at the current descent speed and rate to level off at the selected altitude. This g condition is programmed for passenger comfort.

    • Altitude capture in the descent for the FLCH mode begins when the flight guidance system determines that the flight director will have to command a continuous 1.05 g capture curve at the current descent speed and rate to arrive at a vertical speed of 1500 feet per minute, 1000 feet prior to the level off at the selected altitude. The ASEL mode then finishes the last 1000 feet of descent to the level off at a constant 1500 feet per minute, until the last 100-200 feet. This is done to reduce descent rates in the final portion of the descent to reduce traffic alerts that can occur with higher descent rates.

  2. VNAV Altitude Select {VASEL) - IAS or MACH A/T Mode-VASEL GP Vertical Mode

    • The VNAV altitude select mode, or VASEL, is where the FD arms the VNAV altitude select mode in the same manner as the altitude select (ASEL) mode described previously with the exception that the altitude target is either based on the guidance panel preselector altitude or the FMS computed altitude,whichever occurs first. This mode is annunciated on the right side of the right FMA as VASEL (in green) during capture, but is on the left side of the right FMA in white, when the mode is armed.

  3. Altitude Hold (ALT) - IAS or MACH A/T Mode -ALT GP Vertical Mode

    • The altitude hold mode is also activated automatically following preselected altitude captures. Once the altitude hold mode is active, the guidance panel HOLD button lights. The flight director (FD) produces flight path commands to smoothly capture the selected altitude without overshoots. The altitude hold mode is selected by pushing the HOLD button on the guidance panel. Pushing the button results in the flight director commanding a flight path to maintain current altitude. If the HOLD button is selected, with a vertical mode selected, the altitude target becomes the aircraft altitude when HOLD was selected. However, the ALTITUDE window still maintains the previously selected setting, pending subsequent selection of a vertical mode. If the HOLD button is selected within 100 feet of the preselected value in the ALTITUDE window, the aircraft targets the value in the window and not the altitude at which HOLD was selected.

    • If the aircraft is in a steep climb or descent when the pilot pushes the ALT button there will be a large overshoot, or undershoot, in altitude as the aircraft reverses it's climb or descent to return and capture the aircraft altitude that was locked in when the ALT button was depressed. The rate of reduction in climb or descent, and the subsequent reversal in climb or descent is very gentle, but will delay capture of the requested hold altitude value. A better technique for a rapid level off without overshooting is to disengage the Auto-Pilot and hand-fly the level off, then select ALT or update the altitude pre-selector window with the desired altitude and use a vertical mode nudge (VS, FPA, FLCH) to get it to capture.
  4. VNAV Altitude Hold (VALT) - IAS or MACH A/T Mode -VALT GP Vertical Mode

    • The VNAV altitude hold mode, or VALT, occurs when the FD transitions to altitude hold following a VNAV altitude select (VASEL) capture of the guidance panel preselected altitude or the FMS computed altitude, whichever occurs first. VALT or VASEL displayed in the right box of the FMA are indications of the VNAV vertical mode of operation. Selection of VNAV during cruise flight would changes the right FMA window from ALT to VALT.

  5. Flight Level Change - FLCH A/T Mode -IAS/MACH GP Vertical Modes

    • During descent, Flight Level Change (FLCH) is a vertical change mode that will descend the aircraft at the target airspeed set in the GP speed window with an idle thrust setting. This mode is sometimes referred to as "speed on elevator" meaning that the descent profile is maintained by controlling the aircraft to the speed target with only elevator inputs. FLCH appears on the center window of the FMA (Auto-Throttle mode), with a corresponding IAS or MACH in the vertical mode window of the FMA (right window) --- which is the speed being held during the descent at idle power. With the Auto-Throttle disengaged, FLCH will appear in white on the left-hand side of the center FMA window. This indicates that FLCH is armed for the performance or Auto-Throttle mode, but isn't active until the Auto-Throttle is enabled.

    • In general, FLCH descents from cruise altitude, with normal descents speeds, will have the steepest descent angle and greatest rate of descent. FLCH descents are only initiated by the pilot and will not occur according to the descent mode angle programmed via the Perf I nit page. Data entered via the Descent Modes menu only affects the speed (knots or Mach) portion of the FLCH descent, where VNAV descent programming.

    • To execute a FLCH descent, an altitude lower than the aircraft current altitude must be set in the GP altitude pre-selector window. The FLCH button on the GP is pushed to enter the FLCH vertical mode. The Auto-Throttles are commanded, if engaged, to idle thrust and FLCH becomes the active mode in the center FMA window. The flight director will command a variable descent flight path angle, controlled to keep the airspeed at the speed target (KCAS or MACH) in the GP speed window.

    • If Auto-Throttles are turned off by the pilot, the descent rate of the FLCH descent is controlled by the pilot setting of Nl on the thrust levers. A higher Nl drives a lower descent rate as the flight director controls flight path angle to maintain the speed target in the GP speed window based on the thrust available. Idle is the lowest possible thrust setting and has the highest associated descent angle and rate of descent. Actual thrust lever placement is up to the pilot, and the flight director will modulate the flight path angle as required to maintain the speed target.

    • FLCH will continue descending until ASEL requirements are met for the altitude in the pre-selector window. FLCH will not honor FMS altitude limits associated with a STAR or waypoint altitudes programmed by the pilot, only the pre-selector altitude on the GP.

    • FLCH is currently inhibited in the GSOO below 2000 feet above the destination airport elevation. Descending below 2000 feet will cause the GP to exit the FLCH vertical mode and enter flight path angle (FPA) mode, at the present aircraft FPA, crossing the 2000 foot line. The system uses the destination airport elevation when within 30nm of the destination airport and will use the departure airport elevation to calculate the 2000 foot above airport elevation point, when greater than 30nm from the destination.

  6. Vertical Speed (VS)- IAS/MACH A/T Mode - VS GP Vertical Modes

    • The vertical speed mode of the guidance panel allows the pilot to select a vertical descent rate. The GP button, labeled VS/FPA , is used to engage either vertical speed (VS) or the flight path angle (FPA) mode. When either mode is active, the light above the button illuminates and goes out when the mode is deactivated. When neither VS or FPA mode is active, the flight guidance control system (FGCS) transitions to VS mode when the button is first pushed. Pushing the VS/FPA button when VS is active, changes the active mode to FPA and synchronizes the target FPA to the current aircraft flight path angle. Pushing the VS/FPA button when FPA is active, keeps the FPA mode active and synchronizes the target FPA to the current aircraft flight path angle. Pushing the CHG button when either mode is active will swap between VS and FPA, converting the current FPA target into a VS target, or a VS target to a FPA target respectively.

    • The altitude pre-selector must be decreased, prior to selecting the VS vertical mode, in order to begin a descent in the vertical speed mode. The flight director will control the flight path to maintain the desired vertical speed and the Auto-Throttles will modulate the power, if engaged, to maintain the speed target set on the guidance panel. IAS or MACH appears on the center window of the FMA (Auto-Throttle mode to hold the selected speed in the GP window), with VS in the vertical mode window of the FMA (right window). The flight director will honor the selected vertical speed and sacrifice airspeed to maintain the vertical speed requested. If the vertical descent rate selected is too great, the commanded flight path, and vertical speed, will eventually be reduced to avoid exceeding speed limits.

    • An early cue to the pilot that the power available is too high to maintain the vertical speed target, displayed in the vertical guidance window, and the airspeed target simultaneously, is the display of "POWER" on the right side the center box of the FMA (Auto-Throttle mode). The pilot should reduce the requested vertical speed rate until the center FMA displays "VS" on the right side. The maximum vertical speed that can be commanded in the descent is -8000 feet per minute.

    • During excessive descents, the flight guidance system will initially enter the VMAx vertical mode (Auto-Pilot on), when it's determined that the aircraft will exceed Vmo/Mmo + 5 knots. If the Auto-Pilot is off, and the pilot doesn't follow the VMAX vertical flight director guidance, the FCC will eventually enter the high speed protection mode.

    • The Auto-Throttle overspeed logic will move the throttles to the idle setting when the VMAx vertical mode (Auto-Pilot on) initially activates, if they are not already there, and will engage the Auto-Throttles if they are currently disengaged (unless inhibited). If the descent rate is still too great based on the target vertical speed, then the VMAX vertical mode will command a pull up to maintain Vmo/Mmo. If the Auto-Throttles are disengaged when VS is selected, they should automatically engage when the vertical mode is changed to VS, unless the AT Auto-Engage inhibit is selected on the Systems/AT Control Menu.

    • In the inhibited case, the aircraft will target the selected vertical speed, but will be unable to maintain airspeed unless the pilot appropriately sets the thrust levers. The left side of the center FMA (Performance/ Auto-Throttle mode) will have an IAS or MACH indication in white, signifying that the IAS or MACH speed control mode component of the VS vertical mode is armed, but can't activate due to the Auto-Throttles being inhibited or failed. If the thrust levers are set too low, the aircraft will decelerate and eventually hit a low-speed stop. If set too high, the overspeed protections will eventually function as described above. The overspeed protections will function for Vmo/Mmo, gear and flaps limits.

    • Vertical speed (VS) will continue the descent until ASEL requirements are met for the altitude in the pre-selector window. VS will not honor FMS altitude limits associated with a STAR or waypoint altitudes programmed by the pilot, only the pre-selector altitude set by the pilot.

  7. Flight Path Angle (FPA) - IAS/MACH A/T Mode - FPA GP Vertical Modes

    • The vertical speed mode of the guidance panel allows the pilot to select a vertical descent rate. The GP button, labeled VS/FPA , is used to engage either vertical speed (VS) or the flight path angle (FPA) mode. When either mode is active, the light above the button illuminates and goes out when the mode is deactivated. When neither VS or FPA mode is active, the flight guidance control system (FGCS) transitions to VS mode when the button is first pushed. Pushing the VS/FPA button when VS is active, changes the active mode to FPA and synchronizes the target FPA to the current aircraft flight path angle. Pushing the VS/FPA button when FPA is active, keeps the FPA mode active and synchronizes the target FPA to the current aircraft flight path angle. Pushing the CHG button when either mode is active will swap between VS and FPA, converting the current FPA target into a VS target, or a VS target to a FPA target respectively.

    • The flight path angle (FPA) mode of the guidance panel allows the pilot to select a flight path angle for the descent. The commanded flight path angle will yield a fixed climb gradient, unaffected by wind and speed. For example, a -3° flight path angle will descend the aircraft at 300 feet per nautical mile. This can be useful when trying to ensure a specific descent gradient is met.

    • The altitude pre-selector must be decreased, prior to selecting the FPA vertical mode, in order to begin the descent at the select flight path angle. The flight director will control the flight path angle to the selected value and the Auto-Throttles will modulate the power, if engaged, to maintain the speed target set on the guidance panel. The flight director will attempt to honor the selected flight path angle first and will sacrifice airspeed to maintain the angle requested. If the vertical descent rate selected is too great, the commanded flight path angle will eventually be reduced to avoid exceeding speed limits.

    • An early cue to the pilot that the power available is too high to maintain the vertical speed target, displayed in the vertical guidance window, and the airspeed target simultaneously, is the display of "POWER" on the right side the center box of the FMA (Auto-Throttle mode). The pilot should reduce the requested flight path angle until the center FMA displays "FPA" on the right side. The maximum descent flight path angle that can be commanded is -9.9°.

    • During excessive descents, the flight guidance system will initially enter the VMAx vertical mode (Auto-Pilot on), when it's determined that the aircraft will exceed Vmo/Mmo + 5 knots. If the Auto-Pilot is off, and the pilot doesn't follow the VMAX vertical flight director guidance, the FCC will eventually enter the high speed protection mode.

    • The Auto-Throttle overspeed logic will move the throttles to the idle setting when the VMAx vertical mode (Auto-Pilot on) initially activates, if they are not already at idle. They will also engage the Auto-Throttles if they are currently disengaged (unless inhibited). If the descent rate is still too great based on the target vertical speed, then the VMAX vertical mode will command the pull up to maintain Vmo/Mmo-

    • If the Auto-Throttles are disengaged when FPA is selected, they should automatically engage when the vertical mode is changed to FPA, unless the AT Auto-Engage inhibit is selected on the Systems/AT Control Menu.

    • In the inhibited Auto-Throttle case, the aircraft will target the selected vertical speed, but will be unable to maintain airspeed unless the pilot appropriately sets the thrust levers. The left side of the center FMA (Performance/ Auto-Throttle mode) will have an IAS or MACH indication in white, signifying that the IAS or MACH speed control mode component of the VS vertical mode is armed, but can't activate due to the Auto Throttles being inhibited or failed. If the thrust levers are set too low, the aircraft will decelerate and eventually hit a low-speed stop. If set too high, the overspeed protections will eventually function as described above. The overspeed protections will function for Vmo/Mmo, gear and flaps limits.

    • The flight path angle (FPA) vertical mode will continue the descent until ASEL requirements are met for the altitude in the pre-selector window. FPA will not honor FMS altitude limits associated with a STAR or waypoint altitudes programmed by the pilot, only the pre-selector altitude set by the pilot.

  8. Vertical Navigation (VNAV)

    • Vertical navigation in the descent is designed for Standard Terminal Arrival Routes (STARs) where various altitude, and speed, restrictions exist on a defined route of flight. ATC can subsequently clear the pilot to "descend via ... " to an approach, requiring the pilot to meet all the intermediate altitude restrictions on the descent. The VNAV mode is a useful automation tool that allows the pilot to input the lowest ATC assigned altitude limit into the GP altitude pre-selector window and the flight guidance system manages the task of meeting all the intermediate step-downs and level off restrictions on the arrival.

    • VNAV uses the pilot specified descent angle (Perf lnit Descent tab) and any FMS constraints from the STAR, or input by the pilot, to compute a flight path from the destination back up to the top of descent (TOD). The pilot input descent angle is used wherever there are no FMS constraints (e.g. no arrival loaded) or from the first point on the STAR back up to the TOD. The TOD is depicted on the vertical situation display (VSD) to identify where the airplane should begin the descent to stay on the FMS calculated path.

    • Vertical track alerts appear on the SV-PFD and MAP displays, per the figure shown above. The vertical track alert, or VTA, will annunciate on the PFD as "VERT ALRT TRK CHG" one minute prior to the aircraft reaching the TOD. This allows the pilot time to coordinate for a descent clearance and dial the altitude pre-selector down to the ATC cleared altitude. VNAV will automatically begin the descent on the computed path, starting at the TOD, at the descent angle (and speeds) specified in the Descent Modes menu of Perf lnit or on the path computed by the FMS to satisfy any STAR or pilot entered constraints.

    • The vertical mode for this descent is called VPATH, and annunciates on the rights side of the vertical mode FMA. VPATH will level off at the next lowest allowable altitude, based on either a FMS altitude constraint at a waypoint or the altitude in the pre-selector window. If the pre-selector is dialed down to an altitude on the approach or the minimums for the approach, then the FMS will fly the constructed path through all of the arrival constraints, automatically adjusting the descent angle between two constraints to arrive at the next point at the correct altitude. In VNAV, the FMS will also comply with any required speed changes specified by the STAR, or based on altitude (e.g. 250 KIAS below 10,000 MSL). Furthermore, the FMS will calculate the deceleration points to arrive on speed and altitude at the next specified set of constraints.

    • VNAV will continue descending until VASEL requirements are met for the highest of either the altitude in the pre-selector window or the next STAR altitude restriction is reached. If, during a VNAV descent, the altitude pre-selector isn't decreased to a lower altitude prior to the start of descent for the next altitude constraint, then the aircraft will not automatically start the descent.

    • The PFD will annunciate the vertical track alert (VTA) one minute prior to the planned start of the descent. But, if the pilot doesn't dial down the altitude pre-selector, the FMA will remain in VALT even if the STAR allows a further descent. This normally only can occur at the TOD, since the path is typically constructed for a continuous descent to stay between the arrival altitude limits and then uses the pilot input descent data for TOD to the first point on the arrival. There may be some arrivals with an initial descent and a subsequent extended period at a fixed altitude, but those are rare. If ATC restrictions limit the continuous descent and the next start descent constraint is missed, then once ATC directs a lower altitude past the original desired descent point, and the pre-selector is decreased, the FLCH button must be manually selected to continue the VNAV descent (VFLCH). When the pilot approaches the initial descent path from the TOD, and the altitude pre-selector has not be set lower than the cruise altitude to begin the descent, a "Reset ALT select?" message will be displayed to the pilot on the TSC prior to the VPATH intersection point. This message will also appear, as advanced warning, when the pre-selector is set below the aircraft, but when staying on the current constructed path requires lowering of the pre-selector to stay on the path.

References

Gulfstream GVII-G500 Airplane Flight Manual, Revision 1, August 31, 2018

Gulfstream GVII-G500 Ground and Flight Operations, undated, release as part of GAC-AC-GVII-G500-OM-002, February 20, 2019

Gulfstream GVII-G500 Production Aircraft Systems, Revision 1, Oct 1, 2018

Revision: 20190603
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