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Unusual Attitude Recovery

G500 Abnormal Procedures

THIS IS A WORK IN PROGRESS


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Operating Manual Procedure

[G500 Ground and Flight Operations, Unusual Attitude Recovery, p. 110]

General

  • The SV-PFD is not permitted to display an "all sky" or "all terrain" image when the aircraft is inflight. Because of this, a small, fixed portion of the sky is always displayed at very low pitch angles. Correspondingly, a fixed portion of the terrain is always displayed when the aircraft is at very high pitch angles.

  • The SV-PFD progressively handles undesired aircraft attitude states, with two display formats. These are called the intermediate attitude displays and the unusual attitude displays. The intermediate attitude display mixes elements of blue over brown with SVS so that the crew always has a sense of sky versus terrain, even when at low altitudes or mountainous terrain environments. The intermediate attitude display descriptions and activation criteria are the following:

  • Intermediate Display-- High-Pitch (Climb) Angle Activation

  • Geometric altitude, above the ground, is less than 15,000 feet and the aircraft pitch attitude exceeds +16 to +20 degrees pitch. The pitch limit is +20 degrees at the terrain surface and linearly decreases to +16 degrees pitch at 15,000 feet above the terrain. This intermediate attitude display is exited, and goes back to the normal SV-PFD after 4 seconds, when pitch attitude is reduced to less than 16 to 20 degrees, based on the altitude.

  • Geometric altitude is greater than or equal to 15,000 feet and the aircraft pitch attitude exceeds +16 degrees. This intermediate attitude display is exited, and goes back to the normal SV-PFD after 4 seconds, when pitch attitude is reduced to less than +16 degrees.

  • Intermediate Display-- High-Pitch (Climb) Description

  • With terrain turned on, the intermediate display has a solid shade of brown partially fade into view on the ground side of the zero pitch line (ZPL) to help maintain attitude awareness when the aircraft pitches up and exceeds the angles described above. The brown shading fades in, over the top of the SVS ground presentation, over a 3 degree pitch increase from the initial trigger value (16-20 degrees). When it's fully presented, the brown overlay is 25% transparent.

  • As altitude increases, the displayed terrain tends to drop to the bottom of the display (no bank), and even a small pitch up can make the terrain drop low enough to result in an undesirable sky versus ground representation. To counteract this, a representative ground section, and artificial horizon, is always displayed at the bottom of the screen. This ground display and artificial horizon line do not correspond to the real world representation (i.e. nonconformal), but provide situational awareness to the pilot regarding the direction of the ground and orientation of the horizon. In this case, the lower pitch ladder values may not be displayed. Additionally, the higher pitch ladder displays that do remain are not displayed in correct relationship to the artificial horizon line.

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    Photo: PFD Initial Intermediate Display Mode (Nose High), G500 Ground and Flight Operations, Unusual Attitude Recovery, fig. 48

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  • The next increment of the intermediate display mode will fade in two pitch tape chevrons that indicate the direction toward the zero pitch line, positioned between the 25 and 30 degree pitch ladders, and between the 30 and 35 degree pitch ladders. These pitch tape chevrons fade-in as the pitch transitions from 26 to 28 degrees, and fade-out as the pitch transitions from 28 to 26 degrees.

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    Photo: PFD Full Intermediate Display Mode (Nose High), G500 Ground and Flight Operations, Unusual Attitude Recovery, fig. 49

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    Intermediate Display -- Low-Pitch {Dive) Angle Activation

  • The pitch limit for the appearance of this intermediate display is at dive angles greater than -7.5 degrees, for all altitudes. This intermediate attitude display is exited, and goes back to the normal SV-PFD after 4 seconds, when pitch attitude is reduced to less than -7.5 degrees.

  • Intermediate Display -- Low-Pitch {Dive) Description

  • With terrain turned on, the intermediate display has a blue shading which partially fades over the upper portions of the SVS terrain display to help maintain attitude (sky) awareness when the aircraft pitches down and exceeds the angles described above. The blue shading fades in, over the top of the SVS ground presentation, over a 1 degree negative pitch increase from the initial trigger value (-7.5 degrees). When it's fully presented, the blue overlay is 50% transparent.

  • As the dive angle increases, the displayed sky on the SV-PFD tends to displace off the top of the display (no bank), and very small dive angles can. To counteract this, a representative sky section and artificial horizon is always displayed at the top of the screen. In this case, the sky display and horizon line do not correspond to the real world representation (i.e. nonconformal), but provide situational awareness to the pilot regarding the direction of the sky and orientation of the horizon. In this case the pitch ladders closest to the horizon may not be displayed. Additionally, the pitch ladder displays that remain are not displayed in the correct relationship to the artificial horizon line.

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    Photo: PFD Initial Intermediate Display Mode (Nose Low), G500 Ground and Flight Operations, Unusual Attitude Recovery, fig. 50

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  • The next increment of the intermediate display mode (diving) will fade in three pitch tape chevrons that indicate the direction toward the zero pitch line, positioned between the -20 and -25 degree pitch ladders, between the -25 and -30 degree pitch ladders, and between the -30 and -35 degree pitch ladders. These pitch tape chevrons fade-in as the pitch transitions from - 10 to -13 degrees, and fade-out as the pitch transitions from -13 to -10 degrees.

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    Photo: PFD Full Intermediate Display Mode (Nose Low), G500 Ground and Flight Operations, Unusual Attitude Recovery, fig. 51

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    Unusual Attitude Displays

  • The unusual attitude display appears immediately, when the aircraft pitch attitude exceeds 30 degrees of climb or dive, or if the bank angle exceeds 65 degrees. The unusual attitude display remains until the pitch attitude is reduced to less than 15 degrees of climb or dive, and roll is reduced to less than 30 degrees, for at least 2 seconds. The pitch lines in the unusual attitude display are compressed, similar to the HUD unusual attitude display, and are not accurately scaled on the sky/ground backdrop. The sky/ground backdrop are represented by solid blue and brown coloring, with all FMA, navigation, terrain, runway and obstacle information removed. There are also three gray lines on each side of the ground (brown) portion of the display that are extending radials from the center of the zero--pitch line, fading out at the ends.

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    Photo: PFD Unusual Attitude Mode (Bank Exceedance), G500 Ground and Flight Operations, Unusual Attitude Recovery, fig. 52

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  • All other symbols are removed during unusual attitude mode except: the airspeed tape, including low speed awareness and maximum operating speed parameters, the altitude tape, including low altitude awareness parameter, metric altitude (if selected), Mach readout, AOA readout, 180 degree HSI compass card, HSI aircraft symbol, and heading readout.

  • When the unusual attitude mode is active with pitch values greater than or equal to +10 degrees (climb), a double chevron is displayed with the tip at 60 degrees and a single chevron with the tip at 30 degrees on the pitch ladder display. The chevrons are removed when the pitch boresight is less than +5 degrees.

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    Photo: PFD Unusual Attitude Mode (Nose High Pitch Exceedance), G500 Ground and Flight Operations, Unusual Attitude Recovery, fig. 53

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  • When in unusual attitude mode with pitch values less than or equal to -10 degrees (dive), a double chevron is displayed with the tip at -60 degrees and a single chevron with the tip at -30 degrees. The chevrons are removed when the pitch boresight is less than -5 degrees (less than 5 degrees of dive).

  • During unusual attitudes, the + and - 90 pitch symbols are displayed at the center of the +90 degree and -90 degree pitch lines respectively.

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    Photo: PFD +90 Degree Pitch Symbol (left), -90 Degree Pitch Symbol (right), G500 Ground and Flight Operations, Unusual Attitude Recovery, fig. 54

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  • In unusual attitude mode, the normal boresight or aircraft symbol is replaced with an enlarged boresight symbol and fixed to center, as shown below.

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    Photo: Unusual Attitude Modes Enlarged Boresight, G500 Ground and Flight Operations, Unusual Attitude Recovery, fig. 55

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    Procedural Narrative

    CAUTION

    A SUSPECTED UNUSUAL ATTITUDE MAY BE A FAILED ATTITUDE SOURCE. FIRST INDICATIONS MAY BE DRAMATICALLY INCREASING OR DECREASING AIRSPEED AND ATTITUDE. CONFIRM ATTITUDE BY CROSS CHECKING OTHER ATTITUDE SOURCES.

    Upon detecting an unusual attitude, the Pilot Flying (PF), assisted by the Pilot Monitoring (PM), will immediately initiate a recovery to straight and level flight by performing the appropriate actions described below:

    1. Nose High Unusual Attitude Recovery:

    2. Increase throttles to MCT and increase angle of bank, not to exceed 90°, in the same direction of any existing turn. As the nose of the aircraft approaches the horizon, decrease bank angle to level the wings and set the flight path vector near the horizon. This type of recovery will avoid negative G-Forces.

    3. Nose Low Unusual Attitude Recovery:
    4. Smoothly reduce power to idle, level the wings, and ease the flight path vector up to the horizon. Use the speed brakes to assist in reducing the speed, if required.

References

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

Gulfstream GVII-G500 Ground and Flight Operations, undated

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

Revision: 20190603
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