> For the complete documentation index, see [llms.txt](https://docs.flightsim-studio.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.flightsim-studio.com/boeing-727/systems/flight-instruments.md).

# Flight Instruments

### VERTICAL SPEED INDICATOR

*Indicates airplane rate of climb or descent.*

| <p></p><p><img src="/files/gAEA3i8ajPXPJyzo577l" alt="" data-size="original"></p> | <p></p><p><strong>(1) Vertical Speed Scale</strong></p><ul><li>Indicates vertical speed in feet per minuate x 1000.</li><li>Scale is 0 to 6000 fpm. </li></ul><p><strong>(2) Vertical Speed Pointer</strong></p><ul><li>An accelerometer is incorporated to provide instantaneous reading.</li><li>Positioned by vertical accelerometer and rate of static pressure change.</li></ul> |
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### PNEUMATIC ALTIMETER

*Indicates airplane altitude above reference pressure.*

| <p></p><p><img src="/files/ljhxcNi3VDRynMaRPOeS" alt="" data-size="original"></p> | <p></p><p><strong>(1) Altitude Window</strong></p><ul><li>Indicates vertical speed in feet per minuate x 1000.</li><li>Scale is 0 to 6000 fpm. </li></ul><p><strong>(2) Millibars Window</strong></p><ul><li>Displays barometric setting in millibars as manually set with the <em>BARO set knob</em></li></ul><p><strong>(3) Inches Of Mercury Window</strong></p><ul><li>Displays barometric setting in inches of mercury as manually set with the <em>BARO set knob</em></li></ul><p><strong>(4) Barometric Set Knob</strong></p><ul><li>An accelerometer is incorporated to provide instantaneous reading.</li><li>Positioned by vertical accelerometer and rate of static pressure change.</li></ul><p><strong>(5) 100-Foot Pointer</strong></p><ul><li>Indicates feet on radial dial. Each mark is 20 ft, each digit is 100 ft.</li></ul><p><strong>(6) Inner Altitude Bug</strong></p><ul><li>Manually positioned by altitude bug set knob.</li></ul> |
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### PNEUMATIC AIRSPEED INDICATOR

*Indicates airplane airspeed in knots and mach.*

| <p></p><p><img src="/files/QpkQjKJqnuyC7dzXYtYu" alt="" data-size="original"></p> | <p></p><p><strong>(1) Indicated Airspeed Pointer</strong></p><ul><li>Pointer indicates 0-200 KIAS on outer scale; 200-400 KIAS on inner scale.</li><li>Pointer indicates Mach on window scale.</li></ul><p><strong>(2) Inner Airspeed bug</strong></p><ul><li>Reference speed for autothrottle.</li><li>Manually positioned by (4).</li></ul><p><strong>(3) Airspeed Bugs</strong></p><ul><li>Three manually positioned reference bugs (on outer ring).</li></ul><p><strong>(4) Airspeed Bug Set Knob</strong></p><ul><li>Turned to position inner airspeed bug.</li></ul><p><strong>(5) Max Operating Speed Pointer</strong></p><ul><li>Indicates the max operating speed (Vmo) for existing altitude.</li></ul> |
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### SAT/TAS INDICATOR

*Indicates airplane standard air temperature and true airspeed*

| <p></p><p><img src="/files/ak9vYuwnv0yeUkhnW3Po" alt="" data-size="original"></p> | <p></p><p><strong>(1) Static Air Temperature Indicator</strong></p><ul><li>Indicates static air temperature.</li></ul><p><strong>(2) True Airspeed Indicator</strong></p><ul><li>Indicates true airspeed.</li></ul> |
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### RADIO MAGNETIC INDICATOR

*Combines a magnetic compass with navigation signals from VORs and NDBs to provide bearing information to the selected station.*

| <p></p><p><img src="/files/miIqRpcP38wg7wQTD87h" alt="" data-size="original"></p> | <p></p><p><strong>(1) No. 1 VOR/ADF Selector</strong></p><ul><li>When turned to the left (vertical), selects No. 1 VOR information to the No. 1 VOR/ADF Pointer.</li><li>When turned to the right (horizontal), selects No. 1 ADF information to the No. 1 VOR/ADF pointer.</li></ul><p><strong>(2) No. 2 VOR/ADF Selector</strong></p><ul><li>When turned to the left (vertical), selects No. 2 VOR information to the No. 2 VOR/ADF Pointer.</li><li>When turned to the right (horizontal), selects No. 2 ADF information to the No. 2 VOR/ADF pointer.</li></ul><p><strong>(3) No. 1 & 2 VOR/ADF pointer</strong></p><ul><li>Points towards the selected station based on the given source from (1) & (2).</li></ul> |
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### HORIZONTAL SITUATION INDICATOR

*Integrates the directional gyro, course deviation indicator, and glide slope to provide comprehensive display of flight path relative to a chosen navigation source.*

| <p></p><p><img src="/files/Hb1moSrYjMMtQ5v3vW8e" alt="" data-size="original"></p> | <p></p><p><strong>(1) Miles Window</strong></p><ul><li>Displays associated DME distance.</li></ul><p><strong>(2) Course Window</strong></p><ul><li>Displays course selected by pilot.</li></ul><p><strong>(3) Glideslope Scale & Deviation Pointer</strong></p><ul><li>In conjunction with deviation pointer indicates vertical deviation above or below the glideslope.</li><li>Each mark indicates 1/4-degree.</li><li>Vertical deviation pointer out of view with VOR selected.</li></ul><p><strong>(4) To-From Indicator</strong></p><ul><li>Points toward a line through the VOR station perpendicular to the seleccted course.</li></ul><p><strong>(5) Heading Bug</strong></p><ul><li>Indicates heading selected by pilot.</li></ul><p><strong>(6) Course Deviation Bar & Scale</strong></p><ul><li>As a reference on the course deviation scale, indicates deviation from the selected course.</li><li>Each dot equals 5-degrees on VOR and 1 1/4-degrees on LOC.</li></ul><p><strong>(7) Heading Control</strong></p><ul><li>Rotated to set heading bug.</li></ul><p><strong>(8) Course Control</strong></p><ul><li>Rotated to set course indicator.</li></ul> |
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### ATTITUDE DIRECTION INDICATOR

*Provides information about the orientation of the aircraft relative to the horizon.*

| <p></p><p><img src="/files/3s7TWoFShYyx7LGL6UFU" alt="" data-size="original"></p> | <p></p><p><strong>(1) Go-Around Light</strong></p><ul><li>Illuminates to indicate flight director go-around mode.</li></ul><p><strong>(2) Bank Angle Scale</strong></p><ul><li>Displays roll attitude as indicated by roll index (4).</li></ul><p><strong>(3) Max Bank Angle</strong></p><ul><li>Displays the maximum allowed bank angle.</li></ul><p><strong>(4) Roll Index</strong></p><ul><li>Indicates roll attitude on bank angle scale (2).</li></ul><p><strong>(5) Pitch Scale</strong></p><ul><li>Displays pitch attitude in reference to airplane symbol.</li></ul><p><strong>(6) Fast-Slow Indicator</strong></p><ul><li>Indicates airpseed deviation fast (F) or slow (S).</li><li>References to the captain's inner airspeed bug.</li></ul><p><strong>(7) Glideslope Deviation Scale & Pointer</strong></p><ul><li>Indicates deviation from center of glideslope beam.</li></ul><p><strong>(8) Expanded Localizer Indicator</strong></p><ul><li>Lateral movement from center line indicates displacement from localizer.</li></ul><p><strong>(9) Test Switch</strong></p><ul><li>Push-to-test switch checks the indicator's amplifiers and servos.</li></ul><p><strong>(10) Slip Indicator</strong></p><ul><li>Skid ball indicates amount of yaw.</li></ul> |
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### INSTRUMENT COMPARATOR

*Compares data outputs of flight instruments and displays an appropriate warning when the captain's and first officer's instruments disagree.*

| <p></p><p><img src="/files/7J9O1rdRZRIHisHzhCqv" alt="" data-size="original"></p> | <p></p><p><strong>(1) Monitor Power Light</strong></p><ul><li>Illuminates at loss of electrical power to the comparator.</li></ul><p><strong>(2) Heading Light</strong></p><ul><li>Indicates a heading difference of 6 degrees between HSIs.</li></ul><p><strong>(3) Horizon Pitch Light</strong></p><ul><li>Indicates a difference of 4 to 6 degrees in pitch between ADIs.</li></ul><p><strong>(4) Roll Pitch Light</strong></p><ul><li>Indicates a difference of 4 to 6 degrees in roll between ADIs.</li></ul><p><strong>(5) Glideslope Light</strong></p><ul><li>Both nav receivers mus be tuned to an active localizer freuqnecy; GS flags not in view.</li><li>On at 3/4 to 1-dot difference on HSIs.</li></ul><p><strong>(6) Localizer Light</strong></p><ul><li>Indicates heading selected by pilot.</li></ul><p><strong>(7) Radio Altimeter Light</strong></p><ul><li><p>Indicates a difference between RAs of</p><ul><li>55 ft at 1500 ft</li><li>25 ft at 200 ft</li><li>5 ft at touchdown.</li></ul></li></ul> |
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### RADIO ALTIMETER INDICATOR

*Provides a visual display of airplane terrain clearance, from 0 to 2500 ft. A light will warn the crew that the airplane is at or below the selected altitude.*

| <p></p><p><img src="/files/bY2DHBZx8l3PHlbVWx3d" alt="" data-size="original"></p> | <p></p><p><strong>(1) Altitude Pointer</strong></p><ul><li>Indicates height above ground level (AGL).</li></ul><p><strong>(2) Bug & Control</strong></p><ul><li>Rotated to position bug to selected height</li></ul><p><strong>(3) Test Switch</strong></p><ul><li>Drives altitude pointer to 40 ft and DH light will illuminate.</li></ul><p><strong>(4) DH Light</strong></p><ul><li>Illuminated if airplane is at or below selected height.</li></ul> |
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