AH-64A Symbology Sets

[bradmick]

So, reading through the Alphas -10, I was looking at the symbology description in Chapter 4 (lots different than it is in the Delta I must say) and was thinking, this has got to be a bit confusing. It talks about there being four modes and shows all four of them in the figure it says to reference. So I figured i'd break it down into what you would actually see in each symbology mode.

 

This requires you have the -10 to know what each symbol is, but it breaks each picture breaks down what you'll see when you select that as your symbology. If you've any questions, ask away!

 

Brad

[bradmick]

Actually, for those without the -10, heres the key:

 

1 LOS Reticle Represents the line-of-sight of the crew member selected sight. The reticle

will flash whenever the selected sight LOS is invalid or has failed. The reticle

will also flash whenever the ‘‘ACTIONED’’ weapon is in a NO-GO state. The

High Action Display will prompt the crewmember for the appropriate

condition.

 

2 Alternate Sensor

Bearing

Indicates to the crewmember the other crewmember sensor relative bearing

with respect to helicopter center line.

 

3 Lubber Line Index indicates helicopter magnetic heading.

 

4 Cueing Dots Indicates cued direction for target acquisition. All four dots present and

flashing indicate IHADSS boresight is required.

 

5 Command Heading Indicates heading to fly to next navigation waypoint designated by the

doppler navigation system if bob-up mode of the flight symbology is not

selected. Indicates fixed heading reference when bob-up mode is selected.

6 Acceleration Cue A vectorial representation of the helicopter longitudinal and lateral

acceleration; the display origin is normally the end of the velocity vector. In

the hover and bob-up modes, when the velocity vector exceeds its maximum

scale, the display origin changes to the center of the LOS reticle. The

Acceleration Cue will flash when the HARS inertial platform has gone into

free inertial mode, usually as a result of the LDNS going into memory.

 

7 Velocity Vector A vectorial representation of the helicopter longitudinal and lateral ground

velocities; in hover mode, maximum scale is 6 knots groundspeed; in

transition mode 60 knots groundspeed. The velocity vector will flash when

the HARS inertial platform has gone into the free inertial mode if MUX switch

is in SEC.

 

8 Heading Scale Helicopter magnetic heading scale.

 

9 Cued LOS Reticle A virtual reticle indicating the cued LOS to the appropriate crew member.

Used with the cueing dots.

 

10 Missile Constraints Indicates the required orientation to align the helicopter into constraints for

Hellfire missile engagements. When all constraints for the mode of

engagement are satisfied, the box will go from ‘dashed’ to ‘solid’.

 

11 Radar Altitude A digital display of radar altitude. Displays in 1-foot increments to 50 feet and

in 10-foot increments above 50 feet.

12 Rate of Climb An analog display of rate of climb moving along the left side of the vertical

scale. Tick marks designate 500 and 1000 fpm rates of climb or descent.

 

13 Radar Altitude Vertical

Scale

A vertical scale for the analog display of radar altitude. Tick marks designate

10-foot increments from 0 to 50-feet, and 50-foot increments from 50 to 200

feet. The scale is blanked when radar altitude is greater than 200 feet.

14 Radar Altitude Vertical

Tape

An analog display of radar altitude moving within the vertical scale; also

blanked above 200 feet.

 

15 Skid/Slip Lubber Lines Represent the limits for ‘ball centered’ flight.

 

16 Skid/Slip Ball Indicates the amount of skid or slip the helicopter is experiencing.

 

17 Cued LOS DOT Indicates the cued LOS location within the field of regard. The cued LOS

DOT will flash when the HARS inertial platform has gone into the free inertial

mode.

 

18 Field of View Represents the instantaneous FOV of the crewmember sensor within the

field of regard.

 

19 Sensor Field of

Regard

Represents the total gimbal limits possible for the respective crew member

sensor.

 

20 High Action Display Refer to paragraph 4.28.

21 Rocket Steering

Cursor

Indicates the required orientation to align the helicopter into constraints for

2.75 inch FFAR rocket engagements. During fixed or flight stow rocket

delivery, a broken I beam will appear.

 

22 Hover Position Box Displays helicopter relative position when bob-up mode is selected and

represents an 8 foot square. Maximum displacement is 48 feet laterally or

longitudinally. The Hover Position Box drifts while in a stationary hover.

A drift of 6 feet the first minute is possible, and as much as 23 feet after 5

minutes when using EGI with GPS keyed tracking 4 or more satellites. If

these conditions are not met, a drift of 21 feet per minute is possible.

 

23 Head Tracker Indicates the pilot head position relative to the center line of the helicopter.

This is a virtual symbol whose range of display is 30 degrees vertically and

40 degrees horizontally about the nose of the helicopter. When CPG selects

PLT/GND ORIDE and SIGHT SEL NVS, this symbol indicates his head

position.

 

24 Airspeed A digital display of true airspeed when the ADSS is turned on or not failed. If

the ADSS is OFF or failed, display is ground speed in knots from the doppler

navigation system. Range is 0 to 200, omnidirectional.

 

25 Horizon Line Indicates pitch and roll attitude of the helicopter.

 

26 Engine Torque Indicates the engine torque output by the engines. The magnitude is the

larger of the two engine torque values. If a greater than 12% torque split

occurs between engines, the displayed torque value will flash. At an engine

torque value of 98% or higher, a box around the torque value flashes to

indicate an impending engine torque limit. Symbolic torque value maximum

is 120%.

[Geier]

Interesting read, thx:thumbup:

[bradmick]

The only thing i'm not 100% on is whether or not the Command Heading Index is displayed in the Transition mode. I'll have to consult with my dad, as he flew the Alphas for a long time before switching over to Longbow.

 

Brad

[bradmick]

So a little more on these sets. For those wondering where these would be used.

 

Hover symbology is pretty self-explanatory. It's the symbology set you use while hovering. The velocity vector tells you which direction you're drifting and how much. Using the image we can see that the aircraft displayed is hovering forward and to the right at about 3 knots. How do we know this? Because the Velocity vector saturates (reaches the bottom of the heading tape, well more specifically the line below the luber line) at 6 kts ground speed. Further interpretation tells us that in a few seconds the aircraft will actually be hovering a little less right and little faster, about one knot. How can we tell this? By looking at the acceleration cue. The acceleration cue can be likened to the cyclics position. It can really throw one off when first trying to learn to hover the Apache. You start chasing the cue before you have a feel for the aircraft and bad news befalls you. The aircraft is hovering at about 98% torque at 100 ft off the ground.

 

Bob-Up symbology is handy for if you're in a battle position or wanting to keep yourself over one spot while in an OGE hover. The hover box, which is in the lower left hand corner is an approximately 8 foot box which is planted on the ground when you switch over to hover symbology. When it is fully displaced, you have moved 48 feet from your postion. In the image, the aircraft is forward and right, to get back to the original position, you'll want to hover back and left. The acceleration cue is indicating however that the aircraft is going to be continuing hovering away from the hover box. This is handy, as I said before, if you're in a battle position. You can hover laterally, un-mask and then re-mask and hover back to your original position. Or if you're in a confined area and need the accuracy. Another use for it is say you're coming into a confined area and want to clear yourself into it this is what you do: 1) when the obstacle is under your butt you go into bob up mode, continue flying forward, knowing it displaces at 48 feet when its fully displaced to the bottom of the symbology your aircraft should be cleared to the rear.

 

Transition symbology is useful when transitioning into forward flight. The velocity vector displaces at 60 knots and you also gain the artificial horizon. It gives you a good idea of ground track as well. If the velocity vector is centered, that's where you're going.

 

Cruise symbology is pretty self explanatory I think. It gives you all the information you need in order to fly the aircraft without having to bring your attention inside the cockpit.

 

Apologies for the sporadic updates, spending the day with the girlfriend.

 

Brad

[Sundowner.pl]

Great stuff :thumbup:

 

BTW, Apache CPG would come in handy on this forum too :music_whistling:

[Jascha]

Thank you so much for this info.

 

Two things:

 

2 Alternate Sensor

Bearing

Indicates to the crewmember the other crewmember sensor relative bearing

with respect to helicopter center line.

 

I don't quite get it. Is it: where the other guy is looking at this time?

 

21 Rocket Steering

Cursor

 

Can't find this one. :huh:

[Sundowner.pl]

Here's complete picture:

 

[Jascha]

Thanks! I guess it some sort of super top secret cursor. :lol:

[Ditch3r]

Thanks for Sharing!! :thumbup:

[bradmick]

probably should have clarified. There is Flight symbology, which is broken down into four sub categories, which I covered previously, then there is weapons symbology which I haven't govered. I only left on the images what was relevant to each symbology set.

 

The CPG will have the exact same symbology as the pilot, as the sets are linked. If the CPG clicks onto Hover, the Pilot will have hover symbology, if the Pilot switches to Cruise, the CPG will have Cruise symbology.

 

Weapons are fairly straight forward, as depending on what you have WASd that's what will appear in the symbology.

 

Brad

[bradmick]

I just realized I missed a question. The Alternate sensor bearing lets the pilot/cpg know where the PNVS or TADS system is looking relative to the helicopters center line.

 

Brad