The M-2000C HSI explained

This information should appear in the next update:

The Horizontal Situation Indicator HSI

The Horizontal Situation Indicator, commonly called HSI, is an aircraft flight instrument that combines a Heading Indicator with a VOR-ILS indicator.

Unlike standards HSI used in American aircrafts, the M-2000C HSI was designed to require little to no pilot input. It consists of a compass rose to indicate aircraft true or magnetic heading, a selected auto pilot heading indicator, two needles, a four-digit mechanical display, an operational mode indicator and four failure flags.

The only pilot required inputs are: Operational Mode and TACAN Offset values.

The HSI also controls the type of heading that will be used on all navigation instruments: True or Magnetic.

1. Selected AP Course indicator.

2. DME display

3. Needles

*· Needle 1: Wide.

*· Needle 2 Thin.

4. VAD (TACAN Offset Point) input knob.

5. Compass Rose.

6. HSI mode selector

*· Cv NAV

*· Cm NAV

*· TAC

*· VAD

*· ρ

*· θ

*· TEL

Operational Modes

The HSI has four operational modes: INS/VOR Navigation (NAV), TACAN/VOR Navigation (TAC), TACAN Offset Point/VOR Navigation (VAD) and Ground Controlled Interception (TEL).

*· NAV (main INS/VOR navigation mode): In this mode, the HSI connects with the INS and displays waypoint navigation information along with bearing to selected VOR/ILS station. This is the only mode that allows to select between true or magnetic headings, through its two sub modes:

Cv NAV: In this mode the system uses true heading. Cv stands for Cap vrai (French for True heading).

Cm NAV: In this mode the system uses magnetic heading. Cm stands for Cap magnétique (French for Magnetic heading).

The selection of Cv NAV or Cm NAV also affects the heading indicators in the following instruments: HUD, HDD, ADI.

All other following modes are part of the “Cm” category, i.e. they use only magnetic heading indications.

*· TACAN/VOR Navigation (TAC): In this mode the HSI connects to the TACAN receiver.

*· TACAN Offset Point/VOR navigation (VAD): In this mode the HSI calculates and navigates towards a point offset to the current TACAN station. The offset point location is introduced in polar coordinates, distance and magnetic bearing, by using the VAD (TACAN Offset Point) input knob.

This mode has three sub modes:

VAD: This is the operational mode. The HSI checks if it a valid TACAN Offset Point exists and calculates distance and bearing from the current aircraft position towards the offset.

ρ (Rho): This mode is used to enter the distance in nautical miles from the TACAN station to the offset point.

θ (Theta): This mode is used to enter the magnetic bearing from the TACAN station to the offset point.

Please refer to the TACAN Offset (VAD) Navigation chapter for more information on this mode.

*· Ground Controlled Interception (TEL): In this mode the HSI displays interception information: bearing, distance and interception course, towards a target. This mode is used when the aircraft is under Ground Controlled Interception (GCI).

Note: Ground Controlled Interception is not simulated in DCS and thus this mode is not operational.

HSI Information provided

The HSI needles and indicators show navigation information based on the selected mode.

TACAN Offset Point (VAD) Navigation

The HSI has a special navigation mode called VAD (Vecteur ADditionel, French for Additional Vector). The VAD is an offset point calculated from the position of the selected TACAN station. The system uses the Needle 1 (Wide) and DME (numeric) indicators. The Needle 1 and DME flags will be shown if it is not possible to engage the VAD mode.

For the VAD mode to be operational the following conditions must be met:

1. A TACAN station has been selected and the signal must be received.

2. The polar coordinates from the geographical position of the TACAN station to the offset point have been entered into the system.

When all conditions are met the HSI will navigate directly towards the TACAN Offset Point (VAD) from the aircraft position.

How to operate the VAD mode:

1. Select a TACAN station in the TACAN receiver.

2. Place the HSI in TACAN mode and check that it is receiving a signal from the TACAN station (the DME and Needle 1 flags should not be shown).

3. Place the HSI in θ (Theta) mode.

4. Enter the magnetic bearing from the TACAN station to the VAD by rotating the VAD input knob. The Needle 1 indicator will rotate towards the selected value, note that the DME window will also show the corresponding numeric value.

5. Place the HSI in ρ (Rho) mode.

6. Enter the distance from the TACAN station to the VAD (offset point) by rotating the VAD input knob. The DME indicator will start showing the selected distance. The valid values are from 001.0 to 999.0 nautical miles. The Needle 1 indicator will show the selected θ (Theta)

7. Place the HSI in VAD mode. The system will calculate the geographical position of the offset point from the current aircraft position: The Needle 1 indicator will show the magnetic bearing to the VAD and the DME indicator will show the distance in nautical miles (see the graphic).

HSI Failure Flags

The HSI has four failure flags that indicate an error condition in the HSI:

1. DME Failure: It shows a bar across the DME indicator, blocking the value shown. If it is visible there is an error in the DME value.

2. Needle 1 Failure: It shows an orange tab in the right flag window. If it is visible, then it is not possible to show the bearing to the selected navigation point/station. The Needle 1 indicator will park itself to the 135º position.

3. Needle 2 Failure: It shows an orange tab in the left flag window. If it is visible, then it is not possible to show the bearing to the selected VOR/ILS station. The Needle 2 indicator will park itself to the 225º position.

4. Heading Failure: It shows an orange tab in the bottom flag window. If it is visible, then it indicates a problem with the heading gyro and thus the heading value shown in the HSI and other heading indicators is not reliable. If shown it is recommended to use the auxiliary heading gyro.

Thanks Zeus, good work! :)

Nice!

I have to hand it to the French. They took all the TLAR out of what we used to call point-to-point navigation in TACAN and VOR/DME. Every USAF student first learned how to do it on an RMI (essentially a M2k HSI without anything except a VOR bearing pointer) in the T-37 and the easier method in the T-38 using the more or less eternally standard US HSI. I like it. Simple, elegant, almost fool proof. The only art to using it is applying a wind correction as you proceed to the point. That's basic stuff if you've ever learned to use an RMI. Thanks for the lesson.

Just thinking out loud here but this might be very useful as a very simple solution to avoiding confusion over where you are relative to a bullseye. I'd have to play with it in the jet to figure out how I could use it best.

Hope someone who really understands how and when to use these cool HSI features, will make a YouTube video demonstrating them. A lot of this is over my head.

Thanks for the instructions.

Sent from my SPH-L900 using Tapatalk

I don't think it's physically implemented yet. Zeus tends to give a brief on the system just prior to the feature being introduced to the player branch. The VAD function is the only one really deserving of much mention. The true/mag/TACAN switch settings are quite straightforward.

If you understand how to input an INS BAD waypoint offset by distance, direction (rho, theta) then you get TACAN VAD. If not, no worries.

1. Dial in a TACAN station, change the HSI to TAC display. Needle and range are shown direct to station.

2. HSI to VAD, should be no change of display as rho, theta values start at zero unless the pilot changes them.

3. Switch HSI to rho and crank in a distance. The knob in the lower left of the HSI is held + or - until the range readout is what you want. Let's say that it's 10.0nm in this case.

4. Switch HSI to theta and crank in a direction in a similar way. It will be the digital numbers that usually show a distance but instead it will read 001-360 degrees. Perhaps we set it to 090 for east.

5. Switch back to VAD to use these inputs. Now instead of the needle and range readings showing the direction and distance to the TACAN they show the direction and distance to a calculated point 10nm east of the station. If you fly directly to this location by following the needle until range shows zero you will be 10nm east of the TACAN station.

6. To resume using the TACAN station's true position switch the HSI mode to TAC. Alternatively crank the rho value to 0 in which case TAC and VAD will be identical as before.

A note on the lower left knob for entering the offset data: I've never touched the real thing but I give dollars to doughnuts that it's a spring-loaded device like a household doorknob. Commonly on these types of controls rotating the knob slightly makes the values change slowly and rotating more makes the values change faster. When release the knob spring returns to the original position. And if it was missed before I think the art for the knob is upside down. Every Mirage picture I've seen has the knob with the + on the left, - on the right, and the curved arrow below in the "smiley face" orientation.

I can imagine that the VAD function is useful for entering the Final Approach Point / Fix or any other point on the approach procedure.

Is there any other operational use for this function?

I don't think it's physically implemented yet. Zeus tends to give a brief on the system just prior to the feature being introduced to the player branch.

Just one small correction. It was introduced in the last 2.0.3 update.

I can imagine that the VAD function is useful for entering the Final Approach Point / Fix or any other point on the approach procedure.

Is there any other operational use for this function?

To setup a rendezvous point to form up before flying towards the target or a rendezvous point after an attack. Specially if your flight is using the "spoke wheel" attack (everybody coming from different points of the compass to confuse the anti-air defenses).

The advantage of the VAD over the BAD is that you don't need a flight plan.

@ Frederf good brief :)

The logical order whould be 4 then 3 though, as in:

- Set the bearing first (and while you do that, it's displayed by both the wide needle and the DME window

- Then set the distance (and at this point only the DME window moves, the needle stays where you put it at the previous step, giving you a chance of controlling your VAD input)

- Then with just "one click" (one step to the left) you activate the VAD.

I don't think it's physically implemented yet. Zeus tends to give a brief on the system just prior to the feature being introduced to the player branch. The VAD function is the only one really deserving of much mention. The true/mag/TACAN switch settings are quite straightforward.

 

If you understand how to input an INS BAD waypoint offset by distance, direction (rho, theta) then you get TACAN VAD. If not, no worries.

 

1. Dial in a TACAN station, change the HSI to TAC display. Needle and range are shown direct to station.

 

2. HSI to VAD, should be no change of display as rho, theta values start at zero unless the pilot changes them.

 

3. Switch HSI to rho and crank in a distance. The knob in the lower left of the HSI is held + or - until the range readout is what you want. Let's say that it's 10.0nm in this case.

 

4. Switch HSI to theta and crank in a direction in a similar way. It will be the digital numbers that usually show a distance but instead it will read 001-360 degrees. Perhaps we set it to 090 for east.

 

5. Switch back to VAD to use these inputs. Now instead of the needle and range readings showing the direction and distance to the TACAN they show the direction and distance to a calculated point 10nm east of the station. If you fly directly to this location by following the needle until range shows zero you will be 10nm east of the TACAN station.

 

6. To resume using the TACAN station's true position switch the HSI mode to TAC. Alternatively crank the rho value to 0 in which case TAC and VAD will be identical as before.

 

A note on the lower left knob for entering the offset data: I've never touched the real thing but I give dollars to doughnuts that it's a spring-loaded device like a household doorknob. Commonly on these types of controls rotating the knob slightly makes the values change slowly and rotating more makes the values change faster. When release the knob spring returns to the original position. And if it was missed before I think the art for the knob is upside down. Every Mirage picture I've seen has the knob with the + on the left, - on the right, and the curved arrow below in the "smiley face" orientation.

This is helpful... Thanks!

Sent from my SPH-L900 using Tapatalk

@ Frederf good brief :)

The logical order whould be 4 then 3 though, as in:

- Set the bearing first (and while you do that, it's displayed by both the wide needle and the DME window

- Then set the distance (and at this point only the DME window moves, the needle stays where you put it at the previous step, giving you a chance of controlling your VAD input)

- Then with just "one click" (one step to the left) you activate the VAD.

Good tip. I didn't see that the theta value was shown in both the digital counter and the needle both.

This information should appear in the next update:

 

The Horizontal Situation Indicator HSI

 

Great ! VAD looks very useful for ILS entry point.

I'm going to get roasted for this.

Since the possibilities of ever seeing GCI in DCS are pretty slim (at least in the short term), would you be open to considering enabling the TEL mode under guidance of your own RADAR?

You already get the underlying feature with RDO mode and/or the directeur d'ordres (little square in the VTH).

I therefore don't feel the need to introduce it in the HSI too.

The idea behind having TEL in the HSI is because when you use TEL you're at long distance.

When you use radar, you're at shorter distance.

I'm going to get roasted for this.

 

Since the possibilities of ever seeing GCI in DCS are pretty slim (at least in the short term), would you be open to considering enabling the TEL mode under guidance of your own RADAR?

GCI is usually used for intercepts beyond 100 nmiles.

Logic dictates that it works this way:

1. The radar network detects and enemy formation a long distance away.

2. The interceptors are alerted, but since it will take some time for the enemy to arrive, they have time to do all ground stuff, including INS alignment.

3. The interceptors take-off and upon contact with ground control set their radar for GCI. This is the TEL option that appears when the system is in AA mode.

4. Ground control vectors individual aircraft to individual targets.

5. The pilot enters target data into the system by using the VTB switches. It took me a long time to know what they were for.

7. The target icon appears in the VTB. This is calculated from the data sent by the GCI network. From time to time data is updated via data link.

8. When the aircraft reaches engagement range it deactivates GCI mode and track with its own radar for weapons guidance.

At this point the TEL mode in the HSI is redundant since you are already tracking it in the VTB and HUD.

GCI is usually used for intercepts beyond 100 nmiles.

 

Logic dictates that it works this way:

1. The radar network detects and enemy formation a long distance away.

2. The interceptors are alerted, but since it will take some time for the enemy to arrive, they have time to do all ground stuff, including INS alignment.

3. The interceptors take-off and upon contact with ground control set their radar for GCI. This is the TEL option that appears when the system is in AA mode.

4. Ground control vectors individual aircraft to individual targets.

5. The pilot enters target data into the system by using the VTB switches. It took me a long time to know what they were for.

7. The target icon appears in the VTB. This is calculated from the data sent by the GCI network. From time to time data is updated via data link.

8. When the aircraft reaches engagement range it deactivates GCI mode and track with its own radar for weapons guidance.

 

At this point the TEL mode in the HSI is redundant since you are already tracking it in the VTB and HUD.

Any chance to get this working with LotATC?

Uh uh uh. Would be nice, he?

Worth mentionning is the system never really got into service; let's assume very scarce documentation.

Uh uh uh. Would be nice, he?

 

Worth mentionning is the system never really got into service; let's assume very scarce documentation.

My guess is because France bought E-2 Hawkeyes from the US and the ground network was superseeded. I was told that unfortunately the TEL system is incompatible with the American datalink.

My guess is because France bought E-2 Hawkeyes from the US and the ground network was superseeded. I was told that unfortunately the TEL system is incompatible with the American datalink.

French Air Force bought E-3F Sentry.

The E-2 Hawkeye belong to French Navy.

Contrary to GCI, we can't have an E-3F airborne H24/ 7...

I don't know if there is a link. Perhaps, it iswhat was projected anyway, but the ~10 years between entry into service of the M-2000Cs and the E-3Fs makes me feel unconclusive.

So..how would one do a TACAN mode Y with a friend who is also with T/R on mode Y. How would i set up to see bearing distance to them?

set up to see bearing

Not possible with 2 2000s

So..how would one do a TACAN mode Y with a friend who is also with T/R on mode Y. How would i set up to see bearing distance to them?

It isn't possible with 2 fighters. You will only get distance.

Only planes like tankers are big enough to carry full TACAN station.

You can have full TACAN beacon on the ground (even if mobile device), on ships, air tankers but not small planes like fighters.