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Practical application of the HUD


KirkR
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A discussion kicked off within another thread, regarding the scenarios where the HUD is of most value (IRL) and perspectives from the Challenger pilots regarding how they apply it IRL.  I suppose we'll have to set EVS aside for now, until XP provides Hot Start what is necessary to bring in imagery from the cone cameras (that will be fantastic).

Hopefully this will bring this information more visible for the community.

A picture that @VictoryAJ posted in the other thread:

image.png.f1e0bd218efc96e5100826261b89b62f.png

 

 

Edited by KirkR
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In our company on the CL60 we have EVS (soon to-be EFVS-A) operational approval down to 100ft on an ILS IAP. Then obviously the HUD would be used. 

Besides that we see company wide that the background of the pilot determines often the use: pilots having had extensive use on fighter aircraft as e. g. the F16 tend to use the HUD a lot more. 

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Assuming EVS is quite expensive (infrared camera<s> and associated equipment), what are the key justification factors for it?  I'm assuming:

-  safety and risk reduction for people and assets
-  cost avoidance (fewer go arounds / missed approaches, etc.)

And finally, as configured on the Hot Start CL60, what are the approach limits that can be shot if holding within the regulations regarding equipment?  I assume the pilot / crew certification aspect is there IRL.

 

Edited by KirkR
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Kirk, 

Some of this will be difficult minus a brief video or stream - which I hope to get to soon.

The combination of HUD symbology that is located near the center of the ADI offers a lot of information in a small space. 

  • Flight Path Vector Symbol
  • Acceleration Cue
  • Speed Error Tape

During approach you will also add the Glideslope Reference Line to this mix. With this combination, with a very tight 'scan' you can ascertain the jet's energy state - your deviation from your set speed, where the jet is actually pointed, and if the FPV is on top of the glideslope reference line (typically 3 degrees) and both of those are on top of the runway threshold behind it - life is good. If this isn't the case - all of the info to fix it is right there. Your eyes do not have to scan between the outside world and the PFD. (Especially beneficial if you need reading glasses or cheaters - because the PFD is often in that zone beyond which cheaters are effective, but not far away enough that it's not a little difficult. The HUD is set to optical infinity, so it's as if the symbology is a part of the outside world - once you're accustomed to it)

Some folks have a hard time 'seeing' through the HUD IRL and getting accustomed to it - I used to be one of those folks. I likened it to someone holding their outstretched hand in front of my face. I could either focus on the hand or what was behind it - but not both - so I dismissed the HUD as a distraction.  Then I spent some time as a flight sim enthusiast (100 hours or so) flying the VRS Superbug on FSX and the Falcon in Falcon BMS. I was able to learn the value of the FPV and, on those aircraft, the AOA "E Bracket".  The Challenger is not an F/A-18 of course, and we aren't landing it on a carrier - but the bulleted combination I listed above,  provides similar information in the same small space.

Seeing through the HUD takes persistence and practice.  It took some time to fight the urge to spin the HUD brightness to zero around 100ft above touchdown so I 'could see' and land well again. Yes, as I learned how to look through the HUD the landings were occasionally firm.

Situations which I specifically enjoy / leverage the HUD:

  • Visual approach vertical awareness:
    • The glideslope reference line (GRL) at the typical 3 degree position within the pitch ladder....you can practically extend this in your mind off the HUD's edge to get an idea before lineup is complete if you are high or low. If the threshold is below the GRL, you're high, and if the threshold is above the GRL, you're low. It doesn't take much to interpolate and get an idea of the approach angle you're actually on. For example, if the -5 degree pitch ladder line is superimposed over the threshold.....you're really high! Imagine flying a 5 degree PAPI and how steep that would be. That is exactly what that would mean - you're on a 5 degree path to the threshold.
      • Adding to this - not every runway is served by VGSI equipment (VASI, PAPI, etc). Having the HUD with that GRL gives you vertical path awareness. (Terrain/obstruction clearance, however - is on you, meaning that although the HUD tells you the angular path you're on to the runway......that is ALL it's telling you.)
  • Weather deviations:
    • The FPV answers the important question of 'will we be in THAT buildup?'. Even before I learned to appreciate the HUD - I used it for that purpose, almost like a submarine captain reaching for the periscope. I'd pull the HUD down to answer 'that' important question.  And - you can easily tell how far left or right you'll need to deviate because the heading scale is right there. Not only left or right - but will we be over that stuff?
  • AOA Limit awareness / Stall recovery:
    • In the big sim you can tell the difference between a HUD pilot and a PFD pilot during the stall recovery series.  The HUD will display an AOA limit cue as the jet hits .70 units AOA. The FPV touching the AOA limit cue will be when the shaker fires. As you go through your stall recovery memory items - the HUD shines in answering that question of 'how much do I lower the nose / reduce the AOA'  It's easy - get the FPV under the cue - and keep it there.  The recovery back to normal flight is also greatly aided and accelerated because if you pull too hard (accelerated stall) you will see that AOA limit cue plummet back at your FPV. The pilots using the HUD properly are very smooth with their stall recoveries - and they don't arbitrarily dump the nose and unload excessively because they have INFO!  (The cue vanishes at .65 units during the recovery)
  • Windshear Recovery:
    • Same as the AOA Limit awareness. You can firewall the jet and raise the nose to the AOA limit - and have a nice reference to efficiently maintain an appropriate recovery attitude. Without the HUD we'd be told to get that nose up to the shaker and just keep it out of shaker. That was a little difficult to do without actually 'finding the shaker' and reducing a little. Windshear recoveries in the big sim are often this rapid pitch upwards with sporadic encounters with the shaker - and sometimes depending how un-smooth the captain is - some encounters with pusher. Watching the sim from the outside observation platform is entertaining when they're doing stall recovery series and windshear encounters. The HUD makes it not-so-entertaining for the cheap seats.
  • CFIT recovery:
    • The FPV doesn't lie. If the FPV is pointed at granite - you're going to die. Move the FPV elsewhere.
  • Normal boring level offs and turns:
    • The FPV symbol has gull wings on it. Those aren't because they want you to feel like an F4U Corsair pilot. The angled portion of the gull wing is 30 degrees. You can keep your eyes in the center of that scan with all the stuff I listed above - and achieve a beautiful 30 degree standard bank - just like Uncle George the autopilot - by simply rolling until the gull wings are parallel with the horizon line. No need to move your eyes up to the roll pointer. That would require more pay! The FPV is a thing of beauty for level offs as well. When the FPV is on the horizon - you aren't climbing or descending. It takes the mystery out of the level off in regards to 'how hard do I need to push, or am I pushing too much....
  • Air work in the sim:
    • When we first get to the schoolhouse and big sim we still have to do steep turns. It gets the blood flowing and gets us used to the sim, but let's be honest - we spend most of our time in the jet on the AP. Some more than others. Our scans get rusty. Having the list of symbology I mentioned up top along with the FPV means that when the ATS and FD get turned off (required) the HUD pilots barely deviate from any parameter. You can balance a marble on the glareshield if the pilot knows how to use the HUD to his or her advantage.
  • Takeoff Vspeed awareness:
    • With the HUD you can look down the runway and see the Vspeeds the PM is calling out - as they pass. It's a great cross check and the situational awareness on takeoff is amazing.

In summary - it takes time and effort to get used to. If you don't leverage it correctly and you get overwhelmed by all that green symbology that really isn't adding value to your day,  then unfortunately it will be as if someone is holding their hand in front of your face. The moment you realize you can manage the lateral, vertical, and energy states of the jet by looking at an area the size of a dime or quarter - is a big moment.

We'll save EVS for another day.

 

 

Edited by VictoryAJ
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@Victory AJ - 

Do you use the Flight Director side bars during takeoff as well?

I pop out PFD and the two MFD's (right one for the checklist) and drag them into my RealSimGear G1000 screens.  But my main use of them (given the HUD is my primary focus) is PPOS, engines, checklist and such.

Also, would you rotate the HUD up and out of view (and at what point) for the Teterboro ILS 6 Circle 1 approach as you navigate between the tower and the stadium on the turn/descent into final stabilization for 1?

What would you say is your cockpit "scan" process in context of using the HUD (as PF)?

Edited by KirkR
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5 hours ago, KirkR said:

@Victory AJ - 

Do you use the Flight Director side bars during takeoff as well? I'm not sure I understand what you mean by 'side bars'

I pop out PFD and the two MFD's (right one for the checklist) and drag them into my RealSimGear G1000 screens.  But my main use of them (given the HUD is my primary focus) is PPOS, engines, checklist and such.

Also, would you rotate the HUD up and out of view (and at what point) for the Teterboro ILS 6 Circle 1 approach as you navigate between the tower and the stadium on the turn/descent into final stabilization for 1? No - The HUD is too valuable in helping me stay on speed and on path - while keeping my eyes outside on things like the towers and MetLife (which per James should not be overflown if you desire a stable approach by 500 AGL) The only time the HUD gets rotated up and out of view is getting in or out of the seat or moving around / leaning forward. Sometimes when scanning for distant traffic that is called out - it's easier to dim the HUD all the way vs put it away. 

What would you say is your cockpit "scan" process in context of using the HUD (as PF)? In critical phase my focus is up through the HUD. If applicable per conditions I will incorporate the PFD to see the TAT and the VS setting. (this is one thing about the HUD that bugs me is you see measured VS, not target VS) I'll leverage the PFD/MFD for situational awareness and to see the 'picture' This is a periodic slow scan and while I'm down there - maybe I'll sneak the PFD ADI into things since my head is 'down'. I'm not scanning from HUD to PFD, MFD, FMS, etc in the context like you'd be scanning your primary flight instruments.

 

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4 hours ago, VictoryAJ said:

Do you use the Flight Director side bars during takeoff as well? I'm not sure I understand what you mean by 'side bars'

My mistake.  Not FD side bar; rather, Takeoff Reference Box is what I was referencing.

image.png.2ec291d18450d2e30f50e8bd44e1439c.png

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The TRLI comes along with selecting TOGA. IRL the TRLI is immediately available at rotation. The source cited above is from a training vendor's HUD client guide. More than occasionally things will be lost in translation from the source material to the 3rd party pubs. 

The current sim implementation is based on the client guide (your screenshot) - and the TRB (as the 3rd party has renamed it from TRLI) does not appear until 50ft RADALT. IRL we do not rotate into 'never never land' on the HUD with no pitch target. As the nose rises and the 10-15 degree pitch tape becomes visible - the TRLI is indeed there for you to rotate into. I provided feedback and believe this will be corrected in a future update.

As soon as you transition from TO to another vertical mode, the TRLI vanishes. (Pressing sync on the yoke being one example - which changes the vertical mode to PITCH, or pressing VS is another example)

 

Edited by VictoryAJ
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4 hours ago, VictoryAJ said:

The current sim implementation is based on the client guide (your screenshot) - and the TRB (as the 3rd party has renamed it from TRLI) does not appear until 50ft RADALT. IRL we do not rotate into 'never never land' on the HUD with no pitch target. As the nose rises and the 10-15 degree pitch tape becomes visible - the TRLI is indeed there for you to rotate into. I provided feedback and believe this will be corrected in a future update.

To clarify, you are saying that the TRB is visible as soon as the pitch tape becomes visible, not RADALT 50ft as with the sim?

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  • 1 month later...

Is there a video or doc that shows the HUD symbology and functionality?  I'm interested in using it for guidance during approach/landing.

<<EDIT>>    Please disregard.   Not sure how I missed it the first time around, but I found some good info right here on the forums.  Specifically, this thread:

 

Edited by Pops McDaddyo
Follow-up.
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