BoeingOnFinal
Topic Author
Posts: 440
Joined: Fri Apr 14, 2006 6:47 am

Cat III Approach (with Pic)

Fri Aug 04, 2006 7:32 pm

I saw through some pictures of the lovely DHC Dash 8, and I saw a interesting picture:


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Click here for bigger photo!

Photo © Barry Maas



It has a HUD, how common are those?

And, the remark says: Note the HGS for Cat III capabilities.

What is HGS, I would assume that is the HUD?

And are they required for a Cat III approach?
norwegianpilot.blogspot.com
 
canyonblue737
Posts: 28
Joined: Tue Aug 01, 2006 1:32 pm

RE: Cat III Approach (with Pic)

Fri Aug 04, 2006 9:07 pm

HGS is a heads up guidance system. Many are certified to allow Cat IIIA hand flown approaches.
 
AirWillie6475
Posts: 2372
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RE: Cat III Approach (with Pic)

Sat Aug 05, 2006 4:34 am

All horizon air aircraft the the hud. Can't imagine why, especially since everybody says the pacific northwest has such nice weather.
 
AirWillie6475
Posts: 2372
Joined: Thu Jan 27, 2005 1:45 pm

RE: Cat III Approach (with Pic)

Sat Aug 05, 2006 4:41 am

Quoting Canyonblue737 (Reply 1):
HGS is a heads up guidance system. Many are certified to allow Cat IIIA hand flown approaches.

How do they work? I've heard there's a target that represents the runway and you just try to follow it until touchdown?
 
2H4
Posts: 7960
Joined: Tue Oct 19, 2004 11:11 pm

RE: Cat III Approach (with Pic)

Sat Aug 05, 2006 4:51 am




Quoting AirWillie6475 (Reply 3):
How do they work? I've heard there's a target that represents the runway and you just try to follow it until touchdown?

I'm sure there's some variation from one to another, but you basically keep a little circle centered in a bigger circle until you go visual.




2H4


Intentionally Left Blank
 
cptspeaking
Posts: 567
Joined: Mon Apr 24, 2006 2:49 pm

RE: Cat III Approach (with Pic)

Sat Aug 05, 2006 8:17 am

Quoting 2H4 (Reply 4):
I'm sure there's some variation from one to another, but you basically keep a little circle centered in a bigger circle until you go visual.

Thats the way I understand it as well. I got to fly a pc-based simulator at a Delta booth this past May. It was a 737 HUD sim, and all you do is keep that small circle (flight path) in the big one. Then, as you get closer, it shows a representation of the runway edge and even tells you when to flare by flashing an X on the screen. Also shown is your airspeed and altitude with trend arrows.

The program was from Honeywell...I asked the guy running the booth if there was any way to get a copy, but he said they couldn't give it out. Too bad  Smile

Your CptSpeaking
...and don't call me Shirley!!
 
2H4
Posts: 7960
Joined: Tue Oct 19, 2004 11:11 pm

RE: Cat III Approach (with Pic)

Sat Aug 05, 2006 8:38 am




Quoting CptSpeaking (Reply 5):
Then, as you get closer, it shows a representation of the runway edge and even tells you when to flare by flashing an X on the screen.

Upon exiting the runway, GAME OVER - INSERT COIN should appear.

The previous top ten high scores, based on the lowest degree of glideslope/localizer deviations, should also appear.

Yep. Things would be different if I was in charge....




2H4


Intentionally Left Blank
 
cptspeaking
Posts: 567
Joined: Mon Apr 24, 2006 2:49 pm

RE: Cat III Approach (with Pic)

Sat Aug 05, 2006 2:14 pm

Quoting 2H4 (Reply 6):
Upon exiting the runway, GAME OVER - INSERT COIN should appear.

The previous top ten high scores, based on the lowest degree of glideslope/localizer deviations, should also appear.

Yep. Things would be different if I was in charge....

Somebody has been reading SlamClick's topic on the Brasilian 737s and wet compasses  Wink

Great idea though! I'd put more coins in...

Your CptSpeaking
...and don't call me Shirley!!
 
2H4
Posts: 7960
Joined: Tue Oct 19, 2004 11:11 pm

RE: Cat III Approach (with Pic)

Sat Aug 05, 2006 7:57 pm




Quoting CptSpeaking (Reply 7):
Somebody has been reading SlamClick's topic on the Brasilian 737s and wet compasses

 yes  Guilty as charged....




2H4


Intentionally Left Blank
 
wing
Posts: 1357
Joined: Sun Oct 01, 2000 9:10 pm

RE: Cat III Approach (with Pic)

Fri Aug 11, 2006 5:22 pm

Quoting 2H4 (Reply 6):
Upon exiting the runway, GAME OVER - INSERT COIN should appear.

The previous top ten high scores, based on the lowest degree of glideslope/localizer deviations, should also appear.

Yep. Things would be different if I was in charge....



Quoting CptSpeaking (Reply 7):
Somebody has been reading SlamClick's topic on the Brasilian 737s and wet compasses

Great idea though! I'd put more coins in...

Your CptSpeaking

I am glad you guys like my posts but there is a side note here."Game Over ,insert coin "appears after the engine shut down,if you "exit" from the runway in low visibility it would be more like "Game over Try again!"

I took this especially for you two from my last flight,have fun.WING

follow me on my facebook page" captain wing's journey log"
 
2H4
Posts: 7960
Joined: Tue Oct 19, 2004 11:11 pm

RE: Cat III Approach (with Pic)

Fri Aug 11, 2006 11:29 pm



Ha....that's great, Wing! Thanks for thinking of us!  biggrin 




2H4


Intentionally Left Blank
 
cptspeaking
Posts: 567
Joined: Mon Apr 24, 2006 2:49 pm

RE: Cat III Approach (with Pic)

Sat Aug 12, 2006 2:55 am

Hahahahaha thats awesome!! Thanks a bunch, I'm definitely saving this picture  Smile

Your CptSpeaking  wave 
...and don't call me Shirley!!
 
9VSRH
Posts: 127
Joined: Mon Apr 11, 2005 5:30 pm

RE: Cat III Approach (with Pic)

Sat Aug 12, 2006 8:13 am

Wing just out of interest what is the CHG CODE entry for? A bit of a wild guess but... Is it like the code for the flight deck door lock??
 
doug_or
Posts: 3138
Joined: Sat Mar 18, 2000 9:55 am

RE: Cat III Approach (with Pic)

Sat Aug 12, 2006 10:04 am

Quoting BoeingOnFinal (Thread starter):
It has a HUD, how common are those?

In the US I know QX has them, as does AS and WN.
When in doubt, one B pump off
 
2H4
Posts: 7960
Joined: Tue Oct 19, 2004 11:11 pm

RE: Cat III Approach (with Pic)

Sat Aug 12, 2006 2:40 pm




Quoting Wing (Reply 9):
"Game Over ,insert coin "appears after the engine shut down

...So what pilot actions produce this?






2H4


Intentionally Left Blank
 
BoeingOnFinal
Topic Author
Posts: 440
Joined: Fri Apr 14, 2006 6:47 am

RE: Cat III Approach (with Pic)

Sat Aug 12, 2006 5:35 pm

CTRL+ALT+Delete  Smile Standard Microsoft Airlines procedure!

Thanks for all your help, and for funny imputs.
So let me see if I got it correctly:

A HUD display is not required to operate a cat III approach, but it's required for a handflown cat III approach?
norwegianpilot.blogspot.com
 
flymatt2bermud
Posts: 551
Joined: Tue Jan 31, 2006 11:58 am

RE: Cat III Approach (with Pic)

Sun Aug 13, 2006 4:02 am

Quoting BoeingOnFinal (Thread starter):
Are they required for a Cat III approach?

HUDs are not required by regulation however they may be required by company OPS SPECs.

Quoting AirWillie6475 (Reply 2):
All horizon air aircraft the the HUD. Can't imagine why, especially since everybody says the pacific northwest has such nice weather.

HUDs can be very during night approaches, especially the flair.

Quoting 2H4 (Reply 4):
you basically keep a little circle centered in a bigger circle until you go visual.

True and most pilots continue with the HUD guidance even after breaking out of clouds and typically to touchdown. The biggest and obvious advantage is not having to transition from a lower panel to the windscreen, rather you transition through the HUD.

The sensitivity on the HUD is amazing. 10 degree magnetic is nearly the entire width of the display. From the pilot flying view the sensitivity makes it seem like you are correcting all over the place, but from the non flying view it looks like you nailed the approach all the way down the chute even though you are making frequent pitch and roll adjustments if you are hand flying.
"When once you have tasted flight, you will forever walk the earth with your eyes turned skyward" Leonardo Da Vinci
 
canyonblue737
Posts: 28
Joined: Tue Aug 01, 2006 1:32 pm

RE: Cat III Approach (with Pic)

Sun Aug 13, 2006 9:19 am

There is a lot of special symbology in a HUD and much of it has to do with 1) what brand of HUD and 2) what mode the HUD is in. To vastly symplify, during a CAT III ILS the hud will display a small circle which represents where the HUD computer thinks you should have the aircraft pointed to perfectly fly the ILS and then there is a slightly larger circle which represents where you aircraft is actually pointed. You then manuever the aircraft to position your larger circle directly over the smaller circle, constantly chasing it around to keep it captured. At the same time if not using autothrottles it shows you a speed trend as a small bar which raises or lowers above a center line near the middle of the HUD. (slower or faster from your set target approach speed) You can then move the thrust levers to add more or less power which creates an opposite bar. The goal is to match the thrust lever bar to the same size as the speed trend bar. For example if you are slowing rapidly from where you should be the speed trend bar will grow downward from the center line. You then would push the thrust levers forward to add power and create a power bar equal in size to the speed trend bar. As the aircraft reaccelerated to the proper speed the speed trend bar would shrink back to the center line and you too would reduce thrust to match. If you get the speed perfect there would be neither a speed trend bar, or a thrust lever bar but rather you would simply see the center line.

So the whole way down you and your big circle are chasing the little circle, and you are moving the thrust levers to match the size of the speed trend bar until there are no bars (which almost never happens because speed is rarely perfect. It feels like a lot of work when you are flying it but it really works miracles, it is very possible to fly to 50 AGL then to flare and landing with speed varying no more than 1-2 knots and having the ILS bar flawlessly pegged... all by hand.
 
SlamClick
Posts: 9576
Joined: Sun Nov 23, 2003 7:09 am

RE: Cat III Approach (with Pic)

Sun Aug 13, 2006 9:38 am

One really good thing about the HUD is that the display on the glass is focused at infinity so there is zero transition time for your eyes to go from instrument to runway and lighting. Really nice for us old gray heads in the left seat.

Symbology may be similar to the PFD or simplified.

Also I'm not aware of any operations where they affect allowed minimums. They might, but I just don't know any.
Happiness is not seeing another trite Ste. Maarten photo all week long.
 
canyonblue737
Posts: 28
Joined: Tue Aug 01, 2006 1:32 pm

RE: Cat III Approach (with Pic)

Sun Aug 13, 2006 10:44 am

Quoting SlamClick (Reply 18):
Also I'm not aware of any operations where they affect allowed minimums. They might, but I just don't know any.

I am not sure if you meant "allowed" minimums because indeed for example in SWA's 737's the HGS/HUD allows the aircraft to fly to CAT IIIA mins instead of the normal CAT I mins. Further several airports, such as MDW, have custom airline approach plates that allow for slightly lower than publicly published approach plates if the HUD is used.
 
canyonblue737
Posts: 28
Joined: Tue Aug 01, 2006 1:32 pm

RE: Cat III Approach (with Pic)

Sun Aug 13, 2006 10:57 am

Here is a picture of a HUD in CAT IIIA mode...

http://www.aatl.net/pictures/hgs4000catIIIat50-2.jpg

Near the center you can the large circle, with the small circle inside of it. Like I said the goal is keeping the big circle over the small circle with your flying. The -3.00 line is the set GS decent angle, in this case standard. AS 130 in the upper left corner is the set speed, while the big 130 near the center is the actual speed. The ">" is the speed trend carot, near the center now since the speed is dead on the AS 130 target. GS 130 in the bottom left is the ground speed. You can see a drawn 10 pitch line (solid) near the top, and the bank indicator too. -650 is the decent rate, the vertical line in the middle is the localizer deviation (in this case centered since the a/c is dead on).

The mode overall is very "decluttered" compared to a normal inflight mode with more conventional tape displays etc. and is meant to focus the pilot on pure speed and aircraft control on the approach.
 
SlamClick
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Joined: Sun Nov 23, 2003 7:09 am

RE: Cat III Approach (with Pic)

Sun Aug 13, 2006 11:00 am

Quoting Canyonblue737 (Reply 19):
CAT IIIA mins instead of the normal CAT I mins.

And other airlines have Cat IIIA or IIIB without a HUD.
The minimums themselves are NOT predicated on the installation and use of a HUD.

If XYZ airlines has the requirement in their manual then it is required - but only for them. If you wrote a manual that said that the captain must wear one yellow sock and the FAA approved it then that would be the law - for you but not for anyone else.
Happiness is not seeing another trite Ste. Maarten photo all week long.
 
flymatt2bermud
Posts: 551
Joined: Tue Jan 31, 2006 11:58 am

RE: Cat III Approach (with Pic)

Sun Aug 13, 2006 12:17 pm

The new Air Force C17's have eliminated two Pilot Displays because of the HUD (at both pilot positions). The HUDs accuracy and reliability eliminates the need for the redundant panel information.
"When once you have tasted flight, you will forever walk the earth with your eyes turned skyward" Leonardo Da Vinci
 
DH106
Posts: 595
Joined: Wed Jun 15, 2005 5:32 pm

RE: Cat III Approach (with Pic)

Sun Aug 13, 2006 6:50 pm

Great replies - very interesting!

The DME 2.0 caption at lower right - presumably that's not the ILS DME as the aircraft is arriving over the threshold but the DME of some other NAV aid that's tuned?
...I watched c-beams glitter in the dark near the Tanhauser Gate....
 
BoeingOnFinal
Topic Author
Posts: 440
Joined: Fri Apr 14, 2006 6:47 am

RE: Cat III Approach (with Pic)

Sun Aug 13, 2006 8:49 pm

Awsome information you guys. But, is it a law that the captain is not allowed to take pictures when 50 feet above the ground on final? :p
norwegianpilot.blogspot.com
 
cptspeaking
Posts: 567
Joined: Mon Apr 24, 2006 2:49 pm

RE: Cat III Approach (with Pic)

Sun Aug 13, 2006 10:00 pm

Quoting DH106 (Reply 23):
The DME 2.0 caption at lower right - presumably that's not the ILS DME as the aircraft is arriving over the threshold but the DME of some other NAV aid that's tuned?

Actually it is the ILS DME...the localizer is located at the far end of the runway, so the DME reading includes the entire length of the runway. Take a look at this approach and you'll see what I mean...I put the CAT I approach because the CAT III didn't have any clear DME information for each fix on it. The best place to see it is the profile view towards the bottom right. You'll see that right at the threshold the DME is 1.8 from I-DMP (the localizer).

Your CptSpeaking  wave 

...and don't call me Shirley!!
 
CosmicCruiser
Posts: 2049
Joined: Tue Feb 22, 2005 3:01 am

RE: Cat III Approach (with Pic)

Sun Aug 13, 2006 10:03 pm

Quoting DH106 (Reply 23):
The DME 2.0 caption at lower right - presumably that's not the ILS DME as the aircraft is arriving over the threshold but the DME of some other NAV aid that's tuned?

I didn't look at the pic but by what you wrote , of course it's the LOC DME. Most LOC antennas are at the opposite end of the runway on a front crs. and 2.0 would be about right for a nice long runway...CC
 
canyonblue737
Posts: 28
Joined: Tue Aug 01, 2006 1:32 pm

RE: Cat III Approach (with Pic)

Sun Aug 13, 2006 10:15 pm

Quoting SlamClick (Reply 21):

And other airlines have Cat IIIA or IIIB without a HUD.
The minimums themselves are NOT predicated on the installation and use of a HUD.

If XYZ airlines has the requirement in their manual then it is required - but only for them. If you wrote a manual that said that the captain must wear one yellow sock and the FAA approved it then that would be the law - for you but not for anyone else.

Not quite. The aircraft itself needs additional equipment to be certified down to CATIIIA for example. The requirements for that equipment are UNIVERSAL to all airlines but there are a variety of different types stuff that can meet the requirment. That equipment could be a dual autopilot that can autoland for example. In the case of SWA for example they don't have dual coupling autopilots required to certify a 737 down to CATIIIA mins but they do have the HUD which allows it also. This isn't an OPS SPEC deal, it really is an aircraft certification issue... it is just that allowing an aircraft to fly down to low mins can be done with a variety of equipment and procedures, of which a HUD is just one.

[Edited 2006-08-13 15:33:49]

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