HUD Question
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HUD Question
G'day
Just wondering what the arrow is near the far threshold in this pic? Is it a traffic/TCAS arrow?
Photos: Boeing 737-832 Aircraft Pictures | Airliners.net
Thanks
Just wondering what the arrow is near the far threshold in this pic? Is it a traffic/TCAS arrow?
Photos: Boeing 737-832 Aircraft Pictures | Airliners.net
Thanks
Warning Toxic!
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Heading is 283M on top digital scale and large horizontal scale across the middle and bottom compass scale. The Flight Path Vector (small aeroplane symbol with a circle) shows a descent and right drift. The arrow being offset to the right on the compass scale will be Track Line. Nice picture for 28R at SFO with the HU overlay.
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Horizon pointer I believe.
I believe you are asking about the small veritcal arrow pointing upward just below the horizin. That is the "horizon pointer" and has 3 degrees of blank space on each side of it on the horizon line. In this picture finding the horizon is no problem, but it is designed to help the pilot locate the horizon in the HUD.
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Don't think so. It says at the bottom in digits Hdg 274, Crs 283. You can see the Hdg bug above the long horizontal compass line on 274, and the Crs bug is the Up arrow below the compass line on 283. The little down arrowhead just above the compass line is associated with the attitude indicator just above. You are going where that Up arrow is pointing, just stick it on the runway and your tracking is without error.
The long compass horizontal line is also the artificial horizon, with above it the attitude indicator (body angle) display with a V in it and bank indicator above, and below the compass line, the peculiar circle with wings is the flight path vector showing where the actual flight path is going- sit that on the runway threshold and you will have a happy outcome! However, it does incorporate a drift display which is why it is off to the right, so the actual flight path is really accurate in a vertical sense only, not horizontal. The horizontal offset display showing drift has an unknown scale all of its own. Not sure what the broken horizontal lines above 580 in the middle are.
The long compass horizontal line is also the artificial horizon, with above it the attitude indicator (body angle) display with a V in it and bank indicator above, and below the compass line, the peculiar circle with wings is the flight path vector showing where the actual flight path is going- sit that on the runway threshold and you will have a happy outcome! However, it does incorporate a drift display which is why it is off to the right, so the actual flight path is really accurate in a vertical sense only, not horizontal. The horizontal offset display showing drift has an unknown scale all of its own. Not sure what the broken horizontal lines above 580 in the middle are.
Last edited by Rainboe; 23rd Jan 2009 at 15:45.
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Not sure what the broken horizontal lines above 580 in the middle are.
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Of course! Only things to crack now are the funny white circle on the threshold which looks like something to do with the Flight Path Vector, and the circular scale top right with 5.0 next to it!
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The hud is in primary mode.
3 other modes progressively declutter the display. They're essentially intended for IFR approach or Cat111 (both including flare cues) and visual circuits/ approach.
The arrows near the far threshold show track and heading - you can work out which is which from the fcc demands for a slight fly left. If in any doubt you can see the heading bug sitting well offset to the left. The little cut out in it nestles neatly into the heading when both actual heading and bugged heading coincide. They're often slightly separated as there is a huge difference between single digit entered in the MCP and the actual heading which is accurate to a 5th or 6th of a degree.
This hyper accuracy also extends to the vertical plane with the command circle altered to white for clarity and showing the minor fly down command which is also reflected in the glideslope arrow against the scale to the right.
Another glance at the the aircraft symbol shows two far more subtle cues other than simply placing it over the faked white demand circle.
The left 'wing' of the aircraft shows a slight thickening below it. This extends into a vertical bar growing upwards or downwards and indicating over or below bugged speed. The bar is dynamic, constantly extending or retracting, and when its length extends to the equal diameter of the aircraft symbol that's 5 knots off the selected speed. The bar will extend further to a maximum of 15 knots and is linear. Therefore if you look closely you can see it is a fraction of a knot below bugged speed. One of life's minor joys on the line is watching folks chasing that last fraction of a knot
The second cue there is the right facing carat next to the left wing. It's probably easiest to get it across as an energy pointer. Carat slides down in this case indicating very slightly low energy. Following the command circle would tend to correct both the subtle cues as well as correcting for the ILS.
The hud looks to be the rather elegant 4000 series which attracted the attention of a designer rather than my 2000 done by a draughtsman who'd lost his set of French curves and was a fan of battleship bridge hardware.
The pitch markings vary very usefully and go hand in hand with total change to the display during unusual attitudes to aid recovery. Indications of both bank angle and pitch change markedly to assist the pilot.
Finally, the circular display top right with the 5 in it. There are several options available over and above the basic system and I believe it to be angle of attack. It's a case of believe it to be as my lot didn't opt for it
Regards
Rob
3 other modes progressively declutter the display. They're essentially intended for IFR approach or Cat111 (both including flare cues) and visual circuits/ approach.
The arrows near the far threshold show track and heading - you can work out which is which from the fcc demands for a slight fly left. If in any doubt you can see the heading bug sitting well offset to the left. The little cut out in it nestles neatly into the heading when both actual heading and bugged heading coincide. They're often slightly separated as there is a huge difference between single digit entered in the MCP and the actual heading which is accurate to a 5th or 6th of a degree.
This hyper accuracy also extends to the vertical plane with the command circle altered to white for clarity and showing the minor fly down command which is also reflected in the glideslope arrow against the scale to the right.
Another glance at the the aircraft symbol shows two far more subtle cues other than simply placing it over the faked white demand circle.
The left 'wing' of the aircraft shows a slight thickening below it. This extends into a vertical bar growing upwards or downwards and indicating over or below bugged speed. The bar is dynamic, constantly extending or retracting, and when its length extends to the equal diameter of the aircraft symbol that's 5 knots off the selected speed. The bar will extend further to a maximum of 15 knots and is linear. Therefore if you look closely you can see it is a fraction of a knot below bugged speed. One of life's minor joys on the line is watching folks chasing that last fraction of a knot
The second cue there is the right facing carat next to the left wing. It's probably easiest to get it across as an energy pointer. Carat slides down in this case indicating very slightly low energy. Following the command circle would tend to correct both the subtle cues as well as correcting for the ILS.
The hud looks to be the rather elegant 4000 series which attracted the attention of a designer rather than my 2000 done by a draughtsman who'd lost his set of French curves and was a fan of battleship bridge hardware.
The pitch markings vary very usefully and go hand in hand with total change to the display during unusual attitudes to aid recovery. Indications of both bank angle and pitch change markedly to assist the pilot.
Finally, the circular display top right with the 5 in it. There are several options available over and above the basic system and I believe it to be angle of attack. It's a case of believe it to be as my lot didn't opt for it
Regards
Rob
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Rob,
Like you fly this HUD on a daily basis. We bought the AOA option. You are correct that is what the circle with the 5.0 is displaying. Each increment is 5 degrees with zero being at the 4:30 clock position of the circle. When the jet is in the landing mode the band appears next to and on the outside of the circle showing that you are in the correct AOA range. The triangle at the top is stick shaker and moves as you change configuration climb/descend. As you increase AOA the pointer, running from the center of the circle to the diameter, would move “up” in a counterclockwise direction. As you decrease AOA the pointer moves "downward" in a clockwise direction.
I checked my manuals looking for an answer to the vertical arrow below the horizon question and all I could come up with was a non-specific reference to a “horizon pointer”. It’s odd that none of the pictures in my HUD manual specifically identify the vertical arrow.
I have been looking at this thing in flight and noticed that it “ghosts” just like the airplane symbol and flight path vector does in a strong cross wind. I think I like your “track” explanation more than my horizon pointer answer. It’s odd that my company issued manual doesn’t address it, more likely I haven’t found the correct reference yet. If it is a track pointer then we need to correct our manual.
So much to know...........
Like you fly this HUD on a daily basis. We bought the AOA option. You are correct that is what the circle with the 5.0 is displaying. Each increment is 5 degrees with zero being at the 4:30 clock position of the circle. When the jet is in the landing mode the band appears next to and on the outside of the circle showing that you are in the correct AOA range. The triangle at the top is stick shaker and moves as you change configuration climb/descend. As you increase AOA the pointer, running from the center of the circle to the diameter, would move “up” in a counterclockwise direction. As you decrease AOA the pointer moves "downward" in a clockwise direction.
I checked my manuals looking for an answer to the vertical arrow below the horizon question and all I could come up with was a non-specific reference to a “horizon pointer”. It’s odd that none of the pictures in my HUD manual specifically identify the vertical arrow.
I have been looking at this thing in flight and noticed that it “ghosts” just like the airplane symbol and flight path vector does in a strong cross wind. I think I like your “track” explanation more than my horizon pointer answer. It’s odd that my company issued manual doesn’t address it, more likely I haven’t found the correct reference yet. If it is a track pointer then we need to correct our manual.
So much to know...........
If we are all talking about the little vertical arrow with a stalk........ from memory it points to the inbound course of the landing runway. What I cannot recall is whether it is the landing runways inbound course as found in the FMC or whether it is the course as decided by the course on the Capt's side of the MCP.
The symbol will ghost when the course is outside of the c30 degree view on the HUD, and will show you "quickest" way to turn to align to the runways inbound course.
FWIW we normally change to A III mode by now which "de-clutters" the display and provides even greater accuracy, and overall the HUD is the most commonly unserviceable item on our fleet of 30+ 737's!
The symbol will ghost when the course is outside of the c30 degree view on the HUD, and will show you "quickest" way to turn to align to the runways inbound course.
FWIW we normally change to A III mode by now which "de-clutters" the display and provides even greater accuracy, and overall the HUD is the most commonly unserviceable item on our fleet of 30+ 737's!
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Rainboe, you're wrong. The heading is 283. The HDG 274 in the bottom left hand corner is the SELECTED heading on the MCP panel. Look at the compass rose at the bottom of the screen. The hdg is 283, and the hdg bug (2 rectangles joined together) is selected to 274. You can also see the hdg bug towards the top on the left of the horizontal line that says 28 29 (the hdg display).
The only thing I can't see is the localiser deviation scale? Is it in the compass rose at the bottom?
The only thing I can't see is the localiser deviation scale? Is it in the compass rose at the bottom?
