FighterControl

Hoping the collective knowledge on the forum can help me understand the info displayed in this screen grab of a Jaguar GR3/3A HUD.

I've worked out most of the info but need some help with 7 items of information displayed in the photo.



1- The inverted chevron at the centre top of the pic. Is this indicating the magnetic heading in relation to the true heading, or something else altogether? In the video, it doesn't deviate much either side of the centre indicator.
2- The two sets of data displayed, I can't figure out.
3- In the video, the arrow points in different directions and the numbers change throughout the flight, and again I can't figure it out.
4- Not a clue. Possibly to do with speed, but it doesn't change as rapidly with the change in Knots as the GS figure below it does.
5- I think this is to do with speed, Ground Speed in MPH as opposed to Knots displayed above the Mach No. at the top left. It does change rapidly as the Knots change.
6- No Ground Power/ Kilo Volts?
7- The 282 degrees is in connection with the horseshoe icon at the top right of centre, and indicates heading and direction to the next way point. I can't figure out what the G0050 /G005G means though.

Thanks in advance.

Oops forgot something. Between 1&2 on the left, is a > symbol attached to what looks like a Yellow "L" . This doesn't move all that much, unlike the one on the other side, which shows rate of climb.

6 - As the aircraft looks to be quite low, perhaps GPW = Ground Proximity Warning

GPW - Grand-Pa Womble? Could mean located the Wombles on Wimbledon Common!

mabey you could find something like it on the simulator section
they recreate huds very well and might know.....

1. Possible way point direction
3. Degress to waypoint from the aircraft??
5. Ground speed

Hope that helps

Based on other HUD symbology that's documented on the web I'd say...

1 is a two part symbol. the vertical line is the current track (i.e. where the aircraft is going) and the inverted v is the heading bug, to a waypoint, the target, etc. Line the two up and you'll arrive at the point you want to be at.
2 is showing the current heading (172) but I'm not sure on the other data.
3 is probably wind direction and velocity, it should change direction as the aircraft turns.
5 is ground speed in knots. The large number top left is going to be either indicated or calibrated airspeed.
6 is missing a letter and should say NO GPWS. Not sure about the K V here.

From memory, but from a previous iteration,

1. The vertical 'lubber' line shows aircraft heading (usually true but selectable to magnetic). The inverted V is the aircraft track - ie the direction it is travelling across the ground. The horseshoe shows that the aircraft needs to turn to the right to proceed to the next/selected waypoint - or that the waypoint is off to the right. It will eventually come to the middle when the aircraft is tracking to the WPT.

2. Hmmm - it does look like heading but not sure what the rest is.

3. Computed wind. The aircraft knows its heading and airspeed from the pitot/computer, and it knows its track and speed across the ground from the INS, from which it can resolve the wind.

4. Demanded ground speed - to get to the selected waypoint on time.

5. Current ground speed.

7. Bearing and range to next/selected waypoint is 282T and 13.4NM. The demanded GS, to get there on time is 204kts - at the current GS of 271kts, the aircraft would get there 58 seconds early (0:58E).

Looks like takeoff, speed is 255 and accelerating (hopefully) with a GS of 271. If the pilot continues to fly the current heading, the bearing to the WPT will steadily increase, as will the demanded GS to get there on time. When demanded GS and GS match, with the aircraft tracking to the WPT, it will arrive at the planned time.

Some gaps filled there, so thanks for that.

No.2 is nothing to do with the heading, it's just a coincidence it ties with the heading in the screen grab. Throughout the video it stays on that or 168 even when going 180 degrees in the other direction. The next set of numbers was increasing all the time and I thought it was time elapsed, and it got to over 5000 but started going down again in the last 15-20 minutes of the flight.

No.6, for a short period the K was replaced by an S. I worked in Ground equipment and when I see GPW I think ground power, and the KV was what also had me thinking this, but Ground Proximity sounds good, even though "Bitchin' Betty" can be heard saying "Pull Up"., several times, with NO GPW showing.

The > on the left of the screen is for "G", as you can hear the pilot grunting heavily as the "G" comes on and the arrow goes up the scale.

Again, its a long time ago, but I think the > scale on the left is angle of attack - with the double dots at 12 degrees ?? But it will look the same, as more AOA will produce more G - up to a point!

That sounds plausible Stickshaker, as when the aircraft is flying "straight and level", there is still an indication on the HUD.