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Top right, there's a little cross-hair - it looks like it's for lining something up, since on the second pane there's a little dot.

I haven't seen this on any other HUDs. Appears to be present on all variants including Super Hornet.

F-18 HUD

source

F-18 HUD

simulated - source

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  • $\begingroup$ Interesting....., $\endgroup$ – Carlo Felicione Nov 1 '18 at 17:26
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It is a "Standby Reticle":

A fixed standby reticle (Figure 7–151) is available in the upper right side of the HUD for use in performing visual designations in the event of a HUD failure. The reticle is fixed at a 15-mil depression angle from the gun boresight. If the HUD fails, the HUD symbology is available by selecting HUD via the menu on the left or right DDI [Digital Display Indicator]. To perform a HUD designation in the NAV or A/G [Air/Ground] mode when the HUD is inoperative, the pilot first places TDC [Target Designator Control] priority to the HUD (either by placing the sensor switch to the normal HUD position, or to the left or right DDI displaying the HUD symbology). The mission computer slaves the radar in AGR mode to the LOS [line of sight] of the HUD standby reticle. The pilot maneuvers the aircraft to position the standby reticle over the aim point and actuates the TDC to perform the designation. The aim point position at the LOS of the standby reticle is computed. The pilot may use the HUD display on the left or right DDI to null the steering error when automatic weapon delivery is being conducted.

Source: ED Forums

The standby reticle is used when the HUD fails for designating targets. The pilot must lean to the right and line up the cross-hairs with the dot so that the bore-sight is accurate.

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It is technically the standby reticle as mentioned above but in house it is known more as the seat height marker due to that being the most common use for it.

As soon as you apply battery power the pilot will adjust their seat height lining this up.

Short guys and girls need not lower the seat.

Taller people lowed the seat quite a bit.

You must always check the leg restraint line anchor points are flush with the floor so they don't pierce the rocket motor of the ejection seat.

The HUD is not a display that fails that often so not many people know what this thing is for.

The fact that you can just bring up the HUD page on any of the other displays when it fails and beyond visual range weapons being the default way with regards to tactics means it is seldom used.

Can't give any references as the publications are restricted, but I was a maintainer on this aircraft for over 10 years.

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  • 1
    $\begingroup$ Great insight. Thanks for answering, welcome to Aviation and thanks for your service! $\endgroup$ – FreeMan May 19 '20 at 12:45
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That point and the dot is to know the correct position of the seat height, you must regulate the seat height until you visually match the Cross and the point.

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    $\begingroup$ This seems to disagree with the other answer. Do you have a source? $\endgroup$ – Bianfable May 11 '20 at 15:32
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    $\begingroup$ Do you have any sources for your claims? $\endgroup$ – dalearn May 11 '20 at 17:36
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    $\begingroup$ @Bianfable he has a source now! $\endgroup$ – FreeMan May 19 '20 at 12:45

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