I pushed a commit with the new DPS page SPEC 54 Entry Bearing for the Entry mode.
It is a new display that was available in the latest Shuttle software update (OI-33) which debuted with STS-126:
https://www.nasaspaceflight.com/2008/10/126-debut-oi-33-rco-ability/It helps with situational awareness for Ascent, Entry and ECAL aborts.
Only the Entry part of the Spec 54 is supported for now.
Not too much datas about it.
Here are the informations about the display coming from the OI-33 update at the end of the latest SCOM.
*Three items are available for crew inputs in Spec 54 display (item 41, 1 and 2).
Item 41 will choose the targeted site (and it will update the Entry guidance accordingly).
Item 1 and 2 will allow to select the alternate sites to assess the range / delta azimuth / energy condition.
To use those latest items, the alternate site mode must be activated in OPS 304 display (item 4) (Red arrow).
Two rings with some range indications in Nautical Miles are displayed (4000 / 2000 / 1000 / 500 / 250 / 125).
A white azimuth line links the Shuttle symbol to the targeted landing site.
Pink arrows show the relative position of alt sites on spec 54 and the Shuttle energy status alt sites wise in OPS 304.
*Roll reversal lines are displayed to indicate when the Shuttle should roll in the opposite direction for crossrange consideration.
Dashed lines are for 10 degrees roll reversal and plain lines are for actual roll reversal logic (10° or 17°).
First roll reversal will be done at 10° of delta azimuth (left picture).
Then up to mach 4, roll reversal will happen at 17° of delta azimuth (plain lines "open" in the middle picture).
Below mach 4, roll reversal will happen at 10° of delta azimuth again (right picture).
*Shuttle symbol will bank according to real bank experienced.
*An overbright blank “+” is also displayed off the nose of the orbiter representing the instantaneous impact point (iip). It represents where the Shuttle would end if nothing was changed to the L/D profile (ie. Shuttle bank roughly).