T-ILS Page (DED)

[Frederf]

T-ILS page has some possible issues relating to functionality and display. While some items are stated as fact they are best available assertions only (mostly from good evidence) and so should not be relied upon without other information.

 

Current format

_TCN_A/A_TR__ILS__OFF____
________________________
_______*_______*CMD_STRG_
CHAN_123_____FRQ__108.10_
BAND_X(0)____CRS__123°___

Page function

 

• Asterisk selection in the primary mode: a multi-purpose scratch pad, CMD STRG, and CRS. No asterisks selection of CHAN or FRQ.
  
• Asterisk selection in the backup mode: CMD STRG, FRQ, and CRS. No scratchpad in backup mode.
  
• After ILS frequency entry (scratch pad primary or FRQ backup) asterisks automatically select CRS for course entry.
  
• TACAN band changing is explicitly described as 0 key in scratch pad followed by ENTR and not immediate effect of 0 key alone. (Current behavior possible software revision, please verify).
  
• CMD STRG is initialized enabled by each ILS power on and would require explicit disabling by the pilot. Toggling of CMD STRG is made by placing asterisks around the CMD STRG label and pressing of 0 key. Reverse video is the typical manner of showing such on-off states. While useful steering is only available after frequency, HSI mode, etc. toggling the CMD STRG option should be available at all times.
  

Display formatting

 

• One imagines that the TACAN and ILS portions of the display were allocated as the first and last 12 characters of each line of the display respectively for left-right layout.
  
• Usually padding space character are given to page formats on the left edge when possible to improve readability around the ICP.
  
• Distinct items should be kept far enough apart with spacing to avoid confusion.
  
• Asterisks should only be directly adjacent to the items they alter and not bridge two items by asterisk character occupying the only space between them.
  
• Similar text should align vertically where possible.
  

Using the above assumptions and principles the following is an estimate of the correct layout of the display. Unfortunately manuals seem to not be made with much care as to character width or alignment. Multiple manuals have significantly different layouts and it's likely diagrams are not intended to be exact. Multiple asterisk sets are intended to show only multiple possible positions for the one asterisk set.

 

TACAN Formatting

_TCN_A/A_TR_XXXXXXXXXXXX
____________XXXXXXXXXXXX
_______*12345**CMD_STRG*
_CHAN_123___XXXXXXXXXXXX
_BAND_X(0)__XXXXXXXXXXXX

• Line 1 centered in its 12 characters in longest status text
  
• Lines 1 4 5 left align
  
• Scratchpad centered (as much as practical) in 24 character width to indicate dual TACAN and ILS purpose
  
• CHAN and BAND with one space since never asterisk highlighted.
  
• The word BACKUP is centered under TCN ON when in backup mode
  

ILS Formatting

XXXXXXXXXXXX__ILS__OFF__
________________________
______________*CMD_STRG*
XXXXXXXXXXXX_FRQ__108.10
XXXXXXXXXXXX_CRS_*123°*_

• ILS status centered in 12 characters, minimum 3 spaces from TCN status to separate
  
• ILS status 2 space to match FREQ and CRS
  
• CMD STRG maximum right to give room for scratch pad
  

Combined Formatting

_TCN_A/A_TR___ILS__OFF__
________________________
_______*12345**CMD_STRG*
_CHAN_123____FRQ__108.10
_BAND_X(0)___CRS_*123°*_

This is my best rationalization, research, estimation of how the T-ILS page may function and be formatted. It may be wrong entirely in parts due to differences between various F-16 versions behaving differently or my creative understanding of the desires and motivations behind the design. The developers may have explicit details which supersede these educated guesses. In any case the information put forward may possibly help or be an opportunity for me to learn.