The F70 and F100 FMC has a shopistcated Navaid Remote Tuning functionality that automatically tunes navaids throughout a flight to correct the IRS position and to guarentee position integrity. The navaids that are currently tuned are displayed on the bottom row of the FMC PROG page. 

Small letters indicate the tuned frequency, and large letters indicate the VOR-DME identifier. When the frequency is prefixed by an ‘A’ (e.g. ‘A111.50’), this indicates that the frequency is automatically tuned by the FMC. When the frequency is prefixed by an ‘’R (e.g. ‘R112.10’), this indicates that the frequency is remotely tuned by the pilot, either by entering the identifier or the frequency of a navaid into LSK6L/LSK6R.

A remote tuning can be released by pressing the CLR key with an empty scratchpad, followed by LSK6L or LSK6R.

Remote and auto tuning are only possible as long as the displays on the VOR DME receiver panel on the pedestal indicate dashes ‘---.---’, which is dependent on APP/VOR selection and EFIS mode selection on the EFIS control panels. If a VOR is manually tuned on the VOR DME panel, the frequency displayed on the FMS will be the same as on the panel, and will be prefixed by an ‘M’ (e.g. ‘M113.80’).

A VOR can only be manually tuned on the VOR DME panels on the pedestal if the mode selector on the EFIS Control Panel is set to ARC or ROSE, and the APP/VOR selector is set to VOR. In all other selections, the displays on the VOR DME panels will indicate dashes "---.--", and manual VOR tuning will only be possible via the FMC PROG page.