RAD NAV: DELIBERATE TUNING AND INDEPENDENT CHECKS
Inspect automatic tuning and any deliberate manual selections on RAD NAV. A manually held aid may remain relevant after the route or approach has changed, so review the reason for that selection rather than carrying it forward unnoticed. [66, PDF pp. 469-470,474,477]
For Heathrow's planned ILS, compare runway and approach with the frequency, identifier and course on the current chart. Identify the intended installation and repeat the check during arrival preparation. Correctly entered data for the wrong runway can still produce a convincing-looking radio-navigation setup. [66, PDF pp. 469-470,474,477] [108, PDF pp. 2-4]
Keep the FMS route and raw radio information coherent. The ND route line describes the active lateral plan; raw approach indications provide an independent relationship to the selected aid. Compare both with the chart and aircraft position, particularly after a runway change or vectors that alter the expected intercept. [66, PDF pp. 469-470,474,477]
IN PRACTICE: RAD NAV: verify the aid you actually intend to use
Before you begin: Use the chart for the selected runway/approach and the active database. Do not supply a Heathrow ILS frequency or course from memory for this exercise.
1. Read the current tuning state
Action. Press RAD NAV and inspect the displayed radio-navigation selections. Identify entries you have forced manually, as distinct from selections made by the system for the current flight phase.
Check. You know which selections may persist because of your own intervention. Automatic tuning has not been assumed simply because the page contains sensible-looking frequencies. [66, PDF p. 122] [66, PDF pp. 469-470,474,477]
2. Crosscheck the ILS against the chart
Action. For the actual intended ILS, compare the runway designation, localizer identifier, frequency and front course. Review the selected approach in F-PLN as part of the same check.
Check. The chart, approach selection and tuning refer to the same installation and runway end. No example frequency has become a flight input. [66, PDF p. 474] [66, PDF pp. 199-209]
3. Make a manual entry only when intended
Action. If the procedure calls for manual tuning, enter the charted identifier or frequency into the appropriate ILS field and read back the accepted selection. Complete or verify its course field as required.
Check. The requested aid, rather than a similarly named aid, is selected. The course is the intended front-course reference. [66, PDF p. 474]
4. Confirm identification when reception permits
Action. When the aid is receivable, compare the displayed/received identification with the chart and the tuned selection. At the stand, do not invent a successful signal check for an aid that is not being received.
Check. Database/tuning agreement and actual signal identification have been distinguished. Both will be reviewed before relying on the approach guidance. [66, PDF p. 474] [21, PDF pp. 159-162]
5. Revisit a manual override after a change
Action. After a runway or approach revision, inspect RAD NAV again. To cancel an obsolete manual frequency/identifier, place CLR in the scratchpad and select that field. Then inspect the resulting automatic selection, or brackets if no aid is auto-tuned.
Check. The obsolete override has been removed. Verify the resulting tuning against the revised approach before relying on its guidance. [66, PDF pp. 469-470,474,477]
Complete when: The selected aid and course agree with the intended procedure. Any manual tuning is deliberate, and it will be revisited after a runway or approach change.