- is_valid_node(NULL),
- power_btn_node(NULL),
- freq_node(NULL),
- alt_freq_node(NULL),
- sel_radial_node(NULL),
- vol_btn_node(NULL),
- ident_btn_node(NULL),
- audio_btn_node(NULL),
- backcourse_node(NULL),
- nav_serviceable_node(NULL),
- cdi_serviceable_node(NULL),
- gs_serviceable_node(NULL),
- tofrom_serviceable_node(NULL),
- fmt_freq_node(NULL),
- fmt_alt_freq_node(NULL),
- heading_node(NULL),
- radial_node(NULL),
- recip_radial_node(NULL),
- target_radial_true_node(NULL),
- target_auto_hdg_node(NULL),
- time_to_intercept(NULL),
- to_flag_node(NULL),
- from_flag_node(NULL),
- inrange_node(NULL),
- signal_quality_norm_node(NULL),
- cdi_deflection_node(NULL),
- cdi_deflection_norm_node(NULL),
- cdi_xtrack_error_node(NULL),
- cdi_xtrack_hdg_err_node(NULL),
- has_gs_node(NULL),
- loc_node(NULL),
- loc_dist_node(NULL),
- gs_deflection_node(NULL),
- gs_deflection_deg_node(NULL),
- gs_deflection_norm_node(NULL),
- gs_rate_of_climb_node(NULL),
- gs_dist_node(NULL),
- gs_inrange_node(NULL),
- nav_id_node(NULL),
- id_c1_node(NULL),
- id_c2_node(NULL),
- id_c3_node(NULL),
- id_c4_node(NULL),
- nav_slaved_to_gps_node(NULL),
- gps_cdi_deflection_node(NULL),
- gps_to_flag_node(NULL),
- gps_from_flag_node(NULL),
- gps_has_gs_node(NULL),