Localizer

[Guest Eugen]

Hi,I working on a localizer for my autopilot.I saw in the sdk the k-event AP_LOC_HOLD however in the 747 localizer file the k-event AP_BC_HOLD is used which one is the correct one to use and what is the difference between them.Secondly the localizer can only be armed if the ils freq is tuned, how can I check that ?Thirdly can a check be done to find out if the localizer has been captured ?BrgdsEugen

[phjvh 0]

Eugen,The localizer works on the ILS frequency (but has no glideslope of course).You can use the a:var's:NAV1 HAS LOCALIZER,bool and a few more.and k:event:AP_LOC_HOLD.The other one holds the backcourse; after passing the beacon.You can check with the a:var'sHSI CDI NEEDLE VALID,bool and probably more.Jan"Procul Negotiis"

[Guest bartels]

To second : if you need the information if the tuned and broadcasting staion is an ILS or LOC proceed like described in the other post. If you want to know, if it is an ILS frequency (without a localizer already broadcasting) check the frequency itself: localizer frequencies are the frequencies with "uneven" 100kHz frequency parts above 108.00 MHz and below 112MHz, e.g. 108.10,108.15,108.30,108.35,...111.90,111.95To third you can't check if the localizer is caprtured, I usually check if the HSI LOC deviation is quite small, a pretty good indication of a captured localizer (or VOR).Arne Bartels

[Guest Eugen]

HiI tried to put together some code it doesn't seem to work...Any suggestions ?Eugen(HSI CDI NEEDLE VALID, bool) (A:Autopilot master, bool)(NAV1 HAS LOCALIZER, bool) (L:Localizer, bool) 0 == &&& if{ (A:Radio height, feet) 400 >= if{ 1 (>K:AP_LOC_HOLD) 1 (>L:Localizer, bool) } els{ 0 (>K:AP_LOC_HOLD) 0 (>L:Localizer, bool) } }

[phjvh 0]

Eugen, It seems the light is coming up when the localizer is active.What are you trying to achieve with the ?Perhaps you can omit the amps.What does L Localizer,bool?Jan"Procul Negotiis"

[Guest Eugen]

Hi,What I would like to achieve is the followingto click on the button is only posible when the ils is tuned for the localizer, radio height is above 400 and the autopilot is engaged.Then the light will come on. I am not really sure what what a-var is the counterpart to the k-event AP_LOC_HOLD.Could a boolean value with 1 and 0 ie 1 (>K:AP_LOC_HOLD) 0 (>K:AP_LOC_HOLD) be done the way I have done it ? The intention of the L-var was keep track if it is armed or not.BrgdsEugen

[phjvh 0]

Eugen,May be this one works: (L:Localizer, bool) 1 == (A:Autopilot master, bool)(A:NAV1 HAS LOCALIZER,bool) (L:Localizer, bool) 0 == (A:Radio height, feet) 400 >= if{ (>K:AP_LOC_HOLD) (>L:Localizer, bool) } Jan"Procul Negotiis"

[Guest bartels]

The relation between the A: vars and the K: events for ILS/LOC approaches is a bit difficult and not one to one.K:AP_APR_HOLD toggles the ILS hold state -> (A:AUTOPILOT APPROACH HOLD,bool) and (A:AUTOPILOT GLIDESLOPE HOLD,bool) are both 1.K:AP_LOC_HOLD toggles the LOC hold state -> (A:AUTOPILOT APPROACH HOLD,bool) is 1.This assumes that both states where off. It might be a bit difficult, if you switch from ILS to LOC and vice versa. It is even possible to switch from ILS to BC mode and (A:AUTOPILOT GLIDESLOPE HOLD,bool) is still 1, but there is clearly no glideslope hold commanded from the AP. I suggest you doodel around with the A: vars and K: events and be aware that one K: event can have effect on more then one A: var.I'm not sure if you can use 1 (>K:AP_LOC_HOLD) 0 (>K:AP_LOC_HOLD), but you can use if{ 0 (>K:AP_LOC_HOLD_ON) } els{ 0 (>K:AP_LOC_HOLD_OFF) }Arne Bartels