Message Name:

TAIL PRIMARY NAV LIGHT DOES NOT ILLUMINATE

Tail Navigation Light or Lights do not come ON.

• Tail Navigation Light Bulb
• Primary Tail Navigation Light (DS12)
• Navigation Light Switch
• Failure Indicator Box (A126)
• Tail Strobe Light Power Supply (A127)
• Associated Wiring

Advisory Wire/Service Bulletin: None

Forum Articles/Infoservice/Newsletter: None

1. Set NAV switch to ON.

   1. If all the navigation lights do not come on, perform the troubleshooting ALL NAV LIGHTS DO NOT ILLUMINATE and continue with next step.
   2. If any one of the navigation lights do not come on, continue with next step.

2. Access Navigation Light Status data page on CAIMS and perform:

   • Select System Diag
   • Select ATA 33
   • Select the Navigation Light Status
     
     NOTE: Ensure that the power of the Nav light is selected ON for a minimum of 10 minutes prior to reading the values displayed on the CAIMS data page.

3. Check the status of Primary Navigation Light as follows: Is “TRUE” displayed next to TAIL Primary light in data page?

   1. If NO, go to step 6.
   2. If YES, continue with next step.

4. Replace the NAV light bulb.

   1. If system checks are good, do close out.
   2. If fault remains, continue with next step.

5. Perform a continuity check as follows:
   Tail Primary:

   From	To	Result
   A126P1-P	A126P1-D

   1. If there is no continuity, repair defective wiring as required and do close out.
   2. If there is continuity, go to step 10.

6. Check the status of Primary Navigation Light as follows: If "False" is displayed next to "Tail Primary light" on the data page;

   • Confirm that SB 700-33-023 or 700-1A11-33-008 is NOT incorporated on the aircraft
   • Ensure that the power of the Navigation light is selected ON for a minimum of 10 minutes prior to reading the values displayed on the CAIMS data page
   • Confirm that the Failure Indication Box is connected properly
   • If all good, continue with next step

7. Perform a continuity check as follows:
   Tail Primary:

   From	To	Result
   A126P1-P	A126P1-D

   1. If there is continuity, go to step 10.
   2. If there is no continuity, continue with next step.

8. Ensure that the NAV light bulb is secured into place.

   1. If damages are found, repair or replace as required and do close out.
   2. If damages are not found, continue with next step.

9. Perform a continuity check as follows:
   Tail Primary:

   From	To	Result
   A126P1-D	DS12P-A
   A126P1-P	GS218

   1. If there is continuity, do close out.
   2. If there is no continuity, continue with next step.

10. Replace the failure Indicator box.
11. Do close out.