Garmin GTN 750 Cockpit Reference Guide - Page 44

Message AUDIO PANELAudio panel needs service. AUDIO PANELAudio panel is inoperative or connection to GTN is lost. APPROACH DOWNGRADEApproach downgraded. Use LNAV minima. APR GUIDANCE AVAILABLETouch "Enable APR Output" before selecting APR on autopilot. CDI SOURCESelect appropriate CDI source for approach. Description The GMA 35 is reporting to the GTN that it needs service. The audio panel may continue to function. GTN is configured for Garmin audio panel control (GMA 35) and the GTN cannot communicate with the GMA 35. No control of the GMA 35 will be possible. Approach has been downgraded from LPV or LNAV/VNAV, to an LNAV approach. Vertical guidance will be removed from the external CDI/HSI display. GTN is configured for KAP140/KFC225 autopilot, and approach guidance is now available. Aircraft is on a GPS approach but CDI is set to VLOC, or aircraft is on VLOC approach and CDI is set to GPS and aircraft is less than 2 nm from the FAF. Action Contact dealer for service. Remove power from the GMA 35 audio panel by pulling the circuit breaker labeled, "Audio". The pilot will be able to communicate with the COM 2 radio. Contact dealer for service. Continue to fly the approach using published LNAV minimums. Touch the "Enable APR Output" key on the GTN, this will cause the autopilot to go into ROL mode. Engage the autopilot into approach mode. Select the appropriate CDI source for approach. Messages 38 GTN 725/750 Cockpit Reference Guide (CRG) 190-01007-04 Rev. B