The most intriguing event so far ! Finally happy landing and ending for this flight ! Event : Return-to-Home (RTH) procedure failed to execute as expected during canyon flight. Contributing factors : ▪︎ Negative altitude (- 64 ft ) relative to home point at time of RTH initiation. What the drone should have done : As per Air 3 user manual, page 53, section RTH settings, Preset : distance within 5-50 m and suitable for vision systems → The aircraft will return to home using the best path at current altitude. It’s immediately clear that this scenario works with positive altitudes. It’s much less obvious with negative altitudes because there is a cliff between the pilot and the drone. Some pilots believe that the software doesn’t take negative altitudes into account for RTH (Return to Home). The issue should be referred to DJI. What the drone did : it maintained its altitude (- 64 ft) until the vision system identified the rock wall as a nearby obstacle that could not be bypassed. A collision warning was issued ( red arc + beeping sounds ) and the aircraft activated its failsafe logic. RTH was aborted and the drone entered a hover. After the time out period expires, it will initiate landing. ▪︎ Air 3 has omnidirectional obstacle sensing but complex terrain, low or highly reflective light on walls, shadows or water can confuse it. False obstacle warnings may occur, potentially affecting RTH behavior. Corrective / Preventive actions : 👉 Avoid reliance on RTH in environments with negative relative altitudes, especially in canyons and narrow gorges. Complex terrain may surpass the capacity of the vision systems. Be prepared for contingency plans. 👉 Loss of remote controller signal → Set the action of the aircraft to Hover since RTH might not work. See Page 51 of the Air 3 User Manual. Note : Flying into a canyon is thrilling but presents several specific hazards ( wind/turbulence,RC signal/GNSS Loss ) that can turn minor issues into serious losses. We’ll cover all these in later reports.