DJI Mavic – Accident – 2018-07-06

Drone Manufacturer: DJI
Drone Model: Mavic
Country: United States of America
Type: Accident
Date: 2018-07-06
Applies: Daytime
Pilot Qualifications: Unknown Status
Pilot Flight Experience: Unknown Hours
Link to External Information About This submission:
File Uploaded: None


UAS night missions were being conducted to support multiple night SA {situational awareness} missions of the Kopoho lava area for evaluation of Fissure 22 development, critical infrastructure, repeat velocity sampling and of the lava flow and general observation of the flow from Fissure 8 toward the ocean entry. The mission was launched from “Pohoiki Y.” Pohoiki Y is one of the four established sites utilized during the response. Three flights occurred to the southeast of the launchsite to check on critical infrastructure, channel velocity data, acquire lava spill-over awareness and gather information on developing fissures. The visibility was better than 6sm. The glow from the lava stream and erupting nearby Fissure 8 providing good light. The light revealed cloud layers moving in different directions indicating that wind layers were potentially dynamic and blowing in different directions. Wind direction was part of the preflight briefings. Previous wind checks at altitude were recommended by flight crews that had previously rotated through the incident response. Night operations were integrated on June 25th after Incident Command had requested 24 hr UAS response for situational awareness for emergency responders and data collection. The initial night flying training requires that pilots have receive a daylight orientation of any area that Remote Pilots were expected to fly at night to accomplish a thorough site assessment. The night missions flown on July 7th having been flown by both UAS Pilots during a previous night or night swing shift. Daylight training for night Ops included: Obstacle awareness around flight areas. RTL altitudes were set at a minimum of 1000 feet agl to mitigate temperature concerns from volcanic activity and maintain a safe altitude from obstacles and landscape. Wind checks while climbing to the point of interest while departing to a mission would help to determine the mission length as recommended and established by the earlier teams that responded to the incident. RTL and auto assisted functions are utilized at night to provide accuracy of landings, assist with orientation and to ensure repeatable departure and approaches. For the first missions of the night, the UAS departed and flew to the southeast of the launch site, climbed to 1300 ft msl and continued to the mission area. The winds were monitored and the upper flows were noted to be acceptable for the mission requests. Three following flights occurred to the southeast of the launch site, travelling to mission locations approximately 7500 ft away. Winds southeast and enroute to the points of interest were within aircraft limits, indicating 17-20mph. On the fourth flight, the Mavic departed and went to a nearby channel velocity location to collect data for two minutes. The mission was initiated over the channel with 70{{{{%}}}} battery for two minutes. Upon completion the UAS turned toward Fissure eight to the WNW to collect video and SA. After making a long right turn toward the Fissure, the ground speed suddenly increased. A decision was made to return home and an approach was initiated at a distance of 5000 feet from home and 1300 feet msl. As the aircraft headed home the ground speed dropped to 0-3 mph, indicating a strong flow. In “P-mode” {GPS} the aircraft will obtain 22 mph in a no wind situation. The aircraft was put into RTL which increased the speed to 6 mph. The UAS pilot then cancelled the RTL and activated “sport” mode, and started to descend. The “sport mode” has a forward airspeed of 39 mph in a no wind condition. The aircraft indicated 6mph and 49{{{{%}}}} battery. The pilot opted to descend over the edge of the dried lava flow to expedite the approach to “Home”. Within 2000 feet of the “Home” location the aircraft increased speed between 10-12 mph. When the 30{{{{%}}}} battery warning initiated, the pilot continued to maintain “manual” control to try expedite the approach. With the rapid battery depletion, the aircraft ended up landing 300ft to the west of the home location with a last known location being displayed on the screen with a Lat, Long.. Immediately a search for the UAS was initiated but ended due to hazardous ground terrain, the indicated location being downhill of lava spill activity and thick jungle and old lava pits making travel extremely challenging. The following day, a ground crew attempted a search but suspended searching due to similar environmental safety concerns. At this time, the risk associated with the recovery of the UAS is not a priority for Incident Command.

Reported Cause

The loss of the aircraft has required the UAS Management and Remote Pilots crews operating at night to evolve the protocols for night missions.1. Battery return to home trigger points were raised 20{{%}} to allow enough time to evaluate winds and requirement to return to home. When conducting BVLOS flights, pilots should consider 70{{%}} battery as their first consideration for evaluating returning to home, depending on distance and battery.2. Larger monitor that mirrors the Remote Pilots tablet screen for enhanced awareness and allow for better CRM and situational awareness of distance from home. The “distance from home” information is hard to read at times due to the small size. 3. Winds aloft must be evaluated often. It should not be assumed that because the winds are uniform across the mission area. The heat and velocity of the fissures seem to create micro weather events that may include potentially ferocious winds near the fissures, when it could be calm in other areas.4. Recommendation to fly more batteries to obtain a mission goal instead of trying to “squeeze” one more objective into a single flight. For night missions the recommendation is to be back on the ground with 40-50{{%}} battery. If there are multiple mission objectives for a flight, start with the furthest location and work your way back to “home.”5. Enable “multiple flight modes” to be able to switch back and forth between “Pmode” and “Sport.” RPs should try to take off and land in “Pmode.”6. Disable obstacle avoidance at night. The VOG and LAZE {emissions from the volcano} seems to confuse the UAS when “obstacle avoidance” was enabled, the particulant would seemingly trick the sensors into identifying the emissions as a surface, giving system errors and potentially contributing to the auto-landing of another mavic.7. Illuminating the landing pad a night helps not only orienting the aircraft when returning to land by using the camera, but may assist the accuracy of the “smart landing” feature which relies on stereographic cameras to help align the landing location.8. Using RTL to reduce RP workload and confidence in obstacle avoidance at night as much as practical. Pilots should realize that if battery is low or winds strong a manual approach may be necessary. When coming back to home in RTL, the pilots have predetermined a suitable approach altitude to descend to once clear of the lava, as identified during their day evaluation to maintain clear of obstacles, expediting approaches, making visual contact quicker with the approaching UAS, and increasing general efficiency of operations.9. Fatigue has been identified as a significant concern for night crews. Night crews should feel empowered to rest or nap when necessary to maintain a reasonable level of critical performance.Current operations seem to indicate that the new protocols have increased SA and data collection even though the flights are of slightly shorter duration. This Safecom may be updated to reflect other protocols as incorporated in the future.