Emergency Procedure During Loss of GPS and High Wind
You are flying a small unmanned aircraft (sUAS) for a real estate photography shoot in a rural area. The sUAS is a hexacopter with a flight time of 25 minutes. You are 10 minutes into the flight, at an altitude of 250 feet AGL, when you suddenly lose GPS signal. The sUAS switches to ATTI mode, meaning it no longer holds position and drifts with the wind. The wind is reported as 15 knots from the northwest, gusting to 22 knots. The sUAS is 0.3 miles downwind from your location. The battery is at 60%. The area around you has scattered trees and a few power lines. Your visual observer (VO) is with you and has eyes on the sUAS. The sUAS is drifting toward the power lines.
1. What immediate actions should you take to regain control and avoid obstacles?
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Immediate actions: 1) Remain calm and maintain VLOS; 2) Switch to manual control if not already; 3) Apply control inputs to counteract drift: since wind is from the northwest, the sUAS is drifting southeast toward power lines. The pilot should command the sUAS to fly upwind (northwest) to regain position and increase altitude if safe to avoid obstacles. 4) Reduce altitude if necessary to stay below power lines, but be aware of trees. 5) Use the VO to help navigate around obstacles. 6) If control is not regained, consider initiating a controlled descent in an open area away from power lines. 7) Be prepared to activate return-to-home if GPS reacquires, but only if the home point is safe.
2. What are the regulatory and safety considerations for this emergency, and what should you do after landing?
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Regulatory: Part 107 requires the pilot to avoid undue hazard to other people or property (107.23). In an emergency, the pilot may deviate from regulations to the extent necessary (107.21). Safety: The pilot must prioritize avoiding power lines and people. After landing, the pilot should: 1) Conduct a post-flight inspection of the sUAS for damage; 2) Document the incident, including loss of GPS and actions taken; 3) Review procedures for loss of GPS and consider adding a checklist; 4) Report the incident to the FAA if required (e.g., if there was damage or injury). The pilot should also assess whether the flight should have been conducted given the wind and GPS reliability, and consider using a sUAS with better GPS redundancy or waiting for better conditions.