NASA-LLIS-1714

Abstract

<strong>Abstract:</strong> <br>A high performance jet-powered UAV crashed on landing. A subsequent investigation into the root cause(s) found that the ground support crew did not follow all of the steps in a complex checklist and the pilot did not adhere to the flight parameters dictated by the flight test card. Omission of pre-flight steps resulted in lower than expected engine thrust performance. This off-nominal thrust condition caused the pilot to attempt to compensate throughout the flight. This compensation, along with other complicating factors, caused the pilot to mismanage the UAVs energy, resulting in a landing touchdown speed that was well above rated touchdown speeds, resulting in the collapse of the left main landing gear. The pilot did not have any previous experience with this UAV. A primary complicating factor was that the pilot did not know and was not briefed on several key UAV performance factors, primary of which was maximum touchdown speed. Less than adequate communications between the pilot and ground support crew both in preflight and flight was also a complicating factor. During the crash, the flight crew was exposed to potential injury since they were situated at the runway edge near the UAV touchdown point. <br>Execution of each step in a checklist should be independently verified, especially the complex checklists used in these operations. A pilot briefing on critical vehicle performance parameters should be given even if the pilot is expected to know critical flight parameters. Communications between pilot and ground support crew should be full and open during preflight and flight. Real time warnings should be provided to the pilot when deviating from the planned flight test parameters. The flight crew should maintain a safety barrier device between themselves and the vehicle during the landing sequence.