14 CFR Part 91: General Aviation
Tuesday, September 05, 2017
COBALT AIRCRAFT INDUSTRIES INC Co50 VALKYRIE, registration:
Injuries: 1 Uninjured.
This is preliminary information, subject to change, and may contain errors. Any errors in this report will be corrected when the final report has been completed. NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.
On September 05, 2017, about 1430 Pacific daylight time, a Cobalt Co50 Valkyrie, N523CA, landed hard following an in-flight loss of controllability at the Castle Airport, Atwater, California. Cobalt Aircraft Industries, Inc., was the registered owner and was operating the airplane under the provisions of 14 Code of Federal Regulations (CFR) Part 91. The airline transport pilot, the sole occupant, was not injured; the airplane sustained substantial damage. The local-area test flight originated from Atwater about 1410. Visual meteorological conditions prevailed and no flight plan was filed.
The airplane, serial number PX-04, was manufactured in October 2016 and registered under an Experimental Research and Development airworthiness certificate. The airplane had undergone four previous flights and the accident flight was the pilot's first flight in a Cobalt aircraft. The purpose of the flight was for the pilot to perform an evaluation of handling qualities at various configurations specified in the test card.
The pilot stated that immediately after rotation, he experienced extreme difficulty controlling the airplane. As the airspeed increased, he began to attain some controllability and climbed to about 1,000 feet above ground level. He determined that the ailerons were ineffective but was able to use the rudder for directional control. The pitch stability was sporadic with him experiencing intermittent pitch up and down movements. After about 20 minutes of manipulating the flight controls and practicing climbing and descending using the trim, he managed to stabilize the airplane around 90 kts. He reasoned that he would be able to land the airplane while configured at an increased airspeed using steady thrust control and the rudder for directional control. During landing, with the airplane about 10 feet above the runway surface, the airplane experienced a loss of lift and landed hard. The impact resulted in the right landing-gear leg separating and the airplane subsequently made a 180-degree; the right-wing spar sustained damage.