Monday, March 02, 2020

Flight Control System Malfunction/Failure: Cobalt Co50 Valkyrie, N523CA; accident occurred September 05, 2017 at Castle Airport (KMER), Atwater, Merced County, California

The National Transportation Safety Board did not travel to the scene of this accident.

Additional Participating Entity:
Federal Aviation Administration / Flight Standards District Office; Fresno, California

Aviation Accident Factual Report - National Transportation Safety Board: 

Investigation Docket - National Transportation Safety Board:

Location: Atwater, CA
Accident Number: WPR17LA201
Date & Time: 09/05/2017, 1430 PDT
Registration: N523CA
Aircraft Damage: Substantial
Defining Event: Flight control sys malf/fail
Injuries: 1 None
Flight Conducted Under: Part 91: General Aviation - Flight Test 

On September 05, 2017, about 1430 Pacific daylight time, an experimental Cobalt Co50 Valkyrie airplane, N523CA, landed hard at the Castle Airport, Atwater, California. The airline transport pilot was not injured; the airplane sustained substantial damage. The airplane was registered to and operated by Cobalt Aircraft Industries, Inc. as a Title 14 Code of Federal Regulations Part 91 test flight. Visual meteorological conditions prevailed and no flight plan was filed for the local area flight which originated from Atwater about 1405.

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 he started the flight by making two test runs down the runway. During both test runs he briefly lifted the airplane off the surface in an effort to check the rotation performance. On both attempts, he had full aft back pressure on the control stick and the airplane would not rotate off the runway. The pilot determined that the center-of-gravity (CG) was too far aft and the ground team added 2o to the adjustable ground trim, equating to a total of 10o. The pilot configured the airplane for a departure from runway 31, planning for a rotation speed of 75 kts.

The pilot further stated that after rotation, with the airplane about 50 ft above ground level (agl), he experienced extreme difficulty controlling the airplane. As the airspeed increased, he began to attain some controllability and climbed to about 1,400 ft agl. 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 ft 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 180o turn; the right-wing spar sustained damage.

A representative from Colbalt stated the company reviewed the video recordings and onboard recorders. The recordings disclosed that after a faster-than-expected rotation speed between 80-85 kts, the airplane had no roll control. For the test flight they had an increased weight and had changed the winglet position which contributed to a loss of aileron effectiveness. 

Pilot Information

Certificate: Airline Transport; Flight Instructor
Age: 73, Male
Airplane Rating(s): Multi-engine Land; Single-engine Land; Single-engine Sea
Seat Occupied: Left
Other Aircraft Rating(s): Glider; Helicopter
Restraint Used:
Instrument Rating(s): Airplane
Second Pilot Present: No
Instructor Rating(s): Glider
Toxicology Performed:No 
Medical Certification: Class 2 Without Waivers/Limitations
Last FAA Medical Exam: 05/01/2017
Occupational Pilot: Yes
Last Flight Review or Equivalent:
Flight Time:   (Estimated) 9650 hours (Total, all aircraft), 0.8 hours (Total, this make and model), 7500 hours (Pilot In Command, all aircraft), 6.3 hours (Last 90 days, all aircraft), 6.3 hours (Last 30 days, all aircraft), 0.8 hours (Last 24 hours, all aircraft)

Aircraft and Owner/Operator Information

Registration: N523CA
Model/Series: Co50 VALKYRIE
Aircraft Category: Airplane
Year of Manufacture: 2016
Amateur Built: No
Airworthiness Certificate: Experimental
Serial Number: P04
Landing Gear Type: Retractable - Tricycle
Seats: 5
Date/Type of Last Inspection: 09/04/2017, Continuous Airworthiness
Certified Max Gross Wt.: 3417 lbs
Time Since Last Inspection:
Engines: 1 Reciprocating
Airframe Total Time: 1 Hours at time of accident
Engine Manufacturer: CONTINENTAL MOTORS
ELT: Not installed
Engine Model/Series: TSIOF550-D
Rated Power: 350 hp
Operating Certificate(s) Held: None

Meteorological Information and Flight Plan

Conditions at Accident Site: Visual Conditions
Condition of Light: Day
Observation Facility, Elevation: KMER, 191 ft msl
Distance from Accident Site: 1 Nautical Miles
Observation Time: 1415 PDT
Direction from Accident Site: 34°
Lowest Cloud Condition: Clear
Visibility:  10 Miles
Lowest Ceiling: None
Visibility (RVR):
Wind Speed/Gusts: 7 knots /
Turbulence Type Forecast/Actual: None / None
Wind Direction: 340°
Turbulence Severity Forecast/Actual: N/A / N/A
Altimeter Setting: 29.85 inches Hg
Temperature/Dew Point: 24°C / 18°C
Precipitation and Obscuration: No Obscuration; No Precipitation
Departure Point: Atwater, CA (MER)
Type of Flight Plan Filed: None
Destination: Atwater, CA (MER)
Type of Clearance: VFR
Departure Time: 1405 PDT
Type of Airspace:

Airport Information

Airport: CASTLE (MER)
Runway Surface Type: Asphalt; Concrete
Airport Elevation: 190 ft
Runway Surface Condition: Dry
Runway Used: 31
IFR Approach:None 
Runway Length/Width: 11802 ft / 150 ft
VFR Approach/Landing: Full Stop 

Wreckage and Impact Information

Crew Injuries: 1 None
Aircraft Damage: Substantial
Passenger Injuries: N/A
Aircraft Fire: None
Ground Injuries: N/A
Aircraft Explosion: None
Total Injuries: 1 None
Latitude, Longitude: 37.375833, -120.573056 (est)


  1. Lots of "game change" projects like this one don't reach the flight test stage. The uncritical PR and hot topic websites hoped for success and talked about there being $50 million in preorders of this one in the usual kit completion business model.

    Test pilot is fortunate to have skills to survive the problems of the design. Many don't.

  2. The project continues:

    Flight Video, July 2020: