# NTSB WPR17LA201: Cobalt Aircraft Industries Co50 Valkyrie, N523CA, Atwater, CA, September 5, 2017 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: September 5, 2017, 14:30 local (21:30 UTC) - Place: Atwater, CA - Coordinates: 37.375831, -120.573059 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=37.3758&lon=-120.5731&mi=10 - Phase of flight: [Initial climb](https://openairdocs.org/ntsb-phases/350) (OpenAirDocs' grouping) - Defining event: [Initial climb: Flight control sys malf/fail](https://openairdocs.org/ntsb-events/333) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report May 28, 2020 - Report: Approved by Office Director - NTSB office: Western Pacific Region - Parties: Federal Aviation Administration - NTSB case key (mKey): 95992 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR17LA201 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/95992/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=95992 - Page: https://openairdocs.org/ntsb/WPR17LA201 ## Probable cause A loss of aileron effectiveness due to the airplane's design configuration, which resulted in the pilot's inability to control the roll axis and led to a hard landing. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Performance/control parameters: lateral/bank control](https://openairdocs.org/ntsb-findings/01062023): Aircraft › Aircraft oper/perf/capability · Design (probable cause); cases with it: [Cobalt Aircraft Industries VALKYRIE, 1 case](https://openairdocs.org/ntsb-findings/01062023/cases.md?model=05635N6), [All aircraft, 390 cases](https://openairdocs.org/ntsb-findings/01062023/cases.md) - [Performance/control parameters: directional control](https://openairdocs.org/ntsb-findings/01062020): Aircraft › Aircraft oper/perf/capability · Attain/maintain not possible (probable cause); cases with it: [Cobalt Aircraft Industries VALKYRIE, 1 case](https://openairdocs.org/ntsb-findings/01062020/cases.md?model=05635N6), [All aircraft, 3,958 cases](https://openairdocs.org/ntsb-findings/01062020/cases.md) - [Use of equip/info: aircraft control](https://openairdocs.org/ntsb-findings/02063040): Personnel issues › Task performance · Pilot (probable cause); cases with it: [Cobalt Aircraft Industries VALKYRIE, 1 case](https://openairdocs.org/ntsb-findings/02063040/cases.md?model=05635N6), [All aircraft, 9,295 cases](https://openairdocs.org/ntsb-findings/02063040/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Initial climb: Flight control sys malf/fail](https://openairdocs.org/ntsb-events/333) (defining event); cases with it: [Cobalt Aircraft Industries VALKYRIE, 1 case](https://openairdocs.org/ntsb-events/333/sequence.md?model=05635N6), [All aircraft, 410 cases](https://openairdocs.org/ntsb-events/333/sequence.md) - [Landing-flare/touchdown: Aerodynamic stall/spin](https://openairdocs.org/ntsb-events/241); cases with it: [Cobalt Aircraft Industries VALKYRIE, 1 case](https://openairdocs.org/ntsb-events/241/sequence.md?model=05635N6), [All aircraft, 1,529 cases](https://openairdocs.org/ntsb-events/241/sequence.md) - [Landing-flare/touchdown: Hard landing](https://openairdocs.org/ntsb-events/092); cases with it: [Cobalt Aircraft Industries VALKYRIE, 1 case](https://openairdocs.org/ntsb-events/092/sequence.md?model=05635N6), [All aircraft, 2,102 cases](https://openairdocs.org/ntsb-events/092/sequence.md) ## Analysis The pilot reported that the purpose of the flight was to evaluate handling qualities of the experimental airplane at various configurations specified in the test card. After rotation, with the airplane about 50 ft above ground level (agl), the pilot experienced a loss of aileron control. As the airspeed increased, he began to attain some controllability and climbed to about 1,400 ft agl. After about 20 minutes of manipulating the flight controls and practicing climbing and descending using the trim, he stabilized the airplane around 90 kts. He thought that he would be able to land the airplane 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, which resulted in damage to the right wing spar. For the test flight, the airplane manufacturer had changed the winglet position, which contributed to a loss of aileron effectiveness. ## Factual narrative 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. ## Aircraft - Registration: [N523CA](https://openairdocs.org/deregistered/N523CA-2020-02-03), registration cancelled 2020-02-03, S/N P04, built 2016 (OpenAirDocs) - Reported make and model: COBALT AIRCRAFT INDUSTRIES INC Co50 VALKYRIE - Registry model: [Cobalt Aircraft Industries VALKYRIE](https://openairdocs.org/model/cobalt-aircraft-industries-valkyrie) (registry code 05635N6) (OpenAirDocs) - Registry engine: [Continental TSIOF550-D](https://openairdocs.org/engine/continental-tsiof550-d) (registry code 17415, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: P04 - Year built: 2016 - Airframe hours: 1 - Engines: CONTINENTAL MOTORS TSIOF550-D 350 horsepower reciprocating - Damage: Substantial damage - Flight: Flight test, Part 91 - Operator: Cobalt Aircraft Industries Inc - Registered owner: Cobalt Aircraft Industries Inc - Airworthiness certificate: Special, Experimental (Special) - Last inspection: Continuous airworthiness, September 4, 2017 - Departed: MER, Atwater, CA - Destination: MER, Atwater, CA - Airport: MER, Castle, runway 31, 11,802 × 150 ft, concrete - Equipment: ADS-B, Airframe parachute, Electronic multifunction display, Video recording device, Electronic primary flight display ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 73; injuries: none; flight instructor, airline transport; airplane ratings: single-engine sea, single-engine land, multi-engine land; instrument ratings: airplane; medical: class 2, without waivers/limitations; seat: left; restraint: 4-point; flight hours: 9,650 total, 0.8 in this make and model, 7,500 as pilot in command, 6.3 in the last 90 days, 6.3 in the last 30 days, 0.8 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 340° at 7 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 75 °F, dew point 64 °F - Altimeter: 29.85 inHg - Observed at: KMER, 1 nm away ## FAA reports on this event (1) The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs). - [Accident 20170905015899A](https://openairdocs.org/incident/20170905015899A), Sep 5, 2017: Cobalt Aircraft Ind, Inc CO50, Atwater, CA, Substantial damage. This hard landing accident occurred during an undeclared emergency landing that occured at the conclusion of the first flight of this second prototype Cobalt… ## Docket (3 files) The files NTSB released with the investigation on February 4, 2020, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=95992. 11.6 MB in all. - Pilot - Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 8.7 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40480475&FileExtension=.PDF&FileName=Pilot%20-%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Master.PDF - Operator - Aircraft Accident Report, NTSB Form 6120.1 (item 2, .PDF, 2.8 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40480476&FileExtension=.PDF&FileName=Operator%20-%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Master.PDF - Record of Conversation - Colbalt (item 3, .PDF, 79 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40480477&FileExtension=.PDF&FileName=Record%20of%20Conversation%20-%20Colbalt-Master.PDF From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.