# NTSB WPR17FA139: North Wing Uum Sport X2 912, N492XB, Chelan, WA, July 1, 2017 - Type: NTSB accident investigation - Classification: Accident · Fatal · Field investigation · Final report - Date: July 1, 2017, 07:30 local (14:30 UTC) - Place: Chelan, WA - Coordinates: 47.920276, -119.86972 - Nearby events: https://openairdocs.org/map.md?lat=47.9203&lon=-119.8697&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Defining event: [Maneuvering-low-alt flying: Loss of control in flight](https://openairdocs.org/ntsb-events/240) - Highest injury: Fatal - Injuries: 2 fatal - Status: Completed, report July 8, 2019 - Report: Approved by Office Director - NTSB office: Western Pacific Region - Parties: FSDO, North Wing Inc - NTSB case key (mKey): 95478 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR17FA139 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/95478/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=95478 - Page: https://openairdocs.org/ntsb/WPR17FA139 ## Probable cause The flight instructor's failure to maintain control of the aircraft while demonstrating a spiral dive, which resulted in a loss of control. Contributing to the accident was the instructor's decision to demonstrate a spiral dive maneuver at an altitude that was too low for recovery. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Use of equip/info: aircraft control](https://openairdocs.org/ntsb-findings/02063040): Personnel issues › Task performance · Pilot (probable cause); cases with it: [North Wing Uum SCOUT X-C, 4 cases](https://openairdocs.org/ntsb-findings/02063040/cases.md?model=060006R), [All aircraft, 9,295 cases](https://openairdocs.org/ntsb-findings/02063040/cases.md) - [Performance/control parameters](https://openairdocs.org/ntsb-findings/01062000): Aircraft › Aircraft oper/perf/capability · Not attained/maintained (probable cause); cases with it: [North Wing Uum SCOUT X-C, 1 case](https://openairdocs.org/ntsb-findings/01062000/cases.md?model=060006R), [All aircraft, 1,269 cases](https://openairdocs.org/ntsb-findings/01062000/cases.md) - [Info processing/decision: decision making/judgment](https://openairdocs.org/ntsb-findings/02041520): Personnel issues › Action/decision · Pilot (probable cause); cases with it: [North Wing Uum SCOUT X-C, 1 case](https://openairdocs.org/ntsb-findings/02041520/cases.md?model=060006R), [All aircraft, 3,098 cases](https://openairdocs.org/ntsb-findings/02041520/cases.md) - [Performance/control parameters: altitude](https://openairdocs.org/ntsb-findings/01062012): Aircraft › Aircraft oper/perf/capability · Not attained/maintained (probable cause); cases with it: [North Wing Uum SCOUT X-C, 1 case](https://openairdocs.org/ntsb-findings/01062012/cases.md?model=060006R), [All aircraft, 1,310 cases](https://openairdocs.org/ntsb-findings/01062012/cases.md) - [Terrain: mountainous/hilly terrain](https://openairdocs.org/ntsb-findings/03021010): Environmental issues › Physical environment · Ability to respond/compensate; cases with it: [North Wing Uum SCOUT X-C, 1 case](https://openairdocs.org/ntsb-findings/03021010/cases.md?model=060006R), [All aircraft, 329 cases](https://openairdocs.org/ntsb-findings/03021010/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Maneuvering-low-alt flying: Loss of control in flight](https://openairdocs.org/ntsb-events/240) (defining event); cases with it: [North Wing Uum SCOUT X-C, 2 cases](https://openairdocs.org/ntsb-events/240/sequence.md?model=060006R), [All aircraft, 5,002 cases](https://openairdocs.org/ntsb-events/240/sequence.md) - [Uncontrolled descent: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [North Wing Uum SCOUT X-C, 4 cases](https://openairdocs.org/ntsb-events/470/sequence.md?model=060006R), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md) ## Analysis The flight instructor and the student pilot were conducting a local flight in the weight-shift-control aircraft. An onboard camera captured the accident flight and showed that, at the time of the accident, the instructor was demonstrating a spiral dive maneuver. The video showed that the maneuver was initiated at an altitude that appears to be below 1,000 ft AGL which is a minimum required recovery altitude. During the maneuver, the aircraft's bank angle continued to increase until the aircraft entered a nearly-vertical descent and impacted terrain. Postaccident examination of the wreckage revealed no evidence of a preimpact mechanical malfunction or failure that would have precluded normal operation. ## Factual narrative Recovery from a Steep-banked Spiral Dive According to the Weight-Shift Control Aircraft Flying Handbook (FAA-H-8083-5) Addendum, the purpose of practicing a steep spiral dive is to "build recognition of and a reflexive response to a steep-banked spiraling dive. Start all practice at an altitude that will permit a recovery at no lower than 1,000 feet above the ground (AGL). An altitude of at least 2,500 AGL is recommended…The pilot must be careful not to stall the aircraft or exceed airspeed limitations at all times." The aircraft was manufactured in 2014 and purchased by the instructor in May 2017. The aircraft's maintenance records were not located and its maintenance history could not be determined. The aircraft was equipped with a Rotax 912 series, 80-horsepower reciprocating engine. The engine was situated behind the rear seat in a pusher-type arrangement. The engine was electronically controlled and drove a 3-blade composite propeller. The primary pilot station was the front seat. The rear seat occupant has no access to instruments. Both front and rear seat occupants had access to the control bar. Evidence suggest that the pilot occupied the rear seat and the student the front seat. On July 1, 2017, about 0730 Pacific daylight time, a North Wing Scout XC light sport weight-shift-control (WSC) aircraft, N492XB, was destroyed when it impacted mountainous terrain while maneuvering near Chelan, Washington. The flight instructor and student pilot sustained fatal injuries. The aircraft was owned by the flight instructor who was operating it under the provisions of Title 14 Code of Federal Regulations Part 91. Visual meteorological conditions prevailed at the time of the accident, and no flight plan was filed for the local flight, which originated from Lake Chelan Airport (S10), Chelan, Washington, about 0630. A review of video obtained from an onboard camera revealed that, earlier that morning, the student pilot completed a checkride to obtain a sport pilot certificate. The instructor informed the student pilot that he completed the checkride successfully. They subsequently departed again and continued to fly in the local area. Video showed that the pilots stayed in the traffic pattern before departing to the east. As the aircraft continued to climb away from the airport, the pilots discussed finding an area with less turbulence. About 19 minutes after takeoff for the accident flight, the instructor took over the flight controls and began to demonstrate a spiral dive. As he entered the maneuver, the aircraft's bank angle increased, and the aircraft rotated nearly 360° with its nose pointing straight down. The video stopped recording upon impact. The King County Medical Examiner, Seattle, Washington, performed an autopsy of the flight instructor and the student pilot. The cause of death for both individuals was listed as multiple blunt force injuries. The FAA Bioaeronatical Sciences Research Laboratory, Oklahoma City, Oklahoma, performedtoxicology on specimens from the instructor and the student pilot. Testing of specimens from the instructor detected ethanol in muscle and brain, propanol in muscle, and atorvastatin in liver. Ethanol is the intoxicant commonly found in beer, wine, and liquor. Ethanol may also be produced in body tissues by microbial activity after death. Atorvastatin (often called Lipitor) is a cholesterol-lowering agent. The drug is not considered impairing. The tests for cyanide and carbon monoxide were not performed. Testing of specimens of the student pilot detected ethanol in muscle but not in liver; no drugs were detected in muscle. The tests for cyanide and carbon monoxide were not performed. The 0655 automated observation at Pangborn Memorial Airport (EAT), Wenatchee, Washington, about 35 miles southwest of the accident site, included wind from 310° at 11 knots, 10 miles visibility, temperature 24°C, dew point 9°C, and an altimeter setting of 29.91 inches of mercury. The instructor, age 70, held a private pilot certificate with an airplane single-engine land rating and a flight instructor certificate for light sport aircraft. The pilot was issued a third-class Federal Aviation Administration (FAA) airman medical certificate on April 19, 2016, with a limitation that he must have available glasses for near vision. On the application for that medical certificate, the pilot reported 6,000 total hours of flight experience, of which 100 hours were in the previous six months. A review of the pilot's logbook revealed that he accumulated a total of 3,012.9 hours in the WSC trike category. The student, age 48, held a student pilot certificate and was not required to possess an FAA airman medical certificate. The student's logbooks were not available for review, and his flight experience could not be determined. The aircraft impacted terrain near the top of a hill in mountainous, rocky terrain and was destroyed by impact forces. The wreckage debris path was oriented on a heading about 130° magnetic. The first identified point of contact (FIPC) was a rock about 25 ft below the summit of the hill. The FIPC was characterized by an area of disturbed dirt surrounded by debris, including the front steering fork and the brake reservoir. A portion of the canopy was located left of the FPIC. The main wreckage, including most of the airframe, the engine, the wing, main landing gear, and propeller, was located about 50 ft from the FIPC on a heading of 320°, indicating that, following the impact, it rolled down the hill. One propeller blade was fractured and located about 30 ft north of the main wreckage. The rear seat was located within the main wreckage; the front seat was located along the debris path. Multiple separations throughout the flight control system were observed. All fracture surfaces were consistent with overload. The engine cylinders, crankcase and overhead components were intact and displayed no evidence of catastrophic failure. Disassembly and examination ofthe engine revealed no evidence of abnormal wear or failure of internal components. Negligible impact damage was noted to the crankcase, reduction gear case, cylinders, and accessory section. Rocker arm, valve train, and accessory gear continuity was established by rotating the engine crankshaft by hand. All four cylinders developed pressure when the crankshaft was rotated. Internal examination of the pistons and cylinders using a lighted borescope revealed no anomalies. The piston faces and cylinder bores were clear and undamaged. The spark plugs were removed and displayed normal wear signatures. Impact damage was noted to both carburetors and the ignition system. Examination of the engine revealed no evidence of a preimpact mechanical malfunction or failure. ## Aircraft - Registration: [N492XB](https://openairdocs.org/aircraft/N492XB), registered now, S/N LS9014, built 2014 (OpenAirDocs) - Reported make and model: NORTH WING UUM INC SPORT X2 912 (NO SERIES) - Registry model: [North Wing Uum SCOUT X-C](https://openairdocs.org/model/north-wing-uum-scout-x-c) (registry code 060006R) (OpenAirDocs) - Registry engine: [Rotax 912UL series](https://openairdocs.org/engine/rotax-912ul-series) (registry code 55571, 4 cycle) (OpenAirDocs) - Category: Airplane - Serial number: LS9014 - Year built: 2014 - Damage: Destroyed - Flight: Personal, Part 91 - Airworthiness certificate: Standard, Normal - Departed: S10, CHELAN, WA - Destination: S10, CHELAN, WA ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 70; injuries: fatal; flight instructor, private; airplane ratings: single-engine land; medical: class 3, with waivers/limitations; seat: rear; toxicology performed; flight hours: 6,000 total, 3,012.8 in this make and model - Student pilot; age 48; injuries: fatal; student; seat: front; toxicology performed ## Weather - Conditions: Visual (VMC), Day - Wind: 310° at 11 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 75 °F, dew point 48 °F - Altimeter: 29.90 inHg - Observed at: KEAT, 34 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 20170701010819A](https://openairdocs.org/incident/20170701010819A), Jul 1, 2017: North Wing Uum Inc SCOUT X-C, Chelan, WA, Substantial damage, 2 fatal. On July 02, 2017 N492X impacted into the side of a mountain approximately 20 feet from the summit. The aircraft rolled down the mountain approximately 30 feet… ## Docket (8 files) The files NTSB released with the investigation on April 18, 2019, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=95478. 29.2 MB in all. - Onboard Image Recorder - Specialist's Factual Report (item 1, .PDF, 695 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40472027&FileExtension=.PDF&FileName=Onboard%20Image%20Recorder%20-%20Specialist%27s%20Factual%20Report-Master.PDF - Weather Study (item 2, .PDF, 803 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40472028&FileExtension=.PDF&FileName=Weather%20Study-Master.PDF - Accident Site Examination Summary (item 3, .PDF, 4 photos, 3.5 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40472029&FileExtension=.PDF&FileName=Accident%20Site%20Examination%20Summary-Master.PDF - Engine Examination (item 4, .PDF, 7 photos, 973 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40472030&FileExtension=.PDF&FileName=Engine%20Examination-Master.PDF - Pilot's Logbook (item 5, .PDF, 22.7 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40472031&FileExtension=.PDF&FileName=Pilot%27s%20Logbook-Master.PDF - Statement of Party Representatives to NTSB Investigation (item 6, .PDF, 85 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40472032&FileExtension=.PDF&FileName=Statement%20of%20Party%20Representatives%20to%20NTSB%20Investigation-Master.PDF - Release of Aircraft Wreckage, NTSB Form 6120.15 (item 7, .PDF, 42 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40472033&FileExtension=.PDF&FileName=Release%20of%20Aircraft%20Wreckage,%20NTSB%20Form%206120.15-Master.PDF - Toxicological Reports (item 8, .PDF, 369 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40472034&FileExtension=.PDF&FileName=Toxicological%20Reports-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.