# NTSB ERA13CA195: Phoenix Air U15, N94DK, Foscoe, NC, April 6, 2013 - Type: NTSB accident investigation - Classification: Accident · No injuries · Data collection · Final report - Date: April 6, 2013, 15:40 local (19:40 UTC) - Place: Foscoe, NC - Coordinates: 35.969444, -81.818611 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=35.9694&lon=-81.8186&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Defining event: [Enroute-cruise: Turbulence encounter](https://openairdocs.org/ntsb-events/360) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report August 13, 2013 - Report: Approved by Office Director - NTSB office: Eastern Region Aviation - Parties: FAA/FSDO - NTSB case key (mKey): 86625 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ERA13CA195 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/86625/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=86625 - Page: https://openairdocs.org/ntsb/ERA13CA195 ## Probable cause The motorized glider’s encounter with clear air turbulence, which resulted in substantial damage to the empennage. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Turbulence: clear air turbulence](https://openairdocs.org/ntsb-findings/03032015): Environmental issues › Conditions/weather/phenomena · Effect on equipment (probable cause); cases with it: [Phoenix Air Sro U-15 PHOENIX, 1 case](https://openairdocs.org/ntsb-findings/03032015/cases.md?model=0600079), [All aircraft, 78 cases](https://openairdocs.org/ntsb-findings/03032015/cases.md) - [Empennage structure](https://openairdocs.org/ntsb-findings/01035500): Aircraft › Aircraft structures · Capability exceeded (probable cause); cases with it: [Phoenix Air Sro U-15 PHOENIX, 1 case](https://openairdocs.org/ntsb-findings/01035500/cases.md?model=0600079), [All aircraft, 14 cases](https://openairdocs.org/ntsb-findings/01035500/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Enroute-cruise: Turbulence encounter](https://openairdocs.org/ntsb-events/360) (defining event); cases with it: [Phoenix Air Sro U-15 PHOENIX, 1 case](https://openairdocs.org/ntsb-events/360/sequence.md?model=0600079), [All aircraft, 423 cases](https://openairdocs.org/ntsb-events/360/sequence.md) ## Analysis According to the pilot of the motorized glider, he was flying at an altitude of 6,000 feet mean sea level (msl) en route to his home airport when he noted an episode of turbulence on the avionics logs for his flight path. He climbed to an altitude of 6,500 feet msl to avoid the turbulence and continued to his destination; however, the glider subsequently encountered severe turbulence that lasted for a few seconds. The pilot reported that during that time he heard a cracking noise in the rear of the glider, which he attributed to a loose quart of oil in the baggage compartment. He continued the flight and landed at his home airport uneventfully. While he was cleaning the glider after the flight, the pilot noted substantial damage to the empennage, which included a 12-inch crack to the composite structure under the right side of the vertical stabilizer. The pilot reported no mechanical malfunctions or failures that would have precluded normal operation before the turbulence encounter; further, he stated that he noted no controllability problems with the glider after the turbulence encounter. ## Factual narrative According to the pilot of the motorized glider, he was flying at an altitude of 6,000 feet en route to his home airport when he noted an episode of turbulence on the avionics logs for his flight path. He climbed to an altitude of 6,500 feet and continued to his destination; however, the glider subsequently encountered severe turbulence that lasted for a few seconds. The pilot heard a cracking noise and thought it was a quart of oil loose in the baggage compartment. He continued the flight and landed at his home airport uneventfully. While cleaning the glider after the flight, the pilot noted substantial damage to the empennage, which included a 12-inch crack to the composite structure under the right side of the vertical stabilizer. The pilot reported no mechanical malfunctions or failures that would have precluded normal operation prior to the turbulence encounter and noted that the glider remained controllable as normal after the turbulence encounter. ## Aircraft - Registration: [N94DK](https://openairdocs.org/aircraft/N94DK), registered now, S/N 14/U15, built 2012 (OpenAirDocs) - Reported make and model: Phoenix Air U15 - Registry model: [Phoenix Air Sro U-15 PHOENIX](https://openairdocs.org/model/phoenix-air-sro-u-15-phoenix) (registry code 0600079) (OpenAirDocs) - Registry engine: [Rotax 912ULS series](https://openairdocs.org/engine/rotax-912uls-series) (registry code 55572, 4 cycle) (OpenAirDocs) - Category: Glider - Serial number: 14 - Airframe hours: 121 - Engines: Rotax 912 ULS 100 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Operator: Palmetto Phoenix Associates, LLC - Registered owner: Palmetto Phoenix Associates, LLC - Airworthiness certificate: Special, Experimental light sport (Special) - Last inspection: Annual, September 5, 2012 - Departed: MKJ, Ruiral Retreat, VA - Destination: CUB, Columbia, SC ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 64; injuries: none; sport pilot; airplane ratings: single-engine land; medical: sport pilot, with waivers/limitations; last flight review August 12, 2012; seat: left; flight hours: 122 total, 60 in this make and model, 61 as pilot in command, 21 in the last 90 days, 12 in the last 30 days, 5 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 90° at 7 knots, gusting 15 - Lowest ceiling: none - Temperature: 37 °F - Altimeter: 30.22 inHg ## 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 20130406005399A](https://openairdocs.org/incident/20130406005399A), Apr 6, 2013: Phoenix Air Sro U-15 PHOENIX, Columbia, SC, Substantial damage. Pilot stated on the return trip from north carolina, he experienced Turbulence while cruising at 55OO feet. The pilot felt shaking or jerking lasting only a… ## Docket (3 files) The files NTSB released with the investigation on June 6, 2013, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=86625. 6.9 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 3.4 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40391472&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF - Photograph # 1: View of damage to airplane structure (Courtesy of FAA) (item 2, .PDF, 1.7 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40391861&FileExtension=.PDF&FileName=Photograph%20%23%201%3A%20View%20of%20damage%20to%20airplane%20structure%20(Courtesy%20of%20FAA)-Master.PDF - Photograph # 2: Closer view of damage to airplane structure (Courtesy of FAA) (item 3, .PDF, 1.8 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40391856&FileExtension=.PDF&FileName=Photograph%20%23%202%3A%20Closer%20view%20of%20damage%20to%20airplane%20structure%20(Courtesy%20of%20FAA)-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.