N20YZ accident

NTSB WPR15LA232 · 2015-08-02 · Logan, UT · near LGU

Docket — crew, injuries and powerplant

Summary

The pilot reported that he was participating in a mountain flying training course when the glider encountered a strong downdraft while maneuvering near a mountain ridge and lost lift. The pilot was unable to arrest the glider's descent rate, and the left wing impacted a tree. The pilot reported no preimpact malfunctions or failures with the glider that would have precluded normal operation.

Full narrative

On August 2, 2015, about 1500 mountain daylight time, a Schleicher ASW 20B glider, N20YZ, experienced a loss of lift during cruise flight, and impacted terrain near Logan, Utah. The private pilot owned and operated the glider under the provisions of 14 Code of Federal Regulations Part 91 as a personal flight. The pilot was seriously injured. The glider sustained substantial damage throughout the fuselage and wings. Visual meteorological conditions prevailed for the local flight that departed the Logan-Cache Airport (LGU), Logan, at 1430. No flight plan had been filed.

The pilot reported that he was participating in a mountain flying training course when the glider encountered a strong downdraft while maneuvering near a mountain ridge, and lost lift. The pilot was unable to arrest the glider's rate of descent, and the left wing impacted a tree. The pilot reported no preimpact malfunctions or failures that would have precluded normal operation of the glider.

Postaccident examination of the wreckage revealed that the left wing was completely separated from the fuselage, and the right wing partially separated from the fuselage. The empennage forward of the vertical stabilizer was separated from the fuselage.

Probable cause

The pilot’s failure to maintain glider control when it encountered a strong downdraft while maneuvering near a ridgeline.  The National Transportation Safety Board determined the probable cause of this accident.

Circumstances

Event type
Accident
Highest injury
Serious
Weather conditions
Visual Meteorological Cond
Light condition
Day
Sky condition
NONE
Ceiling (ft)
0
Visibility (sm)
10
Wind direction
360
Wind speed (kt)
6
Temperature (F)
93
Nearest airport
LOGAN-CACHE
Distance from field
5.0
Airport elevation
4457

Aircraft

RegistrationMakeModelDamageFAR part
N20YZ — — SUBS 091

Sequence of events

#OccurrencePhase
1 Maneuvering Loss of lift defining Climb
2 Emergency descent Collision with terr/obj (non-CFIT) Descent

Findings

Finding
Personnel issues-Task performance-Use of equip/info-Aircraft control-Pilot cause
Environmental issues-Conditions/weather/phenomena-Wind-Downdraft-Effect on operation factor
Environmental issues-Physical environment-Object/animal/substance-Tree(s)-Not specified factor