Grob G103C Twin III Acro, N103GH, San Antonio Soaring Society Inc: Accident occurred June 15, 2017 at Boerne Stage Field (5C1), San Antonio, Texas

Additional Participating Entity:
Federal Aviation Administration / Flight Standards District Office; San Antonio, Texas

Aviation Accident Final Report - National Transportation Safety Board:  https://app.ntsb.gov/pdf

Investigation Docket - National Transportation Safety Board: https://dms.ntsb.gov/pubdms

Aviation Accident Data Summary - National Transportation Safety Board:  https://app.ntsb.gov/pdf

http://registry.faa.gov/N103GH

Location: Boerne, TX
Accident Number: GAA17CA343
Date & Time: 06/15/2017, 1540 CDT
Registration: N103GH
Aircraft: BURKHART GROB G103C
Aircraft Damage: Substantial
Defining Event: Landing area undershoot
Injuries: 2 None
Flight Conducted Under: Part 91: General Aviation - Instructional

Analysis

The flight instructor of a glider report that, during landing, about 100 above the ground, a "a sink rate started to develop". He added that, he took over the flight controls and closed the spoilers. The glider impacted the airport perimeter fence and landed short of the runway, then slid into a culvert.

The glider sustained substantial damage to the empennage.

The flight instructor failed to submit the NTSB Form 6120.1 Pilot/ Operator Aircraft Accident/ Incident Report. 

Probable Cause and Findings

The National Transportation Safety Board determines the probable cause(s) of this accident to be:
The student pilot's failure to maintain an adequate glidepath and the flight instructor's delayed remedial action, which resulted in the glider landing short of the runway.

Findings

Aircraft
Descent/approach/glide path - Not attained/maintained (Cause)

Personnel issues
Aircraft control - Student pilot (Cause)
Delayed action - Instructor/check pilot (Cause)

Environmental issues
Gusts - Effect on operation
Fence/fence post - Contributed to outcome

Factual Information

History of Flight

Landing
Landing area undershoot (Defining event)

Landing-flare/touchdown
Collision with terr/obj (non-CFIT)

Flight Instructor Information

Certificate: Airline Transport; Flight Instructor
Age: 67, Male
Airplane Rating(s): Multi-engine Land; Single-engine Land
Seat Occupied: Unknown
Other Aircraft Rating(s): Glider
Restraint Used: Unknown
Instrument Rating(s): Airplane
Second Pilot Present: Yes
Instructor Rating(s): Airplane Single-engine; Glider
Toxicology Performed: No
Medical Certification: Class 2 With Waivers/Limitations
Last FAA Medical Exam: 02/16/2016
Occupational Pilot: Yes
Last Flight Review or Equivalent:
Flight Time: (Estimated) 

Student Pilot Information

Certificate: Private
Age: 57, Male
Airplane Rating(s): None
Seat Occupied: Unknown
Other Aircraft Rating(s): Glider
Restraint Used: Unknown
Instrument Rating(s): None
Second Pilot Present: Yes
Instructor Rating(s): None
Toxicology Performed: No
Medical Certification: Unknown Unknown
Last FAA Medical Exam:
Occupational Pilot: No
Last Flight Review or Equivalent:
Flight Time:

Aircraft and Owner/Operator Information

Aircraft Manufacturer: BURKHART GROB
Registration: N103GH
Model/Series: G103C TWIN II AC
Aircraft Category: Glider
Year of Manufacture: 1989
Amateur Built: No
Airworthiness Certificate: Aerobatic
Serial Number: 34110
Landing Gear Type:
Seats: 2
Date/Type of Last Inspection:  Unknown
Certified Max Gross Wt.:
Time Since Last Inspection:
Engines:
Airframe Total Time:
Engine Manufacturer:
ELT:
Engine Model/Series:
Registered Owner: On file
Rated Power:
Operator: On file
Operating Certificate(s) Held: None 

Meteorological Information and Flight Plan

Conditions at Accident Site: Visual Conditions
Condition of Light: Day
Observation Facility, Elevation: KSAT, 789 ft msl
Observation Time: 2051 UTC
Distance from Accident Site: 15 Nautical Miles
Direction from Accident Site: 135°
Lowest Cloud Condition: Few / 5500 ft agl
Temperature/Dew Point: 36°C / 20°C
Lowest Ceiling:
Visibility:  10 Miles
Wind Speed/Gusts, Direction: 14 knots/ 18 knots, 140°
Visibility (RVR):
Altimeter Setting: 29.93 inches Hg
Visibility (RVV):
Precipitation and Obscuration: No Obscuration; No Precipitation
Departure Point: Boerne, TX (5C1)
Type of Flight Plan Filed: Unknown
Destination: Boerne, TX (5C1)
Type of Clearance: Unknown
Departure Time:  CDT
Type of Airspace: Class G

Airport Information

Airport: BOERNE STAGE FIELD (5C1)
Runway Surface Type: Asphalt
Airport Elevation: 1383 ft
Runway Surface Condition: Unknown
Runway Used: 17
IFR Approach: None
Runway Length/Width: 5006 ft / 60 ft
VFR Approach/Landing: Full Stop 

Wreckage and Impact Information

Crew Injuries: 2 None
Aircraft Damage: Substantial
Passenger Injuries: N/A
Aircraft Fire: None
Ground Injuries: N/A
Aircraft Explosion: None
Total Injuries: 2 None
Latitude, Longitude:  29.725278, -98.694722 (est)