Sunday, May 6, 2018

Stemme S10-VT, N5021: Fatal accident occurred August 24, 2016 in Telluride, San Miguel County, Colorado

Robert "Glider Bob" Saunders


The National Transportation Safety Board traveled to the scene of this accident.

Additional Participating Entities: 
Federal Aviation Administration / Flight Standards District Office; Salt Lake City, Utah
Stemme AG; Strausberg, Germany
US MotorGlider Inc; Ramona, California
Rotech Flight Safety Inc.; Vernon, British Columbia

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

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

http://registry.faa.gov/N5021 


Aviation Accident Factual Report - National Transportation Safety Board 

Location: Telluride, CO
Accident Number: CEN16FA331
Date & Time: 08/24/2016, 1410 MDT
Registration: N5021
Aircraft: STEMME GMBH & CO S10 VT
Aircraft Damage: Substantial
Defining Event: Miscellaneous/other
Injuries: 2 Fatal
Flight Conducted Under: Part 91: General Aviation - Business - Sightseeing 

On August 24, 2016, about 1410 mountain daylight time, a Stemme Gmbh S10-VT self-launching (powered) glider, N5021, was substantially damaged during an in-flight collision with trees and terrain near Telluride, Colorado. The pilot and passenger sustained fatal injuries. The glider was registered to and operated by the pilot under the provisions of 14 Code of Federal Regulations Part 91 as a local sightseeing flight. Visual meteorological conditions prevailed for the flight, which was not operated on a flight plan. The flight originated from the Telluride Regional Airport (TEX), Telluride, Colorado, about 1315.

A witness reported seeing the powered glider climbing out from TEX. The engine "sounded perfect" at a constant power setting at the time. About 15 minutes later, he heard the sound of a "strained engine." It sounded as if there was a "strain on the propeller," similar to a propeller-driven airplane maneuvering during aerobatic flight. About 15 seconds later, the sound of the engine stopped. He subsequently overheard radio communications of mountain staff personnel responding to a downed aircraft.

A second witness observed the powered glider fly by with the engine running. His co-worker commented that the glider seemed to be flying unusually low. It subsequently went out of sight below the tree line. About 10 seconds later, they heard a loud noise, which they initially attributed to work going on in the area. However, with thoughts of the low flying glider, he decided to drive to a nearby ridge where he observed the accident site. He reported the accident to the local authorities.

Pilot Information

Certificate: Commercial
Age: 64, Male
Airplane Rating(s): Single-engine Land
Seat Occupied: Left
Other Aircraft Rating(s): Glider
Restraint Used: 4-point
Instrument Rating(s): None
Second Pilot Present: No
Instructor Rating(s): Glider
Toxicology Performed: Yes
Medical Certification: None
Last FAA Medical Exam:
Occupational Pilot: Yes
Last Flight Review or Equivalent:
Flight Time: 4000 hours (Total, all aircraft), 700 hours (Total, this make and model) 

The pilot's logbook was not available to the NTSB and, as a result, his flight experience could not be determined. The pilot did not hold a current Federal Aviation Administration airman medical certificate, nor was one required to operate a glider. In February 1998, on his most recent application for a medical certificate, the pilot reported a total civilian flight time of more than 4,000 hours. No subsequent applications were on file.

The pilot provided 30-minute and 1-hour sightseeing flights from TEX. Advertisement flyers were available at the TEX fixed based operator. The pilot maintained a website advertising the sightseeing flights. 

Aircraft and Owner/Operator Information

Aircraft Manufacturer: STEMME GMBH & CO
Registration: N5021
Model/Series: S10 VT
Aircraft Category: Glider
Year of Manufacture: 1997
Amateur Built: No
Airworthiness Certificate: Utility
Serial Number: 11-010
Landing Gear Type: Tailwheel
Seats: 2
Date/Type of Last Inspection:  Annual
Certified Max Gross Wt.: 1874 lbs
Time Since Last Inspection:
Engines: 1 Reciprocating
Airframe Total Time:
Engine Manufacturer: Rotax
ELT: Installed, activated, did not aid in locating accident
Engine Model/Series: 914
Registered Owner: On file
Rated Power: 115 hp
Operator: On file
Operating Certificate(s) Held: None 

The pilot purchased the glider in July 2004. A review of the available maintenance records revealed that the most recent entry, dated September 20, 2012, was unsigned. The entry noted the completion of an annual inspection at airframe and engine total times of 1,824.2 hours and 496.3 hours, respectively. 

Meteorological Information and Flight Plan

Conditions at Accident Site: Visual Conditions
Condition of Light: Day
Observation Facility, Elevation: TEX, 9070 ft msl
Observation Time: 1415 MDT
Distance from Accident Site: 5 Nautical Miles
Direction from Accident Site: 315°
Lowest Cloud Condition: Scattered / 6500 ft agl
Temperature/Dew Point: 16°C / 4°C
Lowest Ceiling: Broken / 9000 ft agl
Visibility: 10 Miles
Wind Speed/Gusts, Direction: Calm
Visibility (RVR):
Altimeter Setting: 30.42 inches Hg
Visibility (RVV):
Precipitation and Obscuration: Light - In the Vicinity - Thunderstorms - Rain
Departure Point: Telluride, CO (TEX)
Type of Flight Plan Filed: None
Destination: Telluride, CO (TEX)
Type of Clearance: None
Departure Time: 1315 MDT
Type of Airspace: Class G 

One witness reported light rain and steady surface wind about 8 mph from the northeast about the time of the accident. He stated that there was no thunderstorm activity in the immediate area; however, there was thunderstorm activity across the valley to the north and closer to the airport. Another witness reported that "dark rain clouds" began building near the site about 1 hour before the accident.

Satellite imagery depicted growing cumuliform clouds near the accident site that were moving southeastward at the time. The cloud-top heights over the accident site were about 18,000 feet mean sea level (msl). Weather radar data depicted a rain shower over the site about the time of the accident. The rain shower activity was moving south-southeast and appeared to be dissipating. With dissipating rain shower activity directly above the site at the time of the accident, the glider was in a favorable region for downdrafts.

No Significant Meteorological Information (SIGMET) advisories were in effect for the site at the time of the accident. An Airmen's Meteorological Information (AIRMET) advisory for mountain obscuration due to clouds and mist was in effect at the time of the accident.

A full weather study is available in the docket for this accident case. 

Airport Information

Airport: Telluride Regional (TEX)
Runway Surface Type:
Airport Elevation: 9070 ft
Runway Surface Condition:
Runway Used: N/A
IFR Approach: None
Runway Length/Width:
VFR Approach/Landing: None 



Wreckage and Impact Information

Crew Injuries: 1 Fatal
Aircraft Damage: Substantial
Passenger Injuries: 1 Fatal
Aircraft Fire: None
Ground Injuries: N/A
Aircraft Explosion: None
Total Injuries: 2 Fatal
Latitude, Longitude: 37.893333, -107.833333 

The powered glider came to rest within a small cluster of trees about 5 miles south-southeast of KTEX at an elevation of 11,200 feet. The vicinity of the accident site consisted of mountainous terrain, densely wooded areas, and small meadows. The terrain gradually sloped downhill toward the north/northwest from the accident site. The elevations of ridgelines to the east and south of the site exceeded 12,500 feet.

A postaccident examination and engine test run were conducted by the NTSB investigator-in-charge with the assistance of technical representatives from the airframe and engine manufacturers. The examination and engine run did not reveal any anomalies consistent with a preimpact failure or malfunction. 

Medical And Pathological Information

The Montrose Memorial Hospital Division of Forensic Pathology, Montrose, Colorado, performed an autopsy under the order of the San Miguel County Coroner's Office, and attributed the pilot's death to multiple traumatic injuries sustained in the accident. Toxicology testing performed by the FAA's Bioaeronautical Sciences Research Laboratory, Oklahoma City, Oklahoma, was negative for all drugs in the testing profile. No carbon monoxide or ethanol was detected in blood specimens.


NTSB Identification: CEN16FA331
14 CFR Part 91: General Aviation
Accident occurred Wednesday, August 24, 2016 in Telluride, CO
Aircraft: STEMME GMBH & CO S10 VT, registration: N5021
Injuries: 2 Fatal.

This is preliminary information, subject to change, and may contain errors. Any errors in this report will be corrected when the final report has been completed. NTSB investigators either traveled in support of this investigation or conducted a significant amount of investigative work without any travel, and used data obtained from various sources to prepare this aircraft accident report.

On August 24, 2016, about 1410 mountain daylight time, a Stemme Gmbh S10-VT motor-glider, N5021, was substantially damaged during an in-flight collision with trees and terrain near Telluride, Colorado. The pilot and passenger sustained fatal injuries. The motor-glider was registered to and operated by the pilot under the provisions of 14 Code of Federal Regulations Part 91 as a local sightseeing flight. Visual meteorological conditions prevailed for the flight, which was not operated on a flight plan. The local flight originated from the Telluride Regional Airport (TEX), Telluride, Colorado, about 1315.

A witness hiking between Mountain Village and the St. Sophia gondola station reported seeing the motor-glider under power apparently climbing out from TEX. The engine "sounded perfect" at a constant power setting at the time. About 15 minutes later, he heard the sound of a "strained engine" in the direction of Prospect Bowl. It sounded as if there was a "strain on the propeller," similar to a propeller-driven airplane maneuvering during aerobatic flight. About 15 seconds later, the sound of the engine stopped. He subsequently overheard radio communications of mountain staff personnel responding to a downed aircraft.

A second witness working on the ski patrol shack at the top of the Revelation Lift observed the motor-glider fly by with the engine running. His co-worker commented that the glider seemed to be flying unusually low and it subsequently went out of sight below the tree line. About 10 seconds later, they heard a loud noise, which they initially attributed to other work going on in the area. However, with thoughts of the low flying glider, he decided to drive to a nearby ridge at which time he observed the accident site. He reported the accident to the local authorities.

A third witness driving toward the Lynx building (near lift 13) in Prospect Basin (Bowl), looking directly at Gold Hill, reported observing the motor-glider low on the horizon just above the tree line. The aircraft proceeded south toward Prospect Ridge in what appeared to be a controlled descent. He subsequently lost sight of the aircraft behind a tree line. Although the motor-glider was at a "considerably" lower altitude than he was accustomed to seeing it, it did not appear to be out of control, nor did he perceive it to be in any distress. He and his co-worker subsequently received notification of the accident over their radio and responded to the site.

The motor-glider came to rest within a small cluster of trees in the Prospect Bowl area of the Uncompahgre National Forest/Telluride Ski Area. The accident site was located about 5 miles south-southeast of the Telluride airport at an elevation of approximately 11,200 feet. The vicinity of the accident site consisted of mountainous terrain; densely wooded areas, small meadows and exposed rock. The terrain gradually sloped downhill toward the north/northwest from the accident site. The ridgelines to the east and south of the site exceeded 12,500 feet.

The forward fuselage was oriented on a northwest bearing. The fuselage nose and cockpit area sustained extensive damage. The aft fuselage was separated from, and located immediately adjacent to, the forward fuselage. The aft fuselage was oriented in the opposite direction from the forward fuselage. A tree was positioned between the forward and aft fuselage sections. The branches on the south/southeast side of the tree appeared to have been stripped of branches and bark from a height of about 20 feet above ground level. The southernmost tree in the cluster exhibited a fresh break located about 75 feet above ground level. The empennage, including the rudder and elevators, remained attached to the aft fuselage.

Both wings had separated from the fuselage; they were located immediately adjacent to the fuselage at the time of the on-scene examination. However, local authorities advised that the right wing was initially located over the fuselage and was cut near the root in order to extricate the pilot. The left wing exhibited leading edge impact damage and deformation of the composite structure. The outboard section of the left wing, with the wingtip attached, had separated from the main wing and was located at the accident site. The left aileron was separated and fragmented; it was located at the accident site. The right wing, with exception of the damage at the root and separation of the wing tip, appeared to be intact. The right wingtip was located at the accident site. The right aileron remained attached to the wing.

One of the witnesses reported light rain (sprinkles) and steady 5-8 mph surface winds out of the northeast about the time of the accident. He stated that there was no thunderstorm activity in the immediate area; however, there was thunderstorm activity across the Telluride valley to the north and closer to the airport. Another witness reported that the weather was initially sunny with some clouds and a calm wind. However, about 1300, the weather began to change, with "dark rain clouds" building above Prospect Basin (Bowl) and in the general Telluride vicinity. At 1415, weather conditions recorded at the Telluride airport included a calm wind, with thunderstorms and light rain showers in the vicinity.

Detailed examinations of the airframe and engine are pending. A GPS Secure Flight Recorder (Cambridge Aero Instruments) was recovered at the accident site. Examination of the component and recovery of any retained data by the NTSB Recorders Laboratory is pending.

1 comment:

Anonymous said...

Under the Maintenance Records - Seperate Entries ... Seem odd and not much detail ... Were these from the mechanics computer or was the owner falsifying mx entries? Curious.