# NTSB CEN09LA278: Glasflugel H201B, N17TD, Meadow Lake Airport, CO, May 4, 2009 - Type: NTSB accident investigation - Classification: Accident · Serious injuries · Limited investigation · Final report - Date: May 4, 2009, 13:07 local (19:07 UTC) - Place: Meadow Lake Airport, CO - Coordinates: 39.030059, -104.480224 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=39.0301&lon=-104.4802&mi=10 - Phase of flight: [Takeoff](https://openairdocs.org/ntsb-phases/300) (OpenAirDocs' grouping) - Defining event: [Takeoff: Glider tow event](https://openairdocs.org/ntsb-events/510) - Highest injury: Serious injuries - Injuries: 1 serious - Status: Completed, report September 30, 2009 - Report: Approved by Office Director - NTSB office: Central Region - Parties: FAA - NTSB case key (mKey): 73780 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN09LA278 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/73780/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=73780 - Page: https://openairdocs.org/ntsb/CEN09LA278 ## Probable cause A programming anomaly within the winch's computer aided launch control system, which incorrectly limited the maximum winch speed during launch of the glider. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Misc hardware](https://openairdocs.org/ntsb-findings/01071400): Aircraft › Fluids/misc hardware · Not specified (probable cause); cases with it: [Glasflugel STD LIBELLE 201B, 1 case](https://openairdocs.org/ntsb-findings/01071400/cases.md?model=3800344), [All aircraft, 41 cases](https://openairdocs.org/ntsb-findings/01071400/cases.md) - [Performance/control parameters: airspeed](https://openairdocs.org/ntsb-findings/01062010): Aircraft › Aircraft oper/perf/capability · Attain/maintain not possible; cases with it: [Glasflugel STD LIBELLE 201B, 1 case](https://openairdocs.org/ntsb-findings/01062010/cases.md?model=3800344), [All aircraft, 1,681 cases](https://openairdocs.org/ntsb-findings/01062010/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Prior to flight: Miscellaneous/other](https://openairdocs.org/ntsb-events/900); cases with it: [Glasflugel STD LIBELLE 201B, 1 case](https://openairdocs.org/ntsb-events/900/sequence.md?model=3800344), [All aircraft, 1,556 cases](https://openairdocs.org/ntsb-events/900/sequence.md) - [Takeoff: Glider tow event](https://openairdocs.org/ntsb-events/510) (defining event); cases with it: [Glasflugel STD LIBELLE 201B, 1 case](https://openairdocs.org/ntsb-events/510/sequence.md?model=3800344), [All aircraft, 45 cases](https://openairdocs.org/ntsb-events/510/sequence.md) - [Takeoff: Aerodynamic stall/spin](https://openairdocs.org/ntsb-events/241); cases with it: [Glasflugel STD LIBELLE 201B, 1 case](https://openairdocs.org/ntsb-events/241/sequence.md?model=3800344), [All aircraft, 1,529 cases](https://openairdocs.org/ntsb-events/241/sequence.md) - [Landing-flare/touchdown: Hard landing](https://openairdocs.org/ntsb-events/092); cases with it: [Glasflugel STD LIBELLE 201B, 1 case](https://openairdocs.org/ntsb-events/092/sequence.md?model=3800344), [All aircraft, 2,102 cases](https://openairdocs.org/ntsb-events/092/sequence.md) ## Analysis The glider flight was being conducted to test the operation of a prototype winch launch system utilizing a computer aided launch control (CALC) hydrostatic system. During the launch, a programming anomaly within CALC limited the maximum winch speed to 32 miles per hour, causing the winch cable to release as the glider climbed away from the ground. The pilot pushed the nose of the glider down, but insufficient altitude was available to recover the glider. The glider impacted the runway in a level attitude, cracking the fuselage. ## Factual narrative On May 5, 2009, at 1307 mountain daylight time, a Glasflugel Libelle H201B model glider, N17TD, was substantially damaged during a forced landing following an attempted winch assisted takeoff. The private pilot was seriously injured. The flight was being conducted under the provisions of Title 14 Code of Federal Regulations Part 91 without a flight plan. The local flight was departing from Meadow Lake Airport (00V), Colorado Springs, Colorado. Visual meteorological conditions prevailed at the time of the accident. The flight was being conducted to test the operation of a prototype Hydrowinch, LLC Club Series winch launch system. The pilot stated that during the launch the glider suddenly stopped accelerating and the tow cable disconnected. Video of the accident sequence showed the glider becoming airborne in approximately 30 feet and reaching a maximum height of about 20 feet. The tow cable parachute, which inflates after release from the glider, was seen to inflate as the glider started to become airborne. The glider then nosed over, changed to a level attitude, and impacted the runway. Examination of the glider revealed the fuselage cracked aft of the cockpit. The winch was powered by a diesel engine connected to a computer controlled hydrostatic drive system. The hydrostatic drive system was controlled by a computer aided launch control (CALC) system. CALC was designed to adjust winch acceleration and maximum speed produced through the hydrostatic system based on glider type and weight. In the case of the Glasflugel Libelle H201B, acceleration force should have been limited to about 50 percent of system capability and a desired speed of 65 miles per hour. A review of the computer data for the accident launch showed the computer limited maximum speed to 50 percent, or 32 miles per hour, as opposed to the acceleration force. The winch had conducted seven successful launches in 2008 before suffering a mechanical break down and subsequently having a new computer installed. The accident flight was the second flight operation for the repaired unit. The first attempted flight operation after repair resulted in an aborted takeoff due to a non-CALC related, winch operator error. ## Aircraft - Registration: [N17TD](https://openairdocs.org/aircraft/N17TD), registered now, S/N 556 (OpenAirDocs) - Reported make and model: GLASFLUGEL H201B - Registry model: [Glasflugel STD LIBELLE 201B](https://openairdocs.org/model/glasflugel-std-libelle-201b) (registry code 3800344) (OpenAirDocs) - Registry engine: [NONE](https://openairdocs.org/engine/none) (registry code 00000, none) (OpenAirDocs) - Category: Glider - Serial number: 556 - Damage: Substantial damage - Flight: Flight test, Part 91 - Airworthiness certificate: Standard, Normal - Last inspection: Annual, May 3, 2009 - Departed: OOV, Meadow Lake, CO - Destination: OOV, Meadow Lake, CO - Airport: OOV, Meadow Lake, runway 15, 6,000 × 60 ft, asphalt ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 23; injuries: serious; private; medical: class 2, without waivers/limitations; last flight review April 20, 2009; seat: single; flight hours: 285 total, 1 in this make and model, 240 as pilot in command, 4 in the last 90 days, 4 in the last 30 days, 0 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 20° at 5 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 55 °F - Altimeter: 29.94 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 20090504006309A](https://openairdocs.org/incident/20090504006309A), May 4, 2009: Glasfl H301, Colorado Sprin, CO, Substantial damage. (-23) On 05/04/2009 [privacy data omitted] was pilot of N17TD an H-201B glider that crashed on takeoff and subsequent landing following a winch launch at… ## Docket (4 files) The files NTSB released with the investigation on August 5, 2009, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=73780. 777 KB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 613 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40316415&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF - Witness Statement - Owner (item 2, .PDF, 49 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40316416&FileExtension=.PDF&FileName=Witness%20Statement%20-%20Owner-Redacted.PDF - Witness Statement-Pilot (item 3, .PDF, 47 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40316417&FileExtension=.PDF&FileName=Witness%20Statement-Pilot-Redacted.PDF - Witness Statement (item 4, .PDF, 68 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40316418&FileExtension=.PDF&FileName=Witness%20Statement-Redacted.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.