# NTSB LAX08LA242: Glaser-Dirks Flugzeugbau DG-100G, N132S, Truckee, CA, July 23, 2008 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: July 23, 2008, 13:30 local (20:30 UTC) - Place: Truckee, CA - Coordinates: 39.319999, -120.139442 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=39.3200&lon=-120.1394&mi=10 - Phase of flight: [Initial climb](https://openairdocs.org/ntsb-phases/350) (OpenAirDocs' grouping) - Defining event: [Initial climb: Sys/Comp malf/fail (non-power)](https://openairdocs.org/ntsb-events/330) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report May 12, 2009 - Report: Approved by Office Director - Parties: Federal Aviation Administration - NTSB case key (mKey): 68512 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX08LA242 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/68512/pdf - Page: https://openairdocs.org/ntsb/LAX08LA242 ## Probable cause A malfunction of the tow release mechanism. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Fuselage: aerial tow equipment section](https://openairdocs.org/ntsb-findings/01035301): Aircraft › Aircraft structures · Malfunction (probable cause); cases with it: [Glaser-Dirks Flugzeugbau DG-100G, 1 case](https://openairdocs.org/ntsb-findings/01035301/cases.md?model=3802504), [All aircraft, 7 cases](https://openairdocs.org/ntsb-findings/01035301/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Initial climb: Sys/Comp malf/fail (non-power)](https://openairdocs.org/ntsb-events/330) (defining event); cases with it: [Glaser-Dirks Flugzeugbau DG-100G, 1 case](https://openairdocs.org/ntsb-events/330/sequence.md?model=3802504), [All aircraft, 994 cases](https://openairdocs.org/ntsb-events/330/sequence.md) - [Landing: Off-field or emergency landing](https://openairdocs.org/ntsb-events/440); cases with it: [Glaser-Dirks Flugzeugbau DG-100G, 1 case](https://openairdocs.org/ntsb-events/440/sequence.md?model=3802504), [All aircraft, 3,365 cases](https://openairdocs.org/ntsb-events/440/sequence.md) - [Landing: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [Glaser-Dirks Flugzeugbau DG-100G, 1 case](https://openairdocs.org/ntsb-events/470/sequence.md?model=3802504), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md) ## Analysis About 150 feet above ground level (agl) during a tow to altitude, the glider's tow rope release mechanism activated without the pilot's command. He lowered the nose, regained airspeed, turned left, and landed in sagebrush, which resulted in substantial damage to the fuselage, wings, and right aileron. During the post accident investigation, a Federal Aviation Administration (FAA) inspector was able to cause an uncommanded release of the tow rope an additional two times by tugging on it. The tow release's time in service exceeded the manufacturer's recommended replacement interval. The manufacturer's service recommendations are not regulatory or mandated unless specifically written into the operating limitations for the airplane. ## Factual narrative On July 23, 2008, about 1330 Pacific daylight time, a Glaser-Dirks Flugzeugbau DG-100G, N132S, experienced an uncommmanded release while being towed, and landed off the runway at Truckee-Tahoe Airport, Truckee, California. The pilot/owner was operating the glider under the provisions of 14 Code of Federal Regulations (CFR) Part 91. The private pilot was not injured; the glider sustained substantial damage to the fuselage, both wings, and an aileron. The flight was departing at the time of the accident on a local flight. Visual meteorological conditions prevailed, and no flight plan had been filed. The pilot reported that the lineman connected the tow rope, and gave it a tug prior to the takeoff, which commenced from runway 01. About 150 feet above ground level (agl), the pilot saw his end of the tow rope in front of him, and realized that the glider's release mechanism had activated without his command. He lowered the nose, regained airspeed, turned left, and landed in sagebrush. After 60 yards of ground run, the glider looped to the left, and traveled another 20 yards while rotating about 160 degrees. The fuselage sustained substantial damage about 2 feet aft of the wing trailing edge. The left wing tip, right wing root area, and the right aileron were damaged. The tow pilot stated that he felt the glider release about 200 feet agl, and presumed that the tow rope had broken. After landing, he examined the tow rope, and found that it was intact with the proper fittings in place at each end. During the post accident investigation, a Federal Aviation Administration (FAA) inspector was able to cause an uncommanded release of the tow rope an additional two times by tugging on it. The Tost SH72, serial number 11633 SH, tow release was an original installation, which had been in service for 3,076 hours and 23 years. The manufacturer's recommended replacement interval for the tow release is 2,000 launches or 10,000 actuations. The annual condition inspection requirements in the airplane's operating limitations are to be in accordance with FAR 43 Appendix D. This FAR does not address compliance with manufacturer's service recommendations, which are not regulatory unless specifically written into the operating limitations for the airplane. ## Aircraft - Registration: [N132S](https://openairdocs.org/aircraft/N132S), registered now, S/N E186G152 (OpenAirDocs) - Reported make and model: Glaser-Dirks Flugzeugbau DG-100G - Registry model: [Glaser-Dirks Flugzeugbau DG-100G](https://openairdocs.org/model/glaser-dirks-flugzeugbau-dg-100g) (registry code 3802504) (OpenAirDocs) - Registry engine: [NONE](https://openairdocs.org/engine/none) (registry code 00000, none) (OpenAirDocs) - Category: Glider - Serial number: E186G152 - Airframe hours: 3065 - Damage: Substantial damage - Flight: Personal, Part 91 - Airworthiness certificate: Special, Experimental (Special) - Last inspection: Annual, June 25, 2008, 12 hours before - Departed: TRK, Truckee, CA - Airport: TRK, Truckee-Tahoe, runway 01, 4,650 × 75 ft, asphalt ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 60; injuries: none; private; seat: front; flight hours: 695 total, 189 in this make and model, 18 in the last 90 days ## Weather - Conditions: Visual (VMC), Day - Wind: 300° at 11 knots - Visibility: 8 statute miles - Lowest ceiling: none - Temperature: 81 °F, dew point 28 °F - Altimeter: 30.17 inHg - Observed at: KTRK ## 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 20080723841929A](https://openairdocs.org/incident/20080723841929A), Jul 23, 2008: Glaser DG100G, Truckee, CA, Substantial damage. (-23) During an aero tow, the tow line released uncommanded from the glider at 150 feet above ground level. An emergency landing was performed and the aircraft… ## Other investigations on N132S (1) 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. - [NTSB LAX90DVG18](https://openairdocs.org/ntsb/LAX90DVG18), Aug 28, 1990: Glaser-Dirks D6-100G (N132S), Vacaville, CA, substantial damage. Probable cause: THE UNAUTHORIZED ENTRY ONTO THE RUNWAY BY A VEHICLE OPERATOR. 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.