# NTSB SEA08CA129: Schleicher ASK-21, N361KS, Tehachapi, CA, May 10, 2008 - Type: NTSB accident investigation - Classification: Accident · No injuries · Data collection · Final report - Date: May 10, 2008, 15:40 local (22:40 UTC) - Place: Tehachapi, CA - Coordinates: 35.101387, -118.427223 - Nearby events: https://openairdocs.org/map.md?lat=35.1014&lon=-118.4272&mi=10 - Phase of flight: [Initial climb](https://openairdocs.org/ntsb-phases/350) (OpenAirDocs' grouping) - Defining event: [Initial climb: Miscellaneous/other](https://openairdocs.org/ntsb-events/900) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed, report June 30, 2008 - Report: Approved by Office Director - Parties: Federal Aviation Administration - NTSB case key (mKey): 67978 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=SEA08CA129 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/67978/pdf - Page: https://openairdocs.org/ntsb/SEA08CA129 ## Probable cause The pilot's inadequate preflight procedures and failure to check the spoiler control position, which resulted in the inadvertent deployment of the spoilers during takeoff. A contributing factor was the pilot's misinterpretation of the tow pilot's instructions. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Inspection: preflight inspection](https://openairdocs.org/ntsb-findings/02061510): Personnel issues › Task performance · Pilot (probable cause); cases with it: [Schleicher ASK-21, 1 case](https://openairdocs.org/ntsb-findings/02061510/cases.md?model=38015GY), [All aircraft, 551 cases](https://openairdocs.org/ntsb-findings/02061510/cases.md) - [Action: incorrect action performance](https://openairdocs.org/ntsb-findings/02041015): Personnel issues › Action/decision · Pilot (probable cause); cases with it: [Schleicher ASK-21, 2 cases](https://openairdocs.org/ntsb-findings/02041015/cases.md?model=38015GY), [All aircraft, 1,386 cases](https://openairdocs.org/ntsb-findings/02041015/cases.md) - [Communication (personnel): interpretation/understanding](https://openairdocs.org/ntsb-findings/02063530): Personnel issues › Task performance · Pilot (probable cause); cases with it: [Schleicher ASK-21, 1 case](https://openairdocs.org/ntsb-findings/02063530/cases.md?model=38015GY), [All aircraft, 10 cases](https://openairdocs.org/ntsb-findings/02063530/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Initial climb: Miscellaneous/other](https://openairdocs.org/ntsb-events/900) (defining event); cases with it: [Schleicher ASK-21, 1 case](https://openairdocs.org/ntsb-events/900/sequence.md?model=38015GY), [All aircraft, 1,556 cases](https://openairdocs.org/ntsb-events/900/sequence.md) - [Landing: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [Schleicher ASK-21, 4 cases](https://openairdocs.org/ntsb-events/470/sequence.md?model=38015GY), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md) ## Analysis The glider was being towed to altitude by a tow airplane. During the takeoff initial climb, the spoiler handle was not locked and the spoilers momentarily extended twice and although the pilot felt that he had to input forward control forces, he did not visually check the position of the spoiler control handle. The tow pilot then gave a rudder wave signal to the pilot telling him to check the spoilers; however, because the spoilers appeared retracted when the pilot verified their position, the glider pilot misinterpreted the tow pilot and released the glider from the tow airplane at approximately 100 feet above ground level. The glider pilot force-landed the glider in a field. During the landing, the empennage broke from the remainder of the glider. The glider pilot did not report any mechanical malfunctions with the glider. ## Factual narrative The glider was being towed to altitude by a tow airplane. During the takeoff initial climb, the spoiler handle was not locked and the spoilers momentarily extended twice and although the pilot felt that he had to input forward control forces, he did not visually check the position of the spoiler control handle. The tow pilot then gave a rudder wave signal to the pilot telling him to check the spoilers; however, because the spoilers appeared retracted when the pilot verified their position, the glider pilot misinterpreted the tow pilot and released the glider from the tow airplane at approximately 100 feet above ground level. The glider pilot force-landed the glider in a field. During the landing, the empennage broke from the remainder of the glider. The glider pilot did not report any mechanical malfunctions with the glider. ## Aircraft - Registration: [N361KS](https://openairdocs.org/aircraft/N361KS), registered now, S/N 21224, built 1984 (OpenAirDocs) - Reported make and model: Schleicher ASK-21 - Registry model: [Schleicher ASK-21](https://openairdocs.org/model/schleicher-ask-21) (registry code 38015GY) (OpenAirDocs) - Registry engine: [NONE](https://openairdocs.org/engine/none) (registry code 00000, none) (OpenAirDocs) - Category: Glider - Serial number: 21224 - Damage: Substantial damage - Flight: Personal, Part 91 - Operator: Skylark North - Registered owner: Charles I H Cant - Airworthiness certificate: Standard, Normal - Departed: L94, Tehachapi, CA - Destination: L94, Tehachapi, CA - Airport: L94, Mountain Valley Airport, runway 27R, 4,890 × 36 ft, asphalt ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 37; commercial; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 2; flight hours: 2,095 total, 6 in this make and model ## Weather - Conditions: Visual (VMC), Day - Wind: 10° at 8 knots - Lowest ceiling: none - Temperature: 88 °F, dew point 25 °F - Altimeter: 29.90 inHg - Observed at: WJF, 25 nm away ## 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 20080510857669A](https://openairdocs.org/incident/20080510857669A), May 10, 2008: Schlei ASK21, Tehachapi, CA, Substantial damage. During the takeoff sequence prior to reaching 200 feet, the tow pilot noted that the spoilers were open on the glider. He wagged the rudder, which is the… ## Other investigations on N361KS (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 WPR26LA299](https://openairdocs.org/ntsb/WPR26LA299), Aug 8, 2026: Schleicher ASK-21 (N361KS), Tehachapi, CA, substantial damage, investigation ongoing 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.