# NTSB CEN11CA360: Lammers Sjef J Apache, N566RL, Colorado Springs, CO, May 20, 2011 - Type: NTSB accident investigation - Classification: Accident · Serious injuries · Data collection · Final report - Date: May 20, 2011, 11:45 local (17:45 UTC) - Place: Colorado Springs, CO - Coordinates: 38.940555, -104.401947 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=38.9406&lon=-104.4019&mi=10 - Phase of flight: [Initial climb](https://openairdocs.org/ntsb-phases/350) (OpenAirDocs' grouping) - Defining event: [Initial climb: Loss of control in flight](https://openairdocs.org/ntsb-events/240) - Highest injury: Serious injuries - Injuries: 1 serious - Status: Completed, report October 6, 2011 - Report: Approved by Office Director - NTSB office: Central Region - Parties: FAA/FSDO - NTSB case key (mKey): 79251 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN11CA360 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/79251/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=79251 - Page: https://openairdocs.org/ntsb/CEN11CA360 ## Probable cause The pilot's failure to maintain control of the aircraft during take-off in a cross wind, which resulted in an inadvertent stall. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Action: incorrect action performance](https://openairdocs.org/ntsb-findings/02041015): Personnel issues › Action/decision · Pilot (probable cause); cases with it: [Lammers Sjef J APACHE, 1 case](https://openairdocs.org/ntsb-findings/02041015/cases.md?model=05902WB), [All aircraft, 1,386 cases](https://openairdocs.org/ntsb-findings/02041015/cases.md) - [Wind: crosswind](https://openairdocs.org/ntsb-findings/03034040): Environmental issues › Conditions/weather/phenomena · Ability to respond/compensate (probable cause); cases with it: [Lammers Sjef J APACHE, 1 case](https://openairdocs.org/ntsb-findings/03034040/cases.md?model=05902WB), [All aircraft, 1,008 cases](https://openairdocs.org/ntsb-findings/03034040/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Initial climb: Loss of control in flight](https://openairdocs.org/ntsb-events/240) (defining event); cases with it: [Lammers Sjef J APACHE, 1 case](https://openairdocs.org/ntsb-events/240/sequence.md?model=05902WB), [All aircraft, 5,002 cases](https://openairdocs.org/ntsb-events/240/sequence.md) ## Analysis On the morning of the accident, the pilot had removed his single-surface wing and installed a dual-surface wing on his weight shift aircraft. The winds were calm and he conducted an uneventful test flight. The pilot returned to his hangar and made some adjustments to the control bar but elected to not do another test flight because the winds were increasing at the airport. Later that afternoon, the pilot decided to do a second test flight because the wind had decreased some. The pilot departed with an 80 degree crosswind between 5 and 10 knots. He said that he did not build up sufficient airspeed on the takeoff roll and once he got airborne he was about 5 knots above stall speed and very slow. When the aircraft was approximately 100 feet in the air, he encountered wind shear and the right wing stalled and dropped. The pilot was unable to recover and the aircraft crashed on the right side of the runway, resulting in substantial damage to the entire aircraft. ## Factual narrative On the morning of the accident, the pilot had removed his single-surface wing and installed a dual-surface wing on his weight shift aircraft. The winds were calm and he conducted an uneventful test flight. The pilot returned to his hanger and made some adjustments to the control bar but elected to not do another test flight because the winds were increasing at the airport. Later that afternoon, the pilot decided to do a second test flight because the wind had decreased some. The pilot departed with an 80 degree crosswind between 5 and 10 knots. He said that he did not build up sufficient airspeed on the takeoff roll and once he got airborne he was about 5 knots above stall speed and very slow. When the aircraft was approximately 100 and 150 feet in the air, he encountered wind shear and the right wing stalled and dropped. The pilot was unable to recover and the aircraft crashed on the right side of the runway, resulting in substantial damage to the entire aircraft. ## Aircraft - Registration: [N566RL](https://openairdocs.org/aircraft/N566RL), registered now, S/N 12056, built 2001 (OpenAirDocs) - Reported make and model: LAMMERS SJEF J APACHE - Registry model: [Lammers Sjef J APACHE](https://openairdocs.org/model/lammers-sjef-j-apache) (registry code 05902WB) (OpenAirDocs) - Registry engine: [Rotax 583](https://openairdocs.org/engine/rotax-583) (registry code 55577, 2 cycle) (OpenAirDocs) - Category: Weight-shift - Serial number: 12056 - Engines: ROTAX 582 65 horsepower - Damage: Substantial damage - Flight: Personal, Part 91 - Operator: Lammers Stef J - Registered owner: Lammers Stef J - Airworthiness certificate: Special, Experimental light sport (Special) - Departed: KFLY, Colorado Springs, CO - Destination: KFLY, Colorado Springs, CO - Flight plan: Unknown - Airport: KFLY, Meadow Lake, runway 15 ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 55; sport pilot; flight hours: 340 total, 340 in this make and model ## Weather - Conditions: Visual (VMC), Day - Wind: 150° at 8 knots, gusting 14 - Visibility: 10 statute miles - Lowest ceiling: 9,000 ft broken - Temperature: 50 °F, dew point 36 °F - Altimeter: 29.87 inHg - Observed at: KCOS, 10 nm away ## Docket (1 files) The files NTSB released with the investigation on July 15, 2011, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=79251. 73 KB in all. - Record of Conversation-Pilot (item 1, .PDF, 73 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40350872&FileExtension=.PDF&FileName=Record%20of%20Conversation-Pilot-Master.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.