CEN11CA360 · Lammers Sjef J APACHE
Lammers Sjef J APACHE · Accident: loss of control in flight during initial climb
From Meadow Lake Airport (KFLY) to Meadow Lake Airport (KFLY)
Event
- NTSB case
- CEN11CA360
- Event typeAccident: someone killed or seriously injured, or the aircraft substantially damaged (NTSB definition). Incident: an occurrence that affected or could have affected safety, short of that. Glossary
- Accident
- InvestigationHow far the investigation had got when the record was published: preliminary, ongoing, final or completed. Unknown where the source does not say. Glossary
- Completed
- API-reported fatalities
- 0 · all aircraft and ground
- Ground fatalities
- Unknown
- OperationWhat kind of flying it was, grouped by the rules it flew under: airline (US Part 121), air taxi and commuter (Part 135), general aviation (Part 91 and similar), military or government. Glossary
- General aviation
- WeatherVisual meteorological conditions (VMC): good enough to fly by looking outside. Instrument conditions (IMC): cloud or low visibility, flying by instruments. Glossary
- Visual Meteorological Cond
Lammers Sjef J APACHE
- Aircraft type
- Lammers Sjef APACHE
- Category
- Weight-Shift
- RegistrationThe aircraft's tail number, such as N12345 or G-ABCD. Registrations are reissued, so the same one years apart can be a different aircraft. Glossary
- N566RL
- Operator
- Lammers Stef J
- Onboard fatalities
- Unknown
- Route
- From Meadow Lake Airport (KFLY), Colorado Springs, COTo Meadow Lake Airport (KFLY), Colorado Springs, CO
- Aircraft age
- Not recorded
- Flight rulesThe regulations the flight operated under: in the US, Part 91 (general aviation), Part 121 (airlines), Part 135 (air taxi and commuter) and others; for flights abroad, the NTSB's coarser commercial or non-commercial code. Glossary
- Part 91: General Aviation
- Phase of flightThe stage of the flight when things started to go wrong: standing, taxi, takeoff, initial climb, en route, maneuvering, approach or landing. Glossary
- Initial climb
- Defining eventThe single coded event the NTSB judges best describes what happened (records from 2008 on). Older records name the first occurrence in the sequence instead. Glossary
- Loss of control in flight
- DamageDestroyed: beyond practical repair. Substantial: damage that affects the structure, performance or handling and normally needs major repair. Minor: less than that. Glossary
- Substantial
Cause areas
- Environmental issues › Conditions/weather/phenomena
- Personnel issues › Action/decision
Approximate · Coordinates from the NTSB case API, which marks them as estimated or does not say; no uncertainty radius is established.
NTSB 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 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.
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.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record CEN11CA360
- Event ID
- 20110531X94940
- Case number
- CEN11CA360
- Dataset
- full-current
- Source SHA-256
- 5cf380f0061817c0331a6b2d8cc7e0ee3a79bea469a1001dc5c10e56f35f5ab3
Source notes (4)
- Unreviewed is an editorial label, not an investigation status. API-sourced is not report-checked or human-reviewed. Explicit event totals are used without summing aircraft injury tables; onboard allocation is withheld. Unknown values remain unknown. The operation category is mapped from the NTSB-reported FAR part and has not been reviewed.
- Filled from the NTSB case API where the bulk record had no value: investigation status, coordinates. Values present in the bulk record are kept.
- The date is the local date, which is the same as the UTC date the NTSB stores.
- API snapshot SHA-256: 89818f6011bc9392b46524a8055c6b60319e81d9244e6a162009e1121cb33a99; retrieved 2026-09-15T16:13:45.070Z.