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Aviation safety reports, made easier to study

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May 20, 2011 · Lammers Sjef J Apache · N566RL

Colorado Springs, CO

Overview

Report Status
Final with probable cause
Event Type
Accident
Date
May 20, 2011
Injury Outcomes
1 injury (1 serious injury)
Location
Colorado Springs, CO
Aircraft
Lammers Sjef J Apache
Tail Number
N566RL
Operator
Lammers Stef J
Injuries
Serious
Aircraft Damage
Substantial
NTSB Number
CEN11CA360

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.

NTSB 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.

Full 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.

Flight

Event TypeAccident
Event Time11:45 MDT
Nearest AirportMeadow Lake (0nm)
Runway15
Flight Plan FiledUnknown
Aircraft FireNo

Aircraft

AircraftLammers Sjef J Apache
Tail NumberN566RL
Aircraft CategoryWsft
DamageSubstantial
OperatorLammers Stef J
Operating RulePart 91
Engines1
Engine DetailsRotax · 582 · 65
Seats2

People & Injuries

Injury Summary1 injury (1 serious injury)
Fatal0
Serious1
Minor0
Uninjured0
Total1
Crew 1Age 55 · None

Conditions

ConditionsVMC
LightDaylight
Wind150° @ 8 kt, gusting 14 kt
Visibility10 sm
CeilingBroken clouds 9000 ft
Temperature / Dew Point50 / 36 C
Altimeter29.87 inHg
Observation Time16:54
Weather SourceWFAC

Appendix: Source Data