- Date
- April 26, 2009, 15:10 local (19:10 UTC)
- Place
- Adrian, MI
- Injuries
- 2 uninjured
- Damage
- Substantial damage
- Phase of flight
- Approach
- Aircraft
- N238SBLet L-23 Super Blanik
- Defining event
- Approach-VFR pattern downwind: Windshear or thunderstorm
- Weather
- Visual (VMC) · Day
- Status
- Completed · report July 14, 2009
- Report
- Approved by Office Director
- NTSB office
- Central Region
- Parties
- Federal Aviation Administration - Detroit FSDO
- FAA report
- 20090426011289A
- Case key
- 73750
From the NTSB’s public API. By law, NTSB reports can’t be used as evidence in lawsuits over the accident.
On this page
Probable cause
The flight instructor's inadequate compensation for the strong, gusting crosswind during landing. Contributing to the accident was the flight instructor's decision to attempt flight with known adverse weather approaching the airport.
Findings · 5
NTSB’s coded findings. Those marked are part of the probable cause; the rest are factors or other findings. Under each, the cases with the same finding.
Sequence of events
The events NTSB coded, in order, by phase of flight. The defining event is the one that best describes the accident. Under each, the cases with the same event anywhere in their sequence.
Analysis
Before the accident flight, the glider flight instructor observed adverse weather approaching the airport from the south. He wanted to demonstrate a crosswind landing to his student before ceasing glider operations due to the adverse weather. The glider released from the tow airplane around 1,000 feet above ground level and then proceeded on downwind for runway 29. While on final approach, the flight instructor had difficulty maintaining proper runway alignment due to a strong, gusting crosswind. As a result, he elected to land the glider in a grassy area immediately north of the runway. He noted that his forward visibility was limited by heavy rain. The glider impacted a taxiway sign during the landing, substantially damaging the left wing. Weather radar and surface observations indicated that the airport was affected by a thunderstorm shortly after the glider departed on the local area flight. The thunderstorm produced heavy rain, lightning, and strong winds. During the accident flight, the airport's automated surface observing system recorded a peak wind from 220 degrees magnetic at 42 knots. The glider's maximum demonstrated crosswind component for safe approach, landing and aerotow launching was 16 knots.
Factual narrative
Before the accident flight, the glider flight instructor observed adverse weather approaching the airport from the south. He wanted to demonstrate a crosswind landing to his student before ceasing glider operations due to the adverse weather. The glider released from the tow airplane around 1,000 feet above ground level and then proceeded on downwind for runway 29. While on final approach, the flight instructor had difficulty maintaining proper runway alignment due to a strong, gusting crosswind. As a result, he elected to land the glider in a grassy area immediately north of the runway. He noted that his forward visibility was limited by heavy rain. The glider impacted a taxiway sign during the landing, substantially damaging the left wing. Weather radar and surface observations indicated that the airport was affected by a thunderstorm shortly after the glider departed on the local area flight. The thunderstorm produced heavy rain, lightning, and strong winds. During the accident flight, the airport's automated surface observing system recorded a peak wind from 220-degrees magnetic at 42 knots. The glider's maximum demonstrated crosswind component for safe approach, landing and aerotow launching was 16 knots.
Aircraft
- Registration
- N238SB
- Reported as
- Let L-23 Super Blanik
- Category
- Glider
- Serial number
- 928008
- Airframe hours
- 1,564
- Damage
- Substantial damage
- Flight
- Instructional · Part 91
- Operator
- Adrian Soaring Club, Inc.
- Registered owner
- Adrian Soaring Club, Inc.
- Airworthiness certificate
- Standard, Normal
- Last inspection
- Annual · November 8, 2008
- Departed
- KADG · Adrian, MI
- Destination
- KADG · Adrian, MI
- Airport
- KADG · Lenawee County Airport, runway 29, 1,810 × 150 ft, grass/turf
Matched to the registry by N-number and the event date; the registry’s history has gaps, so older matches can be wrong. Compare the reported make and model.
Flight crew · 2
As NTSB recorded them. NTSB leaves out names.
- Role
- Flight instructor
- Age
- 76
- Injuries
- None
- Certificates
- Flight instructor, Commercial, Private
- Airplane ratings
- Single-engine sea, Single-engine land
- Last flight review
- September 23, 2007
- Seat
- Rear
- Flight hours
- 1,041 total · 400 in this make and model · 5 in the last 90 days · 1 in the last 24 hours
- Role
- Student pilot
- Age
- 41
- Injuries
- None
- Seat
- Front
- Flight hours
- 1 total · 1 in this make and model · 1 in the last 24 hours
Weather
- Conditions
- Visual (VMC) · Day
- Wind
- 240° at 16 knots, gusting 23
- Visibility
- 10 statute miles
- Lowest ceiling
- None
- Temperature
- 82 °F, dew point 54 °F
- Altimeter
- 30.13 inHg
- Observed at
- KADG
FAA reports on this event · 1
The FAA’s own accident and incident reports, matched to the aircraft by N-number and date.