# NTSB MIA93LA150: Berkshire Concept 70, N29BW, Boynton Beach, FL, July 4, 1993

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: July 4, 1993, 13:30 local (17:30 UTC)
- Place: Boynton Beach, FL
- Coordinates: 26.509019, -80.150253 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=26.5090&lon=-80.1503&mi=10
- Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 1 uninjured
- Status: Completed, report March 25, 1994
- Report: Approved by Office Director
- NTSB case key (mKey): 33282
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=MIA93LA150
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/33282/pdf
- Page: https://openairdocs.org/ntsb/MIA93LA150

## Probable cause

THE PILOT'S IMPROPER IN-FLIGHT PLANNING AND THE LACK OF ADEQUATE THERMAL LIFT.

## Sequence of events

In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf).

- Forced landing, landing - flare/touchdown
  - weather condition - no thermal lift (cause)
  - in-flight planning/decision - improper, pilot in command (cause)
- On ground/water encounter with terrain/water, landing - flare/touchdown
  - terrain condition - high vegetation (contributing factor)

## Analysis

AFTER BEING TOWED ALOFT, THE FLIGHT PROCEEDED WEST TO LOCATE THERMALS WHICH WERE REPORTED TO BE GOOD BY ANOTHER GLIDER PILOT. THE FLIGHT WAS ABOUT 4-5 MI WEST OF THE DEPARTURE AIRPORT, AT 1,900 FT, WHEN THE PILOT WAS UNABLE TO LOCATE THERMALS AND ELECTED TO RETURN TO THE AIRPORT. WHILE EN ROUTE HE ENCOUNTERED 'STRONG SINK.' HE THEN CONTINUED IN WHAT WAS DESCRIBED AS 'MILD SINK', AND HE REALIZED THAT HE WOULD BE UNABLE TO LAND AT THE DEPARTURE AIRPORT. HE MADE A FORCED LANDING IN THE EVERGLADES. AFTER TOUCHDOWN, THE GLIDER GROUND LOOPED AND CAME TO REST UPRIGHT.

## Aircraft

- Registration: [N29BW](https://openairdocs.org/deregistered/N29BW-1996-03-28), registration cancelled 1996-03-28, S/N 14 (OpenAirDocs)
- Reported make and model: BERKSHIRE CONCEPT 70
- Registry model: [Berkshire Mfg. CONCEPT 70](https://openairdocs.org/model/berkshire-mfg-concept-70) (registry code 1240104) (OpenAirDocs)
- Category: Glider
- Serial number: 14
- Airframe hours: 739
- Engines: unknown
- Damage: Substantial damage
- Flight: Personal, Part 91
- Operator: Willis, B.N.
- Registered owner: Willis, B.N.
- Airworthiness certificate: Special, Experimental (Special)
- Last inspection: Annual, September 26, 1992, 27 hours before
- Airport: 1X4, Willis Gliderport

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 51; private; airplane ratings: single-engine land; instrument ratings: airplane; medical: class 2, valid medical--w/ waivers/lim; flight hours: 987 total, 6 in this make and model, 869 as pilot in command, 38 in the last 90 days, 14 in the last 30 days, 1 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 80° at 12 knots
- Visibility: 10 statute miles
- Lowest ceiling: none
- Temperature: 90 °F, dew point 73 °F
- Altimeter: 30.00 inHg
- Observed at: PBI, 10 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 19930704025159A](https://openairdocs.org/incident/19930704025159A), Jul 4, 1993: Amtrbs CONCEPT70, Boynton Beach, FL, Substantial damage. High sink rate and no thermals after glider tow. Unable return to base. Landed on a dike and ground looped.

## Other investigations on N29BW (2)

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 MIA96LA080](https://openairdocs.org/ntsb/MIA96LA080), Feb 20, 1996: Berkshire Concept 70 (N29BW), Boynton Beach, FL, destroyed. Probable cause: an engine loss of power and fire for undetermined reasons.
- [NTSB MIA7LDKG11](https://openairdocs.org/ntsb/MIA7LDKG11), Aug 19, 1975: Berkshire C70 (N29BW), Cordele, GA, substantial damage

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.

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