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Accidents · NTSB WPR16LA105 · Final report

Beech B24R accident near Groveland, California, May 10, 2016

On May 10, 2016 at about 7:15 pm local time, a 1976 Beech B24R, registered N2052L, was substantially damaged in an accident during takeoff near Groveland, California (Pine Mountain Lake airport). It was a personal flight under general aviation rules (Part 91). 2 people had minor injuries. The weather was visual conditions (good weather).

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The NTSB's probable cause their words, unchanged

The pilot's decision to conduct an upslope, downwind takeoff combined with an improper flap setting, which resulted in the airplane's inability to clear trees beyond the runway end. The reason for the improper flap setting could not be determined.

Source: NTSB aviation accident database, copy made October 4, 2026. Docket and reports at the NTSB.

What the record shows

Date
May 10, 2016 · about 7:15 pm local time
Place
Groveland, California · Pine Mountain Lake · map
Type
Accident
Injuries
2 people had minor injuries.
Weather
visual conditions (good weather)
Aircraft
Beech B24R, built 1976 · all B24Rs on the register
Registration
N2052L · no longer on the register · serial MC-437
Damage
Substantial damage
Flight
Personal flight · general aviation rules (Part 91)

The NTSB's narrative final · quoted from the NTSB record

The passenger, who was a student pilot, recently purchased the airplane in an estate sale. He and the airline transport pilot, both of whom lived in Mississippi, had traveled to California to retrieve the airplane and fly it back to Mississippi. Before the purchase, the airplane had not been maintained, operated, or flown in almost 11 years. Following the purchase, the owner contracted with a mechanic in California to ensure the airplane was in airworthy condition, which the mechanic reportedly did. The day before the accident, the pilot and owner took the airplane for its first flight after its dormant period and flew one uneventful circuit in the airport traffic pattern, as planned. The following day, the pilot and owner planned to fly the airplane for some systems evaluations. During that takeoff attempt from runway 9, the airplane became airborne but failed to climb and struck trees and terrain beyond the runway end. Although the pilot believed that he was taking off into the wind, witness statements and other evidence indicated that the takeoff was attempted with an approximate 5-knot tailwind. The first 1,000 ft of the runway was level, but the remaining 2,000 ft was sloped uphill. Although the Pilot's Operating Handbook specified using 15° flaps for takeoff, and the pilot reported that he used that setting and did not alter the flap position during the flight, the flaps were found to have been fully retracted at impact. Surveillance camera imagery captured about 2 seconds of the flight, when the airplane was about midfield and 4 ft above ground level (agl). Review of that imagery and audio data indicated that the ground speed was about 68 knots and that the engine speed was about 2,640 rpm; both values were consistent with normal takeoff values. However, the exact winds (and thus airspeed) were unknown, and because the propeller was a constant-speed model, nominal takeoff rpm could be achieved even if the engine was not developing full-rated power. Detailed examination of the airplane, including the engine, revealed that, although its condition was not in accordance with Federal Aviation Administration and manufacturer guidance, none of the observed deficiencies could have caused or contributed to the loss of climb performance, except for one magneto that was found to be mistimed to the engine by 7°. Evidence suggested that this was likely a result of the accident but that could not be determined with certainty. Performance calculations conducted by the airplane manufacturer, which accounted for most of the known takeoff conditions, including fully retracted flaps, indicated that the distance to 50 ft agl was slightly more than the available runway. The estimated airplane takeoff weight was about 300 lbs (11%) below the maximum takeoff weight that was used in the calculations, which would yield better performance than the calculated results. However, those calculations did not account for off-nominal values of the many other variables that could adversely affect takeoff performance, including pilot technique, airframe and engine deterioration, and inaccurate or improperly set instrumentation and controls. Thus, although a successful downwind takeoff with no flaps was unlikely, it might have been possible, but there were too many other unknowns to determine its likelihood with greater certainty. The reason(s) for the retracted flaps could not be determined. It is possible that the pilot forgot to extend them or that they were inadvertently and unknowingly retracted. Given the location of the flap control switch and its design (momentary, paddle-type), it is possible that the pilot extended the flaps to the proper takeoff setting of 15° but that they were subsequently retracted when the nonpilot passenger inadvertently contacted and actuated the flap control. The size and location of the flap position indicator gauge, combined with the location of the flaps (behind the pilot on the low-wing airplane), minimized the possibility that the pilot would notice that they had been retracted.

The complete narrative as the NTSB published it. The NTSB's docket holds the report as a PDF and any photographs, statements and other documents from the investigation.

The factual record from the NTSB's investigation tables, in plain English

What happened, in order

  1. Preflight or dispatch event during prior to flight
  2. Other weather encounter during takeoff
  3. Collision with terrain or object (not controlled flight into terrain) during initial climb
  4. Miscellaneous/other during takeoff defining event

The NTSB's findings

  • cause Personnel issues › Action/decision › Info processing/decision › Decision making/judgment › Pilot
  • cause Aircraft › Aircraft oper/perf/capability › Performance/control parameters › Climb rate › Capability exceeded
  • cause Environmental issues › Physical environment › Terrain › Sloped/uneven terrain › Decision related to condition
  • cause Environmental issues › Conditions/weather/phenomena › Wind › (general) › Decision related to condition
  • cause Personnel issues › Task performance › Use of equip/info › Use of equip/system › Pilot

Pilot

  • Certificate: airline transport pilot, flight engineer
  • Ratings: multi-engine land; single-engine land; instrument: airplane
  • Flight time: 22,812 hours in all; 1 in this make and model; 15 in the last 90 days; 5 in the last 30 days; 15,710 as pilot in command
  • Last flight review: May 27, 2015
  • Medical certificate: Class 3 (without waivers/limitations)
  • Seat: left
  • Injury: minor injuries

The aircraft

  • Airframe total time: 1,461 hours
  • Last inspection: annual inspection, December 22, 2005; 1 hours since
  • Maximum gross weight: 2,750 lb
  • Landing gear: retractable
  • Engine: Lycoming IO360 SER (piston); 1,462 hours total

The flight

  • Departed from: E45 Groveland CA at 7:15 pm
  • Destination: E45 Groveland CA
  • Flight plan: none
  • Runway 9, 3,624 ft by 50 ft

Weather at the time

  • Light: daylight
  • Wind: from 250° at 6 knots
  • Visibility: 10 statute miles
  • Sky: clear
  • Temperature: 77°F (25°C), dew point 54°F (12°C)
  • Altimeter: 29.95 inHg
  • Observation at 7:37 pm from O22, 15 miles away

Injuries

FatalSeriousMinorNone
Flig2

About this page

Everything above comes from the NTSB's public accident database: the narrative, probable cause and findings are the NTSB's own words, and the coded tables behind its report (pilot, aircraft, flight, weather, injuries, sequence of events) are written out in plain English. Pilots' ages, home towns and medical details are left out on purpose. The docket at the NTSB holds the report as a PDF and the investigation's photographs and documents. This site never names pilots, passengers or anyone else involved. A preliminary report describes what is known soon after the event and can change; the final report, with the probable cause, usually follows one to two years later and this page is refreshed when it does. Case number WPR16LA105.