# NTSB LAX96LA172: Bell 206B III, N2750F, San Diego, CA, April 16, 1996 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: April 16, 1996, 16:00 local (23:00 UTC) - Place: San Diego, CA - Coordinates: 32.800922, -117.129783 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=32.8009&lon=-117.1298&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed, report August 20, 1996 - Report: Approved by Office Director - NTSB case key (mKey): 29422 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX96LA172 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/29422/pdf - Page: https://openairdocs.org/ntsb/LAX96LA172 ## Probable cause the student's failure to maintain adequate main rotor rpm and airspeed during a practice autorotation, and the instructor's inadequate supervision of the flight. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Hard landing, landing - flare/touchdown - autorotation - performed, dual student - terrain condition - rough/uneven - planned approach - misjudged, dual student (cause) - distance/altitude - misjudged, dual student (cause) - rotor rpm - not maintained, dual student (cause) - supervision - inadequate, pilot in command(cfi) (cause) - remedial action - delayed, pilot in command(cfi) (cause) ## Analysis While practicing touchdown autorotations, the helicopter landed hard on uneven terrain short of the intended touchdown point. The commercial pilot-rated student was demonstrating a autorotation with a turn to the runway. As he completed the turn and was aligning with the runway, the helicopter rotor rpm dropped to 70 percent. Halfway into the maneuver the flight instructor realized the helicopter was too low and slow to accomplish a power recovery and took control. The helicopter landed short of the runway in rough terrain. A postflight inspection of the helicopter revealed wrinkles in the tail boom. The pilot under instruction held a rotorcraft helicopter rating. ## Factual narrative On April 16, 1996, at 1600 hours Pacific daylight time, a Bell 206B III helicopter, N2750F, landed hard on uneven terrain while practicing touchdown autorotations at Montgomery Field, San Diego, California. The helicopter sustained substantial damage. The certified flight instructor (CFI) and the certificated commercial pilot student were not injured. The helicopter was being operated as an instructional flight under 14 CFR Part 91 when the accident occurred. The local flight originated from Montgomery Field. Visual Instrument meteorological conditions prevailed. The CFI indicated that the commercial pilot was demonstrating an autorotation with a turn from 200 feet above ground level to runway 23. As the commercial pilot completed the turn and was aligning with the runway, the helicopter rotor rpm dropped to 70 percent. According to the CFI, halfway into the maneuver he realized the helicopter was too low and slow to accomplish a power recovery. The flight instructor took control of the helicopter. The helicopter touched down short of the intended point on the runway in rough uneven terrain. Post-flight inspection of the helicopter revealed wrinkles in the tail boom. The commercial pilot under instruction held a rotorcraft helicopter rating. The surface winds at Montgomery Field at the time were reported from 240 degrees at 11 knots. ## Aircraft - Registration: N2750F (not matched to a registry record) - Reported make and model: Bell 206B III - Category: Helicopter - Serial number: 2674 - Airframe hours: 13647 - Engines: Allison 250-C20B 420 horsepower turbo shaft - Damage: Substantial damage - Flight: Instructional, Part 91 - Registered owner: Corporate Helicopters - Airworthiness certificate: Standard, Normal - Last inspection: 100 hour, February 7, 1996, 67 hours before - Departed: MYF - Airport: MYF, Montgomery Field, runway 23, 3,402 × 150 ft, asphalt ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 34; flight instructor, airline transport; instrument ratings: helicopter; medical: class 1, valid medical--no waivers/lim.; seat: left; flight hours: 3,300 total, 1,250 in this make and model, 3,260 as pilot in command, 120 in the last 90 days, 40 in the last 30 days, 5 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 240° at 11 knots - Visibility: 30 statute miles - Lowest ceiling: none - Temperature: 70 °F, dew point 59 °F - Altimeter: 30.00 inHg - Observed at: MYF, 1 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 19960416007549A](https://openairdocs.org/incident/19960416007549A), Apr 16, 1996: Bell 206B, San Diego, CA, Substantial damage. (.4)While practicing touchdown autorotations, the helicopter landed hard on uneven terrain short of the intended touchdown point. The commercial pilot-rated… 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. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.