# NTSB LAX98LA115: Robinson R22 Beta, N4079M, San Luis Obispo, CA, March 15, 1998 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: March 14, 1998, 16:40 local (Mar 15, 1998, 00:40 UTC) - Place: San Luis Obispo, CA - Coordinates: 35.249084, -120.620223 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=35.2491&lon=-120.6202&mi=10 - Phase of flight: [Approach](https://openairdocs.org/ntsb-phases/500) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed, report February 15, 2001 - Report: Approved by Office Director - NTSB case key (mKey): 30051 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX98LA115 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/30051/pdf - Page: https://openairdocs.org/ntsb/LAX98LA115 ## Probable cause The student pilot's inadvertent pulling of the mixture, instead of the carburetor heat, while preparing for the approach, and the flight instructor's inadequate supervision. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Loss of engine power(total) - nonmechanical, approach - vfr pattern - downwind - mixture - inadvertent use, dual student (cause) - supervision - inadequate, pilot in command(cfi) (cause) - Forced landing, emergency descent/landing - Nose over, landing - flare/touchdown - terrain condition - rough/uneven (contributing factor) ## Analysis The flight instructor reported that he and the dual student were doing traffic pattern operations to a grass area parallel to runway 29. The CFI stated that while they were on the downwind leg of the first pattern about 500 feet agl, the student was on the controls and was preparing for the approach with the prelanding checklist. The student reached down to apply carburetor heat, but instead pulled the mixture to idle. The engine stopped and the instructor then took over the controls and performed an autorotation to the grass field. The helicopter continued forward on the ground after the touchdown and the front portion of the skids became imbedded in the ground and the helicopter then nosed over. The blades hit the ground and the helicopter rolled over and came to rest on its right side. ## Factual narrative On March 14, 1998, at 1640 hours Pacific standard time, a Robinson R22 Beta, N4079M, nosed over during a forced landing after takeoff at the San Luis Obispo, California, airport following an inadvertent engine shutdown. The aircraft sustained substantial damage, and the flight instructor and student pilot were not injured. Visual meteorological conditions prevailed and no flight plan was filed. The instructional flight was conducted under 14 CFR Part 91 and originated at 1634. According to the flight instructor, he was conducting an instructional flight with a student pilot who had logged approximately 6 flight hours. They were planning on doing traffic pattern operations to a grass area parallel to runway 29. The instructor stated that while they were on the downwind leg of the first pattern about 500 feet agl, the student was on the controls and was preparing for the approach with the prelanding checklist. The student reached down to apply carburetor heat, but instead released the mixture guard and pulled the mixture to idle. The engine stopped and the instructor reported that he then took over the controls and performed an autorotation to the grass field. The instructor stated that there was an excess of forward speed remaining at the completion of the maneuver, so the helicopter continued forward on the ground. The front portion of the skids became imbedded in the ground and the helicopter then nosed over. The blades hit the ground and the helicopter rolled over and came to rest on its right side. ## Aircraft - Registration: [N4079M](https://openairdocs.org/deregistered/N4079M-2017-07-06), registration cancelled 2017-07-06, S/N 1816, built 1991 (OpenAirDocs) - Reported make and model: Robinson R22 BETA - Registry model: [Robinson Helicopter R22 BETA](https://openairdocs.org/model/robinson-helicopter-r22-beta) (registry code 7640110) (OpenAirDocs) - Registry engine: [Lycoming 0-320 series](https://openairdocs.org/engine/lycoming-0-320-series) (registry code 41508, reciprocating) (OpenAirDocs) - Category: Helicopter - Serial number: 1816 - Airframe hours: 2901 - Engines: Lycoming O-320-B2C 160 horsepower reciprocating - Damage: Substantial damage - Flight: Instructional, Part 91 - Registered owner: Helipro Inc. - Airworthiness certificate: Standard, Normal - Last inspection: 100 hour, February 24, 1998, 72 hours before - Departed: SBP, SAN LUIS OBISPO, CA - Airport: SBP, San Luis Obispo ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 26; flight instructor, commercial; medical: class 2, valid medical--w/ waivers/lim; seat: left; flight hours: 1,205 total, 1,101 in this make and model, 1,172 as pilot in command, 155 in the last 90 days, 85 in the last 30 days, 3 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 300° at 15 knots - Visibility: 15 statute miles - Lowest ceiling: 1,500 ft broken - Temperature: 61 °F, dew point 50 °F - Altimeter: 30.00 inHg - Observed at: SBP ## 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 19980315003419A](https://openairdocs.org/incident/19980315003419A), Mar 15, 1998: Robsin R22BETA, San Luis Obispo, CA, Substantial damage. Student pulled mixture instead carburetor heat on approach. Oil autorotated to grass. Run on fast log. Nosed over. (.4)the flight instructor reported that he… 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.