What happened
The FAA’s narrative, in sentence case. The FAA writes it in capitals and removes private details.
(.19) On October 23, 1999, at 1115 hours pacific daylight time, a Bell 206-L4, N36R, landed hard and rolled over in the Lake Piru riverbed near Santa Clarita, California. The helicopter, operated by ag aviation, teterboro, new jersey, was substantially damaged. Neither the private pilot/owner nor the commercial rated flight instructor were injured. The local training flight conducted under the provisions of 14 CFR part 91 originated from the van nuys airport about 1030. Visual meteorological conditions prevailed and no flight plan was filed. The flight instructor reported that he and the pilot trainee were practicing autorotations to a power recovery in the dry riverbed. He stated that they had performed one practice autorotation with no problems. On the second attempt, the pilot trainee flared about 150 to 200 feet AGL. He attempted to bring in power to initiate the power recovery, but reported that the power did not come back in time to recover to a hovering position. The helicopter landed hard and slid forward in the loose sand. The left skid contacted a log that was embedded in the sand and the helicopter rolled over onto its left side. Control continuity was establish ed from the cyclic and collective controls to their respective servos. The servos operated normally. The linkages from the servos to the swashplate were intact and the swashplate rotated freely. The tail rotor driveshaft section to the transmission was intact; the transmission rotated freely. The freewheeling unit was intact. Preliminary inspection of the engine revealed that all fuel system lines were tight and secure at their fittings. The engine was removed from the helicopter and run on a test cell. The test included: initial idle; seal run in to maximum power; five power point checks; governor droop; and a final idle setting. The engine met all required specifications. The recorded weather observation for van nuys airport at 1151 indicated that the winds were calm. The density altitude for the area was estimated to be approximately 7,500 feet, based on a reported temperature of 84 degrees fahrenheit, and an approximate 5,200-foot elevation. (-23) hard landing due to mismanagement of power and flight controls after a practice autorotation to an attempted power recovery.
As the FAA filed it
(.19) ON OCTOBER 23, 1999, AT 1115 HOURS PACIFIC DAYLIGHT TIME, A BELL 206-L4, N36R, LANDED HARD AND ROLLED OVER IN THE LAKE PIRU RIVERBED NEAR SANTA CLARITA, CALIFORNIA. THE HELICOPTER, OPERATED BY AG AVIATION, TETERBORO, NEW JERSEY, WAS SUBSTANTIALLY DAMAGED. NEITHER THE PRIVATE PILOT/OWNER NOR THE COMMERCIAL RATED FLIGHT INSTRUCTOR WERE INJURED. THE LOCAL TRAINING FLIGHT CONDUCTED UNDER THE PROVISIONS OF 14 CFR PART 91 ORIGINATED FROM THE VAN NUYS AIRPORT ABOUT 1030. VISUAL METEOROLOGICAL CONDITIONS PREVAILED AND NO FLIGHT PLAN WAS FILED. THE FLIGHT INSTRUCTOR REPORTED THAT HE AND THE PILOT TRAINEE WERE PRACTICING AUTOROTATIONS TO A POWER RECOVERY IN THE DRY RIVERBED. HE STATED THAT THEY HAD PERFORMED ONE PRACTICE AUTOROTATION WITH NO PROBLEMS. ON THE SECOND ATTEMPT, THE PILOT TRAINEE FLARED ABOUT 150 TO 200 FEET AGL. HE ATTEMPTED TO BRING IN POWER TO INITIATE THE POWER RECOVERY, BUT REPORTED THAT THE POWER DID NOT COME BACK IN TIME TO RECOVER TO A HOVERING POSITION. THE HELICOPTER LANDED HARD AND SLID FORWARD IN THE LOOSE SAND. THE LEFT SKID CONTACTED A LOG THAT WAS EMBEDDED IN THE SAND AND THE HELICOPTER ROLLED OVER ONTO ITS LEFT SIDE. CONTROL CONTINUITY WAS ESTABLISH ED FROM THE CYCLIC AND COLLECTIVE CONTROLS TO THEIR RESPECTIVE SERVOS. THE SERVOS OPERATED NORMALLY. THE LINKAGES FROM THE SERVOS TO THE SWASHPLATE WERE INTACT AND THE SWASHPLATE ROTATED FREELY. THE TAIL ROTOR DRIVESHAFT SECTION TO THE TRANSMISSION WAS INTACT; THE TRANSMISSION ROTATED FREELY. THE FREEWHEELING UNIT WAS INTACT. PRELIMINARY INSPECTION OF THE ENGINE REVEALED THAT ALL FUEL SYSTEM LINES WERE TIGHT AND SECURE AT THEIR FITTINGS. THE ENGINE WAS REMOVED FROM THE HELICOPTER AND RUN ON A TEST CELL. THE TEST INCLUDED: INITIAL IDLE; SEAL RUN IN TO MAXIMUM POWER; FIVE POWER POINT CHECKS; GOVERNOR DROOP; AND A FINAL IDLE SETTING. THE ENGINE MET ALL REQUIRED SPECIFICATIONS. THE RECORDED WEATHER OBSERVATION FOR VAN NUYS AIRPORT AT 1151 INDICATED THAT THE WINDS WERE CALM. THE DENSITY ALTITUDE FOR THE AREA WAS ESTIMATED TO BE APPROXIMATELY 7,500 FEET, BASED ON A REPORTED TEMPERATURE OF 84 DEGREES FAHRENHEIT, AND AN APPROXIMATE 5,200-FOOT ELEVATION. (-23) HARD LANDING DUE TO MISMANAGEMENT OF POWER AND FLIGHT CONTROLS AFTER A PRACTICE AUTOROTATION TO AN ATTEMPTED POWER RECOVERY.
NTSB investigation
The NTSB’s investigation of this event, with its probable cause and findings. Matched to this report by N-number and date.