# NTSB LAX99LA319: Bell OH58A, N5800K, Salinas, CA, September 18, 1999 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: September 18, 1999, 06:50 local (13:50 UTC) - Place: Salinas, CA - Coordinates: 36.640602, -121.62014 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=36.6406&lon=-121.6201&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report May 9, 2001 - Report: Approved by Office Director - NTSB case key (mKey): 47481 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX99LA319 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/47481/pdf - Page: https://openairdocs.org/ntsb/LAX99LA319 ## Probable cause The pilot's failure to maintain an adequate clearance from all ground obstacles during a low altitude aerial application flight. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - In flight collision with terrain/water, maneuvering - aerial application - terrain condition - berm - object - wire,transmission - clearance - not maintained, pilot in command (cause) - Loss of control - in flight, maneuvering - aerial application - rotor system,tail rotor - separation - aircraft control - not possible, pilot in command - autorotation - initiated, pilot in command - Hard landing, landing - flare/touchdown ## Analysis The pilot was performing low level aerial application work. Wires ran perpendicular to his flight path at the end of a crop row and a berm was located just in front of the wires. The pilot planned to fly under the wires. As he flew under the wires he heard a loud noise to his rear and the helicopter began to rotate clockwise. He increased pitch on the collective and climbed to approximately 100 feet. He could not control the rotation and completed an autorotation to a hard landing. A ground witness saw the helicopter's tail contact the berm. The tail rotor blades were fractured and separated, and, the tail rotor drive shaft was fractured midway between the aft short shaft and the tail rotor gearbox. The fracture exhibited torsional overload signatures angled aft along a 45-degree plane from the bottom to the top of the shaft. The torsional twist was in a clockwise direction as viewed from the rear. The tail rotor drive shaft normally rotates clockwise as viewed from the rear. No preimpact malfunctions were identified with the tail rotor gearbox or pitch control. ## Factual narrative On September 18, 1999, about 0650 hours Pacific daylight time, an Arrow Falcon Exporters, Inc., OH58A, N5800K, landed hard from an autorotation 1 mile south of the airport at Salinas, California. The autorotation was precipitated by a tail rotor strike with terrain and a subsequent loss of antitorque control. R & B Helicopters, Inc., operated the helicopter under the provisions of 14 CFR Part 137. The helicopter sustained substantial damage. The commercial pilot was not injured. The agricultural aerial application flight departed Salinas about 0620. Instrument meteorological conditions prevailed and no flight plan was filed. The pilot stated he was on a westerly pass over a field approaching wires that he planned to fly under. A berm 4 feet high was just in front of the wires. He applied left pedal to avoid the power line pole to his left. He heard a loud noise to his rear and the helicopter began rotating clockwise. As he passed under the wires, he increased pitch on the collective. He climbed to approximately 100 feet and tried to streamline the helicopter but felt he was turning too fast to control it. He commenced an autorotation and pulled collective pitch 10 feet from the ground. The helicopter hit hard and the left skid dug into soft dirt. After it came to rest, the pilot secured the systems and engine. The helicopter suffered damage to the vertical fin, skids, tail boom, and frame. The Federal Aviation Administration (FAA) accident coordinator interviewed a farmhand who thought the helicopter's tail contacted the berm. The coordinator inspected the helicopter after the accident. The tail rotor blades had fractured and separated; the fracture surfaces were irregular. He also observed the lower section of the vertical stabilizer, starting at a point about 6 inches below its mounting point, bent inboard about 20 degrees. He noted the long tail rotor drive shaft fractured midway between the aft short shaft and the tail rotor gearbox. The fracture angled aft along a 45-degree plane from the bottom to the top of the shaft and exhibited torsional twist in a clockwise direction as viewed from the rear. He turned the tail rotor blades by hand and noted the tail rotor gearbox, and the portion of the long tail rotor drive shaft that remained attached, rotated freely. He did not hear or feel any binding or grinding noises in the gearbox. The manufacturer supplied a drawing that indicated the long tail rotor drive shaft rotated clockwise as viewed from the rear. ## Aircraft - Registration: [N5800K](https://openairdocs.org/aircraft/N5800K), registered now, S/N 71-20843 (OpenAirDocs) - Reported make and model: Bell OH58A - Registry model: [Bell OH-58A](https://openairdocs.org/model/bell-oh-58a) (registry code 1181579) (OpenAirDocs) - Registry engine: [Allison T63 series](https://openairdocs.org/engine/allison-t63-series) (registry code 03031, turbo-shaft) (OpenAirDocs) - Category: Helicopter - Serial number: 71-20843 - Airframe hours: 7659 - Engines: Allison T63-A-720 420 horsepower turbo shaft - Damage: Substantial damage - Flight: Aerial application, Part 137 - Operator: R&B Helicopters, Inc. - Registered owner: Brown And Reynolds, LLC - Airworthiness certificate: Special, Restricted (Special) - Last inspection: 100 hour, August 26, 1999, 43 hours before - Departed: SNS ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 55; flight instructor, commercial; airplane ratings: single-engine land; medical: class 2, valid medical--w/ waivers/lim; seat: right; flight hours: 18,000 total, 2,500 in this make and model, 18,000 as pilot in command, 122 in the last 90 days ## Weather - Conditions: Instrument (IMC), Dawn - Wind: 220° at 3 knots - Visibility: 10 statute miles - Lowest ceiling: 600 ft overcast - Temperature: 54 °F, dew point 52 °F - Altimeter: 29.00 inHg - Observed at: SNS, 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 19990918043269A](https://openairdocs.org/incident/19990918043269A), Sep 18, 1999: Bell OH58A, Salinas, CA, No damage. (-23) During an agricultural application the pilot was making a westerly pass, as he came to the end of the field he felt the helicopter yaw to the right, 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.