# NTSB LAX94LA043: Hiller UH-12E, N149HA, Salinas, CA, November 13, 1993 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: November 13, 1993, 09:40 local (17:40 UTC) - Place: Salinas, CA - Coordinates: 36.670276, -121.611 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=36.6703&lon=-121.6110&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report August 1, 1994 - Report: Approved by Office Director - NTSB case key (mKey): 28597 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX94LA043 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/28597/pdf - Page: https://openairdocs.org/ntsb/LAX94LA043 ## Probable cause THE PILOT'S IMPROPER HANDLING OF THE HELICOPTER WHICH RESULTED IN OVERLOADING OF THE ROTOR SYSTEM IN A MANEUVERING TURN DURING AERIAL APPLICATION OF CHEMICAL, AND SUBSEQUENT FAILURE OF THE MAIN ROTOR PADDLE ASSEMBLY. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Airframe/component/system failure/malfunction, maneuvering - aerial application - rotor system,stabilizer bar - overload (contributing factor) - design stress limits of aircraft - exceeded, pilot in command (cause) - rotor system,stabilizer bar - separation (contributing factor) - In flight collision with terrain/water, descent - uncontrolled - terrain condition - open field ## Analysis THE PILOT LOST CONTROL OF THE HELICOPTER WHILE EXECUTING A MANEUVERING TURN WHILE LOADED WITH CHEMICAL AT ABOUT 35 FEET ABOVE THE GROUND. THE MAIN ROTOR HEAD PADDLE ASSEMBLY FRACTURED AND SEPARATED BEFORE THE LOSS OF CONTROL. METALLURGIC EXAMINATION OF THE FRACTURE REVEALED AN OVERLOAD FAILURE MODE. ## Factual narrative On November 13, 1993, at 0940 hours Pacific standard time, a Hiller UH-12E, N149HA, lost control while applying chemicals to a field and collided with level terrain near Salinas, California. The pilot was conducting a visual flight rules aerial application flight under Title 14 CFR Part 137. The helicopter, operated by Helicair Ag, Inc., Salinas, was destroyed by impact forces and postimpact fire. The certificated commercial pilot, the sole occupant, was not injured. Visual meteorological conditions prevailed. The flight originated at Salinas at 0850 hours. The pilot reported that while executing a maneuvering turn at about 35 feet above the ground he lost control of the helicopter and crashed. Examination of the wreckage by the operator revealed a component of the main rotor head fractured and separated before the pilot lost control of the helicopter. The part, a main rotor paddle assembly, was fractured at the cuff and found about 200 feet from the fuselage. The fractured part held the main rotor stabilizer paddle on the main rotor hub. According to the operator, the paddle sustained minor damage that was not consistent with ground impact forces sufficient to fracture the cuff before the separation. The main rotor head cuff and trunnion assembly were examined by the National Transportation Safety Board, Material Laboratory. According to the Safety Board's metallurgist, there was no evidence of preexisting fracture areas found. The fractured cuff assembly exhibited a 45 degree shear plane, indicative of an overstress separation. The main rotor hub cuff assembly was also bent opposite the direction of main rotor rotation. ## Aircraft - Registration: [N149HA](https://openairdocs.org/deregistered/N149HA-2018-03-21), registration cancelled 2018-03-21, S/N HA3049, built 1976 (OpenAirDocs) - Reported make and model: HILLER UH-12E - Registry model: [Hiller UH-12E](https://openairdocs.org/model/hiller-uh-12e) (registry code 4360122) (OpenAirDocs) - Registry engine: [Lycoming VO-540 series](https://openairdocs.org/engine/lycoming-vo-540-series) (registry code 41534, reciprocating) (OpenAirDocs) - Category: Helicopter - Serial number: N3049 - Airframe hours: 5556 - Engines: LYCOMING VO-540-C2A 305 horsepower reciprocating - Damage: Destroyed - Fire: On-Ground - Flight: Aerial application, Part 137 - Registered owner: Helicair Ag, Inc. - Airworthiness certificate: Special, Restricted (Special) - Last inspection: Annual, October 1, 1993, 67 hours before - Departed: SNS ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 47; commercial, flight instructor; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 2, valid medical--no waivers/lim.; seat: center; flight hours: 5,982 total, 171 in this make and model, 5,129 as pilot in command, 24 in the last 90 days, 20 in the last 30 days, 3 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 140° at 6 knots - Visibility: 30 statute miles - Lowest ceiling: none - Altimeter: 29.00 inHg - Observed at: SNS, 6 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 19931113042619A](https://openairdocs.org/incident/19931113042619A), Nov 13, 1993: Hiller UH12E, Salinas, CA, Destroyed. Lost control maneuvering 35 feet above ground. Main rotor assembly fractured. Fracture indicates overstressed. ## Other investigations on N149HA (2) 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. - [NTSB LAX92LA152](https://openairdocs.org/ntsb/LAX92LA152), Mar 27, 1992: Hiller UH-12E (N149HA), Watsonville, CA, substantial damage. Probable cause: A FAILURE OF THE PILOT TO CONDUCT AN ADEQUATE PRE-FLIGHT INSPECTION OF THE AIRCRAFT TO ENSURE THAT THE FUEL SUPPLY WAS FREE OF CONTAMINATES. CONTRIBUTING TO THIS ACCIDENT WAS FUEL CONTAMINATION. - [NTSB LAX86FVM08](https://openairdocs.org/ntsb/LAX86FVM08), Sep 7, 1986: Hiller UH 12E (N149HA), Gonzales, CA, substantial damage 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.