# NTSB LAX93LA319: Hiller UH-12E, N100LM, Dixon, CA, August 11, 1993 - Type: NTSB accident investigation - Classification: Accident · Serious injuries · Limited investigation · Final report - Date: August 11, 1993, 10:45 local (17:45 UTC) - Place: Dixon, CA - Coordinates: 38.389308, -121.810157 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=38.3893&lon=-121.8102&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Highest injury: Serious injuries - Injuries: 1 serious - Status: Completed, report June 30, 1994 - Report: Approved by Office Director - NTSB case key (mKey): 28444 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX93LA319 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/28444/pdf - Page: https://openairdocs.org/ntsb/LAX93LA319 ## Probable cause the failure of the pilot to visually detect and avoid the guy wire. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - In flight collision with object, maneuvering - aerial application - object - wire,static - visual lookout - inadequate, pilot in command (cause) - Nose over, landing - precautionary landing - performed, pilot in command - terrain condition - soft - terrain condition - high vegetation ## Analysis AN FAA INSPECTOR SAID THE HELICOPTER HAD BEEN WORKING THE FIELD FOR ABOUT 2 HOURS DISPENSING INSECTICIDES. THE PILOT DEPARTED THE TRUCK AFTER REFUELING TO FINISH THE REMAINING CORNER OF THE FIELD BEING SPRAYED. THE FIELD IS BORDERED BY A SET OF POWER LINES ON WOODEN POLES WITH A WIRE HEIGHT ABOUT 40 FEET AGL. THE PILOT WAS FLYING UNDER THE POWER LINES DURING HIS SPRAY RUNS. THE LAST TWO POLES HAD A ONE QUARTER INCH GUY WIRE STRUNG BETWEEN THEM ABOUT HALF WAY UP THE POLES. ON THE FINAL PASS IN THE FIELD, THE HELICOPTER COLLIDED WITH THE GUY WIRE. BASED ON HIS INSPECTION OF THE WRECKAGE AND WITNESS OBSERVATIONS, THE FAA INSPECTOR REPORTED THAT THE HELICOPTER COLLIDED WITH THE WIRE AT A POINT BETWEEN THE ROTOR HUB AND THE SWASH PLATE ASSEMBLY, BREAKING THE PITCH CHANGE LINKS. THE PILOT WAS ABLE TO REGAIN PARTIAL CONTROL OF THE HELICOPTER AND WAS ATTEMPTING A RUN ON LANDING CROSS FURROW IN A TOMATO FIELD ABOUT TWO MILES FROM THE WIRE STRIKE. THE HELICOPTER SKIDS CAUGHT ON BOTH THE PLANTS AND THE SOFT FURROWS AND TUMBLED TO A STOP. ## Factual narrative On August 11, 1993, at 1045 Pacific daylight time, a Hiller UH- 12E helicopter, N100LM, collided with a guy wire strung between two power poles and crashed while attempting a forced landing in a field near Dixon, California. The aircraft was operated by Pacific Valley Aviation, Inc., Arbuckle, California, and was on an aerial application flight dispensing insecticides at the time. Visual meteorological conditions prevailed at the time and no flight plan was filed for the operation. The aircraft was demolished in the collision sequence. The certificated commercial pilot, the sole occupant, sustained serious injuries. The flight originated from a truck near the accident site at about 1025 hours on the day of the mishap. An FAA inspector from the Sacramento, California, Flight Standards District Office examined the aircraft and the accident site, and, in addition, interviewed witnesses to the accident. In his report, the inspector said the helicopter had been working the field for about two hours dispensing insecticides. The pilot departed the truck after refueling to finish the remaining corner of the field being sprayed. The field is bordered by a set of power lines on wooden poles with a wire height about 40 feet AGL. The pilot was flying under the power lines during his spray runs. The last two poles had a one quarter inch guy wire strung between them about half way up the poles. On the final pass in the field, the helicopter collided with the guy wire. Based on his inspection of the wreckage and witness observations, the inspector reported that the helicopter collided with the wire at a point between the rotor hub and the swash plate assembly, breaking the pitch change links. The pilot was able to regain partial control of the helicopter and was attempting a run on landing cross furrow in a tomato field about two miles from the wire strike. The helicopter skids caught on both the plants and the soft furrows and tumbled to a stop. ## Aircraft - Registration: [N100LM](https://openairdocs.org/aircraft/N100LM), registered now, S/N 1583 (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: [Allison 250-C20 series](https://openairdocs.org/engine/allison-250-c20-series) (registry code 03020, turbo-prop) (OpenAirDocs) - Category: Helicopter - Serial number: 1583 - Airframe hours: 7635 - Engines: ALLISON 250 C20B 420 horsepower turbo shaft - Damage: Destroyed - Flight: Aerial application, Part 137 - Operator: Pacific Valley Aviation, Inc. - Registered owner: Jim & Carol Miller - Airworthiness certificate: Standard, Normal - Last inspection: Continuous airworthiness, August 8, 1993, 9 hours before - Departed: NONE - Destination: NONE ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 34; commercial; airplane ratings: single-engine land; medical: class 2, valid medical--no waivers/lim.; seat: center; flight hours: 6,500 total, 650 in this make and model, 6,000 as pilot in command, 90 in the last 90 days, 40 in the last 30 days, 8 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 240° at 6 knots - Visibility: 25 statute miles - Lowest ceiling: none - Temperature: 66 °F, dew point 54 °F - Altimeter: 30.00 inHg ## 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 19930811029049A](https://openairdocs.org/incident/19930811029049A), Aug 11, 1993: Hiller UH12E, Dixon, CA, Destroyed. Flying under wires, rotor assembly struck guy sires. Helicopter tumbled on forced landing in tomato field. ## Other investigations on N100LM (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 SEA85LA031](https://openairdocs.org/ntsb/SEA85LA031), Dec 18, 1984: Hiller UH-12ET (N100LM), Hoquiam, WA, substantial damage - [NTSB SEA78FYE11](https://openairdocs.org/ntsb/SEA78FYE11), Mar 6, 1978: Hiller Acft UH-12E (N100LM), Montesano, WA, 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.