# NTSB LAX93LA323: Hughes 369D, N8606F, Chico, CA, August 15, 1993 - Type: NTSB accident investigation - Classification: Accident · Minor injuries · Limited investigation · Final report - Date: August 15, 1993, 10:05 local (17:05 UTC) - Place: Chico, CA - Coordinates: 39.739597, -121.829177 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=39.7396&lon=-121.8292&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Highest injury: Minor injuries - Injuries: 1 minor, 1 uninjured - Status: Completed, report September 26, 1994 - Report: Approved by Office Director - NTSB case key (mKey): 28448 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX93LA323 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/28448/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=28448 - Page: https://openairdocs.org/ntsb/LAX93LA323 ## Probable cause the observer's failure to properly secure stowed items in the rear compartment prior to takeoff and the resultant foreign object damage to the tail rotor system which precluded the pilot from maintaining directional control. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Airframe/component/system failure/malfunction, cruise - normal - security of cargo - inadequate, other crewmember (cause) - rotor system,tail rotor blade - foreign object damage (cause) - Forced landing, descent - emergency - autorotation - initiated, pilot in command - Loss of control - in flight, landing - flare/touchdown - directional control - not possible, pilot in command (cause) - Roll over, landing - flare/touchdown ## Analysis A sheriff's department rents this particular helicopter on an as needed basis for surveillance and rescue missions. All doors are removed for the missions. The pilot said that he had just achieved a cruise altitude of 500 feet AGL when he heard a loud bang and felt a severe vibration throughout the airframe. The pilot stated that he entered a 180 degree autorotation to a clear area in an almond orchard with power. During the landing flare, the helicopter began to spin to the right when the pilot applied collective. He said that he immediately rolled off the power; the helicopter landed hard and rolled over. A ground witness reported that when the helicopter was nearly overhead he saw a cloth like object come out of the helicopter and fly back toward the tail. The helicopter then descended rapidly as it turned 180 degrees until it disappeared behind the trees. Prior to takeoff, the observer had placed a nomex flight suit under some bags tied down in the rear compartment. Subsequent examination of the helicopter and the accident site revealed that the flight suit was unaccounted for and could not be located. Several days after the accident, a search party located a shredded nomex flight suit in the orchard not far from the accident site and back along the direction of the helicopter's flight path. ## Factual narrative On August 15, 1993, at 1005 Pacific daylight time, a Hughes 369D helicopter, N8606F, experienced an inflight loss of control and crashed during an attempted auto rotation near Chico, California. The helicopter was rented by the Butte County Sheriff's Department from P. J. Helicopters of Red Bluff, California, and was on an aerial observation flight. Visual meteorological conditions prevailed at the time and no flight plan was filed for the operation. The helicopter sustained substantial damage. The certificated commercial pilot incurred minor injuries and the observer was not injured. The flight originated at the Ranchero Airport, Chico, California, on the day of the mishap at 1000 hours as a police aerial observation mission. In his written and oral reports, the pilot, who is a Butte County Sheriff's lieutenant, stated that the department rents this particular helicopter on an as needed hourly basis for surveillance and search rescue missions. All four doors are removed from the helicopter for the surveillance missions. The pilot said that he had just departed from the Ranchero Airport and had achieved a cruise altitude of 500 feet AGL when he heard a loud bang and felt a severe vibration throughout the airframe. The pilot stated that he entered a 180 degree auto rotation to a clear area in an almond orchard with power. During the landing flare, the pilot observed that the helicopter began to spin to the right when he applied pitch input to the collective. He said that he immediately rolled off the power and the helicopter collided with the ground, then rolled over. A ground witness reported observing the accident sequence. He stated that he observed the helicopter fly toward his location, then when it was nearly overhead, saw a cloth like object come out of the helicopter and fly back toward the tail. Shortly thereafter, the witness observed the helicopter descend rapidly as it turned 180 degrees until it disappeared behind the trees. In his statement, the pilot reported that he flew to the Ranchero Airport to pick up his observer. The pilot said he had flown with the same individual the day before and had loaned him a nomex flight suit to wear. The pilot noted that when he landed, the observer was waiting on the taxiway and he did not shut down the helicopter. The observer walked to the helicopter then went to the rear compartment for a moment before climbing in the right front seat. The pilot reported that the day after the accident he found out that the observer had worn his own nomex flight suit and had placed the borrowed one under some bags tied down in the rear compartment. Subsequent examination of the helicopter and the accident site revealed that the flight suit was unaccounted for and could not be located. The pilot said that several days after the accident a search party from the Sheriff's department located a shredded nomex flight suit in the orchard. The location of the flight suit was described as not far from the accident site and back along the direction of the helicopter's flight path. ## Aircraft - Registration: [N8606F](https://openairdocs.org/deregistered/N8606F-1994-01-21), registration cancelled 1994-01-21, S/N 370100D (OpenAirDocs) - Reported make and model: HUGHES 369D - Registry model: [Hughes Helicopters HUGHES 369D](https://openairdocs.org/model/hughes-helicopters-hughes-369d) (registry code 4470706) (OpenAirDocs) - Category: Helicopter - Serial number: 370100D - Engines: ALLISON 250-C20B 420 horsepower turbo shaft - Damage: Substantial damage - Flight: Aerial observation, Part 91 - Operator: Butte County Sheriffs'S Dept - Registered owner: P. J. Helicopters, Inc. - Airworthiness certificate: Standard, Normal - Departed: O23 - Destination: O23 ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 46; commercial; airplane ratings: single-engine land; instrument ratings: airplane; medical: class 2, valid medical--w/ waivers/lim; seat: left; flight hours: 3,000 total, 1,000 in this make and model, 2,800 as pilot in command, 100 in the last 90 days, 50 in the last 30 days, 4 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 180° at 8 knots, gusting 10 - Visibility: 30 statute miles - Lowest ceiling: none - Temperature: 81 °F ## 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 19930815029429A](https://openairdocs.org/incident/19930815029429A), Aug 15, 1993: Hughes 369D, Chico, CA, Substantial damage. Loud bang severe vibration. Autorotated. Observer put flight suit in baggage. Blew out of cabin. Tangled tail rotor ## Docket (3 files) The files NTSB released with the investigation on June 3, 1995, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=28448. 650 KB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 507 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40474550&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Master.PDF - Supplement S (item 2, .PDF, 45 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40006507&FileExtension=.PDF&FileName=Supplement%20S-Master.PDF - Pilot's Statement (item 3, .PDF, 99 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40474551&FileExtension=.PDF&FileName=Pilot%27s%20Statement-Master.PDF 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.