# NTSB LAX01LA196: Bell 47G-4A, N110DT, Buttonwillow, CA, May 31, 2001 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: May 31, 2001, 11:36 local (18:36 UTC) - Place: Buttonwillow, CA - Coordinates: 35.429222, -119.489814 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=35.4292&lon=-119.4898&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report February 25, 2003 - Report: Approved by Office Director - Parties: FAA Flt Standards Dist Office - NTSB case key (mKey): 52387 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX01LA196 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/52387/pdf - Page: https://openairdocs.org/ntsb/LAX01LA196 ## Probable cause The pilot's inadequate in-flight planning that resulted in settling with power during an aerial application turn-to-reverse direction and collision with the ground. Factors were high density altitude and a wind shift. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - In flight collision with terrain/water, maneuvering - turn to reverse direction - weather condition - high density altitude (contributing factor) - in-flight planning/decision - inadequate, pilot in command (cause) - settling with power - encountered, pilot in command (cause) - weather condition - sudden windshift (contributing factor) ## Analysis During the aerial application turn-to-reverse direction to continue spraying chemicals, the helicopter began settling with power and collided with the ground. According to the pilot, "near triple digit" temperatures, a wind shift, and a steep 180-degree turn resulted in the power settling that could not be arrested prior to ground impact. The pilot also reported that the temperature over the unplanted field where he was executing the reverse turn was higher than over the corn field he had been spraying. ## Factual narrative On May 31, 2001, at 1136 hours Pacific daylight time, a Bell 47G-4A, N110DT, collided with the ground during an aerial application turn to reverse direction near Buttonwillow, California. The helicopter sustained substantial damage; however, the certificated commercial pilot was not injured. The helicopter was being operated by Inland Crop Dusters, Inc., as an aerial application flight under 14 CFR Part 137 when the accident occurred. The flight had originated in the Bakersfield area earlier that morning. Visual meteorological conditions prevailed at the time and no flight plan had been filed. The pilot was reported by Kern County Sheriff's Deputies to have been performing an aerial application flight when the helicopter crashed. According to the pilot, he was making a series of steep 180-degree turns between aerial application passes. He reported that on the last turn the helicopter began to "settle with power" and there was not enough time to recover. By his account, wind direction was a contributing factor. Wind speeds recorded at Bakersfield weather station were variable at 3 knots. ## Aircraft - Registration: [N110DT](https://openairdocs.org/deregistered/N110DT-2018-06-08), registration cancelled 2018-06-08, S/N 7631, built 1968 (OpenAirDocs) - Reported make and model: Bell 47G-4A - Registry model: [Bell 47G-4A](https://openairdocs.org/model/bell-47g-4a) (registry code 1181031) (OpenAirDocs) - Registry engine: [Lycoming VO-540 series](https://openairdocs.org/engine/lycoming-vo-540-series) (registry code 41534, reciprocating) (OpenAirDocs) - Category: Helicopter - Serial number: RL-691-43 - Airframe hours: 2717 - Engines: Lycoming VO-540-B1B3 305 horsepower reciprocating - Damage: Substantial damage - Flight: Aerial application, Part 137 - Airworthiness certificate: Special, Restricted (Special) - Last inspection: 100 hour, May 16, 2001, 21 hours before - Departed: Unknown, CA - Destination: L62, Buttonwillow, CA - Airport: L62, Elk Hills-Buttonwillow ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 38; injuries: none; commercial; medical: class 2; last flight review January 20, 2000; seat: single; flight hours: 1,800 total, 750 in this make and model ## Weather - Conditions: Visual (VMC), Day - Wind: variable at 3 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 93 °F, dew point 55 °F - Altimeter: 29.87 inHg - Observed at: BFL, 17 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 20010531009989A](https://openairdocs.org/incident/20010531009989A), May 31, 2001: Bell 47G4A, Bakersffield, CA, Substantial damage. (.19)On may 31, 2001, at 1136 hours pacific daylight time, a Bell 47G-4A, N110DT, crashed under unknown circumstances near bakersfield, California. The… ## Other investigations on N110DT (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 LAX05LA187](https://openairdocs.org/ntsb/LAX05LA187), May 25, 2005: Bell 47G-4A (N110DT), Bakersfield, CA, destroyed. Probable cause: the pilot's inadequate visual lookout and failure to maintain clearance from the power lines. - [NTSB LAX98LA197](https://openairdocs.org/ntsb/LAX98LA197), Jun 14, 1998: Bell 47G-4A (N110DT), Shafter, CA, substantial damage. Probable cause: The aircraft's encounter with settling with power, which resulted from the pilot's decision to perform a steep downwind approach. 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.