# NTSB WPR10CA289: Grumman Acft ENG Cor-Schweizer G-164B, N6726Q, Courtland, CA, June 13, 2010 - Type: NTSB accident investigation - Classification: Accident · Serious injuries · Data collection · Final report - Date: June 13, 2010, 10:47 local (17:47 UTC) - Place: Courtland, CA - Coordinates: 38.370834, -121.657501 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=38.3708&lon=-121.6575&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Defining event: [Maneuvering-low-alt flying: Low altitude operation/event](https://openairdocs.org/ntsb-events/220) - Highest injury: Serious injuries - Injuries: 1 serious - Status: Completed, report October 21, 2010 - Report: Approved by Office Director - NTSB office: Western Pacific Region - Parties: Sacramento FSDO - NTSB case key (mKey): 76307 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR10CA289 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/76307/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=76307 - Page: https://openairdocs.org/ntsb/WPR10CA289 ## Probable cause The pilot's failure to maintain clearance from terrain during low-altitude maneuvers. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Performance/control parameters: altitude](https://openairdocs.org/ntsb-findings/01062012): Aircraft › Aircraft oper/perf/capability · Not attained/maintained (probable cause); cases with it: [Grumman Acft ENG Cor-Schweizer G-164B, 7 cases](https://openairdocs.org/ntsb-findings/01062012/cases.md?model=3952802), [All aircraft, 1,310 cases](https://openairdocs.org/ntsb-findings/01062012/cases.md) - [Terrain](https://openairdocs.org/ntsb-findings/03021000): Environmental issues › Physical environment · Response/compensation (probable cause); cases with it: [Grumman Acft ENG Cor-Schweizer G-164B, 7 cases](https://openairdocs.org/ntsb-findings/03021000/cases.md?model=3952802), [All aircraft, 267 cases](https://openairdocs.org/ntsb-findings/03021000/cases.md) - [Attention/monitoring: monitoring environment](https://openairdocs.org/ntsb-findings/02021545): Personnel issues › Psychological · Pilot (probable cause); cases with it: [Grumman Acft ENG Cor-Schweizer G-164B, 11 cases](https://openairdocs.org/ntsb-findings/02021545/cases.md?model=3952802), [All aircraft, 809 cases](https://openairdocs.org/ntsb-findings/02021545/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Maneuvering-low-alt flying: Low altitude operation/event](https://openairdocs.org/ntsb-events/220) (defining event); cases with it: [Grumman Acft ENG Cor-Schweizer G-164B, 10 cases](https://openairdocs.org/ntsb-events/220/sequence.md?model=3952802), [All aircraft, 780 cases](https://openairdocs.org/ntsb-events/220/sequence.md) ## Analysis The pilot reported that during an aerial application flight he was established and stable on an east-to-west spray pass. He recalls checking the pump pressure gauge for an indication of an empty load when he felt and heard a “significant slam” and felt a grinding sensation. The airplane had impacted level terrain and came to rest upside down. The airplane sustained substantial damage to both wings and the tail assembly. The pilot reported that there were no known mechanical malfunctions or failures with the aircraft prior to the accident. ## Factual narrative The pilot reported that during an aerial application flight he was established and stable on an east-to-west spray pass. He recalls checking the pump pressure gauge for an indication of an empty load when he felt and heard a “significant slam” and felt a grinding sensation. The airplane had impacted level terrain and came to rest upside down. The airplane sustained substantial damage to both wings and the tail assembly. The pilot reported that there were no known mechanical malfunctions or failures with the aircraft prior to the accident. ## Aircraft - Registration: [N6726Q](https://openairdocs.org/aircraft/N6726Q), registered now, S/N 237B, built 1977 (OpenAirDocs) - Reported make and model: GRUMMAN ACFT ENG COR-SCHWEIZER G-164B - Registry model: [Grumman Acft ENG Cor-Schweizer G-164B](https://openairdocs.org/model/grumman-acft-eng-cor-schweizer-g-164b) (registry code 3952802) (OpenAirDocs) - Registry engine: [Pratt & Whitney R-985 series](https://openairdocs.org/engine/pratt-whitney-r-985-series) (registry code 52008, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 237B - Airframe hours: 6000 - Engines: P&W R-1340 600 horsepower reciprocating - Damage: Substantial damage - Flight: Aerial application, Part 137 - Operator: Walter Avery, doing business as Harding Flying Service - Registered owner: Harding Flying Service LLC - Airworthiness certificate: Special, Restricted (Special) - Last inspection: 100 hour, May 1, 2010 - Departed: Clarksburg, CA - Destination: Clarksburg, CA ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 52; injuries: serious; commercial; airplane ratings: single-engine land; instrument ratings: airplane; medical: class 2, with waivers/limitations; last flight review June 1, 2010; seat: single; flight hours: 1,990 total, 206 in this make and model, 1,760 as pilot in command, 75 in the last 90 days, 59 in the last 30 days, 0 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 350° at 6 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 79 °F, dew point 48 °F - Altimeter: 30.00 inHg - Observed at: SAC, 11 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 20100613048789A](https://openairdocs.org/incident/20100613048789A), Jun 13, 2010: Grumman Acf G-164B, Davis, CA, Substantial damage. Pilot aparently hit the ground while dusting. The aircraft main landing gear hit the water/ground and flipped over on its back. ## Docket (1 files) The files NTSB released with the investigation on July 14, 2010, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=76307. 460 KB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 460 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40332085&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.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.