# NTSB WPR10LA396: Grumman G164, N6781K, Tracy, CA, August 11, 2010 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: August 11, 2010, 07:15 local (14:15 UTC) - Place: Tracy, CA - Coordinates: 37.757221, -121.330833 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=37.7572&lon=-121.3308&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Defining event: [Maneuvering: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report August 29, 2012 - Report: Approved by Office Director - NTSB office: Western Pacific Region - Parties: Federal Aviation Administration - NTSB case key (mKey): 76931 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR10LA396 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/76931/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=76931 - Page: https://openairdocs.org/ntsb/WPR10LA396 ## Probable cause A total loss of engine power while maneuvering due to an internal catastrophic failure to the master rod and piston connecting rod links. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Engine (reciprocating): recip eng cyl section](https://openairdocs.org/ntsb-findings/01058530): Aircraft › Aircraft power plant · Failure (probable cause); cases with it: [Grumman Acft ENG Cor-Schweizer G-164B, 4 cases](https://openairdocs.org/ntsb-findings/01058530/cases.md?model=3952802), [All aircraft, 373 cases](https://openairdocs.org/ntsb-findings/01058530/cases.md) - [Terrain: wet/muddy terrain](https://openairdocs.org/ntsb-findings/03021035): Environmental issues › Physical environment · Contributed to outcome; cases with it: [Grumman Acft ENG Cor-Schweizer G-164B, 4 cases](https://openairdocs.org/ntsb-findings/03021035/cases.md?model=3952802), [All aircraft, 110 cases](https://openairdocs.org/ntsb-findings/03021035/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Maneuvering: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341) (defining event); cases with it: [Grumman Acft ENG Cor-Schweizer G-164B, 13 cases](https://openairdocs.org/ntsb-events/341/sequence.md?model=3952802), [All aircraft, 3,820 cases](https://openairdocs.org/ntsb-events/341/sequence.md) - [Emergency descent: Off-field or emergency landing](https://openairdocs.org/ntsb-events/440); cases with it: [Grumman Acft ENG Cor-Schweizer G-164B, 17 cases](https://openairdocs.org/ntsb-events/440/sequence.md?model=3952802), [All aircraft, 3,365 cases](https://openairdocs.org/ntsb-events/440/sequence.md) - [Landing-landing roll: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [Grumman Acft ENG Cor-Schweizer G-164B, 21 cases](https://openairdocs.org/ntsb-events/470/sequence.md?model=3952802), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md) ## Analysis During an aerial application flight, the pilot heard a loud bang, which was followed by a loss of engine power and shaking. During the forced landing to a wet field, the pilot activated the left brake to intentionally ground-loop the airplane; however, it did not respond. The airplane continued its forward movement until it struck a fence at the end of the field and came to rest inverted. During the postaccident engine examination, it was discovered that the connecting links for all but the No. 7 cylinder were broken and the master rod was sheared. Due to the extent of internal damage, it could not be determined if the master rod or the connecting link had failed first. ## Factual narrative On August 11, 2010, about 0715 Pacific daylight time, a Grumman Aircraft Engineering Corporation Schweizer G-164B, N6781K, experienced a loss of engine power while maneuvering to spray a field near Tracy, California. Trinkle AG Flying Inc., operated the airplane under the provisions of 14 Code of Federal Regulations Part 137 as an agricultural crop dusting flight. The commercial pilot/owner was not injured; the airplane sustained substantial damage to the wings, fuselage, and tail section. Visual meteorological conditions prevailed for the local area flight and no flight plan had been filed. The National Transportation Safety Board (NTSB) investigator-in-charge (IIC) interviewed the pilot. According to the pilot, he had started flying about 0630 the morning of the accident. The accident flight was the second flight of the day. He reported that the airplane was loaded with 240 gallons of pesticide and about 35 gallons of fuel. While spraying a cornfield, he heard a loud bang, followed by a loss of engine power. The pilot also reported that the engine began shaking. He was able to land the airplane in an alfalfa field, but the field was slick and as he activated the left brake to intentionally ground loop the airplane, it did not respond. The airplane continued its forward movement until it struck a fence at the end of the field. The airplane came to rest inverted in a nearby ditch adjacent to the alfalfa field. The engine was examined under the supervision of a Federal Aviation Administration inspector. During the examination, it was discovered that the head to the number five cylinder was cracked. In addition, the connecting links for all but the number 7 cylinder were broken and the master rod had sheared. They were unable to determine if the master rod or the connecting link failed first. No other anomalies were noted with the airframe or the power plant. ## Aircraft - Registration: [N6781K](https://openairdocs.org/deregistered/N6781K-2022-07-02), registration cancelled 2022-07-02, S/N 472B (OpenAirDocs) - Reported make and model: GRUMMAN G164 (B) - 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 R1340 series](https://openairdocs.org/engine/pratt-whitney-r1340-series) (registry code 52016, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 472B - Airframe hours: 15000 - Engines: Pratt and Whitney R-1340 600 horsepower reciprocating - Damage: Substantial damage - Flight: Aerial application, Part 137 - Operator: Trinkle AG Flying Inc. - Registered owner: Trinkle AG Flying Inc. - Airworthiness certificate: Special, Restricted (Special) - Last inspection: 100 hour, April 23, 2010 - Departed: Tracy, CA - Destination: Tracy, CA - Airport: Private Airstrip ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 34; injuries: none; flight instructor, commercial; airplane ratings: single-engine land; instrument ratings: airplane; medical: class 2, with waivers/limitations; last flight review December 31, 2009; seat: center; flight hours: 3,280 total, 2,200 in this make and model, 200 in the last 90 days, 100 in the last 30 days, 8 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 280° at 10 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 57 °F, dew point 52 °F - Altimeter: 29.89 inHg - Observed at: SCK, 16 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 20100811042329A](https://openairdocs.org/incident/20100811042329A), Aug 11, 2010: Grumman Acf G-164B, Tracy, CA, Substantial damage. Pilot had departed their private airstrip for his second application flight of the day. Shortly after takeoff at aprox 200 feet AGL pilot heard a loud "bang"… ## Other investigations on N6781K (1) 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 ERA16LA242](https://openairdocs.org/ntsb/ERA16LA242), Jul 2, 2016: Grumman Acft ENG Cor-Schweizer G-164 (N6781K), Laurel, DE, substantial damage. Probable cause: A total loss of engine power due to an encounter with a bird, which collided with the spray pump fan assembly and subsequently sent blade fragments into the engine compartment, damaging the throttle… ## Docket (4 files) The files NTSB released with the investigation on July 4, 2012, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=76931. 2.6 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 548 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40371554&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF - Report from Federal Aviation Administration (item 2, .PDF, 20 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40371724&FileExtension=.PDF&FileName=Report%20from%20Federal%20Aviation%20Administration-Redacted.PDF - Photo 1 - Cylinder (FAA) (item 3, .PDF, 1.1 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40371544&FileExtension=.PDF&FileName=Photo%201%20-%20%20Cylinder%20(FAA)-Master.PDF - Photo 2 - Additional View of Cylinder (FAA) (item 4, .PDF, 929 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40371545&FileExtension=.PDF&FileName=Photo%202%20-%20Additional%20View%20of%20Cylinder%20(FAA)-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.