# NTSB DEN08CA135: Grumman G-164A, N7487, Walsh, CO, August 6, 2008 - Type: NTSB accident investigation - Classification: Accident · No injuries · Data collection · Final report - Date: August 6, 2008, 06:30 local (12:30 UTC) - Place: Walsh, CO - Coordinates: 37.349998, -102.25 - Nearby events: https://openairdocs.org/map.md?lat=37.3500&lon=-102.2500&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Defining event: [Maneuvering-low-alt flying: Powerplant sys/comp malf/fail](https://openairdocs.org/ntsb-events/340) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report January 22, 2009 - Report: Approved by Office Director - Parties: FAA Flight Standards District Office - NTSB case key (mKey): 68621 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=DEN08CA135 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/68621/pdf - Page: https://openairdocs.org/ntsb/DEN08CA135 ## Probable cause The total failure of a cylinder head assembly. Contributing to the accident was the lack of suitable terrain for a forced landing. ## 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-164A, 6 cases](https://openairdocs.org/ntsb-findings/01058530/cases.md?model=3952801), [All aircraft, 373 cases](https://openairdocs.org/ntsb-findings/01058530/cases.md) - [Terrain: rough terrain](https://openairdocs.org/ntsb-findings/03021015): Environmental issues › Physical environment · Ability to respond/compensate (probable cause); cases with it: [Grumman Acft ENG Cor-Schweizer G-164A, 4 cases](https://openairdocs.org/ntsb-findings/03021015/cases.md?model=3952801), [All aircraft, 442 cases](https://openairdocs.org/ntsb-findings/03021015/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: Powerplant sys/comp malf/fail](https://openairdocs.org/ntsb-events/340) (defining event); cases with it: [Grumman Acft ENG Cor-Schweizer G-164A, 7 cases](https://openairdocs.org/ntsb-events/340/sequence.md?model=3952801), [All aircraft, 820 cases](https://openairdocs.org/ntsb-events/340/sequence.md) - [Maneuvering-low-alt flying: Off-field or emergency landing](https://openairdocs.org/ntsb-events/440); cases with it: [Grumman Acft ENG Cor-Schweizer G-164A, 12 cases](https://openairdocs.org/ntsb-events/440/sequence.md?model=3952801), [All aircraft, 3,365 cases](https://openairdocs.org/ntsb-events/440/sequence.md) - [Landing-landing roll: Nose over/nose down](https://openairdocs.org/ntsb-events/096); cases with it: [Grumman Acft ENG Cor-Schweizer G-164A, 8 cases](https://openairdocs.org/ntsb-events/096/sequence.md?model=3952801), [All aircraft, 2,287 cases](https://openairdocs.org/ntsb-events/096/sequence.md) ## Analysis The pilot was spraying a corn field; as he was making an aerial application pass, a cylinder on the engine cracked and the engine lost power. The pilot made a forced landing in a nearby field. The airplane crossed a road at a speed of approximately 25 mph and the tail bounced up. After crossing the road, the main tires settled into soft earth and the airplane nosed over. In addition to a bent propeller and "minor top wing damage," the vertical stabilizer was crushed. ## Factual narrative On August 6, 2008, approximately 0700 mountain daylight time, a Grumman G-164A, N7487, registered to and operated by Doyles Ag Services, and piloted by a commercial pilot, was substantially damaged when it nosed over on soft terrain following a loss of power while maneuvering near Walsh, Colorado. Visual meteorological conditions prevailed at the time of the accident. The aerial application flight was being conducted under the provisions of Title 14 Code of Federal Regulations (CFR) Part 137 without a flight plan. The pilot was not injured. The local flight originated from Springfields (8V7), Colorado, approximately 0630. The pilot said he was spraying a corn field southeast of Walsh. As he was making an aerial application pass, a cylinder on the engine cracked --- "blew a cylinder" --- and the engine lost power. The pilot made a forced landing in a nearby field. The airplane crossed a road at a speed of approximately 25 mph and the tail bounced up in the air. After crossing the road, the main tires settled into soft earth and the airplane nosed over. In addition to a bent propeller and "minor top wing damage," the vertical stabilizer was crushed. ## Aircraft - Registration: [N7487](https://openairdocs.org/deregistered/N7487-2022-11-23), registration cancelled 2022-11-23, S/N 964, built 1972 (OpenAirDocs) - Reported make and model: Grumman G-164A - Registry model: [Grumman Acft ENG Cor-Schweizer G-164A](https://openairdocs.org/model/grumman-acft-eng-cor-schweizer-g-164a) (registry code 3952801) (OpenAirDocs) - Registry engine: [Pratt & Whitney R1340 series](https://openairdocs.org/engine/pratt-whitney-r1340-series) (registry code 52016, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 964 - Airframe hours: 5821 - Engines: Pratt & Whitney R1340-AN-1 600 horsepower reciprocating - Damage: Substantial damage - Flight: Aerial application, Part 137 - Operator: Doyles Ag Services LLC - Registered owner: Doyles Ag Services LLC - Airworthiness certificate: Special, Restricted (Special) - Last inspection: Annual, January 1, 2008, 690 hours before - Departed: NONE, Two Buttes, CO - Destination: NONE, Two Buttes, CO ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 42; injuries: none; commercial; airplane ratings: single-engine land; medical: class 2, with waivers/limitations; last flight review March 1, 2007; seat: single; flight hours: 2,500 total, 1,003 in this make and model, 2,400 as pilot in command, 110 in the last 90 days, 30 in the last 30 days, 5 in the last 24 hours ## Weather - Conditions: Visual (VMC), Dawn - Wind: 200° at 4 knots - Visibility: 15 statute miles - Lowest ceiling: none - Temperature: 68 °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 20080806857589A](https://openairdocs.org/incident/20080806857589A), Aug 6, 2008: Grumma G164A, Walsh, CO, Substantial damage. Pilot was conducting agriculture aerial applications and a cylinder blew on the engine. He attempted an emergency landing in a field. The aircraft struck a… 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.