# NTSB SEA04LA065: Grumman G-164, N48564, Nezperce, ID, April 5, 2004 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: April 5, 2004, 08:00 local (15:00 UTC) - Place: Nezperce, ID - Coordinates: 46.239444, -116.240554 - Nearby events: https://openairdocs.org/map.md?lat=46.2394&lon=-116.2406&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report June 30, 2004 - Report: Approved by Office Director - Parties: Spokane FSDO - NTSB case key (mKey): 58999 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=SEA04LA065 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/58999/pdf - Page: https://openairdocs.org/ntsb/SEA04LA065 ## Probable cause The circumferential fracture of the number seven cylinder head while en route to an aerial fertilizer application, leading to a forced landing on soft terrain, resulting in the collapse of the right main gear leg. Factors include soft terrain at the location where the pilot found it necessary to attempt the forced landing. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Loss of engine power(partial) - mech failure/malf, maneuvering - aerial application - engine assembly,cylinder - fractured (cause) - Forced landing, emergency descent/landing - On ground/water encounter with terrain/water, emergency landing - terrain condition - soft (contributing factor) - Gear collapsed, emergency landing - landing gear,main gear strut - overload ## Analysis While en route to apply dry fertilizer to a field, the aircraft's engine popped and then experienced a significant loss of power. Because there was not sufficient power to keep the aircraft airborne, the pilot elected to execute a forced landing in a nearby field. He therefore started dumping his load of fertilizer, and attempted to set the aircraft down on the soft terrain. Although the touchdown was successful, soon thereafter the main gear sank into the soft terrain, and the right main gear leg folded aft. As the gear leg collapsed, the nose and right wing of the aircraft impacted the terrain. A post-accident inspection of the engine revealed that the head of the number seven cylinder had fractured circumferentially just above the location where the head screws into the cylinder barrel. Although the head had not separated from the barrel, the fracture was far enough around the barrel that it created a misalignment of the cylinder geometry to an extent that the intake valve would not close. There was no indication of detonation or any other anomaly that would have been expected to apply greater than normal loads to the cylinder structure. ## Factual narrative On Monday April 5, 2004, approximately 0800 Pacific daylight time, a Grumman G-164, N48564, experienced a main gear collapse during a forced landing in an open field near Nezperce, Idaho. The commercial pilot, who was the sole occupant, was not injured, but the aircraft, which is owned and operated by the pilot, sustained substantial damage. The 14 CFR Part 137 aerial application flight, which departed Nez Perce Municipal Airport, Nezperce, Idaho, about 10 minutes earlier, was being operated in visual meteorological conditions. No flight plan was filed. There was no ELT activation. According to the pilot, while en route to apply dry fertilizer to a field, the aircraft's engine popped and then experienced a significant loss of power. Because there was not sufficient power to keep the aircraft airborne, the pilot elected to execute a forced landing in a nearby field. He therefore started dumping his load of fertilizer, and attempted to set the aircraft down on the soft terrain. Although the touchdown was successful, soon thereafter the main gear sank into the soft terrain, and the right main gear leg folded aft. As the gear leg collapsed, the nose and right wing of the aircraft impacted the terrain. According to the FAA Inspector who responded to the scene, a post-accident inspection of the engine revealed that the head of the number seven cylinder had fractured circumferentially just above the location where the head screws into the cylinder barrel. Although the head had not separated from the barrel, the fracture was far enough around the barrel that it created a misalignment of the cylinder geometry to an extent that the intake valve would not close. According to this same inspector, there was no indication of detonation or any other anomaly that would have been expected to apply greater than normal loads to the cylinder structure. ## Aircraft - Registration: [N48564](https://openairdocs.org/deregistered/N48564-2004-08-30), registration cancelled 2004-08-30, S/N 1675, built 1976 (OpenAirDocs) - Reported make and model: Grumman G-164 - Registry model: [Grumman Acft ENG Cor-Schweizer G-164A](https://openairdocs.org/model/grumman-acft-eng-cor-schweizer-g-164a) (registry code 3952801) (OpenAirDocs) - Category: Airplane - Serial number: 1675 - Airframe hours: 7525 - Engines: Pratt & Whitney R1340-AN-1 600 horsepower reciprocating - Damage: Substantial damage - Flight: Aerial application, Part 137 - Registered owner: Kenneth J. Kuther - Airworthiness certificate: Special, Restricted (Special) - Last inspection: Annual, March 30, 2004, 33 hours before - Departed: 0S5, Nezperce, ID - Destination: 0S5 ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 36; injuries: none; commercial; airplane ratings: single-engine land; medical: class 2, valid medical--w/ waivers/lim; last flight review October 30, 2003; seat: front; flight hours: 5,653 total, 3,768 in this make and model, 5,653 as pilot in command ## Weather - Conditions: Visual (VMC), Day - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 50 °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 20040405006459A](https://openairdocs.org/incident/20040405006459A), Apr 5, 2004: Scwzer G164A, Nez Perce, ID, Substantial damage. (-23) On April 5, 2004 at approximately 0820 hours, a Grumman G-164A N48564 piloted by Mr. Ken kuther, lost power at an altitude of approximately 200 feet AGL.… ## Other investigations on N48564 (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 MKC87LA072](https://openairdocs.org/ntsb/MKC87LA072), Apr 1, 1987: Grumman-Schweizer G-164A (N48564), Dodge City, KS, substantial damage 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.