# NTSB SEA02LA123: Grumman-Schweizer G-164B, N8440K, Weiser, ID, July 6, 2002 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: July 6, 2002, 08:45 local (14:45 UTC) - Place: Weiser, ID - Coordinates: 44.22861, -116.968612 - Nearby events: https://openairdocs.org/map.md?lat=44.2286&lon=-116.9686&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report May 13, 2003 - Report: Approved by Office Director - Parties: FAA Oklahoma City FSDO, FAA Boise FSDO - NTSB case key (mKey): 55159 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=SEA02LA123 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/55159/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=55159 - Page: https://openairdocs.org/ntsb/SEA02LA123 ## Probable cause The fracture of the number 3 cylinder exhaust pushrod resulting in the exhaust valve's inability to open during the exhaust cycle and the subsequent engine stoppage. Contributing factors were the ditch and elevated roadway which the aircraft crossed during the gear collapse. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Loss of engine power(total) - mech failure/malf, maneuvering - aerial application - engine assembly,push rod - fractured (cause) - engine assembly,valve,exhaust - inoperative - Forced landing, emergency descent/landing - Gear collapsed, landing - roll - terrain condition - ditch (contributing factor) - terrain condition - roadway/highway (contributing factor) - Nose over, landing - roll ## Analysis The pilot of the "Agcat" cropduster had just taken off and was making his first spray run over a field when the Pratt & Whitney R-1340 engine began to run rough. He pulled up and executed a right turn away from obstacles crossing the Snake River during which the engine abruptly stopped. The pilot rolled out and executed a forced landing in a beet field during which the aircraft crossed an elevated dirt/gravel roadway bounded on its north and south edges by a shallow ditch, and the aircraft's landing gear separated from the airframe. The aircraft then nosed over and came to a stop. The engine, which had been overhauled and inspected 81 and 31 hours respectively, was examined. The examination revealed that the number 3 cylinder exhaust valve steel pushrod was broken near the rocker arm end of the rod and the rod displayed very slight bending deformation. The separation surfaces of the broken rod end were observed to be mechanically battered. Removal or separation of the exhaust pushrod results in the exhaust valve's inability to open during the exhaust phase cycle for the associated cylinder, and can result in hot exhaust from the cylinder back-flowing out the intake valve when it opens during the intake cycle. ## Factual narrative On July 6, 2002, approximately 0845 mountain daylight time, a Grumman-Schweizer G-164B "Agcat," N8440K, registered to and operated by Weiser Air Service, Inc., and being flown by a commercial pilot, sustained substantial damage during a forced landing following a loss of power during a spray run near Weiser, Idaho. The commercial pilot was uninjured. Visual meteorological conditions existed and no flight plan had been filed. The flight, which was a crop dusting flight, was operated under 14 CFR 137, and originated from Weiser, about 0840 The pilot reported that as he departed the Weiser Municipal airport with 330 gallons of fluid and proceeded north to the destination field (about two miles north of the airport). During the first spray run over the field the engine began running rough ("popping" and "banging"). The pilot terminated the spray, pulled up and turned right away from obstacles and attempted to trouble shoot the problem. As he continued the right turn crossing the Snake River, he dumped the spray load and continued turning back toward the Weiser airport (refer to attached Diagram and NTSB Form 6120.1/2). During the right turn the engine abruptly stopped and the pilot executed a forced landing in a beet field directly ahead. During the landing roll, the aircraft crossed an elevated dirt/gravel roadway bounded on its north and south edges by a shallow ditch, and the aircraft's landing gear separated from the airframe. The aircraft then nosed over and came to a stop. The pilot reported that the aircraft's Pratt & Whitney R-1340, 9-cylinder engine had a total of 1591 hours and had been overhauled 81 hours previous to the accident. The last inspection was conducted May 22, 2002, 31 hours previous to the accident. The engine was shipped to Tulsa Aircraft Engines, Tulsa, Oklahoma, where an examination was conducted on August 16, 2002, under the oversight of an FAA Inspector from the Federal Aviation Administrations Oklahoma City Flight Standards District Office. The inspector reported that the examination revealed the number 3 cylinder exhaust valve steel pushrod was broken near the rocker arm end of the rod and the rod displayed very slight bending deformation (refer to Attachment PTRS-I). Removal or separation of the exhaust pushrod results in the exhaust valve's inability to open during the exhaust phase cycle for the associated cylinder, and can result in hot exhaust from the cylinder back-flowing out the intake valve when it opens during the intake cycle. The Inspector also reported that the separated ends of the push rod displayed extensive battering damage with the ends "mushroomed" over. ## Aircraft - Registration: [N8440K](https://openairdocs.org/deregistered/N8440K-2014-11-20), registration cancelled 2014-11-20, S/N 694B, built 1982 (OpenAirDocs) - Reported make and model: Grumman-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 R1340 series](https://openairdocs.org/engine/pratt-whitney-r1340-series) (registry code 52016, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 694B - Airframe hours: 7384 - Engines: Pratt & Whitney R-1340-S3H1G 600 horsepower reciprocating - Damage: Substantial damage - Flight: Aerial application, Part 137 - Registered owner: Weiser Air Service, Inc. - Airworthiness certificate: Special, Restricted (Special) - Last inspection: 100 hour, May 22, 2002, 31 hours before - Departed: S87, Weiser, ID ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 55; injuries: none; commercial; airplane ratings: single-engine land, multi-engine land; medical: class 2, valid medical--w/ waivers/lim; last flight review March 8, 2002; seat: front; flight hours: 17,174 total, 10,629 in this make and model, 16,686 as pilot in command, 136 in the last 90 days, 60 in the last 30 days, 7 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: calm - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 66 °F, dew point 48 °F - Altimeter: 29.96 inHg - Observed at: EUL, 38 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 20020706015759A](https://openairdocs.org/incident/20020706015759A), Jul 6, 2002: Scwzer G164B, Weiser, ID, No damage. (-23) The pilot departed Weiser airport at 8:45 to begin spraying operations on the Oregon side of the snake river. After one pass the engine began to operate… ## Other investigations on N8440K (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 SEA04LA099](https://openairdocs.org/ntsb/SEA04LA099), Jun 5, 2004: Grumman G-164B (N8440K), Midvale, ID, destroyed. Probable cause: The failure of the pilot to maintain clearance from the high tension powerline. A factor was the powerline. ## Docket (5 files) The files NTSB released with the investigation on March 25, 2003, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=55159. 880 KB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 363 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40461210&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Master.PDF - Attachment PTRS-I (item 2, .PDF, 91 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40178949&FileExtension=.PDF&FileName=Attachment%20PTRS-I-Master.PDF - Photo 1. A view looking north showing the main wheel tracks through the beet field passing over the ditch and east/west elevated dirt road. Digital Image (item 3, .PDF, 153 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40178950&FileExtension=.PDF&FileName=Photo%201.%20%20A%20view%20looking%20north%20showing%20the%20main%20wheel%20tracks%20through%20the%20beet%20field%20passing%20over%20the%20ditch%20and%20east%2Fwest%20elevated%20dirt%20road.%20%20Digital%20Image-Master.PDF - Photo 2. A view looking south from the elevated road past the south side ditch and beyond to the final resting place of N8440K. Digital Image (item 4, .PDF, 146 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40178952&FileExtension=.PDF&FileName=Photo%202.%20%20A%20view%20looking%20south%20from%20the%20elevated%20road%20past%20the%20south%20side%20ditch%20and%20beyond%20to%20the%20final%20resting%20place%20of%20N8440K.%20%20Digital%20Image-Master.PDF - Photo 3. A view showing N8440K inverted at its final resting place with the main gear collapsed/sheared. Digital Image (item 5, .PDF, 127 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40178956&FileExtension=.PDF&FileName=Photo%203.%20%20A%20view%20showing%20N8440K%20inverted%20at%20its%20final%20resting%20place%20with%20the%20main%20gear%20collapsed%2Fsheared.%20%20Digital%20Image-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.