# NTSB SEA99LA067: Grumman G-164B, N6861K, Okanogan, WA, May 19, 1999 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: May 19, 1999, 11:45 local (18:45 UTC) - Place: Okanogan, WA - Coordinates: 48.220611, -119.449722 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=48.2206&lon=-119.4497&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report November 30, 2000 - Report: Approved by Office Director - NTSB case key (mKey): 46447 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=SEA99LA067 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/46447/pdf - Page: https://openairdocs.org/ntsb/SEA99LA067 ## Probable cause A malfunctioning carburetor. Factors include a downdraft, and the soft dirt in a newly plowed field. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Loss of engine power, maneuvering - fuel system,carburetor - malfunction (cause) - weather condition - downdraft (contributing factor) - Nose over, emergency landing - terrain condition - soft (contributing factor) ## Analysis While maneuvering over an orchard that he was preparing to spray, the pilot flew through a sudden downdraft which pushed him up against his seat belt and shoulder straps. About two seconds later, the engine quit and could not be started. The pilot elected to attempt the forced landing in an alfalfa field that was straight ahead of him. The aircraft initially touched down in the alfalfa, but bounced back into the air and touched down a second time in an area that had been freshly plowed. The main gear sank into the soft dirt and the aircraft nosed over. During the post-accident engine inspection, the engine would not start until the carburetor had been struck a couple of time with a hammer. After the carburetor was jarred by the hammer, the engine started and was able to be test run. Disassembly of the carburetor did not reveal whether the float had stuck, an orifice had been temporarily blocked, or whether there had been some other malfunction. ## Factual narrative On May 19, 1999, approximately 1145 Pacific daylight time, a Grumman G-164B, N6861K, nosed over in a freshly-plowed field during a forced landing near Okanogan, Washington. The pilot was not injured, but the aircraft, which was owned and operated by Okanogan Air Service, sustained substantial damage. The local 14 CFR Part 137 aerial application flight, which had been airborne for about 30 minutes, was operating in visual meteorological conditions. No flight plan had been filed, and there was no report of an ELT activation. According to the pilot, while maneuvering over an orchard he was about to spray, the aircraft encountered a "big bump of air" which pulled him up against his seatbelt and shoulder harness. About two seconds later, the engine suddenly lost power, momentarily sputtered, and then quit altogether. The pilot elected to make a forced landing in an Alfalfa field that was straight ahead, so he dumped his remaining chemical and prepared to land. The aircraft initially touched down in the alfalfa, but bounced back into the air and touched down again in a freshly plowed portion of the field. After this second touchdown, the main gear sank into the soft dirt and the aircraft nosed over. During a post-accident engine run, the engine would not start until the carburetor was tapped several times with a hammer. After jarring the carburetor with the hammer, the engine was able to be started and run. Disassembly of the carburetor did not reveal whether the float had stuck, contamination had temporarily blocked an orifice, or whether there was some other malfunction. ## Aircraft - Registration: N6861K (not matched to a registry record) - Reported make and model: Grumman G-164B - Category: Airplane - Serial number: 506B - Airframe hours: 4054 - Engines: P&W R-1340-AN-1 600 horsepower reciprocating - Damage: Substantial damage - Flight: Aerial application, Part 137 - Registered owner: Lockwood Aviation Lp - Airworthiness certificate: Special, Restricted (Special) - Last inspection: Annual, January 26, 1999, 74 hours before - Departed: OKANOGAN, WA ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 30; flight instructor, commercial; airplane ratings: multi-engine land, single-engine land, single-engine sea; instrument ratings: airplane; medical: class 2, valid medical--no waivers/lim.; seat: front; flight hours: 3,043 total, 1,071 in this make and model, 2,961 as pilot in command, 166 in the last 90 days, 90 in the last 30 days, 8 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 61 °F, dew point 30 °F - Altimeter: 30.00 inHg ## 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 19990519005419A](https://openairdocs.org/incident/19990519005419A), May 19, 1999: Scwzer G164B, Okanogan, WA, Substantial damage. Acft engine lost power, and the acft landed in a field and flipped over. (-23) while manuevering over an orchard, a/c encountered a vertical gust, engine lost… 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.