# NTSB SEA98LA140: Grumman-Schweizer G-164A, N7951, Caldwell, ID, July 17, 1998 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: July 16, 1998, 23:00 local (Jul 17, 1998, 05:00 UTC) - Place: Caldwell, ID - Coordinates: 43.660728, -116.630737 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=43.6607&lon=-116.6307&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report February 11, 2000 - Report: Approved by Office Director - NTSB case key (mKey): 43230 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=SEA98LA140 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/43230/pdf - Page: https://openairdocs.org/ntsb/SEA98LA140 ## Probable cause The pilot-in-command's misjudgment of clearance with a power line, resulting in a collision with the line. Factors included a power line and dark night light conditions in the spray area. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - In flight collision with object, maneuvering - aerial application - object - wire,transmission (contributing factor) - clearance - misjudged, pilot in command (cause) - light condition - dark night (contributing factor) ## Analysis The pilot reported that while approaching a field for a spray run, he misjudged the height of a power line in the vicinity of the field and struck the line. The line was cut by the strike. The aircraft, while substantially damaged by the strike, was able to return to its home airstrip and land without further incident. The pilot reported that no mechanical malfunction or failure was involved in the accident. Dark night conditions existed in the accident area at the time. ## Factual narrative On July 16, 1998, approximately 2300 mountain daylight time, a Grumman-Schweizer G-164A agricultural airplane, N7951, operated by Carol's Flying Service of Wilder, Idaho, struck power lines while conducting nighttime agricultural aerial application operations approximately 5 nautical miles south of Caldwell, Idaho. The power lines were cut in the strike. The pilot was able to return to his airstrip near Wilder (from which the flight originated) and land without further incident; he was not injured in the occurrence. Following the occurrence, the airplane was found to have sustained substantial damage. No flight plan was filed for the 14 CFR 137 agricultural aerial application flight. The pilot reported that while approaching a field for a spray run, he miscalculated wire height and struck the wire. He stated that no mechanical failure or malfunction was involved in the accident. The pilot's second class FAA medical certificate, dated January 6, 1998, carried a restriction that the pilot must possess glasses that correct for near and intermediate vision. The pilot reported in an August 10, 1998 telephone query that he was wearing his glasses at the time of the accident. The pilot reported that he had 55 hours of night time within the previous 30 days. Astronomical data computation indicated that at Caldwell, evening twilight on July 16 ended at 2245, and that there was no moon at the time of the accident. The pilot reported the weather as clear with unrestricted visibility. ## Aircraft - Registration: [N7951](https://openairdocs.org/deregistered/N7951-2018-10-23), registration cancelled 2018-10-23, S/N 829, built 1971 (OpenAirDocs) - Reported make and model: Grumman-Schweizer G-164A - Registry model: [Grumman G-164A](https://openairdocs.org/model/grumman-g-164a) (registry code 3952704) (OpenAirDocs) - Registry engine: [Pratt & Whitney R-985 series](https://openairdocs.org/engine/pratt-whitney-r-985-series) (registry code 52008, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 829 - Engines: P&W R-985 450 horsepower reciprocating - Damage: Substantial damage - Flight: Aerial application, Part 137 - Registered owner: Carol'S Flying Service - Airworthiness certificate: Special, Restricted (Special) - Departed: WILDER, ID ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 54; commercial; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 2, valid medical--w/ waivers/lim; seat: center; flight hours: 11,724 total, 7,600 in this make and model, 11,724 as pilot in command, 101 in the last 90 days, 75 in the last 30 days ## Weather - Conditions: Visual (VMC), Night/dark - Wind: calm - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 75 °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 19980716030799A](https://openairdocs.org/incident/19980716030799A), Jul 16, 1998: Scwzer G164A, Caldwell, ID, Substantial damage. (-23)On a night spray operation, the operator was returning to the field with his third load of the evening. He stated he began his descent to make the first… ## Other investigations on N7951 (2) 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 CEN15LA204](https://openairdocs.org/ntsb/CEN15LA204), Apr 15, 2015: Grumman G 164A (N7951), Maysville, OK, substantial damage. Probable cause: The loss of engine power for reasons that could not be determined because a postaccident examination of the airframe and engine did not reveal any anomalies that would have precluded normal operation. - [NTSB IAD76FLT13](https://openairdocs.org/ntsb/IAD76FLT13), Jun 21, 1976: Grumman G-164A (N7951), Covington, TN, 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.