# NTSB WPR12CA025: Cessna 172K, N7276G, Florence, MT, October 30, 2011 - Type: NTSB accident investigation - Classification: Accident · No injuries · Data collection · Final report - Date: October 30, 2011, 16:20 local (22:20 UTC) - Place: Florence, MT - Coordinates: 46.611667, -114.046669 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=46.6117&lon=-114.0467&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Defining event: [Maneuvering-low-alt flying: Low altitude operation/event](https://openairdocs.org/ntsb-events/220) - Highest injury: No injuries - Injuries: 3 uninjured - Status: Completed, report January 18, 2012 - Report: Approved by Office Director - NTSB office: Western Pacific Region - Parties: FAA FSDO - NTSB case key (mKey): 82215 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR12CA025 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/82215/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=82215 - Page: https://openairdocs.org/ntsb/WPR12CA025 ## Probable cause The pilot's failure to maintain clearance from a power line during a low-level flight along a river. Contributing to the accident was the pilot's decision to fly at a low altitude. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Perception/orientation/illusion: perception](https://openairdocs.org/ntsb-findings/02022040): Personnel issues › Psychological · Pilot (probable cause); cases with it: [All aircraft, 61 cases](https://openairdocs.org/ntsb-findings/02022040/cases.md) - [Object/animal/substance: wire](https://openairdocs.org/ntsb-findings/03022032): Environmental issues › Physical environment · Response/compensation (probable cause); cases with it: [All aircraft, 588 cases](https://openairdocs.org/ntsb-findings/03022032/cases.md) - [Info processing/decision: decision making/judgment](https://openairdocs.org/ntsb-findings/02041520): Personnel issues › Action/decision · Pilot (probable cause); cases with it: [All aircraft, 3,098 cases](https://openairdocs.org/ntsb-findings/02041520/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: Low altitude operation/event](https://openairdocs.org/ntsb-events/220) (defining event); cases with it: [All aircraft, 780 cases](https://openairdocs.org/ntsb-events/220/sequence.md) - [Maneuvering-low-alt flying: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md) ## Analysis After a series of takeoffs and landings at several nearby airports, the pilot was returning to his home airport and descended to a low level to follow a river. The pilot reported that the conditions were turbulent for most of the day but that, during that low-altitude leg, the airplane seemed to perform abnormally. While still airborne, a passenger observed that the brake line that was attached to the right main landing gear strut was severed. As a result, the pilot conducted a precautionary landing at a nearby airport. The pilot and passengers observed multiple damage sites on the airplane but, since no one was present at that airport, they reboarded and departed for the home airport where they landed uneventfully. A postaccident investigation revealed that the airplane struck and severed one of several electrical power lines that spanned the river. The wire height at mid river was about 30 to 40 feet above the water. The propeller, cowling, exhaust stack, right wing (multiple places), right wing strut, right main gear brake line, right landing gear wheel fairing, right fuselage, and vertical stabilizer were damaged by the wire strike, and the rear window was punctured. The pilot stated that he did not see any wires and that he was not aware of the wire strike until he examined the airplane after the precautionary landing. Neither the pilot nor the passengers incurred any injuries. ## Factual narrative The pilot departed, conducted a touch-and-go at one airport, landed at another, and then flew north to a third airport, where another touch-and-go was conducted. The airplane then headed south towards the home airport, and the pilot descended to low level and followed a river for a portion of that flight leg. The pilot reported that the conditions were turbulent for most of the day, but during that low-altitude leg, the airplane behavior seemed abnormal. While still airborne, a passenger observed that the brake line that was attached to the right main landing gear strut was severed. As a result, the pilot conducted a precautionary landing at a nearby airport. The pilot and passengers observed multiple damage sites on the airplane, but since no one was present at that airport, they reboarded and departed for the home airport, where an uneventful landing was made. Investigation revealed that the airplane struck and severed one of several electrical power lines, which spanned the river. Those lines were strung between two poles, one on each side of the river. Both poles were set back from the river edge, and the west pole was situated in a loose stand of trees. The approximate wire span was 464 feet, and the wire height at mid river was approximately 30 to 40 feet above the water. Airplane damage from the wire strike included the propeller, cowling, exhaust stack, right wing (multiple places), right wing strut, right main gear brake line, right landing gear wheel fairing, right fuselage, and vertical stabilizer. In addition, the rear window was punctured. The pilot stated that he did not see any wires, and that he was not aware of the wire strike until he examined the airplane after the precautionary landing. Neither the pilot nor the passengers incurred any injuries. ## Aircraft - Registration: N7276G (not matched to a registry record) - Reported make and model: CESSNA 172K (K) - Category: Airplane - Serial number: 17258976 - Airframe hours: 3553 - Engines: Lycoming O-320 150 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Operator: North Star Aviation - Registered owner: North Star Aviation - Airworthiness certificate: Standard, Normal - Last inspection: 100 hour, September 29, 2011 - Departed: MSO, Missoula, MT - Destination: 6S5, Hamilton, MT - Airport: 6S5, Ravalli County ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 38; injuries: none; private; airplane ratings: single-engine land; medical: class 3, without waivers/limitations; last flight review January 4, 2010; seat: left; flight hours: 126 total, 20 in this make and model, 89 as pilot in command, 6 in the last 90 days, 3 in the last 30 days ## Weather - Conditions: Visual (VMC), Day - Wind: 110° at 3 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 54 °F, dew point 30 °F - Altimeter: 30.06 inHg - Observed at: MSO, 20 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 20111030024669A](https://openairdocs.org/incident/20111030024669A), Oct 30, 2011: Cessna 172K, Florence, MT, Substantial damage. On October 30, 2011 N7276G, registered to northstar aviation in hamilton Montana was rented by the pilot for a personal flight. Returning to the hamilton… ## Docket (13 files) The files NTSB released with the investigation on December 6, 2011, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=82215. 6.4 MB in all. - Pilot Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 2.6 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40359117&FileExtension=.PDF&FileName=Pilot%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF - Operator Aircraft Accident Report, NTSB Form 6120.1 (item 2, .PDF, 612 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40358886&FileExtension=.PDF&FileName=Operator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF - Interview Summary - Pilot (item 3, .PDF, 90 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40358860&FileExtension=.PDF&FileName=Interview%20Summary%20-%20Pilot-Master.PDF - FAA Interview Summary - Pilot (item 4, .PDF, 144 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40358861&FileExtension=.PDF&FileName=FAA%20Interview%20Summary%20-%20Pilot-Redacted.PDF - Pilot's Written Statement (item 5, .PDF, 735 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40358858&FileExtension=.PDF&FileName=Pilot%27s%20Written%20Statement-Redacted.PDF - Passenger Written Statement (item 6, .PDF, 133 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40358867&FileExtension=.PDF&FileName=Passenger%20Written%20Statement-Redacted.PDF - Factual Information (With 13 Embedded Photos) (item 7, .PDF, 13 photos, 1.0 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40358857&FileExtension=.PDF&FileName=Factual%20Information%20(With%2013%20Embedded%20Photos)-Master.PDF - Interview Summary- FBO Owner (item 8, .PDF, 82 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40358863&FileExtension=.PDF&FileName=Interview%20Summary-%20FBO%20Owner-Master.PDF - Ground-Based Witness Information (item 9, .PDF, 594 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40358862&FileExtension=.PDF&FileName=Ground-Based%20Witness%20Information-Redacted.PDF - FAA Interview Summary- Power Company Representative (item 10, .PDF, 121 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40358864&FileExtension=.PDF&FileName=FAA%20Interview%20Summary-%20Power%20Company%20Representative-Redacted.PDF - Power Company Damage Assessment (item 11, .PDF, 186 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40358865&FileExtension=.PDF&FileName=Power%20Company%20Damage%20Assessment-Redacted.PDF - Power Company Incident Report (item 12, .PDF, 58 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40359332&FileExtension=.PDF&FileName=Power%20Company%20Incident%20Report-Redacted.PDF - METARs (item 13, .PDF, 24 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40359118&FileExtension=.PDF&FileName=METARs-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.