# NTSB CEN20LA145: Beech 35, N1258Z, Sidney, IA, April 10, 2020 - Type: NTSB accident investigation - Classification: Accident · No injuries · Class 3 · Limited · Final report - Date: April 10, 2020, 12:25 local (17:25 UTC) - Place: Sidney, IA - Coordinates: 40.82611, -95.67028 - Nearby events: https://openairdocs.org/map.md?lat=40.8261&lon=-95.6703&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Defining event: [Enroute-cruise: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed - Report: Approved by Office Director - Investigation class: Class 3 - NTSB office: Central Region - Parties: FAA, Continental Aerospace Technologies - NTSB case key (mKey): 101164 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN20LA145 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/101164/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=101164 - Page: https://openairdocs.org/ntsb/CEN20LA145 ## Probable cause A loss of engine power for reasons that could not be determined. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Not determined](https://openairdocs.org/ntsb-findings/05000000): Not determined › Not determined · Unknown/Not determined (probable cause); cases with it: [Beech N35, 3 cases](https://openairdocs.org/ntsb-findings/05000000/cases.md?model=1151528), [All aircraft, 2,247 cases](https://openairdocs.org/ntsb-findings/05000000/cases.md) - [Engine (reciprocating)](https://openairdocs.org/ntsb-findings/01058500): Aircraft › Aircraft power plant · Failure (probable cause); cases with it: [Beech N35, 2 cases](https://openairdocs.org/ntsb-findings/01058500/cases.md?model=1151528), [All aircraft, 497 cases](https://openairdocs.org/ntsb-findings/01058500/cases.md) - [Terrain: sloped/uneven terrain](https://openairdocs.org/ntsb-findings/03021017): Environmental issues › Physical environment · Contributed to outcome; cases with it: [Beech N35, 1 case](https://openairdocs.org/ntsb-findings/03021017/cases.md?model=1151528), [All aircraft, 270 cases](https://openairdocs.org/ntsb-findings/03021017/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Enroute-cruise: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341) (defining event); cases with it: [Beech N35, 6 cases](https://openairdocs.org/ntsb-events/341/sequence.md?model=1151528), [All aircraft, 3,820 cases](https://openairdocs.org/ntsb-events/341/sequence.md) - [Landing: Off-field or emergency landing](https://openairdocs.org/ntsb-events/440); cases with it: [Beech N35, 4 cases](https://openairdocs.org/ntsb-events/440/sequence.md?model=1151528), [All aircraft, 3,365 cases](https://openairdocs.org/ntsb-events/440/sequence.md) ## Analysis According to the pilot, the accident flight was the third following an annual inspection; the airplane had flown about 1.5 hours since the completion of the annual inspection. About 80 minutes into the flight, the engine ceased to produce power. When the pilot moved the throttle from the cruise setting to idle and then back to the previous setting, the RPM gauge fluctuated, but power could not be restored. He said that while looking for a place to land, he and his passenger began detecting a "slight burning smell." He conducted an emergency landing to a grass field. Upon touchdown, the nose gear collapsed, and the left main gear was compressed up and into the left wing, resulting in substantial damage to the wing. Postaccident examinations of the engine, ignition system, fuel system and propeller governor found no evidence of any anomalies or malfunctions that would have precluded normal operation. ## Factual narrative On April 10, 2020, about 1225 central daylight time (CDT), a Beechcraft N35, N1258Z, was substantially damaged when it was involved in an accident near Sidney, Iowa. The airline transport pilot and passenger were uninjured. The airplane was operated as a Title 14 Code of Federal Regulations (CFR) Part 91 personal flight. According to the pilot, the accident flight was the third following an annual inspection. The airplane had flown about 1.5 hours since the completion of the annual inspection and was topped off with fuel prior to the flight. About 80 minutes into the cross-country flight, while in level cruise flight about 4,500 ft above mean sea level (msl), the engine ceased to produce power. The pilot stated that there was no warning, and the engine instruments appeared normal. He attempted to restore power, but when he turned the key to "START," he heard a sound consistent with an attempt to start an already running engine. When he moved the throttle from the cruise setting to idle and then back to the previous setting, the RPM gauge fluctuated. When the airplane descended to 1,500 ft msl, about 1,000 ft above ground level, he began to look for an emergency landing area. He said that it was at this time that he and his passenger began detecting a "slight burning smell." Unable to reach an airport, he conducted an emergency landing to a grass field. Upon touchdown, the airplane encountered uneven terrain, the nose gear collapsed and the left main gear was compressed up and into the left wing, resulting in substantial damage to the wing. During a postaccident examination, thumb compression was obtained on all cylinders through rotation of the propeller. The impulse coupler could be heard, consistent with internal continuity from the front to the back of the engine. The spark plugs were removed and appeared intact and undamaged, although the manufacturer of the spark plugs (Champion and BG) and spark plug electrode gaps were inconsistent. The magnetos and wiring harnesses were removed and tested on a bench using a hand drill; spark was observed on all ignition harness leads. The propeller governor was examined by the NTSB investigator-in-charge. A small amount of unidentified metallic material and debris was found on the oil screen but not within the accessory. The governor was disassembled and found to be unremarkable. A postaccident examination of the fuel system was accomplished with no anomalies or malfunctions discovered in any components that would have precluded normal operation. Fuel obtained from the gascolator was examined for proper color and the presence of debris or water, with no contamination noted. ## Aircraft - Registration: [N1258Z](https://openairdocs.org/deregistered/N1258Z-2022-01-08), registration cancelled 2022-01-08, S/N D-6712 (OpenAirDocs) - Reported make and model: Beech 35 (N35) - Registry model: [Beech N35](https://openairdocs.org/model/beech-n35) (registry code 1151528) (OpenAirDocs) - Registry engine: [Continental I0-470 series](https://openairdocs.org/engine/continental-i0-470-series) (registry code 17027, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: D-6712 - Year built: 1961 - Airframe hours: 2625 - Engines: Continenal IO-470 reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Airworthiness certificate: Standard, Normal - Last inspection: Annual, March 31, 2020, 2.5 hours before - Departed: 1H0, St Louis, MO - Destination: MLE, Omaha, NE - Flight plan: VFR - Equipment: Electronic flight bag or handheld device, Stall warning system, ADS-B, Handheld GPS, Auto-pilot ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 53; injuries: none; flight instructor, flight engineer, airline transport; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 2, without waivers/limitations; last flight review July 3, 2020; seat: left; restraint: lap only; flight hours: 15,000 total, 40 in this make and model, 7,500 as pilot in command, 50 in the last 90 days, 20 in the last 30 days, 1.5 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 230° at 8 knots, gusting 14 - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 45 °F, dew point 19 °F - Altimeter: 30.18 inHg - Observed at: KSDA, 12 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 20200410007479A](https://openairdocs.org/incident/20200410007479A), Apr 10, 2020: Beech N35, Sidney, IA, Substantial damage. The aircraft annual inspection was completed four days before the accident with 2 hour flown since. On April 10th, 2020 just after 11AM local the aircraft… ## Docket (10 files) The files NTSB released with the investigation on February 1, 2022, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=101164. 7.4 MB in all. - Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 9 pages, 3.3 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=11537581&FileExtension=pdf&FileName=6120_Redacted-Rel.pdf - Propeller governor exam memo (item 2, PDF, 2 pages, 203 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=11537591&FileExtension=pdf&FileName=Prop%20Governor%20Exam-Rel.pdf - Fuel system exam memo (item 3, PDF, 1 page, 212 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=11536664&FileExtension=pdf&FileName=Fuel%20Test%20Memo-Rel.pdf - FAA exam inspector statement (item 4, PDF, 1 page, 195 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=11536755&FileExtension=pdf&FileName=FAA%20Inspector%20Statement-Rel.pdf - FAA record of conversation_engine exam (item 5, PDF, 1 page, 48 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=11556690&FileExtension=pdf&FileName=ROC_FAA-Rel.pdf - Magneto and spark plug examination report (item 6, PDF, 4 pages, 914 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=11536572&FileExtension=pdf&FileName=CEN20LA145%20Mag%20Exam-Rel.pdf - Spark plug STC information (item 7, PDF, 1 page, 76 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=11536582&FileExtension=pdf&FileName=Spark%20Plug%20STC-Rel.pdf - Photos (item 8, PDF, 3 pages, 832 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=11544017&FileExtension=pdf&FileName=Photo%20Array-Rel.pdf - Statement of party representatives to NTSB investigation (item 9, PDF, 2 pages, 876 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=11576979&FileExtension=pdf&FileName=NTSB%20Party%20Form%20-%20CEN20LA145_Redacted-Rel.pdf - Wreckage release (item 10, PDF, 2 pages, 768 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=11611131&FileExtension=pdf&FileName=ST%2020041011%20Wreckage%20Release%20Signed10262020_Redacted-Rel.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.