# NTSB GAA18CA330: Sorensen Danny S BF9 2, N81973, Evanston, WY, May 31, 2018 - Type: NTSB accident investigation - Classification: Accident · No injuries · Data collection · Final report - Date: May 31, 2018, 17:45 local (23:45 UTC) - Place: Evanston, WY - Coordinates: 41.254165, -110.999725 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=41.2542&lon=-110.9997&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Defining event: [Enroute: Fuel exhaustion](https://openairdocs.org/ntsb-events/192) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report November 5, 2018 - Report: Approved by Office Director - NTSB office: General Aviation Accidents - Parties: FAA - NTSB case key (mKey): 97419 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=GAA18CA330 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/97419/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=97419 - Page: https://openairdocs.org/ntsb/GAA18CA330 ## Probable cause The pilot’s failure to fuel the biplane’s main fuel tank before the flight and his inadequate preflight inspection, during which he did not verify the fuel quantity, which resulted in fuel exhaustion ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Fluids: fuel](https://openairdocs.org/ntsb-findings/01071010): Aircraft › Fluids/misc hardware · Fluid level (probable cause); cases with it: [Sorensen Danny S BF9-2, 1 case](https://openairdocs.org/ntsb-findings/01071010/cases.md?model=05622UI), [All aircraft, 1,695 cases](https://openairdocs.org/ntsb-findings/01071010/cases.md) - [Planning/preparation: fuel planning](https://openairdocs.org/ntsb-findings/02061030): Personnel issues › Task performance · Pilot (probable cause); cases with it: [Sorensen Danny S BF9-2, 1 case](https://openairdocs.org/ntsb-findings/02061030/cases.md?model=05622UI), [All aircraft, 719 cases](https://openairdocs.org/ntsb-findings/02061030/cases.md) - [Inspection: preflight inspection](https://openairdocs.org/ntsb-findings/02061510): Personnel issues › Task performance · Pilot (probable cause); cases with it: [Sorensen Danny S BF9-2, 1 case](https://openairdocs.org/ntsb-findings/02061510/cases.md?model=05622UI), [All aircraft, 551 cases](https://openairdocs.org/ntsb-findings/02061510/cases.md) - [Object/animal/substance: ground vehicle](https://openairdocs.org/ntsb-findings/03022025): Environmental issues › Physical environment · Contributed to outcome; cases with it: [Sorensen Danny S BF9-2, 1 case](https://openairdocs.org/ntsb-findings/03022025/cases.md?model=05622UI), [All aircraft, 132 cases](https://openairdocs.org/ntsb-findings/03022025/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Prior to flight: Aircraft servicing event](https://openairdocs.org/ntsb-events/020); cases with it: [Sorensen Danny S BF9-2, 1 case](https://openairdocs.org/ntsb-events/020/sequence.md?model=05622UI), [All aircraft, 70 cases](https://openairdocs.org/ntsb-events/020/sequence.md) - [Enroute: Fuel exhaustion](https://openairdocs.org/ntsb-events/192) (defining event); cases with it: [Sorensen Danny S BF9-2, 1 case](https://openairdocs.org/ntsb-events/192/sequence.md?model=05622UI), [All aircraft, 804 cases](https://openairdocs.org/ntsb-events/192/sequence.md) - [Landing: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341); cases with it: [Sorensen Danny S BF9-2, 1 case](https://openairdocs.org/ntsb-events/341/sequence.md?model=05622UI), [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: [Sorensen Danny S BF9-2, 1 case](https://openairdocs.org/ntsb-events/440/sequence.md?model=05622UI), [All aircraft, 3,365 cases](https://openairdocs.org/ntsb-events/440/sequence.md) - [Landing: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [Sorensen Danny S BF9-2, 1 case](https://openairdocs.org/ntsb-events/470/sequence.md?model=05622UI), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md) - [Landing: Nose over/nose down](https://openairdocs.org/ntsb-events/096); cases with it: [Sorensen Danny S BF9-2, 1 case](https://openairdocs.org/ntsb-events/096/sequence.md?model=05622UI), [All aircraft, 2,287 cases](https://openairdocs.org/ntsb-events/096/sequence.md) ## Analysis The pilot of the biplane reported that he believed he had departed with 38 gallons of fuel in the main fuel tank and 17 gallons in the auxiliary fuel tank. En route, the auxiliary fuel tank ran dry, so he switched to the main fuel tank, which he believed had 35 gallons of fuel remaining. The pilot reported that, while descending to the destination airport, the engine experienced a loss of power. He added that he believed the throttle linkage had broken and that the carburetor was at idle. During the forced landing, he aligned the airplane with a highway and observed four semi-tractor trailers but thought they were ahead of his flightpath. The biplane struck one of the semi-tractor trailers, violently turned right, and then came to rest inverted on the right side of the highway. The biplane sustained substantial damage to the left wings. Postaccident examination revealed that the main fuel tank was empty, and the throttle linkage was intact. The pilot reported that his typical fueling process is to fuel the main fuel tank before fueling the auxiliary fuel tank. He added that he reviewed fuel receipts and found that, before the accident flight, he fueled the auxiliary fuel tank first and, while following his routine, believed that the main fuel tank had already been fueled. This resulted in a departure with 10 gallons of fuel less than planned. The pilot reported that there were no preaccident mechanical failures or malfunctions with the biplane that would have precluded normal operation. ## Factual narrative The pilot of the biplane reported that he believed he had departed with 38 gallons of fuel in the main fuel tank and 17 gallons in the auxiliary fuel tank. En route, the auxiliary fuel tank ran dry, so he switched to the main fuel tank, which he believed had a remaining 35 gallons of fuel. The pilot reported that, while descending to the destination airport, the engine experienced a loss of power. He added that he believed the throttle linkage had broken and the carburetor was at idle. During the forced landing, he aligned the airplane with a highway and observed four semi-tractor trailers, but thought they were ahead of his flight path. The airplane struck one of the semi-tractor trailers, violently turned to the right, and came to rest inverted on the right side of the highway. The airplane sustained substantial damage to the left wings. Postaccident examination revealed that the main fuel tank was empty, and the throttle linkage was intact. The pilot reported that his habitual fueling process is to fuel the main fuel tank before fueling the auxiliary fuel tank. He added that he reviewed fuel receipts and discovered that, before the accident flight, he fueled the auxiliary fuel tank first and, while following his routine, believed that the main fuel tank had already been fueled. This resulted in a departure with 10 gallons of fuel less than planned. The pilot reported that there were no preaccident mechanical failures or malfunctions with the biplane that would have precluded normal operation. ## Aircraft - Registration: [N81973](https://openairdocs.org/aircraft/N81973), registered now, S/N 24601-001, built 2008 (OpenAirDocs) - Reported make and model: SORENSEN DANNY S BF9 2 (NO SERIES) - Registry model: [Sorensen Danny S BF9-2](https://openairdocs.org/model/sorensen-danny-s-bf9-2) (registry code 05622UI) (OpenAirDocs) - Registry engine: [Vedeneyev M14P](https://openairdocs.org/engine/vedeneyev-m14p) (registry code 63601, reciprocating) (OpenAirDocs) - Category: Airplane, amateur-built - Serial number: 24601-001 - Year built: 2008 - Airframe hours: 309.8 - Engines: Vendenyev M-14P 360 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Airworthiness certificate: Special, Experimental (Special) - Last inspection: Condition, March 23, 2018 - Departed: LMO, LONGMONT, CO - Destination: EVW, EVANSTON, WY - Equipment: Handheld GPS ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 68; injuries: none; commercial; airplane ratings: single-engine land; medical: class 2, without waivers/limitations; last flight review October 5, 2016; seat: rear; flight hours: 2,016 total, 310 in this make and model, 1,980 as pilot in command, 33 in the last 90 days, 12 in the last 30 days, 7 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 220° at 19 knots, gusting 25 - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 72 °F, dew point 28 °F - Altimeter: 29.82 inHg - Observed at: KEVW, 2 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 20180531006429A](https://openairdocs.org/incident/20180531006429A), May 31, 2018: Sorensen Danny S BF9-2, Evanston, WY, Substantial damage. On 5/31/2018 at 1700 MST, aircraft N81973 had descended onto I-80 heading westbound just east of Evanston, WY. The aircraft struck the sleeper cab of a moving… ## Docket (2 files) The files NTSB released with the investigation on September 10, 2018, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=97419. 5.2 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 4.3 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40466437&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Master.PDF - Accident Photo (item 2, .PDF, 1 photo, 935 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40466438&FileExtension=.PDF&FileName=Accident%20Photo-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.