- Date
- May 31, 2018, 17:45 local (23:45 UTC)
- Place
- Evanston, WY
- Injuries
- 1 uninjured
- Damage
- Substantial damage
- Phase of flight
- Enroute
- Aircraft
- N81973Sorensen Danny S BF9 2
- Defining event
- Enroute: Fuel exhaustion
- Weather
- Visual (VMC) · Day
- Status
- Completed · report November 5, 2018
- Report
- Approved by Office Director
- NTSB office
- General Aviation Accidents
- Parties
- FAA
- FAA report
- 20180531006429A
- Case key
- 97419
From the NTSB’s public API. By law, NTSB reports can’t be used as evidence in lawsuits over the accident.
On this page
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 · 4
NTSB’s coded findings. Those marked are part of the probable cause; the rest are factors or other findings. Under each, the cases with the same finding.
Sequence of events
The events NTSB coded, in order, by phase of flight. The defining event is the one that best describes the accident. Under each, the cases with the same event anywhere in their sequence.
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
- Reported as
- Sorensen Danny S BF9 2 (NO SERIES)
- Category
- Airplane, amateur-built
- Serial number
- 24601-001
- Built
- 2008
- Airframe hours
- 309.8
- Engine
- 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
Matched to the registry by N-number and the event date; the registry’s history has gaps, so older matches can be wrong. Compare the reported make and model.
Flight crew
As NTSB recorded them. NTSB leaves out names.
- Role
- Pilot
- Age
- 68
- Injuries
- None
- Certificate
- 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
Docket · 2
The files NTSB released with the investigation on September 10, 2018, on NTSB’s docket system: statements, records, photos and specialists’ reports. 5.2 MB in all.
FAA reports on this event · 1
The FAA’s own accident and incident reports, matched to the aircraft by N-number and date.