Cessna 310I accident near Salt Lake City, Utah, August 24, 2017
On August 24, 2017 at about 8:00 pm local time, a 1964 Cessna 310I, registered N8170M, was substantially damaged in an accident during initial climb near Salt Lake City, Utah (South Valley Rgnl airport). It was an aerial observation flight under general aviation rules (Part 91). 1 person had minor injuries. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
A loss of engine power for reasons that could not be determined based on the available information.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- August 24, 2017 · about 8:00 pm local time
- Place
- Salt Lake City, Utah · South Valley Rgnl · map
- Type
- Accident
- Injuries
- 1 person had minor injuries.
- Weather
- visual conditions (good weather)
- Aircraft
- Cessna 310I I, built 1964 · all 310Is on the register
- Registration
- N8170M · no longer on the register · serial 310I0170
- Damage
- Substantial damage
- Flight
- Aerial observation flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
The pilot reported that, during engine start and run up, the left engine shut down twice when the throttle was reduced to idle, and during the engine run-up magneto checks, the engines ran rough with greater than normal losses in rpm. The pilot advanced the throttles and leaned the mixtures to both engines to “clear” what he thought was “carbon buildup on the sparkplugs” and the engines subsequently ran smoothly at idle. The pilot departed, and during the initial climb, noticed that the airplane did not accelerate as normal. The pilot reduced the angle of attack to aid in acceleration and noticed that both engines indicated fluctuations in power, fuel flow, and rpm. He confirmed that the propeller and throttle levers were full forward, and he placed the auxiliary fuel pump to “high.” The airplane continued to decelerate and began to yaw to the left. The pilot banked right and feathered the left propeller, but the airplane continued to descend, and the pilot reduced the mixture controls to idle-cutoff. The airplane impacted two power poles and the ground before skidding to a stop adjacent to a building. A postaccident fire ensued. Examination of the engines revealed dark and sooty deposits on the sparkplug electrodes, consistent with a rich fuel/air mixture ratio. Additionally, the left engine tachometer generator cannon plug was separated and undamaged. It is possible that this plug disconnected during the takeoff and would have resulted in a tachometer indication of a loss of left engine power. It is likely that the left engine fuel flow was not properly adjusted by maintenance personnel when the engine was installed earlier the month of the accident, which created an overly rich fuel-air mixture and resulted in the repeated loss of left engine power during ground operations; however, the reason for the loss of power during the takeoff and the airplane's inability to gain altitude/airspeed during the initial climb could not be determined based on the available information.
The complete narrative as the NTSB published it. The NTSB's docket holds the report as a PDF and any photographs, statements and other documents from the investigation.
The factual record from the NTSB's investigation tables, in plain English
What happened, in order
- Loss of engine power (partial) during initial climb
- Loss of engine power (total) during initial climb defining event
- Loss of engine power (partial) during emergency descent
The NTSB's findings
- Aircraft › Aircraft power plant › Power plant › (general) › Unknown/Not determined
- Not determined › Not determined › (general) › (general) › Unknown/Not determined
Pilot
- Certificate: airline transport pilot, commercial pilot
- Ratings: multi-engine land; multi-engine sea; single-engine sea; instrument: airplane
- Flight time: 2,073 hours in all; 1,080 in this make and model; 94 in the last 90 days; 12 in the last 30 days; 1,523 as pilot in command; 0 on instruments
- Last flight review: August 15, 2016
- Medical certificate: Class 1 (without waivers/limitations)
- Seat: left
- Injury: minor injuries
The aircraft
- Airframe total time: 4,802 hours
- Last inspection: annual inspection, August 9, 2017; 16 hours since
- Maximum gross weight: 5,099 lb
- Seats: 2
- Landing gear: retractable
- Engine 1: Cont Motor I0-470-U SERI (piston); 1,704 hours total
- Engine 3: Cont Motor I0-470-U SERI (piston); 1,704 hours total
- Fire on the ground
The flight
- Departed from: U42 Salt Lake City UT at 8:15 pm
- Destination: U42 Salt Lake City UT
- Flight plan: none
- Runway 16, 5,860 ft by 100 ft
Weather at the time
- Light: daylight
- Wind: from 340° at 11 knots
- Visibility: 10 statute miles
- Sky: a few clouds at 9,500 ft
- Temperature: 90°F (32°C), dew point 45°F (7°C)
- Altimeter: 30.01 inHg
- Observation at 7:54 pm from KSLC, 11 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 1 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
18 documents, released by the NTSB on March 11, 2021. View them here, or download them; the NTSB redacts some personal details before release, and this site shows the NTSB's own titles rather than its file names.
The same docket at the NTSB · documents without a copy here are fetched from the NTSB when you open them.
Everything on this page comes from the NTSB's public records. The narrative, probable cause and findings are the NTSB's own words; the coded tables behind the report are written out in plain English, with pilots' ages, home towns and medical details left out. The documents and photographs are the NTSB's docket, shown as the NTSB released them. This site's own text never names anyone involved. A preliminary report can change; the final report usually follows one to two years later, and the page is refreshed when it does.