Bellanca 17-30A accident near Rock Springs, Wyoming, May 18, 2011
On May 18, 2011 at about 5:15 pm local time, a Bellanca 17-30A, registered N93577, was substantially damaged in an accident during enroute (cruise) near Rock Springs, Wyoming. It was a personal flight under general aviation rules (Part 91). 2 people were killed. The weather was instrument conditions (cloud, fog or low visibility).
The NTSB's probable cause their words, unchanged
The pilot’s decision to continue flight into an area of known adverse weather, which resulted in an accumulation of structural ice that led to a loss of control and in-flight breakup. Also causal was the pilot’s inadequate preflight weather planning.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- May 18, 2011 · about 5:15 pm local time
- Place
- Rock Springs, Wyoming · map
- Type
- Accident
- Injuries
- 2 people were killed.
- Weather
- instrument conditions (cloud, fog or low visibility)
- Aircraft
- Bellanca 17-30A · all 17-30As on the register
- Registration
- N93577 · no longer on the register · serial 73-30591
- Damage
- Substantial damage
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
The pilot’s initial plan was to make the cross-country flight on the day before the flight actually took place. But, since the weather briefing he received forecast clouds, precipitation, and icing conditions along much of the route, the pilot elected not to attempt the flight but instead decided to wait until the next day. Although the weather briefer advised the pilot that the conditions he had described would still be present along the route of flight the next day, including areas of clouds, low ceilings, precipitation, icing conditions, snow, and thunderstorms, the pilot did not call back for an update briefing on the day of the flight, and he did not receive a weather briefing from either of the Direct User Access Terminal Service providers. It is possible that he may have accessed some raw weather data from a National Oceanographic and Atmospheric Administration website before departing for his planned destination. Overlaying the airplane’s radar track on weather radar imagery indicated that, about 30 minutes after departure, the pilot encountered the edge of the forecast weather conditions, entering an area of precipitation where supercooled liquid droplets had been forecast. This most likely resulted in a very rapid accumulation of ice on the airplane’s structure, including its wings and horizontal stabilizer. Soon thereafter, the airplane entered a steep uncontrolled descent, during which the outboard section of the right wing separated as it was stressed beyond the design limitations of the airplane. The airplane continued in a near vertical uncontrolled descent and impacted the terrain with a high amount of energy. Postaccident examination of the airframe, flight controls, and the engine did not find any evidence of a preexisting anomaly.
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
- Structural icing during enroute (cruise) defining event
- Loss of control in flight during maneuvering
- Aircraft structural failure during uncontrolled descent
The NTSB's findings
- factor Personnel issues › Task performance › Planning/preparation › Weather planning › Pilot
- cause Personnel issues › Action/decision › Info processing/decision › Decision making/judgment › Pilot
- Environmental issues › Conditions/weather/phenomena › Temp/humidity/pressure › Conducive to structural icing › Effect on equipment
- Environmental issues › Conditions/weather/phenomena › Ceiling/visibility/precip › Freezing rain/sleet › Effect on equipment
- cause Aircraft › Aircraft oper/perf/capability › Aircraft capability › (general) › Capability exceeded
Pilot
- Certificate: private
- Ratings: single-engine land
- Flight time: 3,080 hours in all; 1,330 in this make and model
- Last flight review: February 23, 2010
- Medical certificate: Class 3 (with waivers/limitations)
- Seat: left
- Injury: fatal
The aircraft
- Airframe total time: 4,632 hours
- Last inspection: annual inspection, May 18, 2010
- Maximum gross weight: 3,325 lb
- Seats: 4
- Landing gear: retractable
- Engine: Cont Motor IO 520 K (piston); 0 hours total
The flight
- Departed from: KPNA Pinedale WY at 4:38 pm
- Destination: KFNL Fort Collins CO
- Flight plan: none
Weather at the time
- Light: daylight
- Wind: from 100° at 15 knots, gusting 22
- Visibility: 10 statute miles
- Sky: broken clouds at 1,900 ft
- Temperature: 43°F (6°C), dew point 36°F (2°C)
- Altimeter: 29.62 inHg
- Observation at 5:54 pm from KRKS, 40 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 1 | |||
| Passengers | 1 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
The docket, the folder of records gathered during an investigation (maintenance records, photographs, witness statements, examinations), has not been read from the NTSB for this case yet; the list appears here once it has. Open the docket at the NTSB.
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.