Pilot Debrief

BELLANCA 17-30A near Rock Springs, WY — 2011-05-18

Final reportWPR11FA228
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Date
2011-05-18
Location
Rock Springs, WY, USA
Aircraft
BELLANCA 17-30A
Registration
N93577
Category
Airplane
Highest injury
Fatal
Fatalities
2
Phase of flight
Climb

Probable cause

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.

NTSB narrative

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.

Analysis

Primary failure mode
VFR into IMC
First missed decision gate
Pilot should have canceled the flight due to adverse weather conditions.

NTSB coding

Evidence available

  • ADS-B / radar
  • Photos
  • 27 docket documents
View NTSB final reportView NTSB docket

Docket documents27

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