Bellanca 17-30A N93577

Summary

On 18 May 2011 at about 17:15 local time, a Bellanca 17-30A registered N93577, operated by Mickey Gilmer, was involved in an accident near Rock Springs, Wyoming, United States. 2 people were on board and 2 died. The aircraft was substantially damaged. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

18 May 2011 at 17:15

Classification

Accident

Location

Rock Springs, Wyoming, United States

Coordinates

42.1736, -108.7906

Aircraft

Bellanca 17-30A

Registration

N93577

Category

Airplane

Engines

1

Operator

Mickey Gilmer

Operating rule

Part 91: General Aviation

Purpose of flight

Personal

Phase of flight

Not recorded

Route

Pinedale → Fort Collins

Aircraft damage

Substantial

Weather

IMC

Light

Day

NTSB number

WPR11FA228

2 people died.

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.

Quoted verbatim from the NTSB record. This site does not paraphrase or interpret it.

Read the full 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.

Quoted verbatim from the NTSB record.