Casualties unknown

2007-02-17: Cessna 340A (N111SC) — Council Bluffs, IA

Council Bluffs, IA, US

On February 17, 2007, a Cessna 340A (registration N111SC) was involved in an aviation accident near Council Bluffs, IA. Investigators recorded the probable cause as: The pilot's continued flight into adverse weather, and his failure to maintain altitude during the instrument approach. Contributing factors were the presence of severe icing, moderate turbulence, and low-level wind shear. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.

Sourcesthe U.S. National Transportation Safety Board (NTSB) historical archivePrimary reportUpdated 1781061362Data APIEditorial standards
Aircraft registered N111SC
Aircraft registered N111SC. Photo: Mark Harkin / CC BY 2.0, via Wikimedia Commons

During a VOR instrument approach, the airplane descended below the minimum descent altitude, reaching 1,400 feet, while encountering severe icing and potential wind shear.

Flight Sequence

The accident occurred while the flight was conducting a VHF Omni Range (VOR) instrument approach to the destination airport. Radar track data show the airplane passed the VOR at an altitude of 2,800 feet. After passing the VOR, the airplane turned right and became established on an approximate magnetic course of 017 degrees. The published final approach course for the procedure was 341 degrees. Subsequently, the airplane entered a left turn, followed immediately by a right turn, until the final radar data point.

Altitude Profile

Altitude returns indicate the pilot initiated a descent from 2,800 feet upon passing the VOR. The airplane descended through 2,000 feet during the initial right turn and reached a minimum altitude of 1,400 feet. The altitude associated with the final radar data point was 1,600 feet. The initial impact point was located about 0.18 nautical miles from the final radar data point, at an approximate elevation of 1,235 feet. The minimum descent altitude (MDA) for the approach procedure was 1,720 feet, indicating the airplane descended below the MDA.

Weather Conditions

Review of weather data indicated the potential for moderate turbulence and low-level wind shear in the vicinity of the accident site. Additionally, icing potential data suggested that the pilot likely encountered severe icing conditions during descent and approach. The pilot had obtained a preflight weather briefing, during which the briefer advised of current Airman's Meteorological Information (AIRMET) advisories for moderate icing and moderate turbulence along the route of flight. The briefer also provided several pilot reports for icing and turbulence.

Postaccident Inspection

A postaccident inspection of the airframe and engines did not reveal any anomalies associated with a preimpact failure or malfunction.

Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20070222X00212. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.