BEECH 99 near Rockland, ME — 2016-03-02

Probable cause

The airplane’s encounter with isolated severe turbulence, which resulted in substantial airframe damage.

NTSB narrative

The commercial pilot was conducting a nonscheduled cargo flight. The pilot reported that, as the airplane was descending on an instrument approach, it encountered continuous light-to-moderate turbulence. As the airplane descended through about 2,000 ft mean sea level at an airspeed of 130 knots, it encountered severe turbulence, and the pilot subsequently executed a missed approach and chose to divert to an alternate airport. The airplane continued to encounter light-to-moderate turbulence en route to the alternate airport, and the pilot landed the airplane uneventfully. Postaccident examination of the airplane revealed that the airframe had sustained substantial damage during the flight. Although there were multiple AIRMETs for widespread moderate turbulence and low-level windshear, there were no pilot reports of, nor SIGMETs forecasting, severe turbulence at the time the pilot received her preflight weather briefing.

Analysis

Primary failure mode

Environmental

First missed decision gate

Pilot could have diverted earlier to avoid severe turbulence.

NTSB coding

• Turbulence encounter · Approach-IFR final approach

Evidence available

• Photos
• 4 docket documents

Docket documents4

• Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1form
• Memorandum for Record - Telephone Interview, Pilotinterview
• Meteorology Summaryother
• Investigation Photographs (Courtesy of Wiggins Airways, Inc.)photos

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