Narrative:

Enroute; I was being vectored around the thunderstorms in the area. Approach was providing information on suitable alternates as the weather was deteriorating. The worst of the weather had passed my destination and I was being vectored south and west of the worst cells. I was at 4;000 ft; assigned a descent to 2;400 ft MSL which I initiated. At approximately 2;900 I began to encounter severe turbulence. I disengaged the autopilot immediately and retarded the throttle to flight idle in an effort to slow the aircraft to a reasonable airspeed to ride out the turbulence. Additionally; I reported to ATC that I was encountering the severe turbulence and was at 2;800 ft. Aircraft bank; pitch and airspeed were each uncontrollable; though often at different times. In other words; for a few seconds I did have control over airspeed using pitch and power; but I did not have control over roll as the aircraft banked hard to the right (initially). After slowing the aircraft to approximately 140 KIAS; I lost control of airspeed and pitch as the aircraft pitched first up then down and the airspeed varied [between] 160 KIAS and 85 KIAS. There was no time in which I did not have control of at least one variable (pitch; bank; speed). As I exited the condition; I noted the power was at approximately 1;500 ft-pounds; flaps were up; pitch was about 5 degrees nose up and the aircraft was descending at approximately 1;500 FPM at 140 KIAS. I corrected by continuing to pitch up; and the vertical speed did decrease slightly. Finally; I was given 'discretion' on heading and altitude (I was in VMC conditions at this time) and was able to exit the condition. The aircraft accelerated and recovered normally and I was able to land without further issue at my destination on a contact approach. The total time for the encounter of the severe turbulence was approximately 30 seconds; though it did seem longer. I contacted operations and maintenance once I was able to inspect the aircraft after parking. I did not see any aircraft damage or damage of any boxes. However; I did note that the aircraft step ladder had come over the aft vertical net and was inside the main cargo compartment. There were no boxes in this compartment as everything had been loaded either in the aft net section or in pods B and C. I queried maintenance to ensure that an inspection was not required and was told that I would be fine unless there was a hard landing. Oddly enough; this was probably one of my 'better' landings; so I was able to continue with my night normally. I informed operations so that a note could be made in case any box contents were damaged. The boxes themselves were still undamaged at this time.

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Original NASA ASRS Text

Title: C208 pilot reports entering severe turbulence at low altitude and losing control during the brief encounter; with large excursions in airspeed; altitude and heading. A normal landing ensues at destination.

Narrative: Enroute; I was being vectored around the thunderstorms in the area. Approach was providing information on suitable alternates as the weather was deteriorating. The worst of the weather had passed my destination and I was being vectored south and west of the worst cells. I was at 4;000 FT; assigned a descent to 2;400 FT MSL which I initiated. At approximately 2;900 I began to encounter severe turbulence. I disengaged the autopilot immediately and retarded the throttle to flight idle in an effort to slow the aircraft to a reasonable airspeed to ride out the turbulence. Additionally; I reported to ATC that I was encountering the severe turbulence and was at 2;800 FT. Aircraft bank; pitch and airspeed were each uncontrollable; though often at different times. In other words; for a few seconds I did have control over airspeed using pitch and power; but I did not have control over roll as the aircraft banked hard to the right (initially). After slowing the aircraft to approximately 140 KIAS; I lost control of airspeed and pitch as the aircraft pitched first up then down and the airspeed varied [between] 160 KIAS and 85 KIAS. There was no time in which I did not have control of at least one variable (pitch; bank; speed). As I exited the condition; I noted the power was at approximately 1;500 FT-LBS; flaps were up; pitch was about 5 degrees nose up and the aircraft was descending at approximately 1;500 FPM at 140 KIAS. I corrected by continuing to pitch up; and the vertical speed did decrease slightly. Finally; I was given 'discretion' on heading and altitude (I was in VMC conditions at this time) and was able to exit the condition. The aircraft accelerated and recovered normally and I was able to land without further issue at my destination on a contact approach. The total time for the encounter of the severe turbulence was approximately 30 seconds; though it did seem longer. I contacted Operations and Maintenance once I was able to inspect the aircraft after parking. I did not see any aircraft damage or damage of any boxes. However; I did note that the aircraft step ladder had come OVER the aft vertical net and was inside the main cargo compartment. There were no boxes in this compartment as everything had been loaded either in the aft net section or in Pods B and C. I queried Maintenance to ensure that an inspection was not required and was told that I would be fine unless there was a hard landing. Oddly enough; this was probably one of my 'better' landings; so I was able to continue with my night normally. I informed Operations so that a note could be made in case any box CONTENTS were damaged. The boxes themselves were still undamaged at this time.

Data retrieved from NASA's ASRS site as of July 2013 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.