Commuter aircraft encounters severe turbulence. Loss of aircraft control, descent toward terrain.

Attributes
ACN	243343
Time
Date	199306
Day	Wed
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : rdg
State Reference	PA
Altitude	msl bound lower : 2200 msl bound upper : 3000
Environment
Flight Conditions	Marginal
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : rdg
Operator	common carrier : air carrier
Make Model Name	Light Transport, High Wing, 2 Turboprop Eng
Flight Phase	cruise other
Route In Use	enroute : on vectors
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : commercial pilot : cfi
Experience	flight time last 90 days : 210 flight time total : 5100 flight time type : 210
ASRS Report	243343
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	altitude deviation : excursion from assigned altitude non adherence : clearance other spatial deviation
Independent Detector	other flight crewa
Resolutory Action	none taken : unable
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

Our flight paralleled a line of thunderstorms for most of our journey from phl to rdg. Rdg cleared us from 4000 ft to 3000 ft. Captain decided to cross through the thunderstorm at its narrowest area. Encountered severe turbulence and loss of altitude control. Aircraft was at 2000 ft at its worse point. Captain's poor judgement and my lack of input caused this incident combined with this flight being the last of a 4 day trip, an 11 hour day, 8.5 of which were spent in the aircraft's seat.

Original NASA ASRS Text

Title: COMMUTER ACFT ENCOUNTERS SEVERE TURB. LOSS OF ACFT CTL, DSCNT TOWARD TERRAIN.

Narrative: OUR FLT PARALLELED A LINE OF TSTMS FOR MOST OF OUR JOURNEY FROM PHL TO RDG. RDG CLRED US FROM 4000 FT TO 3000 FT. CAPT DECIDED TO CROSS THROUGH THE TSTM AT ITS NARROWEST AREA. ENCOUNTERED SEVERE TURB AND LOSS OF ALT CTL. ACFT WAS AT 2000 FT AT ITS WORSE POINT. CAPT'S POOR JUDGEMENT AND MY LACK OF INPUT CAUSED THIS INCIDENT COMBINED WITH THIS FLT BEING THE LAST OF A 4 DAY TRIP, AN 11 HR DAY, 8.5 OF WHICH WERE SPENT IN THE ACFT'S SEAT.

Data retrieved from NASA's ASRS site as of July 2007 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.