BAE146 flight crew encounters moderate to severe turbulence descending into den.

Attributes
ACN	437170
Time
Date	199905
Day	Fri
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : den.airport
State Reference	CO
Altitude	msl bound lower : 12600 msl bound upper : 25000
Environment
Flight Conditions	IMC
Weather Elements	Thunderstorm Turbulence Snow
Light	Daylight
Aircraft 2
Controlling Facilities	artcc : zdv.artcc
Operator	common carrier : air carrier
Make Model Name	BAe 146 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Navigation In Use	other
Flight Phase	cruise : enroute altitude change
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time total : 18000 flight time type : 3000
ASRS Report	437170
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : multi engine pilot : commercial
Events
Anomaly	altitude deviation : overshoot altitude deviation : excursion from assigned altitude inflight encounter : weather inflight encounter : turbulence non adherence : clearance non adherence : far
Independent Detector	other flight crewa other flight crewb
Resolutory Action	flight crew : returned to assigned airspace
Supplementary
Problem Areas	Flight Crew Human Performance Weather
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

Flight boi-den. Cruising FL250, FMS en route to den, turbulence went from light to moderate. Requested and received clearance to descend to FL210. Note: first officer flying and has less than 250 hours in type. At FL210 turbulence continued at moderate and getting stronger. Turbulence kicked off the autoplt and now first officer was hand flying. Flew directly into a snow thunderstorm. WX did not show up on radar. With convective currents, heavy snow and moderate turbulence. Altdevs up to FL216 and down to FL205, several times. I, captain, took control of the aircraft, exited the cell, and leveled the aircraft at FL210 and turned the autoplt back on. Center xferred us to dia approach control. Controller said he was looking for us for last 30 mi. Told him we were just xferred over and that we had our hands full in that cell behind us. Reported moderate turbulence bordering on severe. Controller gave us a descent to 13000 ft and first officer again deviated to about 12600 ft then recovered.

Original NASA ASRS Text

Title: BAE146 FLC ENCOUNTERS MODERATE TO SEVERE TURB DSNDING INTO DEN.

Narrative: FLT BOI-DEN. CRUISING FL250, FMS ENRTE TO DEN, TURB WENT FROM LIGHT TO MODERATE. REQUESTED AND RECEIVED CLRNC TO DSND TO FL210. NOTE: FO FLYING AND HAS LESS THAN 250 HRS IN TYPE. AT FL210 TURB CONTINUED AT MODERATE AND GETTING STRONGER. TURB KICKED OFF THE AUTOPLT AND NOW FO WAS HAND FLYING. FLEW DIRECTLY INTO A SNOW TSTM. WX DID NOT SHOW UP ON RADAR. WITH CONVECTIVE CURRENTS, HVY SNOW AND MODERATE TURB. ALTDEVS UP TO FL216 AND DOWN TO FL205, SEVERAL TIMES. I, CAPT, TOOK CTL OF THE ACFT, EXITED THE CELL, AND LEVELED THE ACFT AT FL210 AND TURNED THE AUTOPLT BACK ON. CTR XFERRED US TO DIA APCH CTL. CTLR SAID HE WAS LOOKING FOR US FOR LAST 30 MI. TOLD HIM WE WERE JUST XFERRED OVER AND THAT WE HAD OUR HANDS FULL IN THAT CELL BEHIND US. RPTED MODERATE TURB BORDERING ON SEVERE. CTLR GAVE US A DSCNT TO 13000 FT AND FO AGAIN DEVIATED TO ABOUT 12600 FT THEN RECOVERED.

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.