C525 has altitude excursion during vectors around WX on initial approach to bhm.

Attributes
ACN	514420
Time
Date	200106
Day	Thu
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : bhm.airport
State Reference	AL
Altitude	msl single value : 6000
Environment
Flight Conditions	IMC
Light	Daylight
Aircraft 1
Operator	general aviation : personal
Make Model Name	Citationjet, C525/C526
Flight Phase	descent : approach
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : multi engine pilot : atp
Experience	flight time last 90 days : 36 flight time total : 6711 flight time type : 74
ASRS Report	514420
Events
Anomaly	altitude deviation : excursion from assigned altitude inflight encounter : turbulence inflight encounter : weather non adherence : clearance
Resolutory Action	flight crew : became reoriented flight crew : returned to assigned altitude
Supplementary
Problem Areas	Weather Flight Crew Human Performance
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

On jun/thu/01 at approximately XA30 hours, 2 qualified pilots, one flying as PIC and the other as sic, were working with the approach controllers at bhm, descending from 11000 ft to an assigned altitude of 6000 ft. Several thunderstorms plus numerous cumulus buildups covered the descent area. The cumulus buildups were close together and near a thunderstorm being circumnaved. In an effort to avoid turbulent air and maintain passenger comfort, the autoplt was disconnected and the aircraft was hand flown to increase maneuverability. During a series of rapid turns, the aircraft was allowed to descend below the assigned altitude of 6000 ft as we dodged buildups. When this was recognized, immediate correction was made and the flight continued without further incident. The problem was caused by the pilot's intense concentration on avoiding very turbulent air and failing to maintain the proper altitude. It could have been prevented by flying a more circuitous, though longer, route around the area of storms and buildups. The pilot should have concentrated on altitude as well as direction.

Original NASA ASRS Text

Title: C525 HAS ALT EXCURSION DURING VECTORS AROUND WX ON INITIAL APCH TO BHM.

Narrative: ON JUN/THU/01 AT APPROX XA30 HRS, 2 QUALIFIED PLTS, ONE FLYING AS PIC AND THE OTHER AS SIC, WERE WORKING WITH THE APCH CTLRS AT BHM, DSNDING FROM 11000 FT TO AN ASSIGNED ALT OF 6000 FT. SEVERAL TSTMS PLUS NUMEROUS CUMULUS BUILDUPS COVERED THE DSCNT AREA. THE CUMULUS BUILDUPS WERE CLOSE TOGETHER AND NEAR A TSTM BEING CIRCUMNAVED. IN AN EFFORT TO AVOID TURBULENT AIR AND MAINTAIN PAX COMFORT, THE AUTOPLT WAS DISCONNECTED AND THE ACFT WAS HAND FLOWN TO INCREASE MANEUVERABILITY. DURING A SERIES OF RAPID TURNS, THE ACFT WAS ALLOWED TO DSND BELOW THE ASSIGNED ALT OF 6000 FT AS WE DODGED BUILDUPS. WHEN THIS WAS RECOGNIZED, IMMEDIATE CORRECTION WAS MADE AND THE FLT CONTINUED WITHOUT FURTHER INCIDENT. THE PROB WAS CAUSED BY THE PLT'S INTENSE CONCENTRATION ON AVOIDING VERY TURBULENT AIR AND FAILING TO MAINTAIN THE PROPER ALT. IT COULD HAVE BEEN PREVENTED BY FLYING A MORE CIRCUITOUS, THOUGH LONGER, RTE AROUND THE AREA OF STORMS AND BUILDUPS. THE PLT SHOULD HAVE CONCENTRATED ON ALT AS WELL AS DIRECTION.

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.