The reporter descended 500 ft below his assigned altitude.

Attributes
ACN	335200
Time
Date	199605
Day	Tue
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : geg
State Reference	WA
Altitude	msl bound lower : 8500 msl bound upper : 9000
Environment
Flight Conditions	Mixed
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : geg
Operator	general aviation : personal
Make Model Name	Bonanza 35
Operating Under FAR Part	Part 91
Flight Phase	cruise other descent other
Flight Plan	IFR
Person 1
Affiliation	Other
Function	oversight : pic
Qualification	pilot : cfi pilot : instrument pilot : commercial
Experience	flight time last 90 days : 67 flight time total : 4000 flight time type : 2600
ASRS Report	335200
Person 2
Affiliation	government : faa
Function	controller : approach
Qualification	controller : radar
Events
Anomaly	altitude deviation : excursion from assigned altitude non adherence : clearance
Independent Detector	other controllera
Resolutory Action	controller : issued new clearance other
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

Deviation from assigned altitude of 9000 ft MSL to 8500 ft MSL. Pilot distracted by sudden VFR conditions, try to use VFR chart for orientation, told to expect a visual approach. Flight director should have been in altitude hold, rather than anticipation of further descent. Controller brought to pilot's attention altitude corrected to 9000 ft. Flight proceeded to felts field.

Original NASA ASRS Text

Title: THE RPTR DSNDED 500 FT BELOW HIS ASSIGNED ALT.

Narrative: DEV FROM ASSIGNED ALT OF 9000 FT MSL TO 8500 FT MSL. PLT DISTRACTED BY SUDDEN VFR CONDITIONS, TRY TO USE VFR CHART FOR ORIENTATION, TOLD TO EXPECT A VISUAL APCH. FLT DIRECTOR SHOULD HAVE BEEN IN ALT HOLD, RATHER THAN ANTICIPATION OF FURTHER DSCNT. CTLR BROUGHT TO PLT'S ATTN ALT CORRECTED TO 9000 FT. FLT PROCEEDED TO FELTS FIELD.

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.