Pilot of small aircraft on IFR flight plan is cleared to descend to 4000 ft. He descends to 3500 ft.

Attributes
ACN	405770
Time
Date	199805
Day	Tue
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : 02a
State Reference	AL
Altitude	msl bound lower : 3500 msl bound upper : 4000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : mgm
Operator	general aviation : personal
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Operating Under FAR Part	Part 91
Flight Phase	descent other
Flight Plan	IFR
Person 1
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : cfi pilot : instrument pilot : commercial
ASRS Report	405770
Person 2
Affiliation	government : faa
Function	controller : approach
Qualification	controller : radar
Events
Anomaly	altitude deviation : overshoot non adherence : clearance
Independent Detector	other controllera
Resolutory Action	other
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

Was told to descend to 4000 ft. Was slow descent, during time conversation with passenger. Unknowingly descended to 3500 ft.

Original NASA ASRS Text

Title: PLT OF SMA ON IFR FLT PLAN IS CLRED TO DSND TO 4000 FT. HE DSNDS TO 3500 FT.

Narrative: WAS TOLD TO DSND TO 4000 FT. WAS SLOW DSCNT, DURING TIME CONVERSATION WITH PAX. UNKNOWINGLY DSNDED TO 3500 FT.

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.