Piper commanche commercial pilot overshoots his altitude in short descent while on autoplt.

Attributes
ACN	509070
Time
Date	200104
Day	Mon
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : zzz.airport
State Reference	US
Altitude	msl bound lower : 8400 msl bound upper : 9100
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Operator	general aviation : personal
Make Model Name	PA-30 Twin Comanche
Flight Plan	IFR
Person 1
Affiliation	other
Function	flight crew : single pilot
Qualification	pilot : commercial pilot : multi engine pilot : instrument
Experience	flight time last 90 days : 25 flight time total : 700 flight time type : 200
ASRS Report	509070
Events
Anomaly	altitude deviation : excursion from assigned altitude altitude deviation : overshoot non adherence : clearance
Resolutory Action	controller : issued advisory flight crew : became reoriented flight crew : returned to assigned altitude
Supplementary
Problem Areas	Flight Crew Human Performance
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

Flying from low to high pressure area. Reset altimeter with new controller -- resulted in 100 ft high. Disconnected autoplt and set shallow descent rate to return to assigned altitude of 9000 ft. Became distraction with navigation duties and did not catch continued descent until center called out deviation at 8400 ft (600 ft low). Prevent recurrence by more frequent scan, including autoplt settings.

Original NASA ASRS Text

Title: PIPER COMMANCHE COMMERCIAL PLT OVERSHOOTS HIS ALT IN SHORT DSCNT WHILE ON AUTOPLT.

Narrative: FLYING FROM LOW TO HIGH PRESSURE AREA. RESET ALTIMETER WITH NEW CTLR -- RESULTED IN 100 FT HIGH. DISCONNECTED AUTOPLT AND SET SHALLOW DSCNT RATE TO RETURN TO ASSIGNED ALT OF 9000 FT. BECAME DISTR WITH NAV DUTIES AND DID NOT CATCH CONTINUED DSCNT UNTIL CTR CALLED OUT DEV AT 8400 FT (600 FT LOW). PREVENT RECURRENCE BY MORE FREQUENT SCAN, INCLUDING AUTOPLT SETTINGS.

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.