Charter pilot exceeds altitude, starts to correct. Questioned by controller. Turns off mode C.

Attributes
ACN	129886
Time
Date	198911
Day	Tue
Local Time Of Day	1801 To 2400
Place
Locale Reference	atc facility : zzz
State Reference	US
Altitude	msl bound lower : 8000 msl bound upper : 9000
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Controlling Facilities	tracon : zzz
Operator	general aviation : instructional
Make Model Name	Small Transport, Low Wing, 2 Recip Eng
Flight Phase	climbout : intermediate altitude
Flight Plan	IFR
Person 1
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : atp
Experience	flight time last 90 days : 75 flight time total : 9000 flight time type : 1200
ASRS Report	129886
Person 2
Affiliation	government : faa
Function	controller : departure
Qualification	controller : radar
Events
Anomaly	altitude deviation : overshoot non adherence : clearance non adherence : far other anomaly other
Independent Detector	other controllera other flight crewa
Resolutory Action	flight crew : returned to intended course or assigned course other
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

Climbed to 9000' instead of 8000'. I didn't realize I was at the wrong altitude until controller asked my altitude. Just as I was leveling at 9000', I lied and said that I was level at 8000', and immediately dove to 8000' and turned off the encoder and told ATC that I would rest transponder. I was into my twelfth hour of duty and may have been a little fatigued, because I remember thinking 9000' on the climb out and didn't register 8000' until controller asked my altitude. Should have a method of posting/indicating assigned altitude, so this isn't depending on pilot's memory--similar to bug on dg for assigned altitude!

Original NASA ASRS Text

Title: CHARTER PLT EXCEEDS ALT, STARTS TO CORRECT. QUESTIONED BY CTLR. TURNS OFF MODE C.

Narrative: CLBED TO 9000' INSTEAD OF 8000'. I DIDN'T REALIZE I WAS AT THE WRONG ALT UNTIL CTLR ASKED MY ALT. JUST AS I WAS LEVELING AT 9000', I LIED AND SAID THAT I WAS LEVEL AT 8000', AND IMMEDIATELY DOVE TO 8000' AND TURNED OFF THE ENCODER AND TOLD ATC THAT I WOULD REST XPONDER. I WAS INTO MY TWELFTH HR OF DUTY AND MAY HAVE BEEN A LITTLE FATIGUED, BECAUSE I REMEMBER THINKING 9000' ON THE CLBOUT AND DIDN'T REGISTER 8000' UNTIL CTLR ASKED MY ALT. SHOULD HAVE A METHOD OF POSTING/INDICATING ASSIGNED ALT, SO THIS ISN'T DEPENDING ON PLT'S MEMORY--SIMILAR TO BUG ON DG FOR ASSIGNED ALT!

Data retrieved from NASA's ASRS site as of August 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.