Medium large transport crew had erroneous mode C readout in sct class east airspace.

Attributes
ACN	477630
Time
Date	200006
Day	Fri
Local Time Of Day	0601 To 1200
Place
Locale Reference	navaid : smo.vor
State Reference	CA
Altitude	msl bound lower : 13000 msl bound upper : 13400
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : sct.tracon tower : mfd.tower
Operator	general aviation : corporate
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Operating Under FAR Part	Part 91
Flight Phase	climbout : intermediate altitude
Flight Plan	IFR
Person 1
Affiliation	company : corporate
Function	flight crew : first officer
Qualification	pilot : atp
Experience	flight time last 90 days : 100 flight time total : 8500 flight time type : 160
ASRS Report	477630
Person 2
Affiliation	company : corporate
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	aircraft equipment problem : less severe other anomaly other
Independent Detector	atc equipment other atc equipment : mode c readout other controllera
Resolutory Action	other
Consequence	other
Supplementary
Problem Areas	Aircraft
Primary Problem	Aircraft

Narrative:

Controller asked us what our altitude was. We showed 13000 ft. She said we were at 13400 ft. We confirmed altimeter setting, and switched mode C to #2.

Original NASA ASRS Text

Title: MLG CREW HAD ERRONEOUS MODE C READOUT IN SCT CLASS E AIRSPACE.

Narrative: CTLR ASKED US WHAT OUR ALT WAS. WE SHOWED 13000 FT. SHE SAID WE WERE AT 13400 FT. WE CONFIRMED ALTIMETER SETTING, AND SWITCHED MODE C TO #2.

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.