Narrative:

During taxi to runway 1R; I noticed tat and sat temperatures were at -01 celsius. This differed from ATC ATIS of +9 celsius. I have found these sensors to be quite reliable and felt further investigation warranted. Notified maintenance and was unable to ascertain why temperatures were different. No ECAM or sd information was showing any faults. Went back to gate; and found air data computer #2 was faulted or failed. No aircraft warning occurred or showed a failure of air data computer #2. When first officer on 3 selector showed appropriate temperatures; captain on 3 and normal showed erroneous value. When adr def and selected off; first officer on 3 ok; but captain on 3 and normal showed amber xx's. I write this to alert the airbus department that an adr failure of some sort occurred but we received no warning or alert. Temperatures; etc; were all green and only my notice of different value of temperature indicated any problem. They switched aircraft on us at the last minute. Callback conversation with reporter revealed the following information: the reporter stated the report was written up mainly to alert airbus that a fault existed and there was no warning. These temperatures were all in the green and did not read the same as the first officer's; which were reading normal. The error was +9 degrees celsius.

Related reports:

Google
 

Original NASA ASRS Text

Title: AN A320 FLT CREW HAD AN AIR DATA COMPUTER FAILURE WITHOUT ANY FAULT INDICATIONS DISPLAYED. DISCOVERED ON TAXI OUT WHEN PIC NOTICED A PLUS 9 DEGS C DIFFERENCE BETWEEN THE CURRENT ATIS TEMPERATURE AND THE OAT DISPLAYED BY THE ACFT.

Narrative: DURING TAXI TO RWY 1R; I NOTICED TAT AND SAT TEMPERATURES WERE AT -01 CELSIUS. THIS DIFFERED FROM ATC ATIS OF +9 CELSIUS. I HAVE FOUND THESE SENSORS TO BE QUITE RELIABLE AND FELT FURTHER INVESTIGATION WARRANTED. NOTIFIED MAINT AND WAS UNABLE TO ASCERTAIN WHY TEMPS WERE DIFFERENT. NO ECAM OR SD INFO WAS SHOWING ANY FAULTS. WENT BACK TO GATE; AND FOUND AIR DATA COMPUTER #2 WAS FAULTED OR FAILED. NO ACFT WARNING OCCURRED OR SHOWED A FAILURE OF AIR DATA COMPUTER #2. WHEN FO ON 3 SELECTOR SHOWED APPROPRIATE TEMPS; CAPT ON 3 AND NORMAL SHOWED ERRONEOUS VALUE. WHEN ADR DEF AND SELECTED OFF; FO ON 3 OK; BUT CAPT ON 3 AND NORMAL SHOWED AMBER XX'S. I WRITE THIS TO ALERT THE AIRBUS DEPT THAT AN ADR FAILURE OF SOME SORT OCCURRED BUT WE RECEIVED NO WARNING OR ALERT. TEMPS; ETC; WERE ALL GREEN AND ONLY MY NOTICE OF DIFFERENT VALUE OF TEMPERATURE INDICATED ANY PROB. THEY SWITCHED ACFT ON US AT THE LAST MINUTE. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED THE RPT WAS WRITTEN UP MAINLY TO ALERT AIRBUS THAT A FAULT EXISTED AND THERE WAS NO WARNING. THESE TEMPS WERE ALL IN THE GREEN AND DID NOT READ THE SAME AS THE FO'S; WHICH WERE READING NORMAL. THE ERROR WAS +9 DEGREES CELSIUS.

Data retrieved from NASA's ASRS site as of January 2009 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.