A320 flight crew reports captain airspeed indicating 40 knots less than first officer airspeed indic...

Attributes
ACN	792263
Time
Date	200806
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : zzz.airport
State Reference	US
Altitude	msl single value : 18000
Environment
Flight Conditions	IMC
Aircraft 1
Controlling Facilities	artcc : zzz.artcc
Operator	common carrier : air carrier
Make Model Name	A320
Operating Under FAR Part	Part 121
Flight Phase	descent : approach
Route In Use	arrival star : n/s
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Experience	flight time last 90 days : 230 flight time total : 15000 flight time type : 5000
ASRS Report	792263
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Events
Anomaly	aircraft equipment problem : critical
Independent Detector	other flight crewa
Resolutory Action	controller : issued new clearance flight crew : overcame equipment problem
Consequence	other
Supplementary
Problem Areas	Aircraft
Primary Problem	Aircraft

Narrative:

On descent; called for flaps 1 degree. First officer queried 'what is your speed?' at this time we realized captain's airspeed indicator read 40 KTS lower than first officer's. Advised ATC we could not accept approach; that we had an airspeed indication issue to work out. ATC issued delay vectors. We called dispatch and maintenance; selected air data to 3 and speeds matched. Checked flight handbook to see additional procedures. Uneventful landing. Advised to have mechanic meet aircraft to explain our indications; and that no ECAM message displayed for the airspeed error.

Original NASA ASRS Text

Title: A320 FLT CREW REPORTS CAPT AIRSPEED INDICATING 40 KNOTS LESS THAN FO AIRSPEED INDICATOR DURING APPROACH.

Narrative: ON DSCNT; CALLED FOR FLAPS 1 DEG. FO QUERIED 'WHAT IS YOUR SPD?' AT THIS TIME WE REALIZED CAPT'S AIRSPD INDICATOR READ 40 KTS LOWER THAN FO'S. ADVISED ATC WE COULD NOT ACCEPT APCH; THAT WE HAD AN AIRSPD INDICATION ISSUE TO WORK OUT. ATC ISSUED DELAY VECTORS. WE CALLED DISPATCH AND MAINT; SELECTED AIR DATA TO 3 AND SPDS MATCHED. CHKED FLT HANDBOOK TO SEE ADDITIONAL PROCS. UNEVENTFUL LNDG. ADVISED TO HAVE MECH MEET ACFT TO EXPLAIN OUR INDICATIONS; AND THAT NO ECAM MESSAGE DISPLAYED FOR THE AIRSPD ERROR.

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

A320 flight crew reports captain airspeed indicating 40 knots less than first officer airspeed indicator during approach.