A-320 crew had 2 of 3 inertial reference faults just after takeoff. The crew returned to the airport...

Attributes
ACN	603809
Time
Date	200401
Day	Thu
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : jfk.airport
State Reference	NY
Altitude	agl single value : 200
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : n90.tracon tower : grr.tower
Operator	common carrier : air carrier
Make Model Name	A320
Operating Under FAR Part	Part 121
Navigation In Use	other
Flight Phase	climbout : initial climbout : takeoff
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp pilot : flight engineer
Experience	flight time last 90 days : 240 flight time total : 18000 flight time type : 1000
ASRS Report	603809
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Events
Anomaly	aircraft equipment problem : critical
Independent Detector	aircraft equipment other aircraft equipment : irs faulted other flight crewa other flight crewb
Resolutory Action	controller : issued new clearance flight crew : diverted to another airport flight crew : landed as precaution other
Consequence	other
Supplementary
Problem Areas	Aircraft
Primary Problem	Aircraft

Narrative:

After takeoff from runway 31L at jfk, inertial reference #1 and inertial reference #3 faulted (2 of our 3 inertial reference units). Both autoplts and autothrust were inoperative and captain's attitude and navigation display blanked. Inertial reference #2 and first officer's instruments were normal. We leveled at 5000 ft, conferred with maintenance control and attempted troubleshooting without success. We then returned to jfk for an overweight landing on runway 31R. Touchdown was smooth and braking normal. The manufacturer will tell you that the odds of such a dual failure are so low that it cannot happen. I am here to tell you I can happen. After the units were reracked and tested, we departed again and again inertial reference #3 faulted. However, the other 2 were normal and we were able to continue.

Original NASA ASRS Text

Title: A-320 CREW HAD 2 OF 3 INERTIAL REF FAULTS JUST AFTER TKOF. THE CREW RETURNED TO THE ARPT OF DEP.

Narrative: AFTER TKOF FROM RWY 31L AT JFK, INERTIAL REF #1 AND INERTIAL REF #3 FAULTED (2 OF OUR 3 INERTIAL REF UNITS). BOTH AUTOPLTS AND AUTOTHRUST WERE INOP AND CAPT'S ATTITUDE AND NAV DISPLAY BLANKED. INERTIAL REF #2 AND FO'S INSTS WERE NORMAL. WE LEVELED AT 5000 FT, CONFERRED WITH MAINT CTL AND ATTEMPTED TROUBLESHOOTING WITHOUT SUCCESS. WE THEN RETURNED TO JFK FOR AN OVERWT LNDG ON RWY 31R. TOUCHDOWN WAS SMOOTH AND BRAKING NORMAL. THE MANUFACTURER WILL TELL YOU THAT THE ODDS OF SUCH A DUAL FAILURE ARE SO LOW THAT IT CANNOT HAPPEN. I AM HERE TO TELL YOU I CAN HAPPEN. AFTER THE UNITS WERE RERACKED AND TESTED, WE DEPARTED AGAIN AND AGAIN INERTIAL REF #3 FAULTED. HOWEVER, THE OTHER 2 WERE NORMAL AND WE WERE ABLE TO CONTINUE.

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.

A-320 crew had 2 of 3 inertial reference faults just after takeoff. The crew returned to the airport of departure.