An md-11 returned to its departure airport following the failure of the captain's CADC.

Narrative:

I was flying the aircraft. At approximately 110 KTS my airspeed and flight director became unreliable. I continued flying the aircraft [but] transferred control to the first officer just after gear retraction as his instruments were normal. [The potential for this] malfunction [had been] briefed as the CADC on the captain's side had just been replaced. Normal checklists were run and we continued to 10;000 MSL. At this point the first officer had control of the radio and I worked the loss of airspeed suspected [checklist] with the relief pilot. After the checklist was complete I sent an ACARS divert message and called flight control. Flight control got hold of maintenance and we all came to the conclusion we should return to our departure airport. Due to our close proximity to the airport (10 miles) and that a divert message was sent and flight control knew of our intentions; an artr was not requested. Approach was notified of our malfunction and we stayed with approach control throughout our coordination with the ground agencies. Landing and block in were uneventful.

Original NASA ASRS Text

Title: An MD-11 returned to its departure airport following the failure of the Captain's CADC.

Narrative: I was flying the aircraft. At approximately 110 KTS my airspeed and Flight Director became unreliable. I continued flying the aircraft [but] transferred control to the First Officer just after gear retraction as his instruments were normal. [The potential for this] malfunction [had been] briefed as the CADC on the Captain's side had just been replaced. Normal checklists were run and we continued to 10;000 MSL. At this point the First Officer had control of the radio and I worked the Loss of Airspeed Suspected [checklist] with the Relief Pilot. After the checklist was complete I sent an ACARS divert message and called Flight Control. Flight Control got hold of Maintenance and we all came to the conclusion we should return to our departure airport. Due to our close proximity to the airport (10 miles) and that a divert message was sent and Flight Control knew of our intentions; an ARTR was not requested. Approach was notified of our malfunction and we stayed with Approach Control throughout our coordination with the ground agencies. Landing and block in were uneventful.

Data retrieved from NASA's ASRS site as of July 2013 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.

Attributes
ACN	1114574
Time
Date	201309
Local Time Of Day	0001-0600
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Make Model Name	MD-11
Operating Under FAR Part	Part 121
Route In Use	Vectors
Flight Plan	IFR
Component
Aircraft Component	Air Data Computer
Person 1
Function	Captain Pilot Flying
Qualification	Flight Crew Air Transport Pilot (ATP)
Person 2
Function	Pilot Not Flying First Officer
Events
Anomaly	Aircraft Equipment Problem Less Severe