Narrative:

During take off; after the 80 KIAS call (at which time I noted both airspeed indicators passing 80 KIAS) just about the time the first officer called V1; I noticed my airspeed indicator was rapidly decreasing. I rotated and glanced down at my instruments and noticed only the ADI appeared normal. I had no airspeed; vertical speed; or increasing altitude indications. I looked over at the first officer's side and all his looked normal; so I transferred control to him. After assuming pilot not flying duties; I had time to see flags through my asi; vsi and altimeter. I selected altn air data computer [alternate air data computer] and got all my instruments back. I continued as pilot not flying. In the climb; EICAS message ATC fail displayed; followed by mach/speed trim and rudder ratio with left air data computer in altn; and the first officer as pilot flying with auto pilot command. These messages cleared as I was getting the QRH out. Looking through the mach airspeed unreliable checklist I saw the note stating the above messages may occur while in altn air data computer. After the messages cleared all appeared normal. We continued to cruise cross checking the altimeters. A little while after being established at cruise (fl 380) the asi command bug began moving beyond the barber pole and the auto throttles moved toward idle. The first officer disconnected the autopilot and the mach/speed trim and rudder ratio messages re-appeared then cleared. I told ATC we were not able rvsm and they cleared us to fl 280. I contacted dispatch to let them know what we were experiencing and to see if maintenance control had any ideas to resolve our problems. Dispatch gave us a fuel burn update for fl 280. We continued to our destination which had VFR weather. I discussed the events with a mechanic post flight.

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Original NASA ASRS Text

Title: A B757-200 Flight Crew suffered numerous system warnings as a result of an Air Data Computer failure; ultimately necessitating a descent below RVSM airspace.

Narrative: During take off; after the 80 KIAS call (at which time I noted both airspeed indicators passing 80 KIAS) just about the time the First Officer called V1; I noticed my airspeed indicator was rapidly decreasing. I rotated and glanced down at my instruments and noticed only the ADI appeared normal. I had no airspeed; vertical speed; or increasing altitude indications. I looked over at the First Officer's side and all his looked normal; so I transferred control to him. After assuming Pilot Not Flying duties; I had time to see flags through my ASI; VSI and Altimeter. I selected ALTN ADC [Alternate Air Data Computer] and got all my instruments back. I continued as Pilot Not Flying. In the climb; EICAS message ATC FAIL displayed; followed by MACH/SPD TRIM and RUDDER RATIO with L ADC in ALTN; and the First Officer as Pilot Flying with auto pilot command. These messages cleared as I was getting the QRH out. Looking through the MACH AIRSPEED UNRELIABLE checklist I saw the note stating the above messages may occur while in ALTN ADC. After the messages cleared all appeared normal. We continued to cruise cross checking the altimeters. A little while after being established at cruise (FL 380) the ASI command bug began moving beyond the barber pole and the auto throttles moved toward idle. The First Officer disconnected the autopilot and the MACH/SPD TRIM and RUDDER RATIO messages re-appeared then cleared. I told ATC we were not able RVSM and they cleared us to FL 280. I contacted Dispatch to let them know what we were experiencing and to see if Maintenance Control had any ideas to resolve our problems. Dispatch gave us a fuel burn update for FL 280. We continued to our destination which had VFR weather. I discussed the events with a Mechanic post flight.

Data retrieved from NASA's ASRS site as of April 2012 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.