Narrative:

All ground operations were normal. On taxi out the first officer (first officer) did verbalized the ground speed and map were ok. The first indication of a problem was at my (captain) callout of 80 knots. There was already a 5 knot split in the 2 primary airspeed indicators. We continued the takeoff. By rotation; the airspeed difference had grown to 10 knots. The first officer choice to delay the rotation due to the speed difference. On climb out the difference was 15 knots; and we received a rudder ratio and ail lockout EICAS message. Everything was delayed at this point; we delayed selecting v-nav; and also delayed selecting an auto-pilot. The fight director drop off. Flap retraction was also delayed. This is a very complex departure out of [this airport]; and the airport is very noise sensitive; plus the added traffic in the fir. The difference in airspeed indicators may have registered a flap overspeed during flap retraction. (Unknown; if we did or did not?) we also do not know if we set off any noise sensors on climb out? The international relief officer (international relief officer) started with the checklist; which directed us to crosscheck the airspeed with the backup airspeed indicator; which showed my (captains) speed was the correct airspeed. I asked the first officer to select alt. Air data. He had called for auto-pilot on; which was placed on center auto-pilot. I ask him to disconnect; and place back on my left side. Again due to delay in getting auto-pilot on; and delay in selecting v-nav; we do now know if we were outside of the departure path on the SID. After working the problem with the international relief officer; and climbing out; all indications went away; about 13;000 feet. We continued the climb; to get out of a very busy fir. I the captain; call [maintenance]; and adviced them of our problem. Since all indication were normal at this point in time; we continued [flight]; without any further problems.

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Original NASA ASRS Text

Title: The flight crew experienced an airspeed variance during takeoff roll and climbout. They performed checklists which validated the correct airspeed input and continued. However; they expressed concern of a possible flap over speed and a noise abatement deviation.

Narrative: All ground operations were normal. On taxi out the First Officer (FO) did verbalized the ground speed and map were OK. The first indication of a problem was at my (Captain) callout of 80 Knots. There was already a 5 Knot split in the 2 primary airspeed indicators. We continued the takeoff. By rotation; the airspeed difference had grown to 10 Knots. The FO choice to delay the rotation due to the speed difference. On climb out the difference was 15 knots; and we received a Rudder Ratio and Ail Lockout EICAS message. Everything was delayed at this point; we delayed selecting V-Nav; and also delayed selecting an auto-pilot. The fight director drop off. Flap retraction was also delayed. This is a very complex departure out of [this airport]; and the airport is very noise sensitive; plus the added traffic in the FIR. The difference in airspeed indicators may have registered a flap overspeed during flap retraction. (unknown; if we did or did not?) We also do not know if we set off any noise sensors on climb out? The International Relief Officer (IRO) started with the checklist; which directed us to crosscheck the airspeed with the backup airspeed indicator; which showed my (Captains) speed was the correct airspeed. I asked the FO to select Alt. Air Data. he had called for auto-pilot on; which was placed on Center auto-pilot. I ask him to disconnect; and place back on my Left side. Again due to delay in getting auto-pilot on; and delay in selecting V-Nav; we do now know if we were outside of the departure path on the SID. After working the problem with the IRO; and climbing out; all indications went away; about 13;000 feet. We continued the climb; to get out of a very busy FIR. I the Captain; call [Maintenance]; and adviced them of our problem. Since all indication were normal at this point in time; we continued [flight]; without any further problems.

Data retrieved from NASA's ASRS site 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.