Narrative:

I was flying the aircraft on takeoff from at ZZZ. After calling for auto throttles; my focus was outside the aircraft on the roll down the runway. No abnormal call outs were made by any crew member while still on the ground. A normal rotation and turnout to an assigned departure heading of 140 followed. The captain switched to the departure frequency and checked in. As this was happening; I was noticing that I was losing airspeed; but as I was at a reduced thrust takeoff power setting; with two good engines; I knew something was not right with my airspeed indication. At that time; the relief officer (international relief officer) noted that the captain's airspeed and mine were not in agreement and that my altimeter was jumping back and forth. Departure called us and asked us to confirm our altitude. Very quickly we got EICAS messages confirming we had a problem (airspeed disagree; rudder ratio; and aileron lockout). We assessed that the captain's instruments were reliable as they were in agreement with the standby instruments and were consistent with our power and pitch attitude. I recommended that the captain take the controls as his instruments were good. The captain did so and responded to departure what our altitude was. I then took over the radios and at the captain's direction asked to level at 8;000 feet. As the international relief officer was looking in the QRH for the appropriate checklist to run based; the captain and I determined that the right side air data was most likely bad. At the captain's direction I switched my air data selector to 'left' and got his data on my side. With all three pilots in agreement that we now had good airspeed and altitude data showing on my side; the captain gave me the control of the aircraft and the radios.our attention then went to whether or not this issue would prevent us from going on a class ii/ETOPS flight. The captain discussed this with dispatch and then we all determined that a return was the most prudent course of action. At the direction of the captain; I obtained clearance to proceed to an authorized dumping area at 8;000 feet and proceeded there. The international relief officer confirmed that 8;000 feet was an approved altitude for dumping and read the checklist. We dumped all the fuel in the center tank.sometime after the decision was made to return to ZZZ; we also got an antiskid EICAS message. During the dumping process; the captain and international relief officer went through the antiskid checklist and communicated with dispatch and maintenance via ACARS and satcom. There were two options for landing. Land overweight or continue to fly and land within structural landing limits. Since we had the antiskid problem; we decided it would be most prudent to burn off the extra fuel before landing. The captain suggested that we fly at flaps 20; 200 knots with the gear extended. Both first officers concurred so that is how I configured the airplane. We discussed whether or not to declare an emergency and since we had an extended landing distance and did not know what the status of our brakes would be upon landing; we all agreed it would be best to declare an emergency. Since I rarely fly the 767-400 the captain decided he would land the airplane. A request to land on the longest runway available was made; but ATC asked if we would please accept the parallel runway. Since the difference was only about 300 feet we obliged. An uneventful approach and landing was made with no auto brakes and smooth brake application below 80 knots only. We turned off the runway at the end and came to a stop. The fire department chocked the nose wheel and inspected the brakes. Their assessment was that there was no problem with them which concurred with our cockpit indications. An uneventful taxi to the gate took place after that.

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Original NASA ASRS Text

Title: B767-400 flight crew reported the instrument panel failed; as well as receiving an Anti Skid EICAS message leading. The crew to decide to return to their departure airport.

Narrative: I was flying the aircraft on takeoff from at ZZZ. After calling for auto throttles; my focus was outside the aircraft on the roll down the runway. No abnormal call outs were made by any crew member while still on the ground. A normal rotation and turnout to an assigned departure heading of 140 followed. The Captain switched to the departure frequency and checked in. As this was happening; I was noticing that I was losing airspeed; but as I was at a reduced thrust takeoff power setting; with two good engines; I knew something was not right with my airspeed indication. At that time; the Relief Officer (IRO) noted that the Captain's airspeed and mine were not in agreement and that my altimeter was jumping back and forth. Departure called us and asked us to confirm our altitude. Very quickly we got EICAS messages confirming we had a problem (Airspeed Disagree; Rudder Ratio; and Aileron Lockout). We assessed that the captain's instruments were reliable as they were in agreement with the standby instruments and were consistent with our power and pitch attitude. I recommended that the Captain take the controls as his instruments were good. The Captain did so and responded to Departure what our altitude was. I then took over the radios and at the Captain's direction asked to level at 8;000 feet. As the IRO was looking in the QRH for the appropriate checklist to run based; the captain and I determined that the right side air data was most likely bad. At the Captain's direction I switched my air data selector to 'L' and got his data on my side. With all three pilots in agreement that we now had good airspeed and altitude data showing on my side; the Captain gave me the control of the aircraft and the radios.Our attention then went to whether or not this issue would prevent us from going on a Class II/ETOPS flight. The Captain discussed this with Dispatch and then we all determined that a return was the most prudent course of action. At the direction of the Captain; I obtained clearance to proceed to an authorized dumping area at 8;000 feet and proceeded there. The IRO confirmed that 8;000 feet was an approved altitude for dumping and read the checklist. We dumped all the fuel in the center tank.Sometime after the decision was made to return to ZZZ; we also got an Antiskid EICAS message. During the dumping process; the Captain and IRO went through the Antiskid Checklist and communicated with Dispatch and maintenance via ACARS and SATCOM. There were two options for landing. Land overweight or continue to fly and land within structural landing limits. Since we had the antiskid problem; we decided it would be most prudent to burn off the extra fuel before landing. The Captain suggested that we fly at Flaps 20; 200 knots with the gear extended. Both First Officers concurred so that is how I configured the airplane. We discussed whether or not to declare an emergency and since we had an extended landing distance and did not know what the status of our brakes would be upon landing; we all agreed it would be best to declare an emergency. Since I rarely fly the 767-400 the Captain decided he would land the airplane. A request to land on the longest runway available was made; but ATC asked if we would please accept the parallel runway. Since the difference was only about 300 feet we obliged. An uneventful approach and landing was made with no auto brakes and smooth brake application below 80 knots only. We turned off the runway at the end and came to a stop. The fire department chocked the nose wheel and inspected the brakes. Their assessment was that there was no problem with them which concurred with our cockpit indications. An uneventful taxi to the gate took place after that.

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.