Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP)
Aircraft Equipment Problem Critical; Deviation - Speed All Types
Flight Crew Returned To Departure Airport; General Maintenance Action
Aircraft; Environment - Non Weather Related
The aircraft had been sitting for a great length of time so it was decided the aircraft should be test flown prior to its first revenue flight. During the initial checks; the radar system failed the test cycles; so the discrepancy was noted in the logbook and maintenance was performed (approximately one hour). All other checks were satisfactory. Taxi normal. Initial takeoff normal 80-kt call normal. At approximately 110 kts I noticed my airspeed indication had blanked. Taxi was indicated in the window. I glanced to the right the FO (First Officer) indications appeared to be normal. We were rapidly approaching V1/Vr 135 kts so I elected to continue. V1/Vr was called and I rotated at a normal rate after the nose wheel left the ground my airspeed tape reappeared; however; the indication was approximately 90-100 kts with visual stall indications. No shaker. Positive rate was called and the gear was raised. At about 100 feet. I transferred control to the pilot monitoring. I had IAS comparator in the PFD and multiple levels one and two alerts. SEL Manual Feel Sel Fadec ALTN (3). A combination of those alerts drives the user to 'Refer to Emergency Non-Alert procedure- AIRSPEED UNRELIABLE.' I called to the pilot in the OBS seat to get the QRH out. I was also handling multiple radio calls. Notified ATC that we had issues with airspeed indications and erratic altimetry issues and to keep us within 20 NM of ZZZ and that we would be returning to ZZZ. The FCP was blanking on numerous occasions we were cleared to 10;000 ft however the altitude window would blank on occasion. Between 6;000-7;000 feet we were trying to ascertain what readouts were accurate as the right-side airspeed was giving erroneous indications altitude readouts seemed erroneous as well. Captain side was reading 90 kts FO side 270 knots standby 230 kts. I asked for a ground speed readout from ATC 380 kts was the response. Then as we leveled at 10;000 feet my airspeed and altitude indications returned to normal as did the FOs. We returned to ZZZ with no other issues. Blocking in Maintenance noted two ADC failures generated by the CFDS below 300 feet.
MD11 Captain reported that at approximately 110 knots a loss occurred of both ADC computer/inputs below 300 feet.