PC-12
Confusion; Human-Machine Interface; Situational Awareness
Aircraft Equipment Problem Critical; Flight Deck / Cabin / Aircraft Event Other / Unknown; Inflight Event / Encounter Weather / Turbulence
Flight Crew Returned To Departure Airport; General Maintenance Action
Aircraft; Human Factors
After deferring an AHRS B failure; the aircraft was scheduled to return to base to undergo maintenance. Prior to taxi out; the airplane was configured to have the co-pilot's side PFD utilize the pilot's side ADAHRS computer. Upon takeoff and just prior to passing through 1;000 AGL; both pilot and co-pilot PFDs failed; displaying ATT FAIL; HDG FAIL and various red Xs on altitude and airspeed indications. There were; however; no abnormalities on the systems MFD or the situational awareness MFD. We decided to return to our departure airport. We advised Tower that we required a precautionary landing due to an avionics issue and would need to keep the airport in sight. On entering left downwind; both PFDs returned to normal. Turning base; both PFDs reverted to failure status. Tower then issued a landing clearance and the before landing checklist was then completed. After turning onto final for Runway 4L; both PFDs returned to normal. A normal landing was made and the aircraft returned to the ramp uneventfully.I recommend the aircraft not be flown in IMC whenever an ADAHRS computer is inoperative.
A PC-12 flight crew departing on a maintenance ferry in marginal weather returned to their departure airport when the one operative ADAHRS failed intermittently shortly after takeoff.