Flight Crew Air Transport Pilot (ATP)
Other / Unknown
Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural MEL / CDL; Deviation / Discrepancy - Procedural Published Material / Policy
General None Reported / Taken
MEL; Company Policy; Aircraft
I was first officer on flight. The flight was dispatched from a maintenance base with an inoperative Primary Flight Display Unit (PFDU) on the first officer's side.  I was extremely concerned about the operation of this aircraft with an inoperative PFD. In over 13000 hours of aviation experience I have never been put in the position of being dispatched to fly a revenue; part 121 flight; 'partial panel.'The EFIS displays are comprised of the captain's and co-pilot's Primary Flight Displays and Navigation Displays. The PFDs present the pilots with the basic information required to fly the aircraft; such as aircraft attitude; airspeed; flight envelope data; vertical speed and altitude. The PFD also presents the Flight Mode Annunciator (FMA) and the flight director. The NDs (Navigation Displays) present flight plan information; aircraft position and flight path; navigation features (airfields; navaids; waypoints; etc); weather radar; flight plan vertical and speed constraints; TCAS information; and terrain.Prior to departure I discussed this MEL with the captain and a check airman. I expressed my concern about operating without a PFD. Everyone was in agreement that this MEL caused the airplane to be operated with a reduced margin of safety. There were no notes or operational procedures in the MEL providing guidance on how the pilots should deal with the loss of this display.  It is not possible to view attitude and airspeed simultaneously with navigation data. I had to choose one or the other. The pilot must press the PFD/ND XFR switch frequently. It is not possible to view terrain and attitude information simultaneously. It is not possible to view TCAS and attitude information simultaneously. Situational awareness is diminished.FMA changes that are required callouts are often out of view. Altitude displays that are required for callouts are often out of view. The AOM (Aircraft Operations Manual) calls for the pilot to view terrain information on the ND in the terminal area in the approach and departure phase of flight. In order to comply with that procedure the pilot must select ND. When ND is selected the FMA is not in view and neither is altitude information. This denies the pilot of displays that are required for altitude callouts and FMA annunciations.  It is also necessary to press the TERR button when radar data is needed. The workload of the first officer increases dramatically with this deferral and his attention becomes entirely 'heads down.' The TCAS information that is normally available is hidden.  RNAV arrivals and departures would be extremely difficult; particularly in convective weather. The pilot would have to switch between ND and PFD; TERR on then off; while trying to comply with multiple speed and altitude restrictions. It is also impossible to see the 'brick' or 'blue stick' on the PFD when the ND is displayed.  AOM advises pilots to set up ND to provide raw data. The pilot is deprived of attitude and airspeed information while viewing this data.  This MEL should only be used to return an aircraft to a maintenance station for repairs. The first officer is deprived of basic safety information and instruments. This reduces situational awareness; makes it easy to miss required callouts; and erodes general flight safety.
Aircraft was dispatched at night with First Officer's display inoperative per MEL.