B737 Undifferentiated or Other Model
Situational Awareness
Aircraft Equipment Problem Critical
Air Traffic Control Provided Assistance; Aircraft Equipment Problem Dissipated; General Declared Emergency
Aircraft; Human Factors
I was the Pilot Flying. We started initial descent on the RNAV Arrival. Around FL300; the autopilot disconnected with the associated warning and also an altitude warning. I began hand-flying the aircraft. The other problems included failed autothrottles; a frozen MCP with 50;000 feet in the altitude window and heading and airspeed were also frozen on inaccurate values. The Captain was coming back from an interphone call to try to rid the Flight Deck of his dinner tray. At this time; I was still responsible for the radios while he was 'off' and I requested a pilot's discretion descent to 10;000 feet. The Captain was very interested in canceling the altitude warning alert; which seemingly could not be canceled by any means; that we had available to us. The Captain began to troubleshoot. I hand flew the aircraft with no autopilot; autothrottles; flight directors; or advanced navigation. I did have primary flight and engine instruments with correct information. The Captain was under the impression that the FMC's were frozen and the ultimate cause of our problem. I was able to see our original magenta course on my map display and attempted to stay on flight planned course by flying the magenta line referencing the cross track error on Progress Page 2 on the First Officer's CDU. The Captain declared an emergency. ATC provided altitudes and headings for [the airport]. ATC also verified headings; altitudes; and distances with us; and we were able to make confirmations (i.e. they showed us heading 210 and we concurred). At this point; we were below FL240 and ATC was trying to understand the nature of our emergency. We were positioned on an extended left downwind. On the downwind; the aircraft seemingly started to correct itself; including the altitude warning ceasing because the MCP came 'unfrozen.' The flight conditions had been and continued to be day VFR; so we accepted a visual to the runway. I flew a non-coupled (no flight director; autopilot; or autothrottle) visual backed up with a raw data ILS. ATC notified us that the emergency equipment was standing by. I landed the aircraft with no further abnormalities.
B737 crew experienced an MCP failure during initial descent; resulting in loss of autopilot; flight directors; auto thrust; and a frozen MCP. An emergency is declared and vectors provided by ATC to a safe landing.