B737-800
Flight Crew Air Transport Pilot (ATP)
Aircraft Equipment Problem Critical
General Declared Emergency
Aircraft
On departure; noticed First Officer airspeed indication erratic. Settled down; but was consistently 4-8 KTS lower than Captain. Did IAS Disagree checklist; referred to Airspeed Unreliable checklist. Completed checklist. Captain airspeed good; First Officer airspeed -4 to -8 KTS; standby airspeed -50 KTS. Captain was pilot flying; we determined aircraft safe to continue; but watched all airspeed closely throughout flight. Approximately 45 minutes from landing noticed Elevator Feel Differential light was on; which stayed on until touchdown. On start of descent; when throttles came back got both engine EEC's reversion to Alternate mode. Did EEC Alternate Mode checklist. All engine parameters were normal; continued descent. As aircraft was leveling from 11;000 FT to 10;000 FT; Captain airspeed indication dropped 50+ KTS. Throttles went to max; and nose pitched over. Captain disconnected throttles; we cross checked airspeed indications Captain/First Officer/PFD; and determined that First Officer airspeed was most accurate. Captain transferred control of aircraft to me. Captain declared emergency and asked for airfield equipment. I continued approach and landing with autothrottles and autopilot off using my airspeed; pitch/throttle position; and AOA indications. Captain's airspeed indication came back close to First Officer's indications. Throughout incident standby airspeed was much lower and unusable. Landing uneventful taxied to gate.
B737-800 First Officer reported airspeed; elevator feel differential; and EEC anomalies. First Officer airspeed was deemed most reliable and flight continued to destination after declaring an emergency.