MD-82
Flight Crew Air Transport Pilot (ATP)
Flight Crew Total 16000
Human-Machine Interface; Confusion
Aircraft Equipment Problem Critical
Flight Crew Diverted; General Declared Emergency
Aircraft
We declared and emergency and diverted uneventfully to the nearest suitable airport due to unreliable airspeed indications at FL330. Conditions at the time were daylight VFR. The Captain was flying and the First Officer pilot not flying. The first indication of a problem was the auto throttle disconnecting followed by an autopilot disconnect. The mach trim light also annunciated on the overhead panel. There were no other failure indications. We moved the Digital Flight Guidance System (DFGS) switch to the First Officer's side in an attempt to reengage the autothrottle and autopilot but they would not engage. In reviewing the Mach Trim Light abnormal; it became evident that there was a discrepancy between the Captain and First Officer's indicated airspeeds and Mach numbers. The Captain's indicated approximately .75M and 270 KTS and the First Officer's .79M and 280 KTS. While running the Unreliable Airspeed Indication Abnormal Checklist it became evident that neither the Captain's nor the First Officer's airspeed and mach indicators were responding properly to adjustments in power settings. The standby airspeed indicator seemed to be the only reliable indicator. Flying reverted to pitch and power settings from the checklist with a standby airspeed indicator crosscheck.
[No substantive additional information was contained in the secondary narrative.]
An MD-82 flight crew diverted to the nearest suitable airport in response to unreliable airspeed/mach indications on both pilots' flight instruments.