AN EMB135 DECLARES AN EMER FOLLOWING ERRONEOUS AIRSPDS; UNCOMMANDED AUTOPLT DISCONNECT; AND FINALLY INST PANEL SMOKE.

Narrative

AT FL310 WE STARTED A DSCNT TO FL260. AT A DSCNT RATE OF 2000-3000 FPM; AND INITIAL PWR SETTING OF APPROX 50%; BOTH AIRSPD INDICATORS READ THE SAME AND SHOWED AN ABNORMAL DECREASE THAT DID NOT CORRELATE WITH THE CURRENT ACFT CONFIGN. AT THIS POINT; WIND NOISE IN THE COCKPIT HAD RISEN AND HELPED CONFIRM THAT BOTH AIRSPD INDICATIONS WERE ERRONEOUS. PWR WAS REDUCED TO IDLE AND THE ACFT WAS LEVELED OFF. SHORTLY THEREAFTER; THE SPD TAPE ON THE CAPT'S SIDE JUMPED SUDDENLY AND HAD A SIGNIFICANTLY HIGHER VALUE THAN THE FO'S. AT THAT TIME THE HIGH SPD ALERT SOUNDED. AS WE BEGAN A DSCNT TO 13000 FT; THE AUTOPLT DISCONNECTED AND WE RECEIVED AN ASSOCIATED AUTOPLT FAILURE MESSAGE ON THE EICAS. THE MESSAGE QUICKLY DISAPPEARED; HOWEVER. IT WAS SHORTLY AFTER THIS TIME THAT THE COCKPIT STARTED TO FILL WITH SMOKE; ORIGINATING FROM UNDERNEATH THE INST PANEL. MEMORY ITEMS AND APPROPRIATE CHKLISTS WERE PERFORMED. AN EMER WAS DECLARED AND WE PROCEEDED DIRECTLY TO ZZZ. THE SMOKE LASTED LESS THAN 5 MINS AND HAD CLRED BEFORE WE LANDED VISUALLY. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR STATED THAT HE ATTEMPTED TO DETERMINE WHAT CAUSED THE EQUIP FAILURES AND SMOKE BUT WAS UNABLE. THE LAST TIME HE FLEW THIS ACFT; THE LOG PAGE COVERING THIS EVENT HAD ALREADY BEEN REPLACED BECAUSE THE BOOK WAS BEYOND 60 DAYS. HE SAID THE ACR ALSO PLAYED DOWN THE INCIDENT AND SO DID NOT SEND RESPOND.