B717 (Formerly MD-95)
Flight Crew Air Transport Pilot (ATP)
Confusion; Troubleshooting
Aircraft Equipment Problem Critical
Flight Crew Landed in Emergency Condition; General Maintenance Action
Aircraft
On arrival at 12;000 MSL we experienced approximately 16 simultaneous Level 3 and 4 alerts. Captain and First Officer PFD DU's did not fail and attitude indication did not fail. Airspeed tape fluctuating wildly from 100 KTS to 500 KTS. Altitude tape fluctuating wildly + and - 2;000 FT. The alerts we could remember are: Stick Pusher Fail; Alternate Trim Fail; Autopilot Fail; Auto Thrust Fail; FCP Fail; Over speed Warning Clacker; Rudder Restricted; CPC Fail; Flight Director Fail; Unable RNP; Intermittent Mode C and TCAS; Brake Pressure Low; Rudder Pitot Fail. Basically we were down to the ISIS [Integrated Standby Instrument System.] No Emergency declared because we did still have control of the aircraft and also in trying to assess which course of action to take; most failures suddenly returned to normal descending through 4;000 FT to 2;000 FT. At that point we could see the airport. Then the multiple alerts and failures started again. Now the first priority was to get the aircraft on the ground. We landed VFR in light snow without incident. It is my understanding that Maintenance basically rebooted the aircraft computers; ran some internal test and returned the aircraft to service. It is my opinion that this aircraft should never have been returned to service in this potentially hazardous condition. If it happened once then it could happen again and next time could result in a life threatening accident. The multiple alerts and aural warnings were almost overwhelming. We worked together using CRM techniques to safely land the airplane.
B717 experienced approximately 16 simultaneous Level 3 and 4 alerts at 12;000 FT during arrival; indicating multiple system failures. The crew was able to continue visually and land at destination safely; although the multiple alerts and aural warnings were described as almost overwhelming.