Since there have been 3 Commuter Airline Crashes in just the recent couple weeks, here is some info I came accross that may shed some light on things ..

http://www.planecrashinfo.com/cause.htm

And check this:
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10/02/1996 Aeroperu
B-757-200 Pasamayo, Peru
The aircraft crashed into the ocean 28 minutes after taking off from Lima, Peru. Pieces of duct tape were found covering sensors, placed there by personnel during aircraft maintenance causing the malfunction of instruments. The crew was not able to correctly determine their altitude and airspeed and with no ground reference over water and at night, crashed into the ocean killing all 70 aboard. A maintenance worker was tried and convicted of negligent homicide for failing to remove the adhesive tape and received 2 years in jail.
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http://www.planecrashinfo.com/unusual.htm