[Ronald_Magnus]

Airline cockpits have a powerful smoke removal system. Whether or not smoke would be so voluminous that the system would not be able to keep up with it is another question.

[Tzfat]

Tell that to the ValuJet crew.

The QRH I used very day, has 8 pages for Avionics Smoke, it is 36 point font so it can be POSSIBLY read - but at the top of the procedure it says, AT ANY TIME IN THIS PROCEDURE, IF SMOKE BECOMES DENSE, IMMEDIATELY TURN TO PAGE 7: SMOKE REMOVAL. On that page, it tells you to turn on certain fans, turn certain fans, and if still dense descended IMMEDIATELY to FL100 OR MEA. Then it tells you to REDUCE SPEED TO 250 KTS, OPEN COCKPIT WINDOW.