David Olive’s business column in today Toronto 
Star had an alarming detail…
“We’re gonna approach this — No. 1 — acknowledging our mistake,” Boeing CEO David Calhoun said a few days after the incident in an address to employees at Boeing’s 737 plant in Renton, Wash.
Calhoun did not say what the mistake was.
National Transportation Safety Board inspectors have said the four bolts that hold the exit door in place are missing. The inspectors have not yet determined whether the bolts were even installed.
It looks like the “mistake” was failing to bolt the door plug onto the plane. 
