Originally Posted by Bucking Bar

At some carriers they dual qual via CD and manual. Take the MD88/90 as examples of aircraft with completely different engines and systems. Then you've got the 757 to 767-400 at Continental and Delta's mix and match 757 - 767 fleet. Figure in one day you could get out of a 175,000 jet and get into an aircraft that weighs just shy of a half million pounds and systems wise, nothing is the same.

The FAA has observed that pilots do a pretty good job following abnormal checklists. If Boeing had their way, everything in current production would be a single type (although the 737 really is anachronistic ... a 1960's overhead with new avionics).

ASA / Expressjet had (has) really good training. IMHO they've always gone well above the minimum standard that you see at some places. It is likely the FAA would waive whatever requirement (if one exists) for getting specific training, or make it inexpensive to comply with.