Londonmet -
I said BACKUP...NOT passenger. As such there IS a role to play.
IF it's so vital to have a co-pilot, how come most GA is single-pilot?
(often with a totally unskilled passenger sat at the second set of controls!
)
So, the reason is because a load of fare-paying passengers have elected to be carried to their destinatoin in an extremely expensive, complex public transport conveyance.
To that end, it's incumbent on the operator and the regulatory authorities to take every precaution to accomplish this. the weakest link is (arguably) the human controller of the machine....a "backup system" is therefore a basic requirement.
I would refer you to the recent case where a passenger flight made an unscheduled landing in Eireland and one of the flight-deck officers was escorted off and later hospitalised with mental-health problems.
The other flight-deck officer appears to have satisfactorily managed the workload of relieving his colleague of responsibility, planning and executing a diversion and satisfactorily landing the aircraft.
I am NOT saying a F/A wasn't used to help with checklists, etc. but this is all a side-issue.-IMO the subject of the thread , acted in a reckless manner and ruined his own carreer.