SAA also has a whole herd of PDI's sitting in the cockpits whose experience levels are certainly not the highest on the continent. But their ego size makes up for it.
The red light you saw could have been the cabin pressure warning if the aircraft was fitted with such a light as some are. If not the crew rely on an aural warning for cabin pressure which is the same sound as the takeoff warning and would have been cancelled had it sounded.
If the crew (and the rest of you) were not on oxygen it could not have been serious cabin pressure loss.
If they descended to 25000 (instead of 28000) it probably meant they had lost an aircon pack and prior to shutting down that pack it could have caused some vibration.
The thrust changes to the engine might have been the crew trying to unblock a stuck valve, HP or even anti-ice valve. If there were problems with the engine actually running it would more than likely have been shut down.
Last edited by JG1; 1st Jan 2013 at 11:07.