Originally Posted by
DaveReidUK
Not really - there are several perfectly good reasons why ICAO allocates separate designators to -300 ERs and non-ERs.
The wingspan was increased from 60.93 to 65.8 meters and with that the fuel capacity was increased from 117,340 liters to 181,283 liters.
Most important issues are gate planning (next to higher air navigation charges and landing fees). I have heard some stories that unnoticed last minute changes in aircraft type from non-ER to an ER's caused wingtips to get uncomfortably close at the gate.
But I doubt that has anything to do with this incident.