I don't think the E Jets make economic sense...
Most of Mt Cook's route structure is too short to make a E Jet worthwhile.
The longest route I think they would fly would be Queenstown - Rotorua... which is 536 NM by the great circle..
The majority of their other routes which are flown are only in the 300-400 nm range.
The longest domestic route Air NZ may cover would be AKL-IVC which works out to 634 NM.
According to Embraer's website, the E190 breaks even at 61% capacity. Thats 60 odd seats to fill and the aircraft breaks even.. and thats on a 600 SM route..
There are only two routes that come remotely close to that distance, AKL-IVC and ROT-ZQN.
Why would you fly a fleet of E-Jets that are not suited to the route structure you are flying... or were only suitable to 2 routes out of the entire lot that you fly?
Sure I see ZQN-ROT furfilling this, but getting a new type to fill one route is a pretty poor business plan.
The Q400 on the other hand breaks even at 57%. Thats selling your seats on a 78 seater at $75 USD a pop... works out to be about $90 ish NZD..
Thats 45 seats at $90 NZD for a 300 NM sector..
Oh wait.. a 300 NM sector... sounds like a Mt Cook route doesnt it?
From my understanding, the ATR breaks even at about 33 seats. Most ATR flights that I end up paxing on are pretty full.. not bad for a 66 seat plane. A marginal increase in the break even level for an additional 10-15 seats of profit doesn't sound too bad when you compare it to the 60 odd seats needed to just get a E Jet off the ground and break even, with no profit.
This is without even mentioning that the Q400 burns about 30% less fuel than the jet to achieve a similar result.
A pretty compelling arguement against the E Jet and for the Q400...
I don't think the ATR will get the nod.. it's now too small for Mt Cook. You want excess capacity to grow into. The Q400 offers that... not to mention better speed. Give the ATR to someone who needs them.. like Air Freight...
Now.. Mt Cook to get E Jets and operate them trans-tasman... now theres a rumour!