Airbus's reconfigured A321neo has been cleared to operate with up to 244 passengers, depending on the precise exit layout.
The reconfigured twinjet – which features a modified fuselage with repositioned exits – enables the maximum seating capacity to reach 244, according to the European Aviation Safety Agency.
EASA states that this requires the aircraft to have "overperforming" Type C exits in the forward and aft fuselage and two Type III overwing exits, plus a Type C door for the repositioned mid-cabin exit.
These modifications allow the maximum seating to be increased from 220, the limit in the original A321, to 244 in the reconfigured A321neo.
But EASA states that the change only defines a "virtual envelope" and "does not constitute an authorisation" for installing the additional seats.
"A separate approval is needed for the installation of the individual customised cabin layout and the necessary cabin adaptations up to 244 seats," it adds.
Airbus confirmed the maximum 244-seat capacity for the jet in a communication to the US Department of Transportation in April.
The airframer had been seeking authorisation to make the A321neo eligible, under US federal regulations, to carry a maximum of 235 passengers if fitted with a derated mid-cabin exit.
Derating the mid-cabin door, located just aft of the wing, from a Type C exit to a Type III can allow more flexibility in the interior layout, says Airbus.
But it also reduces the maximum permitted capacity of the aircraft.
Derating the exit to Type III would normally limit this capacity to just 200 seats – a combined credit of 65 each for the forward and aft Type C doors plus 70 for the overwing exits.
Airbus says that "no additional credit" is given for the derated mid-cabin door, and it is seeking a regulatory exemption to increase the passenger limitation for all the Type III exits from 70 to 105 passengers.
This 35-seat increase would take the A321neo's permitted capacity to 235 passengers.
Airbus states that its request is justified by the results of intermediate-scale evacuation tests, which it performed to assess the various configurations of the A321neo.
It says that its evacuation analysis demonstrates that – for all possible configurations, including the derated door – an "overall safety margin" of around 29% is achieved.