Pakistan International Airlines is seeking at up to 39 single-aisle aircraft for its fleet renewal to 2020, five of which will be expected to arrive by April next year.
The airline, which has issued a formal invitation to lessors, is seeking dry-lease of aircraft with a capacity of around 140 seats, for 10-year periods.
It plans to take five aircraft by April 2012 and then the next 20 at the rate of one per month, until the end of 2013.
PIA said these initial aircraft should "preferably be new" but is prepared to examine second-hand airframes built from 2007.
But it will only consider new aircraft for the remaining 14, for which the carrier has set a delivery schedule of six over 2014-16, two in 2017, and six more for 2018-20.
Twenty-five aircraft delivered from 2017 will be used to replace airframes delivered in 2012-13, said PIA in its invitation.
It said aircraft delivered before 2017 will be replaced on a one-for-one basis "by the latest model aircraft" at a minimum rate of six per year, ensuring that all aircraft which arrived up to 2016 will be replaced by newer-technology airframes by 2021.
"If new technology aircraft are available earlier, [the] replacement plan shall be altered accordingly," added the airline.
PIA has set a 23 January 2012 deadline on offers to bid for the renewal.