Airbus is closer to defining a formal modification programme to retrofit its 'sharklet' wing-tips on baseline A320s, but is still prioritising the forward-fit production process.
The airframer has already rolled out the first example of an A320 whose wings have been built to the sharklet-compatible standard.
Airbus executive vice-president for programmes Tom Williams says the airframer intends to construct 100 aircraft this year with the reinforced wing.
This reinforcement provides the platform enabling sharklets to be fitted on the production line or added later - a process which will involve simply plugging in the modified wing-tip and updating flight control software during an overnight hangar visit.
Williams says a retrofit programme for older A320s will require "peeling back" the outer part of the wing skin and adding reinforcement to the stringer structures, while minimising torsion and any effects on lateral trim.
"[Retrofit] will require a more extensive process of opening the wing and inserting structural reinforcement, but we want complete commonality with the forward-fit sharklet," he states.
Although changes to production aircraft include localised centre wing box reinforcements, Williams believes retrofit would be "manageable" in this regard.
He says Airbus has received "quite a lot of interest" in a retrofit from airlines, but stresses that the airframer wants to ensure the forward-fit effort is "sorted out" - not least because the forward-fit programme is a step towards standardising the sharklet on the A320neo.
This will give the manufacturer a "breathing space", Williams says. But he also states that Airbus wants to make sure that it can obtain enough sharklets to meet demand.
Korean Air's aerospace manufacturing division is the sole supplier of the modified wing-tips and Williams says Airbus is looking at a potential requirement of 90 sets per month. The sharklets will be supplied to the A320 final assembly lines in Toulouse, Hamburg and Tianjin.
Each sharklet is about 2.4m (7.8ft) tall and includes new LED navigation and strobe lighting as well as wing-load reduction through load-alleviation functions of the flight-control system. Although the wing-span increases by 1.7m to 35.8m this does not change the type's airport classification.
Airbus is aiming for certification of the sharklet-equipped A320 with CFM International CFM56 engines by the end of this year. Test flights with the first production aircraft - a CFM56-powered example - will take about nine or 10 months, and Airbus intends to secure approval for all four A320 family members, with their various engine and flight-management system combinations.