Airbus is to conduct the first flight of its sharklet-equipped prototype A320 in October, the airframe having undergone initial preparation for performance testing.
The airframer's flight-test aircraft, MSN1, is having its wings stripped in Toulouse as part of the modification.
Airbus A320 chief engineer Wolfgang Engler says the process involves creating a "clean wing" by removing flaps and slats, then jacking the aircraft into a stress-free condition to remove the wing skin.
Afterwards, the wing will be reinforced internally and fitted with test instrumentation. The aircraft's rear fuselage skin will also be changed for MSN1 to undertake minimum-unstick tests, says Engler.
AirArabia A320 with sharklets
Once the prototype twinjet is modified, it will undergo about 220h of flight tests before the sharklets are removed for Airbus to conduct reference testing with the airframe.
Production development of the sharklet involves rebuilding the aircraft's rib 27 to accommodate the high-performance wingtip, while the outer wing will be reinforced to handle higher torque.
"Rib 8 outwards is where we need to do some strengthening," says Airbus executive vice-president for programmes Tom Williams. There will also be local reinforcement of the centre wing box.
Airbus's schedule sees delivery of the first sharklet wing and initial aircraft assembly in the first quarter of 2012.
Production version test flights, amounting to about 650h across several airframe variants, are scheduled to begin in August next year ahead of certification by the end of 2012.
Carriers will be able to take an A320 with conventional wing fences and "plug in" the sharklets during a one-day maintenance shop visit, says Williams.
Airbus is drawing up a weight-reduction programme throughout the A320 airframe to save about 200kg (440lb) to offset the reinforcement weight and "avoid a penalty" for airlines operating the A320 without sharklets, says Williams.
The resulting wing - part of the evolution to the A320neo - will be "weight neutral", he says. "If you take the wingtip fence [rather than the sharklet], you won't be able to tell the difference."
Middle Eastern budget carrier Air Arabia has become the latest to opt for sharklets and will equip 28 A320s, out of 44 it has on order, with the fuel-saving modification. Deliveries will start in the second quarter of 2013.