Airbus plans to start an initial series of pre-certification flight trials of its A320 winglet design in October.

Airbus had previously flight tested several winglet options, but has picked a different configuration for its so-called “sharklets.” Now, it is readying the first A320 built (MSN0001), to accommodate the loads of the winglet device, which is designed to improve fuel burn more than 3%.

The prototype will undergo about 220 hours of flight testing, says A320 family chief engineer Wolfgang Engler. The trials will first take performance measurements and then examine aeroelastic performance. At the end, the winglet will be replaced with the traditional wing fence used on A320s for further performance measurements and to properly establish the improvement the “sharklets” will deliver.

But these trials will operate with some restrictions as the test A320 will not feature all the structural strengthening the production version will incorporate. As a result, initial flight trials will be limited to around 1.8 g rather than be exposed to 2.5 g.

The shape of the winglet will not be altered, though, as a result of testing, Engler says.

Flight trials using the first production aircraft are due to start in August 2012. The entire flight test program involving eight aircraft—one each for the A318, A319, A320, and A321 with either CFM56 or V2500 engines—is expected to run about 650 flight hours.

Airbus expects the first A320s with winglets to be certified in December 2012, with customer delivery still planned that year.

Once the initial push is over, Airbus will turn its attention to offering retrofit options. Those could be provided by a third party.

The retrofit would provide similar performance benefits, Engler says, but have greater weight because the required wing box and wing strengthening would not be integrated, as is the case on new-build aircraft. That means the overall fuel savings would be lower. In that respect, the retrofit is somewhat of a “compromise,” Engler says, while still providing benefits over the baseline aircraft.