http://www.flightglobal.com/Articles/2006/08/30/Navigation/177/207560/Pictures+Airbus+flies+four+A380+test+aircraft+in+formation+over+Toulouse+including+landing+gear.html

One day after the unplanned return of an Airbus A380 test aircraft due to landing gear sensor problems, the manufacturer flew four of the test aircraft, including the troubled airframe, above Toulouse in formation.

Airbus flew manufacturer's serial numbers 001, 002 and 004, all powered by Roll-Royce Trent 900 engines, in formation with the Engine Alliance GP7200-powered MSN009. The aircraft taxied together then took off from around 09:45 and by 11:00 all four were flying together briefly over the Aéroconstellation facilities in Toulouse.

MSN004 turned back from a positioning flight to Tozeur, Tunisia yesterday due to a sensor mismatch in the landing gear bay, which would have prevented the undercarriage from being extended. All four aircraft flew with gear up.

 
All images © Yannick Delamarre / French Frogs Aviation Pictures