On 5 February 2006, two Shorts SD-360-300 aircraft collided in mid air while manoeuvring in formation near Watertown, WI, USA; both aircraft suffered damage. One aircraft experienced loss of control and impacted terrain with the loss of all occupants and the aircraft while the other made a flapless landing with only partial gear extension due to collision damage at Dodge County Airport, Juneau WI, 13 miles to the north of Watertown, and overan the runway.
The following is taken from the NTSB Report CHI06FA077A:
"Prior to departure, both flight crews decided that they would join-up while in flight to take video and still pictures of each airplane. Both aircraft were Shorts Brothers SD-360-300 turboprop airplanes. While flying in formation, N3735W announced over the radio that they would turn right, toward N372AC, and descend. During the turn, N3735W's left wing impacted the left wing and engine of N372AC. After the collision, N372AC rolled to the left and pitched down significantly before the flight crew regained control of the airplane. After the collision, N372AC was losing hydraulic fluid and eventually had a complete hydraulic system failure. The airplane made an emergency landing at a nearby airport with its flaps retracted and its landing gear partially extended. The airplane overran the end of the runway, coming to rest about 100 feet from the departure threshold. White paint transfer markings and scrapes were observed on the left wing deice boot, the outboard side of the left engine cowling was crushed inboard, the left wing-strut leading edge was torn open and bent, and the lower fuselage skin, immediately forward of the landing gear wheel wells and stub wing, was torn from left to right, consistent with a propeller strike. N3735W impacted terrain and the airplane was destroyed during a subsequent ground fire. The flight crew and passenger were killed. The outboard three-quarters of the left wing was separated from the main wreckage and was not fire damaged. The upper wing surface had linear scrapes diagonally across the wing skin. The left aileron from N3735W was found on the runway where N372AC had landed.
The National Transportation Safety Board determines the probable cause(s) of this accident as follows:
The flight crew failed to maintain clearance from another aircraft as they turned to break formation flight while maneuvering. Contributing to the accident was the decision of both flight crews to fly in formation."
- For further information, see the NTSB Report on the mid-air collision event - CHI06FA077A/B