On February 9, 2015, at 0615 eastern standard time, N30EA and N70EA, both de Havilland Canada DHC 6 Twin Otters, sustained substantial damage when N30EA collided with N70EA, when the pilot lost control during engine start at the Sebastian Municipal Airport (X26), Sebastian, Florida. The pilot of N30EA and the pilot and mechanic on N70EA were not injured. Both airplanes were registered to and operated by Eagle Air Transport, Ottawa, Illinois. An instrument flight rules flight plan was filed for both airplanes and destined for the Exuma International Airport (MYEF), George Town, Bahamas. Visual meteorological conditions prevailed for the positioning flights conducted under the provisions of 14 Code of Federal Regulations Part 91. Both airplanes were parked right next to each other (N30EA was to the right of N70EA) and were preparing to depart. The pilot of N30EA reported that she conducted a normal pre-flight inspection of the airplane and the parking brake was "set." After starting both engines, the pilot advanced the throttles (one at a time) to bring the generators on-line. She said the airplane began to move forward and to the left because the steering-tiller had been positioned "sharply" to the left when the airplane was last parked. The pilot said that when she applied the brakes, there was no response and the airplane turned almost 180 degrees as it collided with N70EA, who also had its engines running. A review of postaccident photographs revealed substantial damage to the right wings and engines of both airplanes. The propeller assembly from N70EA's right engine had sheared off and each blade was damaged. The propeller assembly for N30EA remained attached to the engine and each blade was damaged. The area above the cockpit of N30EA was crushed from impact with N70EA's right wing. The pilot of N30EA reported that after she did an emergency shut-down of the engines; she realized the hydraulic circuit breaker was "pulled." She said she had been told that a mechanic had "pulled" the circuit breaker to bleed down the hydraulic accumulator during maintenance done the night before the accident, which may have resulted in the parking brake and pedal-brakes not having sufficient fluid to operate correctly. However, a review of maintenance logs for N30EA revealed there was no maintenance to the hydraulic system on the airplane prior to the accident. The pilot also stated that she learned after the accident that even though it is not on the checklist, some pilots will pull the hydraulic circuit breaker when shutting down the aircraft to "save a little wear and tear" on the hydraulic pump. It is not known how or why the hydraulic circuit breaker had opened prior to the accident. According to the airplane's Normal Operating procedures, section 2.1.2, Before Starting Engines checklist, the pilot was to confirm that all circuit breakers were "In". When asked how this accident could have been prevented, the pilot said she, "...should have seen the pulled circuit breaker on the prestart flow." The pilot of N70EA stated that he was parked to the left of N30EA and he had just started the engines. He was bringing the generators on-line when the operator's Director of Maintenance (DOM) was boarding the rear of the airplane. The pilot then reached down to turn on the avionics master switch, when N30EA collided with N70EA. He immediately shut down both engines while the DOM exited the airplane.