1998-09-08: This accident occurred on March 10, 1997, but was not reported to either Transport Canada or the TSB until October, when it was brought to the attention of System Safety by Standard Aero of Winnipeg, who were doing maintenance work on C-FSCF
. The two crew members of C-FSCF
, a ski-equipped DHC-6, returned to Points North after a charter flight and they were taxiing the a/c on the icy ramp with the propellors in coarse pitch and the throttles in the idle position. When the a/c began to move toward a parked DC-3, the crew selected the power levers to reverse, however there was no response. The crew then moved the propellors to fine pitch and the right engine accelerated briefly, moving the a/c forward and to the left, but the right wing of the DHC-6 struck the right wing of the DC-3. The ensuing collision caused substantial damage to the DHC-6, and minor damage to the DC-3. The right wing of C-FSCF
was partially torn away from the fuselage, and the right engine was canted down at about a 45 degree angle, such that the propellors almost touched the ground. There was also damage to the leading edges of both a/c. The crew of C-FSCF
were not injured. The design of the DHC-6 Twin Otter is such that when coarse propellor pitch is selected, reverse is not available. If the power levers are selected to reverse when reverse is not available, and the propellor levers are then moved forward to engage reverse, the propellors will move through a positive pitch range before entering reverse and will temporarily impart thrust to the a/c.