Aviation Safety Letter 2/2003
Recently Released TSB reports
The following summaries are extracted from Final Reports issued by the Transportation Safety Board of Canada (TSB). They have been de-identified and include only the TSB's synopsis and selected findings. For more information contact the TSB or visit their Web site at http://www.tsb.gc.ca/. — Ed.
TSB Final Report A01O0164 — In-flight collision
On June 20, 2001, at 20:05 eastern daylight time (EDT), a Robinson R22 helicopter, with only the pilot on board, departed Lindsay, ON, for the Toronto/Buttonville Municipal Airport. At 20:22 EDT, a Cessna 170 took off on Runway 18 from a private grass strip, locally known as Sandford Field, with only one person at the controls, who was never licensed as a pilot. This person planned to conduct one left-hand circuit and landing. At 20:25 EDT, the two aircraft collided in visual meteorological conditions (VMC) at approximately 700 ft AGL. The accident occurred near Uxbridge, over a farmer's field 1 NM south of Sandford Field. The helicopter's tail and the main-rotor system sustained catastrophic damage, rendering the helicopter uncontrollable. The helicopter pitched inverted and plunged to the ground, and the pilot was fatally injured. The C-170 sustained substantial damage; however, the person at the controls was able to control the aircraft and conduct a forced landing in a nearby cornfield.
Findings as to Causes and Contributing Factors — Neither the R22 pilot nor the person at the controls of the C-170 saw the other aircraft in time to avert the collision. The design limitations of both aircraft with respect to pilot visibility, combined with the intercept geometry, contributed to the R22 pilot and the person's failure to see and avoid the other aircraft.
Findings as to Risk — The person at the control of the C-170 was not licensed as a pilot, and the C-170 did not have a valid certificate of airworthiness. The TSB also added that while there were no requirements to broadcast their positions or intentions in the airspace they were flying, the collision might have been averted had either the R22 pilot or the person at the controls of the C-170 been aware of the proximity of the other aircraft through direct or indirect communication.
Editor's Note: In discussing this accident with colleagues, it was argued that the collision may still have occurred had the person at the controls of the C-170 been properly licensed, but we will never know. Nonetheless, this accident is blatant proof that there are some people out there who disregard the system and play by their own rules, and ultimately put legitimate pilots and passengers at greater risk. If you know of anyone flying who should not be, tell someone about it.
TSB Final Report A01W0186 — Collision with terrain
On July 26, 2001, a wheel/ski-equipped Cessna A185F departed Yakutat, AK, to pick up two glacier climbers who had been dropped on the Kennedy Glacier, YT, several days earlier. When the pilot aerially inspected the base camp, located at the 8 500-ft level, he noted that the climbers were not there. After searching the area where the climbers intended to climb, he found them at the 12 000-ft level. Because of inclement weather, they had become stranded, ran low on food and fuel, and were unable to descend to the base camp. The pilot landed close to the climbers. Once all were on board, the pilot commenced a take-off run. Before the aircraft could become airborne, the ski struck snow drifts and ridges associated with crevasses in the glacier. The aircraft then nosed over and dropped about 80 ft into a crevasse. When the aircraft did not return to base, a search was initiated. The aircraft, which was substantially damaged, was found the following day. Both climbers sustained serious injuries. The pilot sustained a fatal head injury.
The pilot had dropped off the two climbers on the Kennedy Glacier on July 10, 2001. Arrangements had been made with the pilot to be picked up at base camp on July 26, 2001. Because of inclement weather, the climbers did not return to the base camp; instead, they set up camp in a conspicuous location at the 12 000-ft level on Cathedral Glacier to await pickup.
On the scheduled day of the pickup, the pilot flew to the base camp, but could not find the climbers. After a brief search of the area, he found the climbers at the higher elevation. He then landed nearby and loaded the climbers and their equipment. The pilot and the climbers discussed glacier conditions and crevasses nearby, some of which were covered with snow.
The take-off began at about 18:15, opposite to the direction the aircraft had landed, at approximately 12 000 ft ASL. The initial portion of the take-off run was down a 10° to 15° slope before it flattened out. This flat area was composed of smaller crevasses that had been covered with snow and had the appearance of shallow depressions. When the aircraft contacted the smaller depressions, it began to skip and turned approximately 10° to the left, as shown by the tracks in the snow.
The aircraft eventually came into contact with the lip of an open crevasse, then with a large drift of compacted snow. The propeller and the skis separated from the aircraft and were found at this location. Shortly after contacting this drift, the aircraft nosed over and fell into the next open crevasse. The aircraft came to rest on its back at the bottom of the crevasse, in a nose-down attitude, at approximately 11 500 ft ASL.
Aerial view of slide path and aircraft at rest in crevasse.
Glacier flying requires the pilot to identify the take-off path and to ascertain reference landmarks that will be visible from the ground before landing. This would prepare the pilot for the likelihood that distant portions of the take-off surface would not be visible during the initial take-off run, due to surface undulations.
Findings as to Causes and Contributing Factors - The series of small depressions in the glacier surface and the 12 000-ft altitude most likely prevented the aircraft from becoming airborne before reaching the larger open crevasses and the associated drifts of compacted snow.
Findings as to Risk — At the time of impact, the pilot was not wearing the shoulder harness provided. This lack of physical restraint contributed to his fatal injuries when the aircraft struck the bottom of the crevasse.
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