Aviation Safety Letter 1/2003
Collision with Wire in Reduced Visibility
On October 13, 1999, a pilot and two passengers departed from Boyce Lake, Ontario, in a float-equipped Cessna A185F aircraft, on a VFR flight to Temagami, Ontario, a distance of approximately 15 NM. At approximately 09:15 eastern daylight time (EDT), a witness near a transmission tower south of Temagami heard an aircraft approaching. The aircraft subsequently came into view, and almost as soon as it was visible, the aircraft struck the anchor wires of the transmission tower and then the tower. The aircraft descended to the ground where an explosion occurred and an intense, post-crash fire broke out. None of the occupants of the aircraft survived. This synopsis is based on the TSB Final Report A99O0244.
The pilot had approximately 550 hr of total flying time, including 220 hr on the occurrence type. Prior to the accident, the pilot had flown from Temagami to Boyce Lake to pick up the two passengers. During this flight, he reported by radio twice, but gave no indication that he experienced any navigational difficulties en route due to weather. The pilot was known to land on lakes and wait when weather was deteriorating.
No aviation weather reports or aerodrome forecasts (TAF) are available for Temagami. However, on the day of the occurrence, a weather package, including significant meteorological reports (SIGMET), area forecasts (FA), aviation routine weather reports (METAR), TAFs, wind and temperature aloft forecasts (FD), notices to airmen (NOTAMs) and radar reports, was faxed to the operator from NAV CANADA's Canadian Sault Ste. Marie FSS. The occurrence flight route was covered by the weather package and was available to the pilot prior to his departure.
An FA issued at 07:30 EDT that day called for a broken, occasionally scattered layer of cloud based at 3 000 ft ASL with a prevailing visibility of 6 SM. Areas with visibility of 2 SM in rain showers and mist were forecast and local ceilings of 400 to 1 000 ft AGL in precipitation, with occasional visibility of 1 to 3 SM in mist. The TAF reports for North Bay, 42 mi. south of the occurrence site, and for Sudbury, 47 mi. southwest of the occurrence site, both included reports of temporary low visibilities, light rain showers and mist. The METARs for the same areas all reported low ceilings, light rain and fog.
At the time of the occurrence, weather in the area was reported as being variably foggy with occasional drizzle falling. The lights from the tower were reported as visible from approximately 1 400 ft, though not clearly because of drizzle and fog. The aircraft could be heard approaching but was not sighted until an instant before the collision with the tower. A second company aircraft departed the float base to search for the downed aircraft. The horizontal visibility was reported as good, but the high ground on which the tower was located was hidden from view by low cloud. The search aircraft passed within 1 mi. of the accident site on more than one occasion while the wreckage was still burning and neither occupant saw the wreckage or smoke.
The tower was approximately 250 ft high and was painted alternately white and orange with lights at the mid-point and the top. The tower lighting and markings were appropriate for the structure in accordance with regulations. It appeared on the Sault Ste. Marie VFR navigation chart and also on the map the pilot used for navigation. It was reported that the pilot was aware of the tower and its location, and the obstruction lights were on at the time of the occurrence.
Analysis - There were no equipment malfunctions prior to or during the flight. The tower was appropriately painted, its lighting was in accordance with existing regulations and was turned on at the time of the accident. Its location was depicted on the map used by the pilot for navigation. The weather information available to the pilot prior to the occurrence flight was adequate and accurate. There was no indication that deteriorating weather conditions were encountered on the flight from Temagami to Boyce Lake; however, on the return trip, the pilot encountered an area of showers and reduced visibility. The TSB determined that the pilot continued flight in deteriorating meteorological conditions and likely did not see the tower and anchor cables in time to avoid the collision.
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