Lingering Effects

By Richard N. Aarons
Source: Business & Commercial Aviation

The 1100 METAR for Yellowknife reported wind, 110 deg. at 12 kt., gusting to 18 kt.; visibility, 3 sm in light rain and mist; sky condition, 500 ft. AGL broken, 1,000 ft. AGL overcast; temperature 6C, dewpoint 5C. Stratocumulus covered most of the sky.

When Air Tindi 200 departed Yellowknife at 1103 under a VFR clearance, the visibility was at the VFR minimums of 3 sm. VFR operations within the control zone were allowed without requiring a special VFR clearance. Once en route, clear of the Yellowknife control zone and below 1,000 ft. AGL, the aircraft was required under Canadian Aviation Regulations to remain clear of clouds with flight visibility not less than 2 sm. Investigators would determine later that the flight to the Lutsel K'e area was conducted on a direct track at low level, below a low, ragged cloud base into reducing visibility.

The last radio call heard from the Caravan was a position report indicating the flight was about 20 mi. from Lutsel K'e. The pilot reported none of the usual information such as arrival intentions and estimated time of arrival. The crew of another aircraft that also was inbound to Lutsel K'e from Yellowknife heard this radio report.

The Air Tindi Caravan failed to arrive at its scheduled time of 1145. The company's representative at Lutsel K'e alerted the Yellowknife operations center at 1223. The last known position appearing on the Air Tindi headquarters SkyTrac database indicated that C-GATV had stopped short of Lutsel K'e, and the company emergency response plan was activated at 1245. Two company fixed-wing aircraft were dispatched on visual and electronic searches. Neither the Joint Rescue Coordination Center nor search aircraft received an ELT signal.

Ultimately, a rescue crew in a float-equipped de Havilland DHC-6 located the wreckage at 1420 and landed on nearby Great Slave Lake. The crew hiked into the accident site and arrived at 1530. The pilot and one passenger were dead. Two passengers suffering serious injuries were shuttled by helicopter to the floatplane and evacuated to Yellowknife at 1800.

The aircraft had crashed some 26 nm west of Lutsel K'e near the crest of Pehtei Peninsula. There was no post-impact fire.

Investigators from Canada's Transportation Safety Board (TSB) surveyed the scene and wreckage. The terrain between Yellowknife and Lutsel K'e consists of gently rolling, tree-covered Canadian Shield rocky outcrops, with interspersed lakes. Ground elevation on the route varied from 600 ft. to 1,100 ft. ASL. The accident site was near the highest point on the route, rising about 500 ft. from the surface of Great Slave Lake. The peninsula is oriented nearly perpendicular to the aircraft's flight path to Lutsel K'e. The first point of impact was at an elevation of 1,013 ft. ASL, about 38 ft. below the top of the peninsula and 20 ft. above the face of a vertical cliff.

At impact, the aircraft was in a nearly level attitude in pitch and roll. First ground impact was by the landing gear, followed by the belly cargo pod and the propeller, all of which separated from the aircraft at this point. The airplane continued up a 10-deg. slope over the top of the hill, became airborne and came to rest inverted 477 ft. down the eastern slope of the peninsula. The cockpit was crushed, and the forward passenger cabin was distorted, with the forward cabin bulkhead mostly dislodged from its attachments. The left wing had folded back and rested on the ceiling of the cabin.

The airplane had been equipped with a SkyTrac GPS-based flight-following system that transmitted aircraft position, altitude, groundspeed and track via satellite link to the company at subscribed 15-min. intervals. The onboard equipment recorded this data at 5-sec. intervals. The 5-sec. interval data were extracted by the TSB laboratory and used to reconstruct the accident flight. The last SkyTrac transmission at 1140 showed the aircraft at rest, indicating the time of the accident.

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