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On August 27, 1992, 3 people were killed when a de Havilland Canada DHC-4 Caribou crashed immediately after takeoff at Gimli Industrial Park Airport.

Wikipedia describes the accident as follows:

Three people were killed on August 27, 1992 when a NewCal Aviation turbine-modified de Havilland Canada DHC-4 Caribou they were aboard crashed on the airfield during climb-out after a short take-off from the airport. The aircraft nosed sharply up, arced right and nosed into the ground. […] The cause was listed as failure to deactivate the plane's gust-lock control in the cockpit, […] [T]he Transportation Safety Board of Canada has no record of this incident.

The entire flight was captured on a video which has circulated on the Internet.

Was this accident ever officially investigated? If not, why not?

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    $\begingroup$ It may have been (and probably was) investigated by the Canadian TSB, but the report is probably not available online as it was during the time that they were "digitizing" reports. $\endgroup$
    – Ron Beyer
    Mar 7, 2019 at 19:43
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    $\begingroup$ The online report database is supposed to cover 1991 and later incidents, but this particular report is not there. The mystery is how they were able to take off with the gust lock engaged, since on the Bou and the Buff (same flight deck) the gust lock T handle latches engaged when pulled aft and it blocks the throttles from being moved out of idle. $\endgroup$
    – John K
    Mar 8, 2019 at 6:39

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It was, but from what I can tell the report has not been digitized yet.

The gust locks were left installed. The aircraft was being operated in the restricted category as they were retrofitting with the PT-6’s.

Here’s an analysis from James Donnelly, Bombardier Aerospace. Starts on page 7.

http://www.asasi.org/papers/2001/Four%20Unrelated%20Accidents.pdf

Essentially the rigging was done incorrectly. The gust locks did reduce engine thrust, but didn’t kill it completely. Takeoff roll was 20% longer than calculated.

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The above answer has errors:

  1. The gust locks were not "left installed"; they were left activated. The DHC-4 has internal gust locks, not external. Said gust lock interacts with the throttle levers in that the gust lock, when activated, normally prevents any advance of throttle levers but this is only valid on a non-modified, piston-powered DHC-4; in this particular DHC-4, converted to PWC PT-6A turboprop engines, the throttle levers--called power levers for turboprops--now, by modification, did not interlock with the gust lock control and now worked fully independently of said gust lock, whether it was activated or not.
  2. "The rigging"? Please elaborate: that of the throttle/power levers or gust lock? It is assumed the throttle levers were replaced by new power levers which were not made to interact with the activation of the gust lock as the previous throttle levers had been, by-design.

It is uncertain whether or not the crew of this aircraft's fatal flight was familiar with this particular aircraft and its modification, or with the DHC-4 generally; what is known is that the gust locks remained activated, the power levers were advanced, the aircraft rolled a remarkably short distance, rotated, pitched up dramatically, climbed over 100 feet, achieved near-vertical pitch, rolled right 90-degrees at apex, continued on, gained speed and nosed into the ground at full power, impacting at a steep angle. All aboard died on impact and the aircraft caught fire shortly after. It should be noted the aircraft did not explode but merely caught fire.

This answer may be wordy but sometimes extra words are necessary to clearly convey fact. Economy of words for the sake of brevity is poor policy.

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    $\begingroup$ Do you have any references for this information? $\endgroup$
    – Jamiec
    Aug 10, 2023 at 7:21
  • $\begingroup$ You shouldn't say "the above answer", even if you firmly believe that your answer will never be upvoted to have more votes than the other answer, because answers can be sorted in several different ways. $\endgroup$ Aug 10, 2023 at 22:22
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The accident was investigated and a report was published the following year, in 1993. The accident report apparently was not available online at the time that the question was posted, but it is available now: investigation number A92C0154 at tsb.gc.ca.

The accident report concluded that

The gust lock system was not fully disengaged prior to flight and one or more of the gust locking pins became re-engaged for undetermined reasons after lift-off. It is unlikely that a control check had been completed prior to take-off and, once airborne, the crew were unable to disengage the gust lock mechanism before losing control of the aircraft.

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