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Accident description
Last updated: 13 December 2017
Status:Final
Date:Thursday 22 May 2003
Time:ca 11:00
Type:Silhouette image of generic DHC3 model; specific model in this crash may look slightly different
de Havilland Canada DHC-3 Otter
Operator:Whiteshell Air Service
Registration: C-GGON
C/n / msn: 225
First flight: 1957
Crew:Fatalities: 0 / Occupants: 1
Passengers:Fatalities: 0 / Occupants: 3
Total:Fatalities: 0 / Occupants: 4
Airplane damage: Substantial
Airplane fate: Repaired
Location:4 km (2.5 mls) E of Lac du Bonnet, MB (   Canada)
Phase: Initial climb (ICL)
Nature:Domestic Non Scheduled Passenger
Departure airport:Lac du Bonnet (North) SPB, MB, Canada
Destination airport:George Lake, MB, Canada
Narrative:
A de Havilland Canada DHC-3 Otter, registered C-GGON, sustained substantial damage in an accident 4 km east of Lac du Bonnet, MB, Canada. All three passengers and the pilot survived. The airplane operated on a flight from Lac du Bonnet, MB to George Lake, MB.
The pilot completed a normal takeoff from the Winnipeg River in an easterly direction and began a shallow climb over the shoreline. As the aircraft levelled at approximately 400 feet agl, there was a loud backfire followed by a complete loss of engine power. The pilot force landed straight ahead; the aircraft struck several large trees and came to rest in a swampy area. The aircraft struck the ground on its left side, both wings broke off, and the engine was buried in the swampy ground.

Probable Cause:

FINDINGS AS TO CAUSES AND CONTRIBUTING FACTORS:
1. A spacer in the No. 3 cylinder push rod tube was installed incorrectly. This initiated the increased wear that eventually prevented the No. 3 exhaust valve from opening, resulting in hot exhaust gases migrating into the induction system and causing the engine failure.
2. Following replacement of the No. 1 cylinder, the operator did not complete a field barometric power reference check, which is used in early identification of an engine problem.
3. The valve adjustment screw protrusion was set beyond specified limits. Had the out-of-limits screw protrusion been noted during adjustment or during a scheduled inspection, an examination might have revealed the excessive wear in the valve train and prevented the engine failure.

Accident investigation:
cover
Investigating agency: TSB Canada
Status: Investigation completed
Duration: 277 days (9 months)
Accident number: A03C0118
Download report: Final report

Sources:
» TSB


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This information is not presented as the Flight Safety Foundation or the Aviation Safety Network’s opinion as to the cause of the accident. It is preliminary and is based on the facts as they are known at this time.
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