Date:	Friday 25 September 2015
Time:	12:03
Type:	Curtiss C-46A-45-CU Commando
Owner/operator:	Buffalo Airways
Registration:	C-GTXW
MSN:	30386
Year of manufacture:	1944
Engine model:	Pratt & Whitney R-2800-51M3
Fatalities:	Fatalities: 0 / Occupants: 4
Aircraft damage:	Substantial, written off
Category:	Accident
Location:	Déline Airport, NT (YWJ) -   Canada
Phase:	Landing
Nature:	Cargo
Departure airport:	Yellowknife Airport, NT (YZF/CYZF)
Destination airport:	Norman Wells Airport, NT (YVQ/CYVQ)
Investigating agency:	TSB
Confidence Rating:	Information verified through data from accident investigation authorities

Narrative:
The Buffalo Airways Curtiss C-46A (C-GTXW) was operating as flight 525 from Yellowknife, NT (YZF) to Norman Wells, NT (YVQ). While en route, approximately 140 nautical miles southeast of Norman Wells at 6500 feet above sea level, the crew noticed a drop in the right engine oil quantity indicator in conjunction with a propeller overspeed. The propeller pitch was adjusted to control the overspeed however, oil quantity indication continued to drop rapidly. A visual confirmation of the right engine nacelle confirmed that oil was escaping via the engine breather vent at an abnormally high rate. The right propeller speed became uncontrollable and the crew completed the "Prop overspeed drill". However, the propeller did not feather as selected. Several additional attempts were made to feather the propeller before it eventually feathered. The engine was secured and the shutdown checklist completed. The crew elected to divert to Tulita, NT (ZFN), but quickly determined that the descent rate would not permit that as an option. The only other option for diversion was Déline, NT (YWJ) where weather was reported at half a mile visibility and 300 feet ceiling. An emergency was declared with Déline radio. BFL525 was able to land at Déline however, the landing gear was not selected down to prevent further loss of airspeed resulting in a belly landing approximately midpoint of runway 08. The aircraft continued off the end of the runway coming to a stop approximately 700 feet beyond the threshold. The crew evacuated the aircraft sustaining no injuries however, the aircraft was destroyed. Buffalo Airways’ initial investigation revealed the engine oil scavenge pump had failed.

17:00 UTC / 11:00 local time:
CYWJ 251700Z 03005G//KT 1/2SM -RASN OVC007 00/M00 A2949 RMK ST8 VIS S 1 WND ESTD SLP000

18:00 UTC / 12:00 local time:
CYWJ 251800Z 03005KT 1/2SM -RASN OVC005 00/M00 A2947 RMK ST8 WND ESTD SLP995

19:00 UTC / 13:00 local time:
CYWJ 251900Z 03010KT 1/2SM -RASN OVC005 00/M01 A2946 RMK ST8 WND ESTD SLP991

CADORS 2015C3600
CBC
myyellowknifenow.com

Other occurrences involving this aircraft

9 November 2012

C-GTXW

Buffalo Airways

0

Yellowknife Airport, NT (YZF)

sub

photo (c) Jan Zocher; Yellowknife Airport, NT (YZF/CYZF); 27 May 2014

photo (c) Graham Evans; Yellowknife Airport, NT (YZF/CYZF); 17 September 2015

Date/time	Contributor	Updates