Accident Convair CV-580 Airtanker C-FKFY,

ASN Wikibase Occurrence # 321266

Date:	Saturday 31 July 2010
Time:	20:24
Type:	Convair CV-580 Airtanker
Owner/operator:	Conair Aviation
Registration:	C-FKFY
MSN:	129
Year of manufacture:	1953
Engine model:	Allison 501-D22G
Fatalities:	Fatalities: 2 / Occupants: 2
Aircraft damage:	Destroyed, written off
Category:	Accident
Location:	15 km SE of Lytton, BC - Canada
Phase:	En route
Nature:	Fire fighting
Departure airport:	Kamloops Airport, BC (YKA/CYKA)
Destination airport:	Kamloops Airport, BC (YKA/CYKA)
Investigating agency:	TSB
Confidence Rating:	Accident investigation report completed and information captured

Narrative:
A Conair Aviation Convair CV-580 Airtanker ("Tanker 448") was destroyed when it crashed near Lytton, BC, Canada. Both crew members were killed in the accident. The airplane was contracted out to the B.C. Ministry of Forest and Lands as it fought a forest fire near Siwash Road, about 18 kilometres south of Lytton.
The CV-580 was accompanied by a Rockwell 690 Turbo Commander, which planned and directed the fire suppression activity. This included a demonstration of the bombing run and a verbal description for the tanker crew as they circled above.
The plan was for Tanker 448 to make 8 left-hand circuits, dropping 1/8 of its retardant load each time.
T448 joined the circuit for its first bombing run close to the Fraser River and then proceeded south-southwest at an altitude of 3432 feet asl and a groundspeed of 140 knots. The aircraft then descended and struck three trees on a knoll at the edge of a ravine at approximately 3020 feet asl about 8 seconds before the crash. The flight crew then dropped retardant and attempted to climb away. About 3 seconds later, the aircraft entered a left-hand spin which continued for one revolution in five seconds in a steep nose-down attitude before the aircraft struck terrain 590 feet below.

Findings as to Causes and Contributing Factors
1. It could not be determined to what extent the initial collision with trees caused damage to the aircraft which may have affected its controllability.
2. Visual illusion may have precluded recognition, or an accurate assessment, of the flight path profile in sufficient time to avoid the trees on rising terrain.
3. Visual illusion may have contributed to the development of a low energy condition which impaired the aircraft performance when overshoot action was initiated.
4. The aircraft entered an aerodynamic stall and spin from which recovery was not possible at such a low altitude.

Accident investigation: