Accident Canadair CL-600-2B16 Challenger 604 N90AG,

ASN Wikibase Occurrence # 323141

Date:	Friday 4 January 2002
Time:	12:07
Type:	Canadair CL-600-2B16 Challenger 604
Owner/operator:	Epps Air Service
Registration:	N90AG
MSN:	5414
Year of manufacture:	1999
Total airframe hrs:	1594 hours
Cycles:	797 flights
Engine model:	General Electric CF34-3B
Fatalities:	Fatalities: 5 / Occupants: 5
Aircraft damage:	Destroyed, written off
Category:	Accident
Location:	Birmingham International Airport (BHX) - United Kingdom
Phase:	Take off
Nature:	Executive
Departure airport:	Birmingham International Airport (BHX/EGBB)
Destination airport:	Bangor International Airport, ME (BGR/KBGR)
Investigating agency:	AAIB
Confidence Rating:	Accident investigation report completed and information captured

Narrative:
Challenger N90AG was prepared for a flight from Birmingham, UK to Bangor. The flight was cleared to taxi at 12:01 hrs. The captain was pilot-non-flying and was seated in the right cockpit seat. During taxi, the crew completed their normal Before Takeoff Checks; these included confirmation that the control checks had been completed and that anti-ice might be required immediately after takeoff. Flap 20 had been selected for takeoff and the following speeds had been calculated and briefed by the pilots: V1 137 kt; VR 140 kt; V2 147 kt. By 12:06, the aircraft was cleared to line up on runway 15. At 12:07 hrs, N90AG was cleared for takeoff with a surface wind of 140°/8 kt. Takeoff appeared normal up to lift-off. Rotation was started at about 146 kt. Lift-off occurred 2 seconds later, at about 153 kt and with a pitch attitude of about 8 degrees nose-up. Immediately after lift-off, the aircraft started to bank to the left. The rate of bank increased rapidly and 2 seconds after lift-off the bank angle had reached 50 degrees. At that point, the aircraft heading had diverged about 10 degrees to the left. Opposite aileron, followed closely by right rudder, was applied as the aircraft started banking; full right aileron and full right rudder had been applied within 1 second and were maintained. As the bank angle continued to increase, progressively more aircraft nose-up elevator was applied. Stick-shaker operation initiated 3.5 seconds after lift-off. The left winglet contacted the runway shoulder, the outboard part of the left wing detached and the aircraft struck the ground inverted, structurally separating the forward fuselage. Fuel released from ruptured tanks ignited and the wreckage slid to a halt on fire. The last recorded aircraft attitude was approximately 111 degrees left bank and 13 degrees nose-down pitch.

CAUSAL FACTORS: "1. The crew did not ensure that N90AG's wings were clear of frost prior to takeoff.; 2. Reduction of the wing stall angle of attack, due to the surface roughness associated with frost contamination, to below that at which the stall protection system was effective.; 3. Possible impairment of crew performance by the combined effects of a non-prescription drug, jet-lag and fatigue."

Accident investigation: