From SKYbrary Wiki
| Summary
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| On 4 January 2002, a Challenger 604 operated by Epps Air Service, crashed on takeoff from Birmingham, UK, following loss of control due to airframe icing.
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| Event Details
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| When
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January 2002
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| Event Type
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FIRE, GND, HF, LOC
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| Day/Night
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Day
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| Flight Conditions
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On Ground - Normal Visibility
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| FIRE
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| Tag(s)
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Post Crash Fire
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| HF
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| Tag(s)
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Ineffective Monitoring
Aircraft acceptance
Fatigue
Procedural non compliance
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| LOC
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| Tag(s)
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Flight Control Error
Environmental Factors
Extreme Bank
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| WX
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| Tag(s)
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In Flight Airframe Icing
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| EPR
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| Tag(s)
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RFFS Procedures
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| Safety Net Mitigations
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| Malfunction of Relevant Safety Net
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No
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| Stall Protection
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Available but ineffective
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| Outcome
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| Damage or injury
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Yes
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| Aircraft damage
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Hull loss
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| Non-aircraft damage
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Yes
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| Injuries
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Nonewarning.png"None" is not in the list of possible values (Few occupants, Many occupants, Most or all occupants) for this property.
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| Fatalities
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Most or all occupants
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| Causal Factor Group(s)
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| Group(s)
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Aircraft Operation
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| Safety Recommendation(s)
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| Group(s)
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Aircraft Operation
Aircraft Airworthiness
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| Investigation Type
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| Type
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Independent
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Loss of Control - Airframe Icing
Description
On 4 January 2002, a Challenger 604 operated by Epps Air Service, crashed on takeoff from Birmingham, UK, following loss of control due to airframe icing.
Synopsis
This is an extract from the History of Flight section of the official report into the accident published by the UK Air Accidents Investigation Branch (AAIB):
“The next morning, the handling pilot and the observer arrived at the aircraft together at approximately 1040 hrs. Evidence from the dispatchers indicated that the APU was started at about 1050 hrs. The commander arrived at approximately 1100 hrs. At different times, each of the two crew members was seen to carry out an independent external inspection of the aircraft. Aircraft refuelling commenced at about 1105 hrs and the aircraft fuel tanks were reported full at about 1140 hrs. Then, following the arrival of the two passengers, the aircraft doors were closed. The occupants were the same as on the arrival flight. During the morning, various witnesses had seen frost/ice on the wing surfaces of N90AG. Other aircraft had been de-iced during the morning, with associated reports of severe to moderate ice accumulation. Evidence from the Cockpit Voice Recorder (CVR) indicated that the operating pilots discussed the presence of frost on the leading edge prior to engine start. However, neither requested deicing and N90AG was not de-iced. The Birmingham METAR at 1150 hrs was as follows: surface wind 150°/6 kt11.112 km/h
3.084 m/s; visibility 8,000 metres; cloud scattered at 700 feet agl and broken at 800 feet agl; temperature minus 2°C with dew point minus 3°C; QNH 1027 mb."
“Following ATC clearance, engine start was at 1156 hrs and N90AG was cleared to taxi at 1201 hrs. All radio calls during the accident flight were made by the commander, 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 kt253.724 km/h
70.418 m/s; Vr 140 kt259.28 km/h
71.96 m/s; V2 147 kt272.244 km/h
75.558 m/s. By 1206 hrs, the aircraft was cleared to line up on Runway 15. At 1207 hrs, N90AG was cleared for takeoff with a surface wind of 140°/8 kt14.816 km/h
4.112 m/s. The pilot in the left seat was handling the controls. Takeoff appeared normal up to lift-off. Rotation was started at about 146 kt270.392 km/h
75.044 m/s with the elevator position being increased to 8°, in the aircraft nose up sense, resulting in an initial pitch rate of around 4°/second. Lift-off occurred 2 seconds later, at about 153 kt and with a pitch attitude of about 8° nose-up. Once airborne, the elevator position was reduced to 3° aircraft nose-up whilst the pitch rate increased to about 5°/second. 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°. At that point, the aircraft heading had diverged about 10° 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 until the end of the recording. 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 and the recorders ceased 2 seconds later. The aircraft struck the ground, inverted, adjacent to the runway. The last recorded aircraft attitude was approximately 111° left bank and 13° nose-down pitch; the final recorded heading was about 114°(M).“
Causal factors identified in the report included:
“…The crew did not ensure that N90AG’s wings were clear of frost prior to takeoff…[and]..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..”
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