Following the 28 November Bombardier Challenger 600 crash at Montrose, Colorado, the US Federal Aviation Administration has conceded it is reviewing a recommendation that it should change its advice about aircraft taking off with frost on their wings. It is still too early to say whether icing was a factor in the Montrose crash, but the circumstances were similar to a January 2002 Challenger 604 crash at Birmingham, UK, where wing icing was determined to be the primary cause.
In the Birmingham accident, the left wing dropped immediately on take-off, hit the ground despite full opposite control inputs, and the aircraft cartwheeled. The UK Air Accidents Investigation Branch says the aircraft had frost on it and had not been de-iced. The Montrose aircraft had not been de-iced, according to the US National Transportation Safety Board, and it also crashed at take-off.
The AAIB recommendations in its Birmingham report included advice that the FAA should strike out of FAR Part 135.227 the words: "Take-offs may be made with frost adhering to the wings or stabilising or control surfaces if the frost has been polished to make it smooth."
Source: Flight International
