Airworthiness Directives; BAE Systems (Operations) Limited Model BAe 146 and Model Avro 146-RJ Airplanes

We are adopting a new airworthiness directive (AD) for the products listed above. This AD results from service history of incidents and accidents involving transport category turbojet airplanes without leading edge high lift devices. This service history shows that even small amounts of frost, ice, snow, or slush on the wing leading edges or forward upper wing surfaces can cause an adverse change in the stall speeds and stall characteristics, and can negate the protection provided by a stall protection system. While there have been no accidents or incidents related to wing contamination associated with the BAE Systems (Operations) Limited Model BAe 146 and Model Avro 146- RJ airplanes, these airplanes are also transport category turbojet airplanes without leading edge high lift devices, and therefore may be similarly sensitive to small amounts of wing contamination. This AD requires revising the airplane flight manual to include a new cold weather operations limitation. We are issuing this AD to prevent possible loss of control on takeoff resulting from even small amounts of frost, ice, snow, or slush on the wing leading edges or forward upper wing surfaces. We are issuing this AD to require actions to correct the unsafe condition on these products.