Given the following context:

Up until the 18th century, the inhabitants of Chadderton raised domestic farm animals, supplementing their incomes by the spinning and weaving wool in the domestic system. Primitive coal mining was established by the 17th century, and the factory system adopted in the late-18th century. During the Victorian era, Chadderton's economy was heavily dependent on manufacturing industries, especially the spinning of cotton, but also the weaving of silk and production of hats. By the 20th century the landscape was covered with over 50 cotton mills. Industries ancillary to these sectors, including coal mining, brick making, mechanical engineering, and bleaching and dyeing were present. Chadderton developed an extensive coal mining sector auxiliary to Chadderton's cotton industry and workforce. Coal was transported out of the township via the Rochdale Canal. The amount of coal was overestimated however, and production began to decline even before that of the local spinning industry; Chadderton's last coal mine closed in 1920.Since the deindustrialisation of the region in the mid-20th century, these industries have been replaced by newer sectors and industries, although many of the civic developments that accompanied industrialisation remain in the form of public buildings; a town hall, public baths and library. The few surviving cotton mills are now occupied by warehousing and distribution companies, or used as space for light industry.British aircraft manufacturer Avro built a factory in south Chadderton in 1938–39, later known as BAE Chadderton. It was one of the largest employers in the area, producing a variety of aircraft models including Ansons, Manchesters and Bristol Blenheims. During the Second World War, 3,050 Avro Lancaster bombers were built at the Chadderton factory—over 40 per cent of the Royal Air Force's fleet. Post World War Two the Avro Vulcan was designed and built, as well as the Avro Shackleton and Avro Lincoln. After the Aircraft and Shipbuilding Industries Act 1977, Avro became part of the...

answer the following question:

What aircraft model made at BAE Chadderton during the second world war was over 40 per cent of the Royal Air Force's fleet? 

Avro Lancaster bombers