sentences:  The first flight of the Andover was on 28 June 1924.Because the "Desert Air Route" was transferred to Imperial Airways, no order was placed by the RAF, so Avro manufactured only three Type 561, which were transferred to RAF Halton, location of Princess Mary's RAF Hospital.In spite of the lack of commercial success, a single Type 563 variant was developed by Avro, which had an additional washroom and a baggage compartment.