On 9th March 1937 British Air Force came into possession of a bomber Armstrong Whitworth Whitley Mk. I. The first aircrafts were used in No. 10 Squadron RAF. The totally metal construction was powered by 2 Rolls Royce Merlin engines. The crew of this aircraft consisted of 5 people. The bomber reached a speed of 309 km/h and could carry up to 1,5 tons of bombs. Its weaponry was composed of 2 machine guns 7,7 mm (0,303 in.). In Whitleye bombing units the bombers were used until 1942, coast guard units used them for another year.