On 1 August 2008, an Embraer 195 being operated by Flybe on a scheduled passenger service from Manchester to Belfast City with the No 2 air conditioning pack inoperative in accordance with the MEL was passing FL 156 in the climb in day IMC approximately 40nm northwest of the WAL VOR when the No 1 Air Cycle Machine (ACM) failed, releasing smoke and fumes into the aircraft. A MAYDAY was declared and a diversion to the Isle of Man was carried out. After donning oxygen masks the pilots had great difficulty communicating with each other, ATC and cabin crew, because of technical problems with the masks. During the subsequent emergency evacuation ordered by the aircraft commander, the right over-wing emergency exit door became jammed and unusable.