The single fin on the Eurofighter Typhoon experiences buffet loads caused by burst vortices which originate from the canard and wing leading edges at high angles of attack. The sides of the top-mounted airbrake, when deflected, also shed vortices which impinge, after bursting, on the fin. Buffeting from the extended airbrake is highest when the airbrake effective angle of attack is greatest, which for a fully-extended airbrake is greatest at low aircraft angle of attack and least when manoeuvring.[20] The McDonnell Douglas F/A-18 Hornet twin fins are subject to buffeting from the breakdown or bursting of the LEX vortex in front of the tail.[21] The addition of a LEX fence significantly reduces the buffeting and increases fin fatigue life.[22]