Before the accident, Concorde had been arguably the safest operational passenger airliner in the world with zero passenger deaths-per-kilometres travelled; but there had been two prior non-fatal accidents and a rate of tyre damage some 30 times higher than subsonic airliners from 1995 to 2000.[267][268][269][270] Safety improvements were made in the wake of the crash, including more secure electrical controls, Kevlar lining on the fuel tanks and specially developed burst-resistant tyres.[271] The first flight with the modifications departed from London Heathrow on 17 July 2001, piloted by BA Chief Concorde Pilot Mike Bannister. During the 3-hour 20-minute flight over the mid-Atlantic towards Iceland, Bannister attained Mach 2.02 and 60,000 ft (18,000 m) before returning to RAF Brize Norton. The test flight, intended to resemble the London–New York route, was declared a success and was watched on live TV, and by crowds on the ground at both locations.[272]