The Tupolev Tu-144LL being used in joint US-Russian supersonic-transport flight-test studies had its Ìrst supersonic excursion during a 1h 3min flight from Zhukovsky on 21 May. Mach 1.42 was achieved during 13min of supersonic flight, at an altitude of 39,000ft (12,000m). It was the sixth flight undertaken since the flying programme began on 29 November, 1996. The second supersonic flight, to a speed of Mach 1.8 at an altitude of 49,000ft, was due to have been made on 23 May.
Source: Flight International
