During the second demonstration flight at the Paris Air Show ’73 a low pass was made over runway 06. At the end of the runway the aircraft entered a steep climb. While the canards on the forward fuselage were being retracted, the Tu-144 entered a steep dive. The disturbed airflow may have caused one or more engines to flame out. In order to regain control the canards were deployed again. The crew tried to pull out of the dive, causing the overstressing of the airframe. The left canard-wing is reported to have separated, striking the wing and puncturing the fuel tank. The Tupolev broke up and crashed in flames into the small town of Goussainville. It appears that, for safety reasons, the Tupolev factory had restricted the control surface deflection to a maximum of 5 degrees with canards extended. For the second day of the show Tupolev wanted a more impressive flight demonstration, certainly in comparison with the other supersonic transport (SST) at the air show: Concorde. Engineers thus disabled the 5-degree limitation. A latent erroneous set-up of the auto-stabilizer electronics now could have serious effects. After retraction of the canards the auto-stabiliser reacted by deflecting the elevons 10 degrees down. This caused the SST to enter a sudden dive.