The UK Civil Aviation Authority and its French equivalent the DGAC listed seven basic engineering changes which had to be completed before each Concorde had its certificate of airworthiness returned, including:
fitting Kevlar/rubber lining to the vulnerable fuel tanks above the wheels. This is intended to self-seal, reducing fuel flow from any leak should tyre debris pierce the tank; use of new Michelin NZG radial tyres which are more resistant to damage and would release lighter tyre tread sections if the tyre were to explode; armouring the electrical wiring in the undercarriage bay to reduce potential ignition sources for leaking fuel; undercarriage water deflectors should not contain retention cable because of its damage potential; the tyre pressure detection and warning system must be working on departure; electrical power to the brake cooling fans - the most powerful electrical supply to the undercarriage - is automatically isolated during the take-off and landing runs.Source: Flight International
