In Flight: En route from London to Tokyo, a pilot’s-eye view of life in the sky.

TAKEOFF As we push back from our gate at Heathrow Airport we light the Boeing 747’s engines in pairs, starting with those under the starboard wing. A sudden hush falls in the cockpit as the air flow for the air-conditioning units is diverted. It’s this, air alone, that begins to spin the enormous techno-petals of the fans, faster and faster, until fuel and fire are added, and each engine wakes with a low rumble that grows to a smooth, unmistakable roar.