How Concorde’s stretch led to one of aviation’s quirkiest time capsules

Supersonic flight on the Concorde created hidden time capsules that revealed just how demanding the aircraft’s journeys were.

At Mach 2, the jet stretched by nearly a foot, opening seams inside the cockpit.

British Airways crews slipped their caps into the gap, where the cooling metal later clamped them shut.

The caps remain in place today, sealed inside the aircraft as part of Concorde’s story.

Inside Concorde’s hidden ritual

At twice the speed of sound, Concorde’s skin heated to extreme levels.

Temperatures at the nose rose above 120°C, while much of the fuselage reached around 90°C.

The 202-foot jet lengthened by up to 12 inches, and the stretch was visible in the cockpit.

A seam beside the flight engineer’s panel opened during cruise.

Some British Airways crews placed their caps inside, knowing the gap would close on descent.

Once sealed, the caps became permanent time capsules inside the jet.

In 2003, engineer Trevor Norcott placed his cap in Concorde G-BOAG during its delivery flight to Seattle.

The aircraft is now displayed at the Museum of Flight with the cap still hidden inside.

Crews managed Concorde within narrow limits.

Speed and altitude were always linked to the temperature of the airframe. Even the white paint was chosen to reflect heat and keep the metal within safe margins.

Supersonic flight depended on constant monitoring to protect the aircraft.

Legacy of the time capsules

Concorde entered service in the 1970s and carried fewer than 100 passengers at record speeds across the Atlantic.

Its Olympus 593 engines powered sustained supersonic flight, bringing New York within three and a half hours of London.

The workload in the cockpit was heavy.

Chief Pilot Mike Bannister described it as ‘twice as fast, twice as high, and twice as many things to do’.

The time capsules show how a technical effect of supersonic flight became part of crew tradition.

They remain sealed inside Concordes now kept in museums, unseen by visitors who walk past the airframes.

The caps are reminders of the aircraft’s unique conditions and of the people who flew it at speeds no other passenger jet has matched.

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