After years of front-line service, in July 1964, a cracked spar was found in one of the three Valiants (either WZ394 – Wynne, or WZ389 – Morgan) on Operation Pontifex. This was followed on 6 August by a failure of the starboard wing rear spar at 30,000 ft, in WP217, an OCU aircraft from Gaydon captained by Flight Lieutenant "Taffy" Foreman. The aircraft landed back at Gaydon but without flap deployment because damage to the starboard rear spar caused the flap rollers to come out of their guides so that the flap would not lower on that side. Later inspection of the aircraft also showed the fuselage skin below the starboard inner plane had buckled, popping the rivets; the engine door had cracked and the rivets had been pulled and the skin buckled on the top surface of the mainplane between the two engines. Both of these aircraft were PR variants.