A Brazilian Airbus A321-200 operating as TAM airlines flight JJ-3307 had to return to Rio de Janeiro and perform an emergency landing after sustaining substantial damage upon entering an embedded thunderstorm wrought with hail.
The plane was climbing out of Rio de Janeiro's runway 10 when the crew stopped the climb at approximately 18,000 feet following a hail strike cracking both windshields and damaging the nose cone. They were able to return to Rio de Janeiro for a safe landing on runway 10 about 40 minutes after departure. There were no injuries, but the aircraft received substantial damage that is still being assessed.
Local news reports that lightning damaged the aircraft's internal radome, preventing the crew from receiving radar weather images in the cockpit of the impending storm. The resulting encounter with severe hail created major damage to the nose cone and cracked the front windscreen. The windows are made with three plies of glass. The first two inner layers are the two structural plies. The outermost layer is a non structural ply and is the one that usually pops. To have all three layers break is virtually impossible. Reports do not indicate what layers were cracked.
Historic weather radar at the time of the flight indicates some heavy returns that would not be have been visible from the cockpit without the help of onboard weather receiving equipment. Further investigation will reveal to what extent the crew was briefed on weather conditions before the flight began.