On 15 January 2013, at about 1500 Coordinated Universal Time (UTC), a Cessna Citation 750, registered VH-RCA departed Faleolo International Airport, Samoa for Sydney Airport, New South Wales, with two flight crew and five passengers on board. About 1 hour 35 minutes into the flight the crew received a WSHLD HEAT INOP L (windshield heat inoperative left) message on the engine-indicating and crew-alert system (EICAS) and approximately 2 minutes later the windshield outer ply shattered with a loud bang. An immediate descent was commenced along with a turn towards Nadi International Airport, Fiji. The flight continued to Nadi without further incident and there were no injuries to passengers or crew.
The manufacturer reported that they had experienced two reliability issues with the windshield part number installed on the aircraft (9914380-11/-12). It was likely that the electrically heated windshield had been affected by moisture ingress resulting in a degradation of the electrical connection between the bus bar and the heating film. Changes to the windshield to address the issue were incorporated into part number 9914380-13/-14. There have been no reported cases of either of the failure modes in the -13/-14 windshields.
While the failure of the windshield involved the outer pane only, and did not result in a depressurisation, the precautions taken by the flight crew to descend to a lower altitude and diversion to the alternate airport highlighted the importance of good flight planning.