A fam­i­ly from Spain was about to cel­e­brate the ninth birth­day of one of their chil­dren when their sight­see­ing he­li­copter broke apart in midair and crashed in­to the Hud­son Riv­er be­tween New York City and New Jer­sey, killing all six peo­ple aboard in the lat­est U.S. avi­a­tion dis­as­ter, of­fi­cials said Fri­day.

Au­thor­i­ties in­clud­ing the Na­tion­al Trans­porta­tion Safe­ty Board are in­ves­ti­gat­ing Thurs­day’s mid-af­ter­noon crash. There has been no word of a cause. The NTSB plans to brief re­porters Fri­day.

The vic­tims in­clud­ed Siemens ex­ec­u­tive Agustin Es­co­bar, his wife, Mer­cè Cam­prubí Mon­tal, a glob­al man­ag­er at an en­er­gy tech­nol­o­gy com­pa­ny, and three chil­dren, in ad­di­tion to the pi­lot, a per­son briefed on the in­ves­ti­ga­tion told The As­so­ci­at­ed Press. The per­son could not dis­cuss de­tails of the in­ves­ti­ga­tion pub­licly and spoke on con­di­tion of anonymi­ty. The pi­lot al­so died.