Sarah Chester and her daughter Payton Chester of Orange County were on board the aircraft on Sunday morning when it crashed in Calabasas, California, according to The New York Times.
St. Margaret’s Episcopal School confirmed the news in a memo obtained by PEOPLE, in which the school said Payton was enrolled in eighth grade and Sarah served on its board of trustees.
The mother is survived by her husband Chris and her two sons, Hayden and Riley, who are in 10th grade.
“This is an unimaginable loss for the Chester family and the entire St. Margaret’s community,” read the memo. “We are a community in mourning. Our greatest strength is when our St. Margaret’s community pulls together with arms around one another, and this is one of those times.”
A representative from St. Margaret’s Episcopal School did not immediately respond to PEOPLE’s request for comment.
Todd Schmidt, who identified himself as Payton’s elementary school principal, wrote on Facebook that Payton and Sarah were “two gorgeous human beings.”
“As a principal, we work with some amazing families…the Chesters were one of those…engaged, supportive, encouraging, and full of mischief and laughter…and they had the best kiddos,” he wrote. “This family made such a huge impact at … they were genuine, kind-hearted, and caring…to the staff, to other families…and yes, especially to me.”
He added: “While the world mourns the loss of a dynamic athlete and humanitarian, I mourn the loss of two people just as important…their impact was just as meaningful, their loss will be just as keenly felt, and our hearts are just as broken. … The world is just a little less without you both in it. May you both Rest In Peace and know the deep impact you had on our lives. You will be so sorely missed.”
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The National Transportation Safety Board confirmed the aircraft involved in the fatal crash, which is still under investigation, was a Sikorsky S-76.
Girls basketball coach Christina Mauser, of Harbor Day School in Orange County, was also among those on board the private helicopter.
Her husband Matt Mauser confirmed the news on Facebook, writing: “My kids and I are devastated. We lost our beautiful wife and mom today in a helicopter crash. Please respect our privacy. Thank you for all the well wishes they mean so much.”
John Altobelli, the head baseball coach at Orange Coast College, was also flying on the aircraft — alongside his wife Keri Altobelli and their daughter, Alyssa Altobelli, the school confirmed in a statement on their website.