SPRINGFIELD (Burlington) — The men who died in plane crash in Burlington County on Wednesday were flying for a good cause.

The pilot, Robert Winner, 69, of Marlton, and Timothy Scannevin, 71, of Southampton, were on a Hawker Beechcraft 58 Baron aircraft that was headed to Hyannis, Massachusetts, where they were going to transport a patient to Philadelphia for medical treatment.

The plane went down off Smithville-Jacksonville Road in Springfield around 9 a.m. on Wednesday. The NTSB is investigating the cause of the crash, according to State Police.

According to a statement by the nonprofit Angel Flight East, Winner had flown 16 flights for the Pennsylvania-based organization since 2013. The nonprofit said it was the first crash related to a flight that the group had arranged.

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Philly.com reported that federal records show Winner owned the plane.

"The directors and staff of Angel Flight East are deeply saddened that this accident occurred, and their thoughts and prayers are with Robert and Timothy, and their loved ones," the organization said.

Winner's son Jeff Winner told Philly.com that his family sold their Moorestown farm in 2005 in order to preserve the land as open space. Jeff Winner said that his father got "great satisfaction" from flying for Angle Flight East and kept a diary of his flights.

Scannevin often accompanied Winner on the Angel Flight assignments, according to Jeff Winner.