The owner of a small plane in a deadly Hawaii crash said there were no mechanical issues when he rented it to the pilot.

Aircraft Maintenance and Flight School Hawaii owner Jahn Mueller said today the single-engine plane had an alternator issue when he rented it to Dean Hutton about three weeks ago. He says the alternator was fixed when Hutton rented the same plane Friday.

“There’s always something to fix on an airplane,” Mueller said. Hutton was able to land normally during that previous flight, Mueller said.

Federal investigators haven’t yet determined what caused the plane to crash in an inaccessible mountainous area on the island of Oahu. Hutton and his three passengers died in the crash. They were four friends remembered by loved ones for their kind hearts and contagious positivity, the Honolulu Star-Advertiser reported.

A U.S Coast Guard helicopter spotted the wreckage Saturday. The National Transportation Safety Board hasn’t yet sent investigators to the area, agency spokesman Keith Holloway said.

Hutton was a frequent customer who rented planes from him often, Mueller said.

“He was a great guy,” Mueller said. “I never flew with him, so I don’t know his pilot skills.”

Mueller also owns another single-engine plane that crashed near a Honolulu freeway carrying three men last month. There were no major injuries when the plane crashed and ended up under a freeway bridge that spans a stream.