The National Transportation Safety Board report says a mechanic told David McElroy the plane had a faulty tachometer and shouldn't be flown. The instrument measures engine revolutions.
The report also says that a friend of the pilot told investigators the single-engine Socata TB10 had problems climbing three days before the crash.
The lone survivor, Erik Unhjem, said he was unaware of the conversation between the mechanic and the pilot. His wife, Jane, was killed in the crash.
The Unhjems, of Goshen. N.Y., were interested in buying the aircraft and had taken it for a test flight when it crashed last August.