Brian Rayner, an NTSB air safety investigator, at the site where...

Brian Rayner, an NTSB air safety investigator, at the site where a small plane crashed in Mattituck on June 8. Credit: Randee Daddona

The pilot of the small plane that crashed in an empty farm field in Mattituck this month, killing both people on board, had lost altitude over Sound Avenue before steering over the field seconds before losing contact with air traffic controllers, according to a federal report.

The National Transportation Safety Board, in its preliminary report on the June 8 crash, offered an account of the final moments of the flight that ended in a post-crash fire.

The report, released June 14, did not draw conclusions or provide analysis as to why the plane’s engine apparently failed. A final report is to be issued at an unspecified date.

Pilot Robert Mark, 66, of Oakdale — traveling with his longtime girlfriend Susan Quagliano, 57, and their dog in a Beechcraft A36 Bonanza — left Long Island MacArthur Airport for Bedford, Massachusetts, at 9 a.m. Communications during the taxi, engine run-up and takeoff were routine, the report states.

Eleven minutes later, at 3,325 feet, 107 knots and one mile north of the shoreline near Riverhead, the Beechcraft began to descend, according to the report.

The aircraft veered right and crossed the coast at 2,175 feet and 88 knots. Mark contacted air traffic control and announced the airplane had experienced "engine failure" and that he planned to land in a field, the report states.

The airplane descended over Sound Avenue before Mark turned it left and reversed course to the west over Harbes Family Farm in Mattituck, where it crashed.

The report said a witness asked another bystander whether the low-flying plane was a crop duster. One witness said he heard the engine, another said he did not.

The plane lost radar contact at 25 feet above ground at 88 knots, 200 feet east of the accident site.

Surveillance footage depicted the airplane at a low altitude in a steep left bank, turning west before hitting the ground and disappearing from view. A dark plume of smoke then appeared on the footage, according to the report. The cockpit, cabin, tail assembly and both wings were consumed by the fire.

The couple died in the crash, though the dog escaped.

The wreckage path spanned 105 feet, and all components were accounted for, the report states.

The aircraft was manufactured in 1990. Its last annual inspection was on Feb. 21 and its last maintenance on May 31. Mark held a private pilot certificate with ratings for airplane single-engine land and instrument airplane. His most recent FAA third-class medical certificate was issued May 24 when he reported 11,090 hours of flight experience.