What happened
The FAA’s narrative, in sentence case. The FAA writes it in capitals and removes private details.
(-23) Pilot russel reported in an interview the following events resulting in the forced emergency landing. On the day and time referenced, Mr. Russel as instructor, and student funke operating the helicopter, were enroute to the training area east of mount diablo known as "the flats." While cruising at approximately 60-65 knots and 4,200 ft. altitude, instructor russel reports a "two stage" vibration occurred. In the first stage, lasting a "split second", there occurred a subtle vibration, followed immediately by a second stage vibration of a "heavy and violent" nature. The second vibrations were followed by the loss of the left door of the helicopter. Mr. Russell immediately assumed control of the helicopter. At the onset of the heavy vibrations, Mr. Russel entered an autorotation mode. He sought a landing site, and executing an approximately 10 degree left turn, descended to earth in what he described as a normal autorotation. At no time was a loss of engine power experienced. Pilot russel executed shut-down procedures upon landing, and exited the helicopter with no injuries to himself or his student pilot.
As the FAA filed it
(-23) PILOT RUSSEL REPORTED IN AN INTERVIEW THE FOLLOWING EVENTS RESULTING IN THE FORCED EMERGENCY LANDING. ON THE DAY AND TIME REFERENCED, MR. RUSSEL AS INSTRUCTOR, AND STUDENT FUNKE OPERATING THE HELICOPTER, WERE ENROUTE TO THE TRAINING AREA EAST OF MOUNT DIABLO KNOWN AS "THE FLATS." WHILE CRUISING AT APPROXIMATELY 60-65 KNOTS AND 4,200 FT. ALTITUDE, INSTRUCTOR RUSSEL REPORTS A "TWO STAGE" VIBRATION OCCURRED. IN THE FIRST STAGE, LASTING A "SPLIT SECOND", THERE OCCURRED A SUBTLE VIBRATION, FOLLOWED IMMEDIATELY BY A SECOND STAGE VIBRATION OF A "HEAVY AND VIOLENT" NATURE. THE SECOND VIBRATIONS WERE FOLLOWED BY THE LOSS OF THE LEFT DOOR OF THE HELICOPTER. MR. RUSSELL IMMEDIATELY ASSUMED CONTROL OF THE HELICOPTER. AT THE ONSET OF THE HEAVY VIBRATIONS, MR. RUSSEL ENTERED AN AUTOROTATION MODE. HE SOUGHT A LANDING SITE, AND EXECUTING AN APPROXIMATELY 10 DEGREE LEFT TURN, DESCENDED TO EARTH IN WHAT HE DESCRIBED AS A NORMAL AUTOROTATION. AT NO TIME WAS A LOSS OF ENGINE POWER EXPERIENCED. PILOT RUSSEL EXECUTED SHUT-DOWN PROCEDURES UPON LANDING, AND EXITED THE HELICOPTER WITH NO INJURIES TO HIMSELF OR HIS STUDENT PILOT.
NTSB investigation
The NTSB’s investigation of this event, with its probable cause and findings. Matched to this report by N-number and date.
Other reports on N20256 · 1
Matched to the same aircraft by N-number and date.