NTSB Identification: CHI93FA378.
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Accident occurred Monday, September 27, 1993 in LANSING, MI
Probable Cause Approval Date: 10/20/1994
Aircraft: AERO COMMANDER 690A, registration: N242TC
Injuries: 2 Fatal.
NTSB investigators either traveled in support of this investigation or conducted a significant amount of investigative work without any travel, and used data obtained from various sources to prepare this aircraft accident report.
THE AIRPLANE DEPARTED IN IMC CONDITIONS ON AN IFR FLIGHT PLAN. SHORTLY AFTER TAKEOFF THE PILOT TOLD THE DEPARTURE CONTROLLER HE HAD '...A PROBLEM.' THE AIRPLANE'S FLIGHT PATH WAS A SERIES OF LEFTHAND TURNS WHILE PERFORMING DESCENTS AND ASCENTS. REPORTS OF ENGINE SOUNDS VARIED FROM HIGH RPM TO LOW RPM. MANY WITNESSES REPORTED THE AIRPLANE DESCENDING OUT OF, AND CLIMBING INTO, CLOUDS. THE AIRPLANE WAS OBSERVED IN A 45 DEGREE ANGLE DESCENT, RIGHT WING LOW, AS IT COLLIDED WITH TREES AND THE GROUND. THE ON-SCENE INVESTIGATION FOUND AN INTERMITTENT ELECTRIC GYRO SYSTEM INVERTER, A BROKEN FILAMENT ON THE INVERTER POWER 'OUT' LIGHT BULB, ELECTRICALLY POWERED GYRO'S ROTORS DID NOT HAVE ROTATIONAL DAMAGE, AND A VACUUM POWERED ATTITUDE INDICATOR ROTOR WITH ROTATIONAL DAMAGE. THE PILOT'S TOXICOLOGY REPORT STATED 45 MG/DL OF ETHANOL DETECTED IN HIS MUSCLE TISSUE.
The National Transportation Safety Board determines the probable cause(s) of this accident to be: was the pilot-in-command not maintaining aircraft control during the intermittent operation of the electrically operated attitude gyro. Factor's associated with this accident are an fluctuating (intermittent) electrical system inverter and the pilot-in-command not performing remedial action by using the vacuum powered attitude gyro and other flight instruments once the airplane was making a series of climbs, descents, and heading changes. Full narrative available
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