What happened
During an instrument climb-out from Teterboro Airport, the pilot received instructions from departure control to climb and maintain 4,000 feet MSL after being placed in radar contact. The pilot acknowledged these instructions while at a radar-recorded altitude of 1,800 feet MSLE.
Data indicates the aircraft reached an altitude of 2,800 feet MSL before beginning a descent. Numerous witnesses observed the aircraft descending from the clouds; one witness reported that the descent appeared to be a spin with no forward motion. There were no fatalities reported in this event.
The investigation
An examination of the wreckage on-scene revealed that the left propeller had one blade bent aft by approximately 120 degrees, while the other blade remained straight and unbent. The propeller was not in the feathered position at the time of the incident.
A teardown of the left engine revealed that two of the six fuel injector nozzles were restricted. Records showed that the last documented cleaning of the fuel injection system occurred in 1985, despite the manufacturer, Bendix, recommending cleaning every annual inspection or 100 flight hours.
Additionally, the investigation determined the aircraft was 188 lbs over its maximum gross weight. The center of gravity (CG) was also approximately 1 inch aft of the maximum aft limit. An aft CG position increases the minimum controllable airspeed (VMC).