Cessna 172S N6345L accident near New Smyrna Beach, Florida

Probable cause

The flight instructor's failure to recognize or implement adequate remedial action to counter the effects of spatial disorientation. Contributing to the accident was the spatial disorientation experienced by one or both pilots.

NTSB analysis

With sunset approaching and nearing coastal water, the flight instructor and the private pilot under instruction were completing a cross-country instrument training flight. One of the pilots contacted air traffic control and reported the airplane's altitude at 7,000 feet. The controller told the pilots to expect vectors for a visual approach to the destination airport. They cancelled their instrument flight rules flight plan, angled the airplane offshore, and completed a right-turning pattern before returning to the shoreline. About 13 minutes after sunset, the airplane again proceeded offshore and appeared to make a general, one and one-half, circle-like pattern to the left, with the last full circle much tighter than the first half circle. During the last full circle, the airplane's altitude decreased from 3,100 feet to 1,700 feet in 14 seconds, a rate of descent of about a 6,000 feet per minute. Witnesses stated that they saw the airplane descending at a high rate, not in a spin, but in a nearly vertical, extreme nose-low attitude before it impacted the water. Wreckage examination confirmed that the airplane impacted the water nose low, left wing down, and slightly inverted. No preexisting mechanical malfunctions or failures were noted with the airplane that would have precluded normal operation, and radar returns did not indicate that any objects detached from the airplane in flight.

Weather observations recorded about 2 nm inland and about 10 minutes before the accident indicated visibility of 5 statute miles in light mist, scattered clouds at 800 feet above ground level (agl), and a broken cloud layer at 1,900 feet agl. With diminished lighting conditions, cloudy conditions inland, and a mostly overwater sight picture, it is likely that there was little or no discernible horizon. A loss of horizon reference is conducive to the onset of spatial disorientation. The pilot at the controls was likely not using or believing his instruments, instead, relying on his senses to determine airplane orientation. He then likely attempted to level the airplane by feel and by pulling back on the yoke while in the left turn, which made the turn tighter and lowered the airplane's nose until the airplane was in a vertical descent. It could not be determined which pilot was at the controls or whether both may have been at some point; however, the flight instructor had the ultimate responsibility to maintain safety of flight.

Text from the NTSB. Open the NTSB docket for ERA11FA146 for the full record.