Aircraft: Cessna 206. Injuries: 1 Minor. Location: Arcadia, Fla. Aircraft damage: Substantial.
What reportedly happened: The density altitude at the time of the accident was calculated to be about 2,300 feet. The pilot, who was attempting a water takeoff, used 10° of flaps to get the airplane off the water. It climbed to about 400 feet but would not maintain altitude and began to descend. The pilot executed a forced landing into a field where the airplane collided with trees.
After recovery of the airplane, the engine was removed and test run. No pre-accident mechanical malfunctions or failures were found that would have precluded normal engine operation.
A review of the performance chart revealed that the airplane, in a clean configuration and at a maximum gross weight of 3,800 pounds, should have been able to maintain a rate of climb of 600 feet per minute. Although the pilot estimated the gross weight was 3,695 pounds, post-accident weight and balance calculations revealed the estimated weight of the airplane at takeoff was 3,855 pounds, which was 55 pounds above the maximum allowable gross weight.
Investigators determined that it is likely that the high density altitude combined with operation over the airplane’s maximum permitted takeoff gross weight resulted in the airplane’s inability to climb or maintain altitude.
Probable cause: The pilot’s decision to take off in high density altitude conditions with the airplane over its maximum gross weight, due to the pilot’s improper weight and balance calculations, which resulted in the airplane’s inability to climb or maintain altitude.
NTSB Identification: ERA11LA451
This August 2011 accident report is provided by the National Transportation Safety Board. Published as an educational tool, it is intended to help pilots learn from the misfortunes of others.