Flight Details
The pilot was conducting an on-demand air taxi flight in a float-equipped airplane from a seaplane base on a public lake to a remote lakeside home. On board were a passenger and her young son. The passenger also brought cargo, including an unexpected 800 lbs of mortar bags. After loading, witnesses who helped push the airplane out reported that it appeared very aft heavy. The pilot stated he would offload "cement blocks" if he could not take off.
Takeoff Attempts
Witness videos showed the pilot attempted one takeoff using only three-quarters of the available waterway. He then step taxied around the lake and performed a step-taxi takeoff, again not using the full length of the lake. The airplane lifted off and barely climbed over trees on the south end of the lake before descending and impacting terrain.
Pre-Impact Conditions
A home surveillance video captured the airplane seconds before the crash. Three seconds before ground impact, the estimated altitude was 115 ft above ground level (agl) and the groundspeed was about 64 mph, which was low and much slower than the normal climb speed of 80 mph. As the airplane banked left to turn on course, it rolled through 90°, likely experiencing an aerodynamic stall. Analysis of engine rpm sound revealed the engine was operating near maximum continuous power up until impact. A postaccident examination of the airframe and engine found no evidence of mechanical malfunctions or failures that would have precluded normal operation.
Weight and Balance
A postaccident calculation estimated the airplane's gross weight at the time of the accident was 75 lbs over the approved maximum gross takeoff weight, and the center of gravity was 1.76 inches aft of the rear limit. Although the airplane was able to take off, the out-of-limit weight-and-balance condition increased its stall speed and degraded its climb performance, stability, and slow-flight characteristics.
Pilot Experience
The pilot had been recently hired by the operator. He flew his first commercial flight in the same make and model, float-equipped airplane the week before the accident. He had accumulated 12.9 flight hours and 13 sea landings and takeoffs in the accident model airplane since being hired as a part-time pilot.
Probable Cause
According to the official investigation, the probable cause was the pilot's exceedance of the airplane's critical angle of attack during departure climb, which resulted in an aerodynamic stall. Contributing to the accident was the pilot's improper decision to load the airplane beyond its allowable gross weight and center of gravity limits, coupled with his lack of operational experience in the airplane make, model, and configuration.