Cessna 180 N3119D accident near Austin, Texas

Probable cause

The pilot's improper decision to attempt to take off after two previous failed attempts from choppy water with a high outside temperature and the airplane near its maximum gross weight, which degraded the airplane’s performance and resulted in its inability to maintain adequate airspeed and sustain a climb.

NTSB analysis

The commercial pilot was attempting to take off from a lake for an air tour flight with two passengers onboard. He noted that, after accelerating to get on step, it took "a bit longer than usual" to do so due to a high outside air temperature and choppy water conditions, which he realized could affect the airplane's performance. The airplane hit some waves just before reaching a takeoff speed about 45 mph, lifted off briefly, settled back down, and bounced twice. All indications appeared normal, and the airplane began to climb, but the pilot did not "feel" the usual acceleration after the airplane lifted off the water. Once the airplane was flying in ground effect, the pilot leveled it off a little to increase the airspeed, but the airspeed did not increase. After reaching between about 25 and 35 ft above the water, the airplane began descending, and it could not maintain altitude or airspeed. The pilot pitched the airplane's nose down a little to increase the airspeed, but the airspeed did not substantially increase, and the airplane began descending faster. The airplane's left pontoon impacted the water, which collapsed and then contacted the rotating propeller.

Postaccident examination of the airplane revealed no evidence of any preimpact mechanical malfunctions or failures that would have precluded normal operation. The Airplane Flying Handbook stated, in part, that, "under conditions of …high temperature, and/or maximum gross weight, the airplane may be able to lift off but will be unable to climb out of ground effect." After the accident and upon request, the pilot provided the Federal Aviation Administration investigator weight and balance calculations for the accident flight, which showed that the airplane was either at or above its maximum gross weight. This in conjunction with the high outside air temperature likely degraded the airplane's performance, which prevented it from being able to sustain a climb. The pilot was aware that such conditions could affect the airplane's performance and should not have attempted to take off.

Text from the NTSB. Open the NTSB docket for CEN17LA283 for the full record.