The final report by the National Transportation Safety Board states that carburetor icing caused a small plane to crash off Makaha last year.
On May 23, 2016, Eric Kawamoto and his wife were returning to Honolulu from Kauai when the plane lost engine power and crash-landed in the water. They suffered visible scrapes and were greatly shaken, but felt lucky to be alive.
Back then, Kawamoto told KHON2 that his plane had plenty of fuel and recently passed its annual inspection.
One year later, the NTSB says icing caused a loss of engine power to the single-engine Beech C23, tail number N6697Y, that resulted in the pilot ditching the plane into the water.
The report also found that a delay by the pilot in applying carburetor heat contributed to the icing, and that the area was conducive to carburetor icing at the time of the crash.
“Weather conditions in the area at the time of the accident were conducive to the formation of carburetor icing at glide and cruise power and serious carburetor icing at glide power. If the pilot had either kept the carburetor heat on or applied it earlier, the loss of engine power and subsequent ditching could have been avoided.” – NTSB Report
The interisland flight originated from Lihue Airport about 20 minutes prior to the accident with an intended destination of Kalaeloa Airport in Kapolei.
Kawamoto reported that during the climb to cruise portion of the flight, the engine began to run rough. He applied carburetor heat, which resolved the roughness, and he continued his climb to 5,500 feet mean sea level.
As the flight was approaching Oahu, the engine began running rough, in addition to a reduction of engine rpm to about 1,700. Kawamoto applied carburetor heat and adjusted the mixture, but was unsuccessful at restoring engine power.
Kawamoto then initiated a forced landing into the ocean, with the plane coming to rest nose low partially submerged within about 20 feet of water, about 50 to 75 feet from the shoreline.