Plane & Pilot
Tuesday, November 5, 2013

The Weather Picture


The NTSB wants you to be able to see what’s happening in places you’re going to


The controller assumed that the pilot was operating in VFR conditions. The controller instructed the pilot to "turn southbound now," as the flight path was still heading toward the mountains. She wasn't sure if the airplane could climb fast enough to avoid the terrain, but thought it was best for him to turn away from the mountains toward lower terrain.

The NTSB determined that the probable cause of the accident was the pilot's continued visual flight into IMC at an altitude insufficient to ensure adequate terrain clearance.

Cessna 172M
A Cessna 172M crashed into terrain near Pahala, Hawaii. The commercial pilot and his two passengers were killed. The Part 135 air tour flight departed Kailua-Kona in VFR conditions. The flight was supposed to last two hours and 30 minutes. The planned altitude was 2,000 feet.

The pilot opened his VFR flight plan with ATC. The airplane was in radar contact only part of the time. It was seen by the pilot of another aircraft in an area where lava from a volcano was entering the ocean. When the airplane didn't return to Kailua-Kona at its scheduled time, a search began. The search was expanded and additional assets were brought in the next day. The airplane wasn't found until five days later, in a rainforest on the southeastern side of the Mauna Loa volcano. The airplane was at an elevation of 4,500 feet approximately nine nautical miles inland from the coast. The terrain was moderately sloped, rugged volcanic rock.

A weather study performed by an NTSB meteorologist indicated that the flight around the island would have been VFR with two low-level cloud layers. Cloud tops were generally about 7,500 feet during the morning, and developing to greater than 14,000 feet by early afternoon. The accident site was near the western edge of the cloud layer. Patchy rain or drizzle was likely in the accident area around the time of the accident.

A witness who was about a mile away from the accident site reported that the weather was very foggy, misting and rainy. A helicopter pilot had lowered the witness into the forest about an hour before the crash. The pilot then made two trips with building material and supplies. He terminated his last planned trip because of deteriorating weather, which included clouds, mist and volcanic haze.

The NTSB determined that the probable cause of this accident was the pilot's continued VFR flight into IMC and his failure to remain clear of rising terrain, while deviating from his planned route of flight. Contributing to the accident were clouds and mountainous terrain that made safe navigation difficult.

Peter Katz is editor and publisher of NTSB Reporter, an independent monthly update on aircraft accident investigations and other news concerning the National Transportation Safety Board. To subscribe, write to: NTSB Reporter, Subscription Dept., P.O. Box 831, White Plains, N.Y. 10602-0831.



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