Aviation Accident Summaries

Aviation Accident Summary SEA94LA035

BROOKINGS, OR, USA

Aircraft #1

N8829J

PIPER PA-28-180

Analysis

WHILE EN ROUTE ON AN IFR FLIGHT PLAN, THE PILOT ENCOUNTERED ICING CONDITIONS. THE AIRCRAFT EXPERIENCED BOTH STRUCTURAL AND INDUCTION ICING, AND THE PILOT INITIATED A DESCENT AS THE AIRCRAFT BEGAN TO LOSE POWER. EVENTUALLY THE ENGINE LOST ALL POWER, AND THE PITOT TUBE ICED OVER. THE AIRCRAFT IMPACTED THE TERRAIN WHILE THE PILOT WAS ATTEMPTING A FORCED LANDING IN A SMALL UNFORESTED AREA. BECAUSE THE PILOT HAD LIMITED HIS 'WEATHER BRIEFING' TO SELECTED DUAT SYSTEM DATA AND AN ABBREVIATED FLIGHT SERVICE STATION BRIEFING, HE FAILED TO RECEIVE AN AIRMET WARNING OF OCCASIONAL ICING CONDITIONS ALONG HIS ROUTE OF FLIGHT.

Factual Information

On November 22, 1993, approximately 1515 Pacific standard time (PST), a Piper PA-28-180, N8829J, impacted the terrain during an attempted forced landing about four miles north of Brookings, Oregon. The private pilot, who was the sole occupant of the aircraft, received serious injuries, and the aircraft sustained substantial damage. The personal pleasure flight, which had departed McNary Field, Salem, Oregon, about 1335 PST, was in instrument meteorological conditions when the accident sequence began. The pilot was on an IFR flight plan, and the ELT, which was activated by the impact, was turned off at the scene. A review of the audio tapes of the pilot's communications with Seattle Center revealed that the pilot encountered icing conditions while cruising at 9,000 feet MSL and passing through clouds about 20 miles north of Brookings. The pilot reported that he had picked up ice, and that he thought he had intake icing and was having trouble keeping the engine running. The pilot, who could not maintain altitude because of a steady loss of power, also reported that his pitot tube had iced over, resulting in his airspeed indicator dropping to zero. During the emergency descent, the pilot reported that he had experienced a total loss of power, and that he was going to try to attempt to glide to the coast. During this glide, the pilot was advised that Brookings Airport was at his twelve o'clock position, about three and a half miles ahead. He then elected to attempt to make it to the airport, and reported that his engine had gained "...some partial power back." While attempting to reach the airport, the pilot radioed that he was "...in real trouble here...", and was "...coming down on terrain." The aircraft was discovered where it had impacted the terrain in a small unforested area that was rough and uneven. A post-crash investigation revealed that the pilot had obtained weather information from the GTE DUAT system about three and one- half hours prior to his departure. While using this system the pilot requested Surface Observations (SAs), Terminal Forecasts (FTs), Winds Aloft Forecasts (FDs), Notice To Airmen (NOTAMs), and Pilot Reports (UAs) for Salem, Oregon (SLE), Eugene, Oregon (EUG), Medford, Oregon (MFR), North Bend, Oregon (OTH), Crescent City, California (CEC), and Arcata, California. He then contacted McMinneville Flight Service Station (FSS) about one-half hour prior to his departure. During his telephone conversation with the FSS, the pilot filed his IFR flight plan and limited his "weather briefing" to a request for winds aloft and cloud tops. By limiting his "weather briefing" to the above requested data, the pilot failed to receive AIRMET ZULU, which was issued at 1145 PST, and was valid until 1800 PST. AIRMET ZULU, which included the geographical area through which the accident aircraft's route of flight passed, warned of "...occasional moderate rime and mixed icing in clouds and precipitation from the freezing level too 17,000 feet." The winds aloft forecast the pilot received from the DUAT system showed the forecast 6,000 foot MSL temperature in the area of the icing encounter to be minus 10 degrees celsius, and the forecast 9,000 foot temperature to be minus 16 degrees celsius.

Probable Cause and Findings

THE PILOT'S INADEQUATE PREFLIGHT PLANNING/PREPARATION, AND ICING OF THE INDUCTION AIR FILTER/SCREEN. FACTORS INCLUDE WEATHER CONDITIONS CONDUCIVE TO ICING, AND ROUGH/UNEVEN TERRAIN IN THE AREA OF ATTEMPTED LANDING.

 

Source: NTSB Aviation Accident Database

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