Aviation Accident Summaries

Aviation Accident Summary ANC99LA018

ANCHORAGE, AK, USA

Aircraft #1

N4185P

Piper PA-23-160

Analysis

The airline transport pilot was attempting to ferry the airplane to the Anchorage International Airport, located about 3 miles from Merrill Field. He stated that the airplane did not have a current annual inspection, and that he had obtained an FAA ferry permit for the one-time maintenance ferry flight. He added that the airplane had not been operated for about two months, and that the airplane was stored outside with the main fuel tanks about 3/4 full. The pilot reported that during the initial climb from runway 24, about 100 feet above the runway, engine power was lost on the right engine, followed by a surge in engine power, and then total loss of power on the right engine. He stated that the airplane had progressed beyond a point where he could safely abort the takeoff, and he elected to continue the takeoff with one engine operating. He said that he was unable to maintain altitude, airspeed, and directional control due to the inoperative engine on the right side, and made a forced landing. The airplane descended into a railroad maintenance yard, struck a power line, and a maintenance tool shed. The airplane sustained substantial damage to the fuselage, wings, and tail. A fuel sample taken from the airplane wreckage exhibited visible contaminants.

Factual Information

On December 19, 1998, about 1515 Alaska standard time, a wheel equipped Piper PA-23-160 airplane, N4185P, sustained substantial damage during takeoff from Merrill Field, Anchorage, Alaska. The airplane was being operated as a visual flight rules (VFR) maintenance ferry flight under Title 14, CFR Part 91, when the accident occurred. The solo airline transport pilot received minor injuries. Visual meteorological conditions prevailed, and no flight plan was filed. During an interview with the National Transportation Safety Board (NTSB) investigator-in-charge on December 21, the pilot reported that he was attempting to ferry the airplane to the Anchorage International Airport, located about 3 miles from Merrill Field. He stated that the airplane did not have a current annual inspection, and that he had obtained an FAA ferry permit for the one-time maintenance ferry flight. He added that the airplane had not been operated for about two months, and that the airplane was stored outside with the main fuel tanks about 3/4 full. The pilot reported that during the initial climb from runway 24, about 100 feet above the runway, engine power was lost on the right engine, followed by a surge in engine power, and then total loss of power on the right engine. The pilot stated that the airplane had progressed beyond a point where he could safely abort the takeoff, and he elected to continue the takeoff with one engine operating. He said that he was unable to maintain altitude, airspeed, and directional control due to the inoperative engine on the right side, and made a forced landing. The pilot sustained a head injury as a result of the accident, and was unable to provide any further information concerning the accident. A multiengine airplane rated pilot witnessed the accident airplanes departure to the west, and said the flight path was "very low and slow, and the airplane appeared to be flying sideways while it made a right turn." The witnesses noted that the left engine was operating at a very high power setting, and the right propeller was rotating very slowly. The airplane descend into a railroad maintenance yard, struck a power line, and a maintenance tool shed. The airplane sustained substantial damage to the fuselage, wings, and tail. The National Transportation Safety Board investigator-in-charge visited the accident scene on December 22, and examined the airplane wreckage. The right wing fuel tank was extensively damaged, and breached. A fuel sample was obtained from the right gascolator, and right carburetor float bowl. The sample taken from the right gascolator appeared light yellow in color, and exhibited trace amounts of visible contaminants. The sample taken from the right carburetor float bowl appeared dark yellow in color, and also contained trace amounts of visible contaminates. A laboratory analysis was unattainable due to the limited quantity of fuel available for collection. On December 31, 1998, an examination of the right engine carburetor was conducted at The Accessory Shop, Inc., Anchorage, Alaska. The examination revealed that the needle valve retaining clip was installed backwards, and the measured float drop was 1/16 inch below acceptable limits. The inlet fuel screen was removed from the carburetor body. The screen contained fibrous material. Review of the right engine logbooks disclosed that the engine accrued 1,852.7 hours since being overhauled. Since the overhaul, the number three, and number four engine cylinders were changed after the engine had accrued 443.1 hours. On January 7, 1999, an engine examination was conducted at B.J. Custom Aircraft Engines, Inc., Palmer, Alaska. Disassembly exposed the following engine anomalies: Removal of the number two rocker valve cover revealed that the exhaust valve cap was found loose within the valve cap area. Witness marks matching the size and shape of the loose valve cap were noted on the inside of the rocker cover. Removal of the number three and four rocker covers revealed that the both exhaust valve caps were missing. There were no witness marks noted on the rocker covers. Both magnetos produced spark at all terminals upon hand rotation. Both propeller blades were in the feathered position.

Probable Cause and Findings

A loss of engine power due to fuel contamination. A factor associated with the accident was the pilot's failure to maintain directional control.

 

Source: NTSB Aviation Accident Database

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