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N6687Y accident description

Hawaii map... Hawaii list
Crash location Unknown
Nearest city Laupahoehoe, HI
19.986114°N, 155.243504°W
Tail number N6687Y
Accident date 06 Dec 1995
Aircraft type Piper PA-23-250
Additional details: None

NTSB Factual Report


On December 6, 1995, about 2308 Hawaiian standard time (hst), a Piper PA-23-250, N6687Y, operated by an airline transport rated pilot, was destroyed when it impacted trees and the terrain at the 4,500' level of Mauna Kea volcano on the island of Hawaii, near the town of Laupahoehoe, Hawaii. The location of the accident was about 90 nautical miles southeast of the intended destination airport. The pilot sustained fatal injuries. The personal 14 CFR Part 91 flight was operating on an IFR flight plan in night visual meteorological conditions. The flight departed Oakland, California, at 0757 hst with the intended destination of Kahului, Hawaii.

Prior to the accident flight, the airplane was equipped with auxiliary tanks, exclusively for this flight. These consisted of two 100 gallon, and one 40 gallon metal tanks installed in the cabin of the airplane. The total fuel capacity of the airplane, including the standard fuel, was 380 gallons. A sample fuel consumption chart representing the make and model airplane is attached to this report. The flight plan called for a time en route of 13:29 hours. The calculated time en route, based on actual departure time and radar data, from takeoff to the approximate accident time was 15:09 hours.

The original flight plan was for a departure from Oakland at 0836 with a proposed arrival time in Kahului of 2205. The actual departure occurred at 0757. The pilot was instructed to and had been making hourly position reports. The last report and contact with the flight occurred at 1821, when the flight reported a position of 655 nautical miles east of Kahului. The accident airplane was located on radar at 2200:10. A number of attempts by air traffic control facilities and repeated attempts of radio contact relays between the accident airplane and other airplanes was not successful. Precipitous terrain is situated between the radar site and the airplane's represented radar position. Radar contact continued until 2222:33, when it was lost. During the time the accident airplane was in radar contact, secondary radar data indicated the airplane at an altitude of 7,900 feet above mean sea level and on a southwest heading. The last radar contact was approximately 108 nautical miles at a bearing of 45.5 degrees from the accident location. There were no eyewitnesses to the accident.


The pilot was born September 21, 1936. He was the holder of an airline transport rating for multiengine land airplanes. His logbook indicated the most recent biennial flight review was on December 10, 1994. He was the holder of a first class medical certificate issued on December 4, 1995.


The airplane was a Piper PA-23-250, N6687Y, serial number 27-4009. Airframe and engine logbooks were not found in the wreckage and to date have not been located. The owner of the accident airplane claimed that the logbooks were in the airplane; however, an extensive post accident examination failed to turn up the logbooks at the accident site or in the airplane. Representatives of the owner conducted an exhaustive search for the logbooks and they were not forthcoming. Exact total time on engines and airframe, last inspection, and maintenance details were not determined.


A synopsis of radio communications between the accident airplane and the Federal Aviation Administration is included as an addendum to this report.

During the initial phase of the accident flight radio communications between the air traffic facilities and the airplane were direct; however, during later phases, the communications were from relayed messages through other aircraft.

The last known radio contact established the accident airplane 655 nautical miles east of Kahului at 8,000 feet mean sea level. No additional contact with the accident airplane proved successful either through direct or relayed attempts, although many were made for several hours prior to and after the assumed time of the accident.


The airplane wreckage was located in a triple canopy jungle on the hillside of Mauna Kea. The accident occurred at the 4,500 foot level above sea level. The slope of the terrain was about 3 degrees in the direction of travel of the airplane. The airplane wreckage entered the jungle on an approximate heading of 240 degrees magnetic. The debris trail measured 240 feet. Initial tree contact indicated near wings level from broken branches. The left wing was found at the base of trees near the initial impact point. The right horizontal stabilizer was located about 95 feet forward of the initial indication of impact. The fuselage, remainder of the empennage, engines with propellers, and the left wing were located with the right side of the airplane against the right bank of a dry creek bed.

Both wings had separated at the fuselage. The left wing was next to the fuselage in its normal position. Continuity of the flight cables was established. The vertical stabilizer and rudder were separated; however, rested in position of top of the fuselage.

No preexistent mechanical anomalies were found in the engines or airframe, during the on-scene investigation.

Fuel lines and tanks were compromised during the impact sequence. The odor of fuel was present around the impact scene; however, it was not possible to obtain an exact measurement or estimate of the amount of usable fuel remaining at the time of the accident. Both propellers remained attached to their respective engines and exhibited scoring on the camber faces with nicking of the leading edges, and bending and twisting evident.

The altimeter read 5,100 feet, with a Kollsman window reading 30.10 inches of Mercury. The auto-pilot was turned on as was the heading mode; however, the altitude hold was not engaged. The number one navigation radio was selected to 115.3 MHz, and both number one and number two omni bearing selectors were selected to 210 degrees.


An autopsy on the pilot was completed on December 8, 1995, by the Coroner of the County of Hawaii, at Hilo, Hawaii. No pre-existing pathological anomalies were found during the examination. A toxicological examination of specimens from the pilot was done and proved negative for those drugs screened.


A Specialist's Report of Investigation, Recorded Radar Study, was completed by the NTSB Office of Research and Engineering on March 8, 1996, and is included as an addendum to this report.


Party to the investigation was the Federal Aviation Administration, Flight Standards District Office, Honolulu, Hawaii.

The wreckage was released to a representative of the pilot's estate on December 10, 1995.

NTSB Probable Cause

the pilot falling asleep at the controls due to fatigue. Factors were: the pilot's inadequate preflight preparation and the dark night.

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