NTSB Factual Report

HISTORY OF FLIGHT

On April 12, 1995, at 0843 central daylight time a Beech 65-B80, N7057J, operated by Air Cargo Masters, Inc., of Brandon, South Dakota, and piloted by an airline transport rated pilot, departed controlled flight and impacted trees and terrain, approximately seven miles southwest of the Harry Stern Airport, Wahpeton, North Dakota. The airplane was destroyed and the pilot sustained fatal injuries. The 14 CFR Part 135 flight was operating on an IFR flight plan. Weather in the vicinity of the accident was reported as IMC. The flight departed Sioux Falls, South Dakota, about 0815, as an on-demand cargo flight with the intended destination of Fargo, North Dakota.

At 0626 the pilot of N7057J, called the Federal Aviation Administration (FAA), Huron Flight Service Station (FSS). During the conversation with the FAA briefer the pilot received current and forecast weather, pilot reports, winds aloft and filed an IFR flight plan from Sioux Falls, South Dakota, to Fargo, North Dakota. A transcription of the conversation between the pilot and the FSS briefer is attached to this report. Included in the weather briefing were current and forecast reports containing icing conditions.

En route to Fargo, North Dakota, cruising at 6,000 feet, the pilot of N7057J was in radio communication with the FAA Minneapolis Air Route Traffic Control Center (ARTCC). A transcribed copy of these radio communications are attached to this report. At 0810, the pilot of N7057J reported, "Yeaaa we're picking up some ice here. Any chance of four?" The flight was cleared to descend to 5,000 feet. Again at 0821, the pilot requested, "Any chance of getting four?" But was denied clearance, wherein, the ARTCC controller asked about icing. To this the pilot responded, "Yeah we've got ice for sure." One minute later the flight was cleared to descend to 4,000 feet. At 0831, the ARTCC controller inquired of the flight, "... are you out of the icing?" To which the pilot responded, "Nah, we're still in icing up here ... ." Following this there was some discussion about the flight diverting to Wahpeton, North Dakota, and the airplane's ability to climb above the icing. At 0833, the flight was cleared to descend to 3,600 feet. Three seconds after this clearance, the pilot stated, "This is, ah we're, we just lost one of um.. ." After this radio communication, continued uninterrupted radio communications between the ARTCC and N7057J, were not possible. The ARTCC controller began to relay messages through N150BC, and later through Mesaba Airlines Flight 3249. Information was relayed to the pilot and back to the controller as the flight continued to lose altitude. At 0838, a message was relayed to the ARTCC controller that, "... he's at two thousand and ah still in the clouds, but the ice is coming off good." The last radio communication between Mesaba Airlines Flight 3249 and the pilot of N7057J occurred at 0842. At 0843, another relay was attempted, but the pilot did not respond. At 0846, FAA and flights confirmed they were receiving Emergency Locator Transmitter (ELT)signals on frequency 121.5 mhz.

There were no eyewitnesses to the accident. Shortly after the ELT signals were verified, a call was made to an operator at the Harry Stern Airport, Wahpeton, North Dakota. He was able to get airborne, and receive the signal; however later stated that he was unable to locate the accident airplane due to low clouds and encountering instrument meteorological conditions. After approximately one hour, he was able to return to the area of high signal strength of the ELT and locate the wreckage.

OTHER DAMAGE

Trees and foliage were damaged during the descent of the airplane.

PERSONAL INFORMATION

The pilot, age 46, was the holder of an airline transport rating. He had accumulated 6,100 hours flight time with 250 hours in the make and model of the accident airplane. He held a second class medical certificate issued May 16, 1994. His most recent biennial flight review was five months prior to the accident.

AIRCRAFT INFORMATION

The airplane was a Beech 65-B80, serial number LD-291, N7057J. The airplane had a total time in service of 6,887 hours at the time of the accident. The most recent 100 hour inspection was on December 29, 1994. The airplane had accumulated 81 hours since the inspection.

METEOROLOGICAL INFORMATION

Residents and a pilot who was looking for the accident airplane said that instrument meteorological conditions existed in the vicinity of the accident site at the time of the accident. They stated that the weather was characterized by low ceilings, below 1,000 feet.

COMMUNICATIONS

A transcript of portions of radio communications between the pilot and FAA facilities is attached to this report. This transcript also includes telephone conversation prior to the accident flight between the pilot and FAA FSS.

En route the accident airplane descended below an altitude where the FAA facilities were able to maintain uninterrupted radio communication. During this period radio transmissions were relayed by two other airplanes, N150BC, and Mesaba Airlines Flight 3249.

WRECKAGE AND IMPACT INFORMATION

The airplane wreckage was located in an area of small timber growth. The direction of travel was on a heading of 280 degrees. There were broken branches from tree tops for 70 feet beginning at the initial impact with trees about 50 feet in height and leading up to the main wreckage. Trees within 20 feet of the wreckage were broken to the ground.

The airplane was found in a near vertical attitude, nose down with the final heading to the southeast. The landing gear and flaps were in the retracted position.

The left wing sustained tree impact damage that separated a portion of the wing and tip. The outboard section was located 45 feet from the main wreckage. The inboard section remained attached to the wing center section. The inboard wing exhibited tree impact damage of the leading edge that started at the separation point and continued inboard about four feet. The outboard edge of the outboard flap was bent upward and exhibited a tree impact mark. The wing bowed upward at the outboard edge.

The right wing sustained tree impact damage that separated the outboard wing in two sections. The outboard section was located 20 feet from the main wreckage. The inboard section remained attached to the center section. The inboard wing exhibited tree impact damage to the leading edge that started at the separation point and continued inboard about six feet. The wing was twisted with the leading edge curling upward and aft.

The fuselage sustained ground impact damage with the nose section crushed rearward and to the left. The fuselage and center section were fractured at the aft spar. The sides of the fuselage were bent and wrinkled.

The empennage remained attached to the fuselage; however, the tail cone was bent to the right of the centerline of the airplane, aft of the rear cabin entry door. The left horizontal stabilizer, left elevator, vertical stabilizer, and rudder sustained minor damage during impact. One-third of the right horizontal stabilizer and right elevator separated during impact.

The outboard section of the right elevator separated into two sections. Both the right horizontal stabilizer and right elevator sections were located under the empennage section.

Control continuity was established in that all terminal ends of controls were intact and in their proper locations.

The right engine remained partially attached to its mount although it had moved aft into the firewall and nacelle. The gear box and propeller separated from the engine and were located six feet southeast of the engine, partially impacted in the ground. Upon removal from the ground, the right propeller exhibited polishing of the cambered side with leading edge impact marks. All three blades were bent aft and had spanwise twisting. The spinner was collapsed around the propeller hub exhibiting twist in the direction opposite rotation. Tree limbs were found the impact path to four inches in diameter indicating cut marks consistent with propeller strikes and exhibiting black paint transfers similar to that on the propeller face.

The left engine remained attached to the mounts and firewall in the nacelle area. The propeller remained attached to the engine and was feathered. The cowling was intact around the engine. Upon removing the top cowling, the right magneto was found separated from its mount, but remained attached by way of the ignition harness.

After the cargo was removed from the wreckage it was weighed. The actual weight of the cargo was compared to the weight and balance on the manifest for the flight, and was 60 pounds greater than shown on the manifest.

MEDICAL AND PATHOLOGICAL INFORMATION

A post mortem examination of the pilot was conducted at St. Francis Medical Center, Breckenridge, Minnesota, on April 12, 1995. No pre-existent anomalies were noted during this examination which contributed to the accident or the pilot's death.

Specimens were collected for toxicology testing from the pilot. These tests were negative for those drugs screened.

TESTS AND RESEARCH

On May 23, 1995, both the left and right engines were further examined. During that examination, the left engine was disassembled for further inspection. The oil pump filter, and oil pressure relief valve were found to contain aluminum chips.

The connecting hose between the air filter and the intake air sump was deteriorated and pieces of the material were missing. When the diffuser cover to supercharger was removed the vanes on the compressor wheel exhibited a texture as though they had been sandblasted. Little bits of rubber and fiberglass from intake hoses were found on the diffuser vanes.

The engine rotated freely and there was continuity throughout.

A compression check indicated no compression on cylinder #5. On disassembly a hole was found in the piston head which ran down through the ring grove area and through the piston skirt. The top piston ring was absent. The next ring was missing 3" of the ring. The oil control ring was separated where a hole was burned through it.

The #1 cylinder was found to have the top ring broken with the ring land worn to double its normal size.

The timing of the left magneto to the engine was established prior to removal. Both magnetos sparked when tested on a test bench.

The right engine was inspected for continuity, compression, and the oil pump filter for contamination. No abnormalities were noted. Both magnetos sparked.

ADDITIONAL DATA/INFORMATION

Parties to the investigation were the Federal Aviation Administration, Flight Standards District Office, Fargo, North Dakota; Lycoming, Williamsport, Pennsylvania; and Beech Aircraft, Wichita, Kansas.

The airplane wreckage was released to a representative of the owner on March 11, 1996.

NTSB Probable Cause

the pilot/mechanic's inadequate maintenance (inspection) of aircraft and the pilot's failure to maintain airspeed (VMC). Factors were icing conditions, deteriorated induction air ducting, and failure of a piston assembly.