CHI01FA080
CHI01FA080

HISTORY OF FLIGHT

On February 7, 2001, at 0705 central standard time, a Beech 58, N52BA, operated by Silverhawk Aviation, was destroyed when it impacted the terrain about .4 miles north of the Ainsworth Municipal Airport (ANW), Ainsworth, Nebraska. The 14 CFR Part 135 cargo flight departed the Lincoln Municipal Airport (LKN), Lincoln, Nebraska, at 0530 en route to Valentine Municipal Airport (VTN), Valentine, Nebraska, on an instrument flight rules (IFR) flight plan. The airplane encountered icing conditions en route and was diverting to ANW. While on approach to runway 17 (6,802 feet by 110 feet, asphalt), the airplane impacted the ground on a heading of 280 degrees. The commercial pilot received fatal injuries and the pilot rated passenger received serious injuries.

At 0445, the pilot contacted the Federal Aviation Administration's (FAA) Columbus Automated Flight Service Station (AFSS) to get a standard weather brief and filed an instrument flight plan. The AFSS weather briefer stated the following:

"O.K. had IFR forecasted in the Valentine/Ainsworth area, ceilings occasionally below one thousand and/or visibility below three miles and precipitation and mist. Turbulence across the entire route of flight, light to occasional moderate below twelve thousand, and icing light to occasional moderate rime/mixed in clouds in precipitation below twenty thousand across there. Low pressure system moving from the four corners areas up to North Central Colorado at this time, continuing to track slowly Northeastward bringing precipitation into the area as the day goes on. Currently, weather deteriorates slightly as you go westward; it doesn't really start deteriorating until you get past Valentine. At this time, Lincoln is saying eleven thousand broken, visibility ten, wind easterly at ten. Valentine is four thousand five hundred overcast, visibility ten, wind southeasterly at seventeen gusting to twenty-two. The only pilot report we have about twenty minutes ago in the Lincoln area, a Caravan at nine thousand had some light rime icing. Area forecast for Eastern and Central Nebraska, they're saying ten thousand broken layers to twenty-five thousand at this time. Should be gradually decreasing until sunrise until it becomes two thousand to three thousand overcast with visibility occasionally three miles and light snow pellets in the central portions of the state. Don't have a terminal forecast at Valentine, area forecast is best we have. Lincoln forecast coming back today is saying one thousand five hundred scattered to broken, two thousand five hundred overcast, visibility occasionally four miles and light rain showers and/or mist. Winds aloft twelve thousand across your route of flight southwesterly two four zero at forty-two knots this morning. No NOTAMS at this time across the area that'll affect you."

At 0544, the pilot contacted the FAA Columbus AFSS via the Remote Communications Outlet at Lincoln, Nebraska, requesting an instrument clearance from Lincoln, Nebraska, to Valentine, Nebraska. The clearance was issued.

At 0550, the pilot reported leaving 3,500 feet for 6,000 feet.

At O612, the pilot reported he was picking up light, mixed ice at 6,000 feet.

At 0629, the pilot reported he was encountering light mixed icing at 8,000 feet.

At 0632, the pilot reported he was picking up light ice and requested any pilot reports. Air traffic control (ATC) reported there were no pilot reports available for that area.

At 0637, the pilot reported he was "picking up pretty good ice," and requested a descent to 6,000 feet.

At 0643, the pilot reported he was "picking up lots of ice right now." He requested the VOR Runway 17 Approach to ANW, and he was cleared for the approach.

The person who received the Tc-99m shipment at Valentine, Nebraska, reported the pilot called her about 0645 on November 7, 2001, to inform her that weather was precluding him from landing at VTN, and that he would be landing at ANW.

At 0652, the pilot reported he was unable to maintain 6,000 feet due to icing and requested a lower altitude. He was cleared to descend to 5,000 feet.

At 0653, the flight was cleared for the approach to ANW. The pilot reported he was still picking up icing.

At 0658, while on the outbound leg of the approach procedure, the pilot reported, "… moderate mixed icing, and we are in and out of clouds right now, uh, in freezing rain."

At 0658, ATC instructed the pilot to switch frequencies to the advisory frequency at ANW, and to contact Columbia Flight Service after landing. The pilot acknowledged the instruction. The pilot made no further radio transmissions.

The pilot rated passenger reported that during the flight, no mention was made about the expected weather, or getting an update on the weather, or any discussion about the location of the front.

He reported the de-ice boots were being used often, but the airspeed was going down. He reported that when the airplane was cleared for the approach, the forward visibility through the front windshield was zero due to ice. He reported the anti-ice alcohol for the windshield had run out. He reported he could see the airport through the side window while on the downwind. He reported he felt the airplane buffet and the pilot applied full power but soon after the airplane impacted the ground.

N52BA impacted the frozen terrain about 3,070 feet north-northeast of the approach end of runway 17 at ANW.

PERSONNEL INFORMATION

The pilot was a commercial rated pilot with single and multi-engine land ratings. He had a total of about 2,450 hours of flight time, and 240 hours were in the make and model of the accident aircraft. He held a Second Class Medical Certificate. The pilot was a Certified Flight Instructor with single engine, multi-engine, and instrument ratings. The pilot had worked for Silverhawk Aviation since August 13, 1998.

The pilot rated passenger had recently been hired by the operator. He was observing the flight but not performing flight duties.

AIRCRAFT INFORMATION

The airplane was a twin engine Beech 58, serial number TH-52. The airplane seated six and had a maximum gross weight of 5,400 pounds. The engines were 285 horsepower Continental IO-540-C engines. The last 100-hour inspection was conducted on September 1, 2000. The airplane accumulated 88 hours since the last inspection and had a total time of 9,930 hours.

The aircraft was equipped with de-icing boots on the wings and horizontal stabilizer. It was equipped with alcohol anti-icing equipment on the propeller and windshield.

The Pilot's Operating Manual for the Beechcraft Baron 58, effective for Serial TH-1 through TH-772, stated the following limitations:

"This airplane is approved for the following type operations when the required equipment is installed and operational as defined herein:

1. VFR day and night.
2. IFR day and night.

Warning

Ice protection equipment which may be installed on this airplane has not been demonstrated to meet requirements for flight into known icing conditions."

METEOROLOGICAL CONDITIONS

At 0450, the observed weather at ANW was: wind 110 degrees at 16 knots, visibility 10 miles; sky condition overcast at 4,200 feet, temperature 26 degrees F, dew point 23 degrees F; altimeter 29.84.

At 0650, the observed weather at ANW was: wind 120 degrees at 13 knots, visibility 2 miles, sky condition overcast 1,000 feet, temperature 26 degrees F, dew point 25 degrees F, altimeter 29.86.

At 0710, the observed weather at ANW was: wind 120 degrees at 14 knots, visibility 2 miles, sky condition overcast 700 feet, temperature 26 degrees F, dew point 25 degrees F, altimeter 29.86.

At 0452, the observed weather at ANW was: wind 120 degrees at 10 knots; visibility 2.5 miles; sky condition - light freezing rain/mist; few clouds at 1,000 feet, broken 1,500 feet, overcast 1,900 feet; temperature 35 degrees F; dew point 23 degrees F; altimeter 29.84.

At 0652, the observed weather at ANW was: wind 120 degrees at 13 knots gusting to 21 knots, visibility 4 miles, light freezing rain mist, sky broken 800 feet, overcast 1,300 feet, temperature 28 degrees F, dew point 25 degrees F, altimeter 29.84. Remarks - ceiling 600 feet variable 1,000 feet.

The Area Forecast issued at 2245 on February 6 and valid until 1500 February 7, forecasted occasional light snow and ice pellets over central Nebraska.

The Area Forecast issued at 0445, but not disseminated until 0501, on February 7, forecasted the presence of low cloud ceilings, 3 - 5 miles visibility, light freezing rain, snow, ice pellets, and mist.

The following In-Flight Weather Advisories (AIRMET) were available to the pilot:

AIRMET ZULU was issued at 0245 on February 7, 2001, and was valid until 0900 on February 7. It advised that occasional moderate rime/mixed icing in cloud in precipitation between freezing level and Flight Level (FL) 200. (See National Transportation Safety Board Meteorology Factual Report)

An officer from the Brown County Sheriff's Office reported he had responded to the airplane accident. He reported his response time was slowed due to the weather conditions that included freezing rain and ice.

The Nebraska State Patrol report indicated the weather conditions prior to and immediately after the accident were freezing rain, and that all surfaces were ice-covered to approximately 1/4 inch thick.

WRECKAGE AND IMPACT INFORMATION

The airplane impacted a frozen cornfield on a heading of about 280 degrees. The wreckage path was approximately 260 feet in length and came to rest on its belly with the nose of the airplane heading 215 degrees. Much of the airplane was consumed by postimpact fire.

The wings and empennage remained attached to the fuselage. The outboard section of the left wing exhibited crushing and buckling along the bottom side of the leading edge of the wing. The inboard section of the wing exhibited extensive fire damage. The left main landing gear was found about 200 feet along the wreckage path. The left flap remained attached to the wing and was fire damaged.

The right wing exhibited extensive fire damage along the entire span of the wing. It did not exhibit leading edge crush. The right main landing gear separated from the wing and was found about 160 feet along the wreckage path. The right aileron separated from the wing and was found about 85 feet from the initial impact point.

The empennage was fire damaged and the right horizontal stabilizer and elevator were consumed by fire. The vertical stabilizer was fire damaged and was intact, but the rudder was partially consumed by fire. The left horizontal stabilizer and elevator exhibited fire damage but were intact.

The cockpit and cabin were consumed by fire. No instrument or switch positions were obtained from the cockpit. The fuel selectors were found in the OFF position at the selector valves.

Cable continuity was exhibited from the cockpit to the wings and empennage.

The left and right engines remained attached to the wings, but both propellers were separated from the engines. The left propeller was found about 210 feet along the wreckage path, and the right propeller was found about 195 feet along the wreckage path.

The left propeller blades exhibited "S" bends and chordwise scratching. One of the right propeller blades was bent back about 45 degrees and the outer half of the blade exhibited an S bend. Chordwise scratching was evident. The other blade was bent back about 25 - 30 degrees and exhibited blade twist. The blade exhibited chordwise and diagonal scratching on the front face.

The left engine and right engine were removed from the airframe for examination. The left engine crankshaft was turned and thumb compression was obtained from No. 2,3,4, and 5 cylinders. Cylinder No. 1 was burned and the rocker box cover was melted over the rocker arms. Cylinder No. 6 had impact damage on the front of the cylinder. Both magnetos produced spark on all leads when the crankshaft was turned.

The right engine received extensive burn damage. Both magnetos and all ignition leads were burned and no spark was produced. Only 75 degrees of turn could be obtained from the crankshaft. Continuity was noted through to the accessory section. All pistons were observed to move.

MEDICAL AND PATHOLOGICAL INFORMATION

An autopsy was performed on the pilot at the Saint Joseph Hospital, Omaha, Nebraska.

A Forensic Toxicology Fatal Accident Report was prepared by the FAA Civil Aeromedical Institute. The report was negative for substances tested.

ADDITIONAL INFORMATION

The cargo on the airplane consisted of 18 doses (syringes) of technetium-99m isotope (Tc-99m) used in medical imaging. The Tc-99m isotope has a half-life of six hours. Typically, radioactive materials are completely extinguished after ten half-lives. The on-site investigation of the accident began approximately 72 hours after the accident occurred.

A manager at Synchor, the firm that prepared the Tc-99m, reported that Silverhawk Aviation was used routinely to transport Tc-99m to Valentine, Nebraska, and that Silverhawk Aviation was the only operator contracted by Synchor to fly its shipments. All shipments to other hospitals were routinely transported by ground. He reported that the shipment would be delivered to the pilot by 0530 and the pilot would depart for Valentine, Nebraska. He reported that the pilot had the authority to cancel the flight, normally for low ceilings or rain. He reported flights were cancelled a "couple of times a year."

A manager at Silverhawk Aviation reported the pilot had the authority to cancel the flight.

Parties to the investigation included the FAA, Teledyne Continental Motors, and the Raytheon Aircraft Company.

The wreckage was released to Silverhawk Aviation.




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