NTSB Accident Report
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.
