NTSB Factual Report

HISTORY OF FLIGHT

On December 10, 2012, about 2016 central standard time (CST), a Messerschmitt Bolkow-Blohm model BK 117-A3 helicopter, N911BK, impacted the ground near Compton, Illinois. The pilot, flight nurse, and flight paramedic were fatally injured, and the helicopter sustained substantial damage from impact forces. The emergency medical services (EMS) equipped helicopter was registered to Rockford Memorial Hospital, and operated by Air Methods Corporation under the provisions of 14 Code of Federal Regulations Part 135 as an on-demand air-taxi flight. Night visual meteorological conditions prevailed for the flight, which operated on a company visual flight rules flight plan. The flight originated from the Rockford Memorial Hospital Heliport (LL83), Rockford, Illinois, about 1958 and was en route to the Mendota Community Hospital Heliport (14IL), Mendota, Illinois, where it was to pick up a patient for transport back to the Rockford Memorial Hospital.

The helicopter was based at the Rockford Memorial Hospital (LL83), Rockford, Illinois. The purpose of the accident leg of the flight was to position the helicopter for a subsequent air medical inter-facility patient transport flight from the Mendota Community Hospital to the Rockford Memorial Hospital. The request was received by the Rockford Memorial Hospital Dispatch Center and the pilot was notified at 1927. During the initial call requesting the flight, the pilot confirmed acceptance of the flight. At 1959, the pilot reported to the dispatch center that he was departing from the helicopter's base at the hospital. He reported that he lifted off with one hour forty-five minutes of fuel and three persons on board and was en route to Mendota, Illinois. During the initial radio call the pilot stated that the risk category was alpha. At 2010, the pilot radioed that he was 12 minutes from Mendota. At 2016, the pilot contacted the dispatch center notifying that he was aborting the flight due to the weather conditions encountered. No further communications were received from the helicopter.

Flight track data for the helicopter showed that it departed LL83 at 1958 and proceeded south on a direct course toward 14IL. When the helicopter was about 13 miles from 14IL, it initiated a right turn. The initiation of the turn coincided with the time that the pilot reported that he was returning to base. The flight track then showed a slight descent before the end of the data. The last recorded position was about 0.75 miles east southeast of the main wreckage site.

PERSONNEL INFORMATION

The pilot held an airline transport pilot certificate with a helicopter rating. A type rating for Bell 206 helicopters was listed on the certificate. The certificate also listed private pilot privileges for single-engine land airplanes. He was issued a first-class airman medical certificate, with a restriction for corrective lenses, on July 17, 2012.

According to the operator's report, the pilot had accumulated 7,619 hours total flight experience with 446 hours in the same make and model helicopter as the accident helicopter. He had flown 27 hours in the preceding 90 days and 11 hours in the preceding 30 days. His most recent flight review was conducted on January 11, 2012. The flight review was conducted in a BK 117 Helicopter.

The pilot was assigned to a VFR only flight operations base. The training records indicated that during the January 11, 2012, flight review the pilot performed a limited review of instrument flight procedures. The instrument procedures listed on the training form consisted of recovery from instrument meteorological conditions, and an instrument landing system (ILS) instrument approach. Since the pilot was assigned to a VFR only operation, a full review of instrument procedures was not required.

According to operator duty time records, the pilot had started his shift about one hour prior to the start of the accident flight. He had been on-duty a total of 61.2 hours during the preceding five days and had accumulated 2:47 (h:mm) of flight time, including 1:49 of night flight, during that period. The duty time records showed that the pilot worked shifts of about 12 hours each day. With about 12 hours of time off between work shifts.

AIRCRAFT INFORMATION

The helicopter was a turbine-powered twin-engine medium utility–transport helicopter with a single main rotor system and an anti-torque tail rotor mounted on the rear of the helicopter. It was powered by two Lycoming LTS 101-650 B-1 engines bearing serial numbers LE45139EA and LE45306EA respectively. Each engine was rated to produce 592 shaft horsepower for short durations and 550 horsepower continuously. The helicopter was equipped with two doors on each side of the helicopter and a two-piece clam-shell door at the rear of the fuselage under the tail-boom. The accident helicopter was configured for patient transport. In addition to the two pilot stations, the rear of the helicopter had provision for a patient litter, two rearward facing seats, and a two position side facing bench seat.

The helicopter had accumulated 10,836 hours total flight time as of the date of the accident. Engine number one had accumulated 9,800 hours total time in service and engine number two had accumulated 10,518 hours total time in service. The most recent inspection was performed on November 1, 2012 under an Approved Airworthiness Inspection Program (AAIP).

METEOROLOGICAL INFORMATION

The pilot had WSI and Aviation Sentry Weather as computer based weather resources available to him before the flight, but neither system logs access, so there was no record or knowledge of the weather information obtained by the pilot before the flight.

The National Weather Service (NWS) Surface Analysis Chart for 2100 depicted a warm front stretching from northern Iowa northwestward into the northern Plains. A surface high pressure center with a pressure of 1021-hectopascals (hPa) was located in Oklahoma. The station models around the accident site depicted air temperatures in the mid 20's to low 30's Fahrenheit (F), with temperature-dew point spreads of 5° F or less, a west wind between 5 and 15 knots, cloudy skies, and light snow.

The area surrounding the accident site was documented utilizing official NWS Meteorological Aerodrome Reports (METARs) and Specials (SPECis).

Rochelle Municipal Airport (RPJ) was the closest official weather station to the accident site located about 2 miles south of Rochelle, Illinois, and had an Automated Weather Observing System (AWOS) whose reports were not supplemented by a human observer. RPJ was located 9 miles north of the accident site, at an elevation of 781 feet, and had a 1° westerly magnetic variation.

At 1955, the RPJ weather observation was, wind from 270° at 6 knots, 10 miles visibility, light snow, an overcast ceiling at 3,100 feet above ground level ( agl), temperature of -1° C, dew point temperature of -2° C, and an altimeter setting of 29.93 inches of mercury. Remarks: automated station with precipitation discriminator, temperature of -1.3° C, dew point temperature of -2.4° C.

At 2015, the RPJ weather observation was, wind from 290° at 8 knots, 7 miles visibility, light snow, an overcast ceiling at 3,300 feet agl, temperature of -1° C, dew point temperature of -2° C, and an altimeter setting of 29.94 inches of mercury. Remarks: automated station with precipitation discriminator, temperature of -1.5° C, dew point temperature of -2.3° C.

At 2035, the RPJ weather observation was, wind from 280° at 6 knots, 7 miles visibility, light snow, an overcast ceiling at 3,300 feet agl, temperature of -2° C, dew point temperature of -2° C, and an altimeter setting of 29.94 inches of mercury. Remarks: automated station with precipitation discriminator, temperature of -1.7° C, dew point temperature of -2.5° C.

At 2055, the RPJ weather observation was, wind from 280° at 9 knots, 7 miles visibility, light snow, scattered clouds at 1,200 feet agl, scattered clouds at 1,800 feet agl, an overcast ceiling at 3,300 feet agl, temperature of -2° C, dew point temperature of -3° C, and an altimeter setting of 29.94 inches of mercury. Remarks: automated station with precipitation discriminator, temperature of -1.8° C, dew point temperature of -2.8° C

Airmen's Meteorological Information (AIRMET) Zulu and Sierra were valid for the accident site at the accident time. They were issued at 1445 and forecasted moderate icing between the freezing level and 12,000 feet (with the freezing level between the surface and 4,000 feet), and IFR conditions with ceilings below 1,000 feet and visibility below 3 miles in precipitation and mist:

RFD was the closest site with a NWS Terminal Aerodrome Forecast (TAF). The TAF valid at the time of the accident was issued at 1720 and was valid for a 24-hour period beginning at 1800. The TAF expected wind from 270° at 6 knots, visibility greater than 6 miles, and a broken ceiling at 2,500 feet agl around the time of the accident.

The Area Forecast issued at 1345 forecasted a broken ceiling at 3,500 feet msl with tops at 7,000 feet. Until1500, widely scattered light snow showers were expected.

Weather radar imagery at 2017 cst near the accident site and aircraft's location indicated small droplets sizes, or a small amount of hydrometeors in the beam, hydrometeors that are spherical or near spherical in shape as they fall, and all the hydrometeors in the scan near the accident site had the same or very similar physical characteristics. One indicator, Zdr, was an indicator of the shape of the dominant hydrometeors. Negative Zdr values indicated a more vertical shape, positive values indicated a more horizontal shape, and values near zero indicated a near spherical hydrometeor shape. In between the aircraft's location at 2007 and 2017 cst there was a distinct change in the Zdr values, with two small horizontal bands of enhanced Zdr where the Zdr values were between 0.25 and 1.5 dB. The recorded Zdr enhancement indicated that these were areas where the hydrometeors were more horizontal than vertical as they fell, characteristics consistent with freezing drizzle and supercooled liquid water.

COMMUNICATIONS

The communications between the Rockford Memorial Hospital Communications Center and the pilot of N911BK were provided by the Rockford Memorial Hospital via a CD re-recording of the communications. The communications were provided in 6 sections. Each section was preceded by an audio header stating the date and time of the recording. The following is a transcription of those re-recordings.

The people recorded were as follows:

- PLT – The pilot of N911BK

- RMH – The person on-duty at the Rockford Memorial Hospital Communications Center

- MCH – The caller from the Mendota Community Hospital

December 10, 2012 at 7:27 pm

- Dial tone

- PLT - react (pilot's name)

- RMH - hey (pilot's name), (RMH CC employee's name)

- PLT - yep

- RMH - just checking to see how mendota looks

- PLT - oh man you're going to start on me right away aren't you

- RMH - hey I'm just trying to get it out of the way early

- PLT - yeah it looks okay

- RMH - does it all right i'll call you back

- PLT - all right bye

- RMH - yeah the pilot said that should be fine

- MCH - really fabulous okay so what um it's going to be um doctor (doctor's name) is accepting

- RMH - is that (patient name)

- MCH - yes um do you have a room number for her actually do you have all the information

- RMH - actually let me put you on hold real quick and get some info here

December 10, 2012 at 7:50 pm

- (Alert Tone)

- PA ANNOUNCEMENT - attention react flight crew your flight to mendota is a go flight is a go patient weighs one hundred and five kilos and you're coming back through d as david three o four d as david three o four

December 10, 2012 at 7:59 pm

- PLT - and roc comm react one an hour forty five on the fuel three p o b's about 22 minutes risk category alpha

- RMH - good copy React one

December 10, 2012 at 8:10 pm

- PLT – roc comm react one ops normal twelve minutes down to mendota

- RMH - good copy react twelve on e t a

December 10, 2012 at 8:16 pm

- PLT – roc comm react one

- RMH - react one

- PLT - yeah we're going to have to turn around and come back uh we got ran into some weather down here we're going to have to go back to rockford

- RMH - good copy aborting due to the weather

- PLT - that's affirmative

December 10, 2012 at 8:27 pm

- RMH - react one ops check

December 10, 2012 at 8:27 pm

- RMH - react one roc comm ops check

No further recordings were provided.

WRECKAGE AND IMPACT INFORMATION

The helicopter impacted a level, harvested agricultural field in a rural area. About two miles east-southeast of the accident was a large windmill farm. Each of the windmills had a flashing beacon mounted on top. Except for the windmill farm, the lighting in the general area was sparse and consisted of only the lights from the widely spaced houses in the area. Ground impact marks and wreckage distribution indicated that the helicopter impacted in a nose-low inverted attitude. The helicopter was fragmented and distributed in a fan-shaped pattern to the north. The main impact crater contained the engines, main rotor transmission, rotor head and mast, and the cockpit section of the fuselage. The main rotor head was about four feet below the surface of the surrounding terrain. The cargo section of the fuselage and the tail boom were distributed along the remainder of the wreckage path. All four main rotor blades and the tail rotor blades were located in the immediate area of the accident scene. Subsequent examination of the wreckage included a partial layout of components, and examinations of the flight control system, rotor systems, transmission and drive system, engines and instrumentation. Postaccident examination of the wreckage revealed no evidence of mechanical malfunctions or failures that would have precluded normal operation.

MEDICAL AND PATHOLOGICAL INFORMATION

An autopsy of the pilot was performed by the Lee County Coroner's Office, Dixon, Illinois, on December 12, 2012. The pilot's death was attributed to injuries received in the accident.

Toxicology testing was performed by the FAA Civil Aerospace Medical Institute. Testing results were negative for all substances in the screening profile.

TESTS AND RESEARCH

The AWOS at RPJ began to report light rain at 2135 CST (after the accident time) even with an air temperature reported below freezing. This was not an isolated METAR report as for the next 2 hours RPJ reported light rain several times when the air temperature was reported below freezing and below 28° F. RPJ was an FAA-approved Level III P/T AWOS which reported wind speed and direction, temperature, dew point, pressure, cloud height, visibility, present weather, and thunderstorm information and was within specification of FAA Advisory Circular No. 150/5220-16D. When the temperature was less than 28° F and precipitation was reported an AWOS-III P/T should have reported the precipitation either as snow or unknown precipitation 99 percent of the time. The AWOS-III P/T was not equipped with a freezing rain sensor or equipment. An inspection of the RPJ AWOS was done on December 18, 2012, and all RPJ AWOS equipment was and had been performing normally. The FAA Technical Operations Service provided the following information regarding AWOS equipment in the National Airspace System (NAS):

AWOS does not generate a report of freezing rain without a freezing rain sensor.

All present weather equipped AWOS as well as ASOS and Automated Weather Sensor System (AWSS), can report light rain with a measured temperature below freezing.

The present weather sensor is an intelligent stand-alone device that measures precipitation types and the rate of fall. The present weather sensor uses its internal built-in temperature sensor to report precipitation other than liquid precipitation (RA).

ADDITIONAL INFORMATION

The operator, Air Methods, was a commercial on-demand air taxi operator specializing in helicopter emergency medical services (HEMS). Air Methods provides air medical emergency transport services under three separate operating models: the community-b

NTSB Probable Cause

The inadvertent encounter with inclement weather, including snow, freezing rain, and reduced visibility conditions,  which led to the pilot’s spatial disorientation and loss of aircraft control.