United States of America

The MU-300 on-demand passenger charter flight sustained substantial damage during a landing overrun on a snow/ice contaminated runway. The captain, who was also the company chief pilot and check airman, was the flying pilot, and the first officer was the non flying pilot. Instrument meteorological conditions prevailed at the time of the accident. Area weather reporting stations reported the presence of freezing rain and snow for a time period beginning several hours before the accident. The captain did not obtain the destination airport weather observation until the flight was approximately 30 nautical miles from the airport. The flight received radar vectors for a instrument landing system approach to runway 30 (5,401 feet by 100 feet, grooved asphalt). The company's training manual states the MU-300's intermediate and final approach speeds as 140 knots indicated airspeed (KIAS) and Vref, respectively. Vref was reported by the flight crew as 106 KIAS. During the approach, the tower controller (LC) gave the option for the flight to circle to land or continue straight in to runway 30. LC advised that the winds were from 050-070 degrees at 10 knots gusting to 20 knots, and runway braking action was reported as fair to poor by a snow plow. Radar data indicates that the airplane had a ground speed in excess of 200 knots between the final approach fix and runway threshold and a full-scale localizer deviation 5.5 nm from the localizer antenna. The company did not have stabilized approach criteria establishing when a missed approach or go-around is to be executed. The captain stated that he was unaware that there was 0.7 percent downslope on runway 30. The company provided a page from their airport directory which did not indicate a slope present for runway 30. The publisher of the airport directory provided a page valid at the time of the accident showing a 0.7 percent runway slope. Runway slope is used in the determination of runway performance for transport category aircraft such as the MU-300. The airplane operating manual states that MU-300 landing performance on ice or snow covered runways has not been determined. The airplane was equipped with a cockpit voice recorder with a remote cockpit erasure control. Readout of the cockpit voice recorder indicated a repetitive thumping noise consistent with manual erasure. No notices to airman pertaining to runway conditions were issued by the airport prior to the accident.

The pilot was flying a three leg IFR cross-country, and was on an ILS approach in IMC weather conditions for his final stop. Radar data indicated that the pilot had crossed the final approach fix inbound and was approximately 3 nm from the runway threshold when he transmitted that he had "lost an engine." Radar data indicates that the airplane turned left approximately 180 degrees, and radar contact was lost. A witness said "the airplane appeared to gain a slight amount of altitude before banking sharply to the left and nose diving into the ground just over the crest of the hill." Postimpact fuel consumption calculations suggest that there should have been 50 to 60 gallons of fuel onboard at the time of the accident. Displaced rubber O-ring seals on two Rulon seals in the left fuel valve and hydraulic pressure/deflection tests performed on an exemplar fuel valve suggest that the fuel selector valve was in the auxiliary position at the time of impact. The airplane's Owner's Manual states: "The fuel selector valve handles should be turned to LEFT MAIN for the left engine and RIGHT MAIN for the right engine, during takeoff, landing, and all emergency operations." No preimpact engine or airframe anomalies, which might have affected the airplane's performance, were identified.

The airplane was destroyed by impact forces and fire, when it impacted the ground about 3.7 miles from the destination airport. The airplane had been cleared for an ILS approach to the airport. No anomalies were found during the on-scene examination of the airframe, engine or gyroscopic flight instruments that could be associated with a pre-existing condition. The minimum descent altitude for the approach is 243 feet above ground level. The inbound course for the instrument approach is 298 degrees magnetic. The radar data shows that the airplane headed in a northerly direction prior to commencing a left turn onto the inbound course of the instrument approach. The last radar return, was received prior to the airplane reaching the locator outer marker for the approach. Altitude returns show the airplane descending from a pressure altitude of 4,000 feet to a pressure altitude of 2,800 feet. The 2,800-foot return was the final return received. The wreckage path was distributed on a magnetic heading of approximately 145 degrees. The weather reporting station located at the destination airport recorded a 100 foot overcast ceiling with 1 statute mile of visibility about 20 minutes prior to the accident. The current weather was available to the pilot via the Automated Weather Observing System at the destination airport. No communications were received from the airplane after controllers authorized the pilot to change to the destination airport's advisory frequency.

A US Army Pilatus UV-20A collided in midair with a Cessna 182C during parachute jumping operations. The collision occurred about 4,800 feet mean sea level (msl) (2,800 feet above ground level (agl)) on the northeast side of runway 12 abeam the approach end. Both aircraft had made multiple flights taking jumpers aloft prior to the accident. The Pilatus departed runway 12 about 5 minutes prior to the Cessna's departure on the same runway. The drop zone was on the airport west of the intersections of runways 12 and 03. The Pilatus departed to the south and began a climb to the jump altitude of 5,500 feet msl, which was 3,500 feet agl. The pilot began the jump run on the southwest side of the runway paralleling it on a heading of about 300 degrees and when he was 1 to 2 minutes from the drop zone broadcast the intent to drop jumpers. The first jumper stated that it normally took him between 1 minute and 1 minute 15 seconds to reach the ground. As he neared the ground he observed everyone running toward the crash site. The Cessna pilot had four jumpers on board and said that his usual practice is to plan his climb so that the jump altitude (5,000 to 5,500 feet msl) is reached about the same time that the aircraft arrives over the jump zone. He departed runway 12 and made a wide sweeping right turn around the airport to set up for the jump. As the Pilatus neared the jump zone the Cessna was greater than 1,000 feet lower and west of the Pilatus climbing on a northerly heading. The Cessna pilot planned to make a right turn to parallel the left side of runway 12, and then turn right toward the drop zone. The jumpers in the Cessna looked out of the right side, and watched the Golden Knights exit their airplane. The jumpers said that their altimeters read 2,500 feet agl. The Cessna pilot turned to a heading of 120 degrees along the left side of the approach end of runway 12. He heard the Pilatus pilot say on Common Traffic Advisory Frequency that the Pilatus was downwind for runway 12. Based on witness observations, at this point the Pilatus was in a descending turn heading generally opposite to the downwind heading on the northeast side of the runway. Everyone in the Cessna heard a loud bang, the Cessna pilot felt something hit him in the head, and the airplane pitched down and lost several hundred feet of altitude. He noticed a blur of yellow and white out of his left window. The lead jumper decided that they should exit, and they all jumped. The Cessna pilot decided that the airplane was controllable, and landed safely. Both civilian and military witnesses on the ground heard the Pilatus pilot call downwind for runway 12. About 10 seconds later they heard intense transmissions over the loud speaker, and looked up and observed the Pilatus in a nearly vertical, nose down slow spiral. There was an open gash in the top of the Cessna's cabin on the left side near the wing root. The green lens and its gold attachment fitting from the Pilatus were on the floor behind the pilot's seat.

The pilot departed with the airplane contaminated with ice, into known severe icing conditions, and was unable to maintain altitude, subsequently impacting trees and terrain. Witnesses reported the accident airplane arrived at the departure airport contaminated with ice. Several witnesses stated they asked the pilot if he needed the airplane deiced prior to his next departure and the pilot stated he did not need any deice service. Several witnesses said they noticed the pilot chipping-off ice from the airplane prior to his departure. While en route the pilot reported the airplane had encountered icing conditions and he was unable to maintain altitude. Several thick pieces of ice were recovered around the accident site and one of the recovered ice pieces had a semicircular shaped edge that was consistent with a leading edge of an airfoil. No pre-impact anomalies were found with the leading edge de-ice boots that were installed on both wings, vertical and horizontal stabilizers, and wing struts. Federal Aviation Regulations state that all ice contamination shall be removed prior to flight. The Cessna 208B Pilot Operating Handbook indicates that continued flight into known icing conditions must be avoided.

During an instrument approach, upon descending to the prescribed minimum descent altitude, about 1/2 mile from the missed approach point, the pilot failed to maintain flying airspeed. The airplane stalled, rolled left, and in an uncontrolled descent collided with a commercial building 0.96 nm from the runway's displaced threshold. The accident occurred during the return portion of a round trip flight, while on final approach to the pilot's alternate airport due to a weather-induced diversion. Moderate intensity snow showers and freezing fog existed. During the initial approach, the reported visibility was 1 1/2 miles. About the time the pilot passed the final approach fix, the visibility decreased to 1/2 mile, but the pilot was not informed of the decrease below his 1-mile minimum requirement. The pilot had maintained the recommended 140-knot approach speed in the icing conditions until about 3 1/2 miles from the runway. Thereafter, the airplane's speed gradually decreased until reaching about 75 knots. After the airplane started vibrating, the pilot increased engine power, but his action was not timely enough to avert stalling. Company mechanics maintained the airplane. On previous occasions overheat conditions had occurred wherein the environmental ducting melted and heat was conducted to the adjacent pneumatic tube that provides deice air to the empennage boots. During the accident investigation, the deice tube was found completely melted closed, thus rendering all of the empennage deice boots dysfunctional.

The aircraft was cleared direct and to climb to 14,000 feet. During the climb out, the controller inquired several times as to the flights altitude. The pilot's response to the controllers queries were exactly 10,000 feet lower than what the controller was indicating on radar. Eventually the controller instructed the pilot to stop altitude squawk, which he did. During the last communication with the pilot, he reported that he was level at 14,000 feet. During the next approximately 45 minutes, the aircraft was observed proceeding generally in the direction of its destination. When the controller observed the flight track turn approximately 45 degrees to the right and headed generally northwest, he attempted to contact the pilot without a response. The tracking then turned about 90 degrees to the left for a few minutes, then turned 180 degrees to the right. The aircraft dropped from radar coverage shortly thereafter. On site investigation revealed that the aircraft broke-up in flight as the wreckage was scattered generally east-to-west over the mountainous terrain for approximately .3 nautical miles. Further investigation revealed that the right wing separated at the wing root in an upward direction. Separation points indicated features typical of overload. The right side horizontal stabilizer separated upward and aft. The left side horizontal stabilizer remained attached however, it was twisted down and aft. The aft fuselage was twisted to the left. Both engines separated in flight from the wings. Post-crash examinations of the airframe and engines did not reveal evidence of a mechanical failure or malfunction. Both altimeters were too badly damaged to test. Autopsy and toxicology results indicated that the pilot had severe coronary artery disease with greater than 95% narrowing of the left anterior descending coronary artery by atherosclerotic plaque. The coroner also reported that superimposed upon this severe narrowing was complete occlusion of the lumen by brown thrombus. Toxicology results indicated a moderate level of diabetes. The pilot's actions leading up to the accident were consistent with an incapacitation due to hypoxia. The role of a possible heart attack was unclear, since it is possible that it occurred as a result of the hypoxia.

The aircraft was on an IFR clearance and climbing through a cloud layer when it broke up in flight following an in-flight upset. The weather conditions included multiple cloud layers from 4,000 to 13,000 feet, with a freezing level around 7,000 feet msl. An AIRMET was in effect for occasional moderate rime to mixed icing-in-clouds and in-precipitation below 18,000 feet. As the airplane began to intercept a victor airway, climbing at about 2,000 feet per minute (fpm), and passing through 6,700 feet, the airplane began a series of heading and altitude changes that were not consistent with its ATC clearances. The airplane turned right and climbed to 8,600 feet, then turned left and descended to 8,000 feet. The airplane then turned right and climbed to 8,500 feet, where it began a rapidly descending right turn. At 1034:33, as the aircraft was descending through 7,000 feet, the pilot advised ATC "four Juliet victor I just lost my needle give me..." No further transmissions were received from the accident airplane and the last radar return showed it descending through 3,200 feet at about 11,000 fpm. Analysis of radar data shows the airplane was close to Vmo at the last Mode C return. Ground witnesses saw the airplane come out of the clouds in a high speed spiral descent just before it broke up about 1,000 feet agl. Examination of the wreckage showed that all structural failures were the result of overload. The aircraft was equipped with full flight instruments on both the left and right sides of the cockpit; however, the flight director system attitude director indicator and horizontal situation indicator were only on the left side. The aircraft was also equipped for flight into known icing conditions, with in part, heated pitot tubes (left and right sides), static sources, and stall warning vanes. During the on-scene cockpit examination, except for the pitot heat switches, the cockpit controls and switches were found to be configured in positions consistent with the aircraft's phase of flight prior to the in-flight upset. The right pitot heat switch was found in the ON position, while the left switch was in the OFF position. The left pitot heat switch toggle lever was noticeably displaced to the left by impact with an object in the cockpit. With the exception of the left pitot heat, the anti-ice and deice system switches were all configured for flight in icing conditions. The pitot heat switches, noted to be of the circuit breaker type (functions as both a toggle switch and circuit breaker), were removed from the panel and sent to a laboratory for examination and testing. Low power stereoscopic examination of the switches found that the right switch was intact, while the toggle lever mechanism of the left switch was broken loose from the housing. Microscopic examination of the left switches housing fracture surface revealed imbedded debris and wear marks indicative of an old fracture predating the accident. The broken left switch could be electrically switched by physically holding the toggle lever mechanism in the appropriate ON or OFF position. The electrical contact resistance measurements of the left switch varied between 0.3 and 1.4 ohms, and was noted to be intermittently open with the switch in the ON position. Both switches were then disassembled. While particulate debris was found in both switches, the left one had a significant amount of large coarse fibrous lint-like debris. The flexible copper conductor of the left switches circuit breaker section had several broken strands, and the electrical contacts were dirty. The laboratory report concluded that the left switches toggle was bent to the left in the impact sequence; however, the housing fracture predated the accident and allowed an internal build-up of large coarse fibrous lint-like debris. The combined effects of the broken housing, the resulting misalignment of the toggle mechanism, the dirty contacts, and the large coarse lint debris prevented reliable electrical switching of the device and presented the opportunity for intermittently open electrical contacts. Continuity of the plumbing from the pitot tubes and static ports to their respective instruments was verified. Electrical continuity was established from the bus power sources through the circuit breakers and switches to the heating elements of the pitot tubes and static sources. The heating elements were connected to a 12-volt battery and the operation of the heating elements verified.

The pilot arrived at Mexia-Limestone County Airport (TX06), Mexia, Texas, sometime before 1100. Once onboard the airplane, a witness, and an acquaintance of the pilot, closed and locked the airplane's cabin door for the pilot, and walked away from the airplane. He also reported that after the engines to the airplane were started, the airplane stayed on the ramp and idled for 10 to 15 minutes. No one saw the pilot taxi to the runway, but he taxied to the north end of Runway 18 for a downwind takeoff to the south. Examination of the accident site found the wreckage oriented along a path consistent with an extended centerline of runway 18. The airplane was found along a fence line approximately 1/4 mile from the departure end of Runway 18. The airplane's track was along a 183-degree bearing, and there was a large burn area prior to and around the debris zone along the wreckage path. Examination of the cockpit revealed a 9/16-inch hex-head bolt inserted in the control lock pinhole for the control column. Under normal procedures Cockpit Check in the Duke 60 Airplane Flight Manual, for Preflight Inspection the first item listed is: 1. "Control Locks - REMOVE and STOW". In addition, under normal procedures Before Starting checklist in the Duke 60 Airplane Flight Manual, the fourth item to check is listed as: 4. "Flight Controls - FREEDOM OF MOVEMENT and PROPER RESPONSE"

The airplane was in instrument meteorological conditions and the pilot was cleared for an approach. As the airplane neared the final approach fix, the controller observed the airplane diverge from the approach course and change altitude rapidly. Shortly thereafter, the pilot said he had "all sorts of problems." The pilot requested and received vectors to an alternate airport. At 1748:29, the pilot was cleared for an ILS approach and was told to report when "established" on the approach. When asked if he was established on the ILS course, the pilot replied "I sure hope so." The controller observed the airplane descend below the published glide slope intercept altitude and advised the pilot to climb back to 2,000 feet. The pilot reported "I have problems." When asked the nature of the problem, the pilot reported "...I'm all over the place...I think I'm iced up..." Radar data indicated the airplane's radar track began following a left descending turn from 1,900 feet, about 1 minute before radar contact was lost. At 1751:33, the controller advised the pilot that his altitude was 1,000 feet, and requested that he climb to 3,000 feet. The pilot responded, "hey, I'm trying like hell." Radar contact with the airplane was lost about 1752, at 800 feet. A witness near the accident site stated he observed the airplane come out of the clouds, "wobbling" from side to side, make a "hard" left turn and strike the ground. He stated the engine was "loud" and seemed to be at "full throttle." Examination of the airplane did not reveal any pre impact mechanical malfunctions. The pilot purchased the accident airplane about 2 months prior to the accident. His total flight time in make and model was estimated to be about 200 hours. Airman's Meteorological Information (AIRMET) Zulu, Update 4, for Ice and Freezing Level was valid for the accident site area at the time of the accident. The AIRMET advised of occasional moderate rime/mixed icing in cloud in precipitation below 12,000 feet. The AIRMET reported the freezing level was from the surface to 4,000 feet. According to United States Naval Observatory astronomical data obtained for the accident site area, Sunset occurred at 1723, and the end of civil twilight was at 1751. The airplane was equipped with both wing leading edge and empennage de-icing boots. The switches for the de-icing boots were observed in the "Auto" position. The propeller de-ice and windshield anti-ice switches were observed in the "off" position.