Pontiac-Oakland County

The crew departed Pontiac-Oakland County Airport on a cargo service to Livingston-Mission Field Airport (flight RAX698). After touchdown on runway 22, the airplane was unable to stop within the remaining distance and overran. It went down into a ravine, lost its undercarriage and came to rest with both engines torn off. Both crew members evacuated safely.

While on final approach, the airplane gradually slowed to near its stall speed. About 600 ft beyond the last recorded data, the airplane impacted the ground in a nose-down attitude that was consistent with a stall. Postaccident examination revealed no preaccident mechanical failures or malfunctions that would have contributed to the accident. Witnesses near the accident site reported very heavy sleet with low visibility conditions, whereas a witness located near the final approach flightpath, about 2 miles before the accident site observed the airplane fly by below an overcast cloud layer with no precipitation present. Based on the witness accounts and weather data, the airplane likely entered a lake effect band of heavy sleet during the final portion of the flight. The airplane was modified with 5-bladed propellers, and other pilots reported it would decelerate rapidly, especially when the speed/propeller levers were moved to the high rpm (forward) position. The pilot usually flew a larger corporate jet and had not flown the accident airplane for 8 months. The passenger was a student pilot with an interest in becoming a professional pilot. The pilot’s poor airspeed control on final approach was likely influenced by a lack of recency in the turboprop airplane. The workload of inflight deicing tasks may have also contributed to the poor airspeed control. The aerodynamic effects of the heavy sleet that was encountered near the accident site likely contributed to the stall to some degree.

During the 3.5-hour flight preceding the accident flight, the airplane used about 156 gallons of the 196 gallons of usable fuel. After landing, the airplane was topped off with 156 gallons of fuel for the return flight. During the preflight inspection, a line serviceman at the fixed based operator observed the right main fuel tank sump become stuck in the open position. He estimated 5 to 6 gallons of fuel were lost before the sump seal was regained, but the exact amount of fuel lost could not be determined. The lost fuel was not replaced before the airplane departed. Data from an on board GPS unit indicate that the airplane flew the return leg at an altitude of about 4,500 feet mean sea level for about 4 hours. About 4 minutes after beginning the descent to the destination airport, the pilot requested to divert to a closer airport. The pilot was cleared for an approach to runway 18R at the new destination. While on approach to land, the pilot reported to the air traffic control tower controller, “we exhausted fuel.” The airplane descended and crashed into a forested area about 1/2 mile from the airport. Post accident examination of the right and left propellers noted no leading edge impact damage or signatures indicative of rotation at the time of impact. Examination of the airplane wreckage and engines found no malfunctions or failures that would have precluded normal operation. The pilot did not report any problems with the airplane or its fuel state before announcing the fuel was exhausted. His acceptance of the approach to runway 18R resulted in the airplane flying at least 1 mile further than if he had requested to land on runway 18L instead. If the pilot had declared an emergency and made an immediate approach to the closest runway when he realized the exhausted fuel state, he likely would have reached the airport. Toxicological testing revealed cyclobenzaprine and diphenhydramine in the pilot’s system at or above therapeutic levels. Both medications carry warnings that use may impair mental and/or physical abilities required for activities such as driving or operating heavy machinery. The airplane would have used about 186 gallons of fuel on the 4-hour return flight if the engines burned fuel at the same rate as the previous flight. The fuel lost during the preflight inspection and the additional 30 minutes of flight time on the return leg reduced the airplane’s usable fuel available to complete the planned flight, and the pilot likely did not recognize the low fuel state before the fuel was exhausted due to impairment by the medications he was taking.

The flight was scheduled to pick up cargo at the destination airport and then deliver it to another location. During the descent and 14 minutes before the accident, the airplane encountered a layer of moderate rime ice. The captain, who was the pilot flying, and the first officer, who was the monitoring pilot, made multiple statements which were consistent with their awareness and presence of airframe icing. After obtaining visual flight rules conditions, the flight crew canceled the instrument flight rules clearance and continued with a right, circling approach to the runway. While turning into the base leg of the traffic pattern, and 45 seconds prior to the accident, the captain called for full flaps and the engine power levers were adjusted several times between 50 and 95 percent. In addition, the captain inquired about the autopilot and fuel balance. In response, the first officer stated that he did not think that the spoilerons were working. Shortly thereafter, the first officer gave the command to add full engine power and the airplane impacted terrain. There was no evidence of flight crew impairment or fatigue in the final 30 minutes of the flight. The cockpit voice recorder showed multiple instances during the flight in which the airplane was below 10,000 feet mean sea level that the crew was engaged in discussions that were not consistent with a sterile cockpit environment, for example a lengthy discussion about Class B airspeeds, which may have led to a relaxed and casual cockpit atmosphere. In addition, the flight crew appears to have conducted checklists in a generally informal manner. As the flight was conducted by a Part 135 operator, it would be expected that both pilots were versed with the importance of sterile cockpit rules and the importance of adhering to procedures, including demonstrating checklist discipline. For approximately the last 24 seconds of flight, both pilots were likely focusing their attention on activities to identify and understand the reason for the airplane's roll handling difficulties, as noted by the captain's comment related to the fuel balance. These events, culminating in the first officer's urgent command to add full power, suggested that neither pilot detected the airplane's decaying energy state before it reached a critical level for the conditions it encountered. Light bulb filament examination revealed that aileron augmentation system and stall warning lights illuminated in the cockpit. No mechanical anomalies were found to substantiate a failure in the aileron augmentation system. No additional mechanical or system anomalies were noted with the airplane. A performance study, limited by available data, could not confirm the airplane's movements relative to an aileron augmentation system or spoileron problem. The level of airframe icing and its possible effect on the airplane at the time of the accident could not be determined.

At 0314, the pilot reported to the Air Traffic Control (ATC) Tower that he wanted to divert from his destination to land at a closer airport, and was cleared for a visual approach. At 0325, the pilot issued a "Mayday." On final approach the airplane struck a building and wires about 1/2 mile short of the runway. Witnesses that saw the airplane just before impact said that the airplane was low, there was no in-flight fire, and the engine sounds "...appeared to be a fluttering sound as if air [was] passing through the propeller." The pilot had filed for a cruise altitude of 15,000 feet, with a time en route of 5 hours, and fuel on board 6 hours. Weight and balance calculations showed that the pilot was operating about 722 pounds above the maximum gross weight for the takeoff, climb, and maximum cruise power settings. The Pilot Operating Handbook calculations showed that most of the fuel would have been used during the flight. The engine and propeller examinations revealed that both engines were not producing power at impact (windmilling). There were no discrepancies found with the engines or propellers. Examination of the propellers revealed that they were not in the feather position and they were not in beta/reverse position. Line personnel at the departure airport confirmed that all the tanks were topped off (282 gallons added). It took the flight 32 minutes to reach a cruise altitude of 15,000 feet, which calculated to about 293.3 pounds (1 gallon of Jet "A" equals 6.7 pounds), and a flight time of 4.9 hours from takeoff to impact. Sample calculations indicated that the fuel burn rate would have caused the airplane to use 2,649.3 pounds of Jet "A" turbine fuel during the flight. The flight departed with all tanks full 384 gallons usable (2,572.8 pounds), which calculates to insufficient fuel for the completion of the flight. Two gallons of fuel was drained from the right nacelle tank at the crash site, and there was no evidence of in-flight leakage. The sample calculations do not consider performance degradation for operating the airplane above the maximum allowable gross weight, which would cause the fuel consumption to go up because more power was required for the overweight conditions. The pilot's flight plan was for economy cruise, plus the airplane was over gross weight at takeoff, and there are no performance charts for that condition. So, the performance was even poorer than shown on the maximum power chart for climb and cruise. Calculations of the maximum allowable fuel that could be on board the aircraft showed that only 1851 pounds of turbine fuel could be carried to start the flight at the maximum allowable weight, or about 3.2 hours of flight. The en route winds aloft at the airplane's altitude indicated a slight tailwind for half the flight and a headwind of about 15 knots for the remainder of the flight.

The airplane collided with the tops of trees during an ILS approach near the middle marke. Witnesses heard the airplane strike the trees and a '...whop, whop, whop sound...' it made as it continued its flight. Other witnesses observed the airplane flying a curved, descending, flight path until the aircraft impacted the ground. Visibility was reported as 1/2 mile at the airport. The on-scene examination revealed no airframe or engine anomalies that would prevent flight. A section of the right propeller and other pieces of airframe were found along the approach path after initial impact with trees. The trees along the flight path were about 30 to 60 feet high. The tops of the taller trees were broken or had fresh cut marks on their limbs. The pilot's blood alcohol level was 216 (mg/dL, mg/hg).

Pilot was on final approach when he stated he got a fuel crossfeed 'warning' light. He then proceeded to try to troubleshoot the fuel system by cycling the right boost pump switch, and 'reset and arm' the auto crossfeed. He stated the crossfeed light came on again followed by the right fuel pressure light, and he experienced a power loss on the right side. When he feathered the right engine, the left engine also experienced a loss of power. The pilot cleaned up the airplane and ditched in the lake short of the airport. The investigation revealed the left wing fuel tanks were empty, and the left nacelle tank was collapsed. The right wing fuel tanks were empty, and the right nacelle tank contained 19 gallons of fuel. The fuel supply, transfer, and crossfeed systems were functionally checked, and were operable. All cockpit fuel system lights indicated normal system operation.

Approximately 2 minutes after the flight (N84UM) had climbed and leveled at FL290, the ARTCC controller noticed there was no return from the aircraft's transponder. The controller transmitted an advisory, but got no reply. He made several more radio calls and received 2 replies. Later, a review of the radio transcript indicated the pilot's 1st reply was something about 'ice.' In his 2nd response to an inquiry from the controller about 'how do you hear me,' he replied 'good.' After that there was no further contact with the flight. Wreckage from the aircraft was found scattered over a 6 miles area, indicating an in-flight breakup. Pieces from the horizontal stabilizers were found from 2 to 6 miles from the main wreckage. The right wing was found 2 miles from the main wreckage and the left outboard wing panel was found about 1 mile from the right wing. During a preflight briefing, the pilot was advised of turbulences and icing conditions; he was told to expect light to moderate rime icing in clouds thru 15,000 feet, but the aircraft was equipped for flight in icing conditions. A check of the pilot's liver fluid showed a benzoylecgonine (cocaine metabolite) level of 0.136 mg/l. Both occupants were killed.

While on final approach to land at night, the left engine lost power due to fuel starvation. Attempts to restart the engine were not successful. While the pilot was attempting a restart, the aircraft drifted to the right of the runway centerline and toward the proximity of hangars. The pilot stated that due to the power loss and wind conditions, he elected to land on airport property. Gear extension was delayed until just before landing. The aircraft touched down before the right main landing gear was fully extended and locked. Subsequently, the right main gear collapsed and the aircraft skidded about 500 feet before coming to rest. An examination revealed the nacelle and main fuel tanks were empty, but fuel was still remaining in the auxiliary tanks.

Aircraft was scheduled for an instructional flight. During the weather briefing, the CFI told the FSS specialist that the flight would include engine out practice. Witness statements indicate that the aircraft rolled sharply to the right and nosed down after attaining about 100 feet of altitude during the climb after takeoff. The aircraft struck the ground left prop and left wing tip first, in an inverted flight attitude. During the post accident investigation, the right engine power lever was subjected to lab exam and it was found that the lower aft part of the lift gate detent was worn. This created a ramping effect between the rounded edge of the lift gate and the flight idle stop. A worn lift gate detent would allow the power lever to inadvertently be moved into the beta range, causing asymmetrical drag and degraded airplane performance, particularly in critical phases of flight. All three occupants were killed.