Great Falls

After landing on runway 08 at Lewistown Airport, the twin engine airplane started to skid then veered off runway to the left. While contact a snow covered terrain, it slid for few dozen metres and came to rest with its left wing severely damaged. All three occupants evacuated safely.

About one minute after takeoff on a night Instrument Flight Rules (IFR) contract cargo flight, the tower controller advised the pilot that he was squawking the wrong transponder code. Although the pilot reset the transponder to the correct code, he was advised that he was still squawking the wrong code. He then realized that he had selected the wrong transponder, and then switched to the correct one. During the time the pilot was dealing with this issue, the airplane drifted about 30 degrees right of the assigned heading, but the pilot returned to the correct heading as he was contacting the departure controller. The departure controller cleared him to continue his climb and instructed him to turn left about 120 degrees, which he did. About 40 seconds after initiating his left turn of about 120 degrees, while climbing straight ahead through an altitude about 4,700 feet above ground level (AGL), the pilot was instructed to turn 20 degrees further left. Almost immediately thereafter, the airplane began turning to the right, and then suddenly entered a rapidly descending right turn. The airplane ultimately impacted the terrain in a nearly wings-level nose-down attitude of greater than 45 degrees. At the moment of impact the airplane was on a heading about 220 degrees to the right of the its last stabilized course. The investigation did not find any indication of an airframe, control system, or engine mechanical failure or malfunction that would have precluded normal flight, and no autopsy or toxicological information could be acquired due to the high amount of energy that was released when the airplane impacted the terrain. The determination of the initiating event that led to the uncontrolled descent into the terrain was not able to be determined.

The cross-country flight was on an instrument flight rules (IFR) flight plan, approximately 42 nautical miles from the tower-controlled destination airport, when the pilot was cleared for the visual approach. Dark night visual meteorological conditions prevailed, and there was an overcast layer of clouds at 11,000 feet. After the en route radar service was terminated, the pilot contacted the local control tower and made a garbled and partially unintelligible transmission. Shortly after the time of the transmission, local law enforcement personnel received reports of a downed aircraft. The wreckage was located later that evening approximately 80 feet below the peak of a ridge that rose to an elevation of approximately 5,700 feet. From the initial point of contact with terrain, the debris path was scattered over the crest of the ridge and continued down the opposing side, in a south-southeast direction, toward the airport. The ridge was the highest obstruction between the accident location and the destination airport. The airport is located in a large valley and is surrounded by rising mountainous terrain. At night, clouds and terrain are difficult for pilots to see, and a gradual loss of visual cues can occur as flight is continued toward darker terrain. Additionally, the horizon is less visible and less distinct at night than during the day. Because the pilot was descending the airplane over rural, mountainous terrain that provided few visual ground reference cues, and because the overcast cloud layer would have prevented moonlight from illuminating the terrain, it is likely that the pilot did not see the rising terrain as the airplane continued toward it. The airplane was equipped with an Enhanced Ground Proximity Warning System; however, impact damage to the unit precluded post accident testing. It is not known how the unit was configured during the flight or what type of alerts the pilot received prior to impact. Post accident examination of the wreckage, to include both engines, did not disclose evidence of a mechanical malfunction prior to impact. Additionally, no evidence was found to suggest an in-flight structural failure.

During climbout, the airplane encountered an area of freezing rain resulting in rapid airframe ice accretion and loss of climb capability. The pilot informed ATC that he was unable to maintain altitude and requested and received clearance back to Great Falls, the departure airport. ATC radar showed that the airplane then began a right turn over mountainous terrain extending up to 8,309 feet prior to loss of radar contact (lower and relatively flat terrain, down to less than 5,000 feet, was located to the left of the aircraft's track.) During the last minute of radar contact, the aircraft was in a right turn at a descent rate of about 400 feet per minute; the aircraft passed less than 1/2 mile from the 8,309-foot mountain summit just prior to loss of radar contact, at an altitude of 8,400 to 8,500 feet. The aircraft crashed on the southwest flank of the 8,309-foot mountain about 1/2 mile south of the last recorded radar position. Wreckage and impact signatures at the crash site were indicative of an inverted, steep-angle, relatively low-speed, downhill impact with the terrain. The investigation revealed no evidence of any aircraft mechanical problems.

The flight was on a practice nondirectional beacon (NDB) approach to Great Falls runway 34 in visual conditions. Abeam the final approach fix, the aircraft was 4 miles right of course. Upon being advised of this by ATC, the pilot corrected back to final with a 60-degree intercept angle, rolling out on course 3 miles from the runway. When the pilot called missed approach, the local controller (a trainee) instructed the pilot to make a 360-degree right turn to enter right downwind for runway 3, and the pilot acknowledged. The controller trainee then amended this instruction to a 180-degree right turn to enter right downwind for runway 21, then to a 180- degree right turn to enter right downwind for runway 3. The crew did not acknowledge the amended instruction. Controllers then observed the airplane had crashed. Witnesses reported the airplane entered a steep descent from a right turn and impacted the ground at a steep angle. The flight was described as recurrent training required by the owner's insurance; however, the second aircraft occupant's airline transport pilot and flight instructor certificates had been revoked, and he held only a private pilot certificate. Investigators found no evidence of aircraft malfunctions.

The Short Brothers SD3-60 cargo flight was being vectored for the VOR/DME RWY 28R approach to the Billings Logan International airport during instrument meteorological conditions. Weather conditions one minute before the accident were winds 020 at 13 knots, light snow and mist, and visibility was deteriorating rapidly. The co-pilot (occupying the right seat) was flying the aircraft, and the PIC (occupying the left seat) was handling radio communications. At 0812:25, having crossed the final approach fix, the aircraft descended through 100 feet above the MDA (3,940 feet or 426 feet above the runway threshold), and immediately thereafter the crew visually acquired the runway. At 0813:01 the aircraft's GPWS alert of 'SINK RATE' was heard, followed 2 seconds later by the PIC calling for 'POWER,' and a 2 second delay to ground impact. The co-pilot had logged a total of 103 hours in the SD3-60 (all within the previous 90 days,) while the PIC had just begun flying the aircraft in Montana's late fall weather after a 6 year assignment flying in the Hawaiian islands. The left main landing gear collapsed in overload during the ground impact.

The captain reported: 'Shortly after V1...there was a loss of power to the left engine....' (FAR Part 1 defines V1 as takeoff decision speed.) However, the first officer, who was the pilot flying, stated the captain retarded power on the left engine as a training exercise. The first officer stated there was no preflight discussion of emergency procedure practice. The airplane became airborne about 3,500 feet down the runway; the crew subsequently lost control of the aircraft, and it crashed to the left of the runway, and a fire erupted. The crew escaped with minor injuries. A teardown of the left engine was performed under FAA supervision at the engine manufacturer's facilities; the engine manufacturer reported that damage found during the teardown 'was indicative of engine rotation and operation at the time of impact....' Both airspeed indicator bugs were found set 9 to 11 knots below the V1 speed on the takeoff and landing data (TOLD) card. No evidence of an aircraft or engine malfunction, to include inflight fire, was found at the accident site.

Because of the failure of the thrust reverser relay circuit board, the thrust reversers failed to deploy when selected by the pilot. Because the reversers failed to deploy, the 'reversers in transition' lights, and the 'reversers deployed' lights did not illuminate. Even though the aircraft flight manual warns against moving the reverser throttle levers into the power range without the illumination of these lights, the pilot did so anyway. The pilot continued to select reverse power even after the activation of the throttle mismatch warning horn, resulting in an increase in forward thrust while attempting to stop. During this sequence of events the second-in-command moved the parking brake lever to full override, locking the main wheel brakes and overriding the antiskid system.

Airspur flight 500, a domestic cargo flight, departed Kalispell, MT, at 1903 mdt with an IFR flight plan to Great Falls, MT. At 1922, the pilot notified Salt Lake ARTCC he was returning to Kalispell due to a rough running engine. Shortly thereafter, the pilot reported the engine had failed completely. The pilot made an emergency forced landing on a mountain ridge at the approximately 5,500 feet level in IFR conditions. Accident location was approximately 18 nm east of Kalispell. Engine disassembly later revealed the #4 connecting rod had failed catastrophically. The pilot escaped with minor injuries.

The pilot, sole on board, was completing a night cargo flight from Helena to Great Falls. On approach, he encountered poor weather conditions when the airplane struck the ground and crashed few miles short of runway threshold. The aircraft was destroyed and the pilot was killed. At the time of the accident, weather conditions were below minimums.