Montana

The airplane was on the final approach segment of an instrument flight rules (IFR) cross country flight that originated approximately 3 hours and 45 minutes prior to the accident when radio communications with the aircraft were lost. The aircraft wreckage was located the following day approximately 2.8 miles from the destination airport. The airplane impacted terrain in a vertical descent and flat attitude and came to rest upright on its fuselage and wings. The cockpit and cabin were intact and both wing assemblies remained attached to the fuselage. Evidence of forward velocity and/or leading edge deformation was not observed to the wings or fuselage. Mixed ice was noted along the leading edge of both wings. At the time of the accident, weather conditions were reported as low ceilings and low visibility due to snow and mist. The accident occurred during dark night conditions. Air traffic control (ATC) transcripts indicated that shortly after entering the holding pattern at 11,000 feet the pilot was issued an approach clearance for the ILS. The pilot acknowledged the clearance and approximately two minutes later ATC communications with the pilot were lost. Pilot logbook records showed that the pilot's total flight time was approximately 1,987 hours. In the six-month period preceding the accident, the pilot logged approximately 40 hours total time, 9 hours of actual instrument time and 7 instrument approaches in the accident airplane. The pilot's total night flying experience was approximately 51 hours. The pilot made no entries in his pilot logbook indicating that he had flown at night in the six-month time frame preceding the accident. Pilots flying the ILS approach prior to the accident aircraft reported mixed icing during the descent and final approach. Post accident examination of the aircraft revealed no evidence to indicate a mechanical malfunction or failure.

Immediately after taking off and raising the landing gear, the pilot noticed the left engine began to lose power. The airplane subsequently veered to the left before impacting up slopping terrain in a left wing low attitude, resulting in a fire breaking out which consumed the left side of the airplane. A postaccident examination revealed that the left engine had sustained thermal but no impact damage, and that the engine's right hand turbocharger had no thermal or impact damage. A further examination indicated that no restrictions were found in the center section of the turbocharger and there was no damage to the housing or the impeller; however, the impeller was frozen in the center section and would not turn. Indications of grooving and scraping from a lack of lubrication to the bearings and drive shaft was observed. No mechanical anomalies with the aircraft were noted by the pilot prior to takeoff which would have prevented normal operations.

While on the return leg of a non-scheduled 14 CFR Part 135 VFR cross-country flight, the airplane collided with mountainous terrain at approximately 9,100 feet above mean sea level. Prior to the accident, the pilot informed air traffic control that he was VFR and level at 8,500 feet MSL. Dark night conditions prevailed at the time of the accident. The aircraft crashed on the south-facing slope of the 9,100-foot mountain near the last recorded radar position. Wreckage and impact signatures at the crash site were indicative of high energy and shallow impact with the terrain. The investigation revealed no evidence of any aircraft mechanical problems.

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.

While flying a night visual approach, the co-pilot flared too high above the runway. As the aircraft floated down the runway, the speed decreased, and the pilot-in-command took control. Because he felt the aircraft was approaching a stall, he initiated a go-around. During the attempted go-around, the pilot-in-command found it necessary to keep both hands on the control wheel due to the fact that the aircraft had been trimmed to the full nose-up position during the landing flare. Even with both hands on the control wheel, the aircraft became very difficult to control. Although the co-pilot moved the throttles to maximum power and began retraction of the flaps, the pilot-in-command's remedial action had occurred too late to successfully execute the go-around. It was later discovered that during the operator's initial training, both crew members had been taught to apply full nose-up trim after crossing the runway threshold and reducing the power to idle. This action, which the operator eliminated from the landing sequence procedure after this accident, was inconsistent with the instructions in the Beech 99 Pilots Operating Manual.

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 aircraft disappeared from ATC radar immediately after being cleared to descend from 12,000 feet to 10,000 feet. ATC radar data showed the aircraft at 11,900 to 12,000 feet for approximately the last 6 minutes prior to the disappearance, with the last Mode C altitude and discrete transponder code 2402 (at 0221:03) reported as 11,800 feet. The last three returns, 12,000, 11,900, and 11,800, are consistent with the start of a descent from 12,000 feet. Due to construction at the radar antenna site, the area where the aircraft disappeared was blocked from radar coverage. Subsequent attempts by the controller to contact the aircraft were unsuccessful. A 7,000- to 7,500-foot overcast was reported at the destination, along with lower clouds and precipitation. Documentation at the accident site indicated an approximate level flight path from the broken treetops to the area of ground impact into a northwest-facing 60-degree mountain slope at approximately the 5,600-foot level. The wreckage was not located for approximately two months. Post-accident examinations of the aircraft's Bendix/King KEA130A (United Instruments 5035PB-P57) encoding altimeter revealed needle impressions on the indicator face and pointers consistent with an altitude indication of 12,620 feet. The internal components of the unit were severely damaged and a functional test was not possible. The aircraft was equipped with a copilot's altimeter. Only the faceplate was recovered and examined. One impression on the main faceplate revealed a needle impression by the 100-foot pointer consistent with 560 feet. The position of the 1,000-foot pointer could not be determined. The pilot's 4-day activity history showed that he was returning from a demanding 3-day work assignment, that his recent sleeping schedule was irregular, and that he had been awake about 20 hours at the time of the accident. There was no evidence found of a mechanical failure or malfunction at the time of the accident.

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.

The pilot received a full weather briefing from a Flight Service Station (FSS) on the morning of the accident. The FSS briefer told the pilot that moderate turbulence and icing prevailed along the pilot's intended route of flight, and that there were forecasts for isolated thundershowers. The briefer advised the pilot to call for an update just prior to departure. The pilot departed on the flight almost 3 hours later without calling for an update. He received an IFR clearance after 15 minutes of delays, then proceeded on course to his destination. About 35 minutes after departure, while cruising at 16,000 feet, the pilot reported that he was 'in the clouds and the bumps are big time.' About 3 minutes later, the pilot radioed that he was 'in a dive and I don't...' The airplane impacted terrain in a nose-down, inverted attitude and exploded. Analysis of recorded radar and meteorological data indicates that the airplane encountered a thunderstorm, strong updrafts, downdrafts, and turbulence.