United States of America

The pilot stated that on initial climb, at about 400 feet agl, the crew smelled something burning, followed by light smoke in the cabin. Both engines appeared normal visually. The odor and smoke increased, and the left fire warning light illuminated. The left engine was shut down and the prop feathered. The pilot increased power on the right engine; however, the airplane would not climb or maintain airspeed. A gear and flaps up forced landing was made into a field. The pilot stated that he believed an exhaust clamp broke allowing a segment of exhaust to scorch cowling and activate the fire warning system. Examination of the left engine revealed that the lower fire detection elements were fused and broken free, and that the hydraulic lines were burned through.

The company chief pilot/check pilot was giving a check flight to a company first officer (f/o). An FAA inspector was aboard to observe the check pilot's ability to give proficiency check flights. Soon after liftoff on the 2nd takeoff, the check pilot simulated an engine failure. The f/o, who was wearing a vision limiting device, allowed the airplane to drift to the left, but the FAA inspector noted that the f/o successfully regained directional control. The inspector then looked away from the cockpit, and when he looked back, the airplane was descending. Moments later, it collided with the ground. The FAA inspector reported that the check pilot was looking to the left, outside of the aircraft, and did not have his hand near the power quadrant. Review of the CVR tape revealed that, from the time the f/o was given the simulated left engine failure until impact, the check pilot did not say anything to the f/o. No maintenance discrepancy or material deficiency was noted during the investigation. The f/o had 3925 hours in this make/model of aircraft.

While cruising at FL240, a propeller (prop) hub arm on the left prop failed, releasing the prop blade, which struck a 2nd blade, breaking off its tip. This resulted in a severe engine vibration and shutdown of the left engine. The left engine was forced downward and inboard on its mounts. The cabin depressurized, possibly from blade contact. The flight crew made an emergency descent and received a vector to divert for an ILS approach to Dubuque. The airplane was incapable of maintaining altitude and descended in instrument conditions. Subsequently, it collided with a silo and crashed about 8 miles south of Dubuque. An investigation revealed the left prop hub failed from fatigue that initiated from multiple initiation sites on the inside diameter surface of the hole for the pilot tube. There was evidence that the fatigue properties of the hub were reduced by a combination of factors, including machining marks or scratches, mixed microstructure, corrosion, decarburization, and residual stresses. All eight occupants were killed, among them George Mickelson, 52, Governor of South Dakota.

At the time flight AA102 landed at DFW Airport, it was raining and there were numerous thunderstorms in the area. Shortly after touchdown on runway 17L, the pilot loss directional control when the airplane began to weathervane and the captain failed to use sufficient rudder control to regain the proper ground track. The airplane eventually departed the right side of the runway. At the time of landing the wind (a cross wind) was blowing at 15 knots with gusts approximately 5 knots above the steady wind speed. The aircraft was damaged beyond repair and all 202 occupants were evacuated, among them 40 were injured, two seriously.

The aircraft was on an air ambulance (EMS) flight and was cleared for the ILS runway 08 approach at Casper, WY. Radar data showed the aircraft tracking and descending normally on the DME arc, until it was below radar coverage for the area. Subsequently, it collided with the top of a ridge, along the localizer centerline, before reaching the outer marker, about 8 miles from the airport. Elevation of the crash site was about 5,800 feet; minimum descent altitude before intercepting the ILS glide slope was 7,100 feet; crossing altitude at the outer marker was 6,700 feet. All four occupants were killed, a patient, two doctors and a pilot.

Radar data showed the airplane tracking north of the planned route. It made several heading changes, and descended to 500 feet msl. The pilot advised ATC that he was landing at Shreveport, and was assigned a transponder code. No further transmissions were received by ATC. The airplane impacted transmission lines, poles, and trees approx 19 miles northwest of the airport. Examination of the propellers revealed that the right spinner dome marks equated to 74°; the operating range is 17-35°. The three blades of the left propeller showed only leading edge damage at the tips. Examination of the right engine revealed the following: carbon buildup in the exhaust and intake manifolds, exhaust valves pitted and scored, valve seats worn and pitted, spark plugs worn, compression below 60 on 4 cylinders, and a separated magneto block with pitting and fretting. Time since last annual inspection by operator maintenance personnel was 78 hrs. The left engine and accessories were extensively damaged by fire. The pilot, sole on board, was killed.

Pireps provided to the pilot by FSS prior to takeoff indicated that fog and low visibility had been encountered on the pilot's route to the east, forcing airplanes to return to Nome. In addition, as the flight taxied for takeoff, the pilot was told '... VFR is not recommended to the east...'. The airplane impacted flat snow covered terrain in a steep left wing down attitude approximately 4 miles east of the departure end of the runway. The area was a treeless, snow covered flat coastal plain bordered by a sea frozen with white ice. The pilot had returned to work 4/1 after a 30-day suspension following a takeoff accident, and was assigned only to Cessna 207 'VFR only' airplanes. The poi did not discuss the earlier accident or the pilot with the operator's management.

N500AK encountered icing in flight before start of ILS approach. Radar data showed that before reaching outer marker, it slowed in a manner that was consistent with a power reduction (or partial loss of power), then it entered a steep descent and crashed. Examination revealed engines were not operating at impact and that propellers had been feathered. No preimpact part failure or malfunction of engines, propellers or anti-ice system was found. There was evidence that engine inlet anti-ice annunciator lights and stability augmentation system (SAS) fault warning light were illuminated during impact. The engine manufacturer reported that flameouts had occurred in other aircraft, during or following operation in icing conditions, sometimes after descent into warmer air. Flight manual noted that if icing was encountered with anti-ice system off, select continuous ignition and then select engine and propeller heat (1 engine at a time, ensuring first engine was operating satisfactorily before selecting second engine) and engage sas heat. All four occupants were killed.

A witness reported that the airplane used the entire runway to get airborne, reached about 300 feet agl after liftoff, and drifted right. It then impacted trees about 1/3 mile from the departure end of the runway. Damage to the trees indicated that the airplane was in a right bank at impact. Both propellers showed evidence of rotation at impact. Estimated weight calculations showed that the airplane was at least 165 lbs in excess of max gross weight; this does not include an unknown amount of fuel on board prior to the last refueling. The pilot, sole on board, was killed.

A Cessna 421 crashed after an inflight breakup. Investigation disclosed that the left outboard portion of the elevator assembly (including the balance weight) separated first, resulting in empennage flutter and subsequent in-flight breakup of the empennage. The left elevator outboard hinge and support structure exhibited evidence of hinge overtravel. The left horizontal stabilizer front spar had failed downward; rivets that attached the left outboard hinge to the rear spar of the left stabilizer had sheared; and the left elevator center hinge had been pulled off the rear spar. About 100 flight hours before the accident, maintenance was performed to repair the left elevator balance weight (which was loose) and to repair a damaged stiffener in the center structure of the horizontal stabilizer. However, when examined after the accident, the balance weight was tight and the repair to the stiffener was intact. All three occupants were killed.