United States of America

American Eagle Flight 4184 was scheduled to depart the gate in Indianapolis at 14:10; however, due to a change in the traffic flow because of deteriorating weather conditions at destination Chicago-O'Hare, the flight left the gate at 14:14 and was held on the ground for 42 minutes before receiving an IFR clearance to O'Hare. At 14:55, the controller cleared flight 4184 for takeoff. The aircraft climbed to an enroute altitude of 16,300 feet. At 15:13, flight 4184 began the descent to 10,000 feet. During the descent, the FDR recorded the activation of the Level III airframe de-icing system. At 15:18, shortly after flight 4184 leveled off at 10,000 feet, the crew received a clearance to enter a holding pattern near the LUCIT intersection and they were told to expect further clearance at 15:45, which was revised to 16:00 at 15:38. Three minutes later the Level III airframe de-icing system activated again. At 15:56, the controller contacted flight 4184 and instructed the flight crew to descend to 8,000 feet. The engine power was reduced to the flight idle position, the propeller speed was 86 percent, and the autopilot remained engaged in the vertical speed (VS) and heading select (HDG SEL) modes. At 15:57:21, as the airplane was descending in a 15-degree right-wing-down attitude at 186 KIAS, the sound of the flap overspeed warning was recorded on the CVR. The crew selected flaps from 15 to zero degrees and the AOA and pitch attitude began to increase. At 15:57:33, as the airplane was descending through 9,130 feet, the AOA increased through 5 degrees, and the ailerons began deflecting to a right-wing-down position. About 1/2 second later, the ailerons rapidly deflected to 13:43 degrees right-wing-down, the autopilot disconnected. The airplane rolled rapidly to the right, and the pitch attitude and AOA began to decrease. Within several seconds of the initial aileron and roll excursion, the AOA decreased through 3.5 degrees, the ailerons moved to a nearly neutral position, and the airplane stopped rolling at 77 degrees right-wing-down. The airplane then began to roll to the left toward a wings-level attitude, the elevator began moving in a nose-up direction, the AOA began increasing, and the pitch attitude stopped at approximately 15 degrees nose down. At 15:57:38, as the airplane rolled back to the left through 59 degrees right-wing-down (towards wings level), the AOA increased again through 5 degrees and the ailerons again deflected rapidly to a right-wing-down position. The captain's nose-up control column force exceeded 22 pounds, and the airplane rolled rapidly to the right, at a rate in excess of 50 degrees per second. The captain's nose-up control column force decreased below 22 pounds as the airplane rolled through 120 degrees, and the first officer's nose-up control column force exceeded 22 pounds just after the airplane rolled through the inverted position (180 degrees). Nose-up elevator inputs were indicated on the FDR throughout the roll, and the AOA increased when nose-up elevator increased. At 15:57:45 the airplane rolled through the wings-level attitude (completion of first full roll). The nose-up elevator and AOA then decreased rapidly, the ailerons immediately deflected to 6 degrees left-wing-down and then stabilized at about 1 degree right-wing-down, and the airplane stopped rolling at 144 degrees right wing down. At 15:57:48, as the airplane began rolling left, back towards wings level, the airspeed increased through 260 knots, the pitch attitude decreased through 60 degrees nose down, normal acceleration fluctuated between 2.0 and 2.5 G, and the altitude decreased through 6,000 feet. At 15:57:51, as the roll attitude passed through 90 degrees, continuing towards wings level, the captain applied more than 22 pounds of nose-up control column force, the elevator position increased to about 3 degrees nose up, pitch attitude stopped decreasing at 73 degrees nose down, the airspeed increased through 300 KIAS, normal acceleration remained above 2 G, and the altitude decreased through 4,900 feet. At 15:57:53, as the captain's nose-up control column force decreased below 22 pounds, the first officer's nose-up control column force again exceeded 22 pounds and the captain made the statement "nice and easy." At 15:57:55, the normal acceleration increased to over 3.0 G. Approximately 1.7 seconds later, as the altitude decreased through 1,700 feet, the elevator position and vertical acceleration began to increase rapidly. The last recorded data on the FDR occurred at an altitude of 1,682 feet (vertical speed of approximately 500 feet per second), and indicated that the airplane was at an airspeed of 375 KIAS, a pitch attitude of 38 degrees nose down with 5 degrees of nose-up elevator, and was experiencing a vertical acceleration of 3.6 G. The airplane impacted a wet soybean field partially inverted, in a nose down, left-wing-low attitude. Based on petitions filed for reconsideration of the probable cause, the NTSB on September 2002 updated it's findings.

Crashed in unknown circumstances near Haines while completing a survey flight on behalf of the fish and wildlife Department. Both occupants were killed.

After taking off on an IFR flight, the airplane was observed to climb into a low overcast. The pilot contacted departure control and reported climbing through 2,200 feet for an assigned altitude of 5,000 feet msl. Shortly thereafter, radar and radio contact were lost, and the airplane crashed in a steep dive. During an investigation, no preimpact part failure or malfunction was found, though the airplane was extensively damaged during impact. The pilot's logbook indicated that he had flown three instrument approaches on 3/3/94 and that he had flown 3.1 hours in actual instrument conditions since that date.

The private pilot with about 3,000 hours of reported flight time and no instrument rating departed his home base, Thermal, California, for a short cross-country flight to Las Vegas, Nevada. There was no record of a preflight weather briefing, and no flight plan was filed. When the pilot failed to arrive at his destination, a search was initiated. The wreckage was located 6 days after it departed Thermal with the help of radar data. According to the radar data, the airplane was at 16,100 feet when it started a series of maneuvers while descending. Postcrash examination of the wreckage revealed that the left wing outer panel, aileron, and left engine were located some distance from the main wreckage. The weather at the time of the accident was reported as marginal VFR with thunderstorm cell activity in the area. The airplane did not have a working oxygen system nor was it equipped for instrument flight nor icing conditions.

As the airplane approached 22,000 feet, the pilot reported that both engines stopped running within seconds of each other. During the emergency landing approach the airplane collided with trees. Onscene investigation revealed no mechanical anomalies with the engines. The fuel system was empty, other than traces of fuel found in the left and right engine's fuel injector servos and flow dividers. Both wing fuel tank caps o-rings were hardened and had flat spots on them. The caps' opening tabs were able to be opened at 8 and 3 lbs of force, respectively. The company holding the airplane's type certificate states an opening force of 16 lbs of force is required. The company's annual inspection checklist requires that the tabs be checked. No record of this being accomplished was found in the airframe logbook. The pilot operating handbook states that the fuel cap tab tension must be checked during the preflight inspection.

The aircraft crashed while maneuvering to land at Pittsburgh International Airport, Pittsburgh, Pennsylvania. Flight 427 was operating under the provisions of 14 Code of Federal Regulations Part 121 as a scheduled domestic passenger flight from Chicago-O'Hare International Airport, Chicago, Illinois, to Pittsburgh. The flight departed about 1810, with 2 pilots, 3 flight attendants, and 127 passengers on board. The airplane entered an uncontrolled descent and impacted terrain near Aliquippa, Pennsylvania, about 6 miles northwest of the destination airport. All 132 people on board were killed, and the airplane was destroyed by impact forces and fire. Visual meteorological conditions prevailed for the flight, which operated on an instrument flight rules flight plan.

Witnesses stated that the airplane was on final approach to runway 03 with the landing gear and flaps extended. One witness reported that when the airplane was about 50 to 100 feet above the ground, he heard the engine go to full power, and the airplane entered a steep climbing right turn. The witness stated that the airplane looked very slow during the steep climb. While in the climb, the airplane's wings leveled and then the airplane banked left and nosed down into the ground. A no-radio gyrocopter had just taken off on runway 03. Both occupants were killed.

While in cruise flight in a level six thunderstorm over the Atlantic Ocean, the pilot reported the airplane's 'gyro' had failed. The airplane then began a left turn and disappeared off radar. The airplane and its occupants were located on the ocean floor about 48 days after the accident. The airplane had broken apart in-flight. The outboard section of each wing and the tail section were not recovered. The airplane's pneumatic system was destroyed. According to fss records, the pilot had been briefed on the weather along his route of flight.

While in level flight, the airplane's right wing separated and, during the separation sequence, wing fuel ignited. Subsequent laboratory examination of right-side, center-wing fragments revealed two fatigue cracks that propagated to overstress fractures. One of the cracks was within the underside wing skin below a doubler, and the other was within the doubler itself. The total size and origin of the fatigue regions could not be determined due to damage to fracture surfaces and a lack of available material. The airplane was delivered new to the U.S. Air Force in December 1957 and was retired from military service in 1986. In May 1990, the FAA issued a restricted-category special airworthiness certificate authorizing the airplane to dispense aerial fire retardant. At the time of the accident, the airplane had a total of 20,289 flight hours, 19,547 of which were acquired during its military service. The inspection and maintenance programs used by the operator, which were based on military standards, included general visual inspections for cracks but did not include enhanced or focused inspections of highly stressed areas, such as the wing sections, where the fatigue cracks that led to those accidents were located. The operator did not possess the engineering expertise necessary to conduct studies and engineering analysis to define the stresses associated with the firefighting operating environment and to predict the effects of those stresses on the operational life of the airplanes.

The plane was observed to enter a valley with mountains on both sides. While the pilot was maneuvering the airplane to the left to reverse direction, it collided with terrain. Witnesses reported the plane's engine sounded normal and that the weather was good with clear skies, unlimited visibility and light wind. A pilot who flew over the accident site minutes after the mishap reported the area was devoid of turbulence. This was a part 135, on-demand, lodge/hunting guide operation. All three occupants were killed.