Accident Briefs: Spring 2019

CESSNA 340
Bartow, FL/Injuries: 5 Fatal

The instrument-rated private pilot and four passengers boarded the multiengine airplane inside a hangar. The pilot then requested that the airplane be towed from the hangar to the ramp, since he did not want to hit anything on the ramp while taxiing in the dense fog. Witnesses heard the pre-takeoff engine run-up toward the end of the runway but could not see the airplane as it departed; the engines sounded normal during the run-up and takeoff. A witness video recorded the takeoff but the airplane was not visible due to the dense fog. During the takeoff roll the airplane's tires chirped, which is consistent with the wheels touching down on the runway with a side load. The video ended before the accident occurred. The witnesses stated that the takeoff continued and then they heard the airplane impact the ground and saw an explosion. The weather conditions at the time of the accident included visibility less than 1/4 mile in fog and an overcast ceiling at 300 ft above ground level. The airplane's weight at the time of the accident was about 105 lbs over the maximum takeoff weight, which exceeded the center of gravity moment envelope. The excess weight would have likely extended the takeoff roll, decreased the climb rate, and increased the amount of elevator pressure required to lift off of the runway.

A majority of the airplane was consumed by postcrash fire. The ground impact marks and wreckage distribution were consistent with the airplane rolling left over the departure end of the runway and impacting the ground inverted in a nearly vertical, nose-low attitude. Examination of the engines revealed operating signatures consistent with takeoff power at the time of impact. The elevator trim tab and actuator were found beyond their full up travel limits and the trim cable exhibited tension overload separations near the actuator. It is likely that, when the cable separated in overload, the chain turned the sprocket and extended the actuator rod beyond full travel. No anomalies were observed with the airframe, engines, or cockpit instrumentation that would have precluded normal operation. The investigation was unable to determine the status of the autopilot during the accident takeoff.

Based on the evidence it's likely that when the airplane entered instrument meteorological conditions the pilot experienced spatial disorientation, which resulted in a loss of control and descent into terrain.

Probable cause(s): The pilot's loss of control due to spatial disorientation during takeoff in instrument meteorological conditions.

RV7
Arlington, Arizona/Injuries: 2 Fatal

The airline transport pilot and private pilot-rated passenger were in cruise flight when radar contact was lost. Wreckage and impact signatures revealed that the airplane impacted the ground in an inverted, left-wing-down, nose-down attitude. The cockpit canopy, vertical stabilizer, and rudder were found about 1 mile from the main wreckage. Examination of the engine found no abnormalities that would have precluded normal operation.

Examination of the airframe revealed biological matter in a dented section underneath the horizontal stabilizer, as well as bird feathers in the cockpit under the passenger seat. DNA and microscopic examination of the specimens were consistent with a rock pigeon. All fracture surfaces examined were consistent with overstress failure; there were no indications of any preexisting damage such as cracks or corrosion. The fracture surfaces of the spars, skins, stabilizers, and other components from the horizontal stabilizer, vertical stabilizer, and rudder assemblies exhibited features consistent with secondary fractures (such as from ground impact or after the bird strike). There were no clear indications that any of the components that fractured in overstress did so prior to ground impact or independently of the bird strike. It is possible that the pilot made an evasive maneuver before or during impact with the bird, that in combination, resulted in an overstress structural failure of the, vertical stabilizer and rudder, which in turn resulted in the pilot's inability to maintain control of the airplane.

Probable cause(s): The inflight overstress separation of the vertical stabilizer and rudder during flight which resulted in the pilot's inability to maintain airplane control. Contributing to the accident was an inflight collision with a bird.

E CHRISTAVIA MK 1
Grand Detour, IL/Injuries: 2 Serious

The private pilot was flying an experimental airplane at a low altitude along a river when the airplane struck a power line suspended 30 ft above the river, causing the airplane to cartwheel. The power line wrapped around the airplane, and the airplane descended straight down, impacting the ice-covered river.

A postaccident examination of the airplane showed that the fuselage forward of the instrument panel, the engine cowling, and the engine were bent upward about 30°. The forward fuel tank between the cabin and the engine had broken open, and the smell of fuel was apparent. The airplane's propeller showed indications that the engine was producing high power when the airplane struck the power line. Flight control continuity was confirmed. Examination of the engine and other airplane systems showed no preimpact anomalies. Thus, the accident likely occurred because the pilot did not see the power line suspended across the river while he was flying close to the river surface.

Probable cause(s): The pilot's failure to see and avoid the power line. Contributing to the accident was the pilot's intentional flight at low altitude.

BEECH A36
Loveland, CO/Injuries: 2 None

The accident occurred when a helicopter (N878BC) and an airplane (N777YF) collided midair while on approach to the airport. The helicopter pilot intended to fly a practice instrument approach to the runway, perform the missed approach procedure, and enter the published holding pattern. The airplane pilot intended to enter the traffic pattern, with appropriate spacing, for a full stop landing on the same runway. The airplane pilot had the helicopter in sight and was following the helicopter to the runway. While on final approach, the airplane pilot thought that the helicopter had entered a hover and asked the helicopter pilot about his intentions. The helicopter pilot indicated that he would be flying the missed approach procedure and then returning to the airport, but the airplane pilot incorrectly heard the helicopter pilot's response and believed that the helicopter was going to hover near the end of the runway and then proceed to the east. As a result, the airplane pilot expected the helicopter to be east of the airport, which was a common location for local helicopter training, when the airplane would be landing; however, the helicopter was on approach to the runway at that time. During the airplane's approach, the airplane pilot lost sight of the helicopter. The airplane continued to land and collided with the helicopter.

Probable cause(s): The airplane pilot's failure to see and avoid the helicopter while in the traffic pattern, which resulted in a midair collision between the two aircraft. Contributing to the accident was the airplane pilot's misunderstanding of the helicopter pilot's intentions and the airplane pilot's expectation that the helicopter would be clear of the runway.