ERA16LA078

The pilot's inadequate preflight inspection and his subsequent failure to maintain airplane control, which resulted in an access door opening after takeoff, and the airplane exceeding its critical angle of attack and experiencing an aerodynamic stall.

On the day of the accident, a line service technician had disconnected the airplane from a battery charger. After disconnecting the battery, he left the right access door open which provided access to the fuel control unit, fuses, fuel line, oil line, and battery charging port as he always did. He then towed the airplane from the hangar it was stored in, and parked it in front of the airport's terminal building. The three passengers arrived first, and then about 30 minutes later the pilot arrived. He uploaded his navigational charts and did a preflight check "which was normal." The engine start, taxi, and engine run up, were also normal. The wing flaps were set to 10°. After liftoff he "retracted the landing gear" and continued to climb. Shortly thereafter the right cowl door opened partially, and started "flopping" up and down 3 to 4 inches in each direction. He reduced the torque to try to prevent the right cowl door from coming completely open. However, when he turned on the left crosswind leg to return to the runway, the right cowl door opened completely, and the airplane would not maintain altitude even with full power, so he "put the nose back down." The airplane struck trees, and then pancaked, and slid sideways and came to rest, in the front yard of an abandoned house. The private pilot and one passenger received minor injuries. Two passengers received serious injuries, one of whom was found out of her seat, unconscious, on the floor of the airplane shortly after the accident, and died about 227 days later. During the investigation, it could not be determined, if she had properly used the restraint system, as it was found unlatched with the seatbelt portion of the assembly extended. Examination of the wreckage revealed no evidence of any preimpact failures or malfunctions of the airplane or engine that would have precluded normal operation. It was discovered though, that the right access door had not been closed and latched by the pilot before takeoff, as examination of the right access door latches and clevis keepers found them to be functional, with no indication of overstress or deformation which would have been present if the access door had been forced open due to air loads in-flight, or during the impact sequence. Further examination also revealed that the battery charging port cover which was inside the compartment that the right access door allowed access to, had not been placed and secured over the battery charging port, indicating that the preflight inspection had not been properly completed. A checklist that was provided by a simulator training provider was found by the pilot's seat station. Examination of the checklist revealed that under the section titled: "EXTERIOR PREFLIGHT" only one item was listed which stated, "EXTERIOR PREFLIGHT…COMPLETE." It also stated on both sides of the checklist: "FOR SIMULATOR TRAINING PURPOSES ONLY." A copy of the airplane manufacturer's published pilot's operating handbook (POH) was found in a cabinet behind the pilot's seat where it was not accessible from the pilot's station. Review of the POH revealed that it contained detailed guidance regarding the preflight check of the airplane. Additionally, it was discovered that the landing gear was in the down and locked position which would have degraded the airplane's ability to accelerate and climb by producing excess drag, and indicated that the pilot had not retracted the landing gear as he thought he did, as the landing gear handle was still in the down position. Review of recorded data from the airplanes avionics system also indicated that the airplane had roughly followed the runway heading while climbing until it reached the end of the runway. The pilot had then entered a left turn and allowed the bank angle to increase to about 45°, and angle of attack to increase to about 8°, which caused the airspeed to decrease below the stalling speed (which would have been about 20% higher than normal due to the increased load factor from the steep turn) until the airplane entered an aerodynamic stall, indicating that the pilot allowed himself to become distracted by the open door, rather than maintaining control of the airplane.

Airplane Flying Handbook Under the heading, "Door Opening In-Flight," the FAA's Airplane Flying Handbook (FAA-H-8083-3B) states: In most instances, the occurrence of an inadvertent door opening is not of great concern to the safety of a flight, but rather, the pilot's reaction at the moment the incident happens. A door opening in flight may be accompanied by a sudden loud noise, sustained noise level, and possible vibration or buffeting. If a pilot allows himself or herself to become distracted to the point where attention is focused on the open door rather than maintaining control of the airplane, loss of control may result even though disruption of airflow by the door is minimal." The handbook explains that, in the event of an inadvertent door opening in flight or on takeoff, the pilot should concentrate on flying the airplane. It states that "there may be some handling effects, such as roll and/or yaw, but in most instances, these can be easily overcome." It further states that, "if a door opens after lift off, do not rush to land. Climb to normal traffic pattern altitude, fly a normal traffic pattern, and make a normal landing." The handbook cautions that "attempting to get the airplane on the ground as quickly as possible may result in steep turns at low altitude." It further cautions the pilot to complete all items on the landing checklist and to "remember that accidents are almost never caused by an open door. Rather, an open door accident is caused by the pilot's distraction or failure to maintain control of the airplane." Aerodynamic Stalls The Airplane Flying Handbook, also contained information regarding aerodynamic stalls, advising that, at low angles of attack (AOA), the airflow over the top of the wing flows smoothly and produces lift with a relatively small amount of drag. As the AOA increases, lift as well as drag increases; however, above a wing's critical AOA, the flow of air separates from the upper surface and backfills, burbles and eddies, which reduces lift and increases drag. This condition is a stall, which can lead to loss of control if the AOA is not reduced. The handbook further advised that, it is important for the pilot to understand that a stall is the result of exceeding the critical AOA, not of insufficient airspeed. The term "stalling speed" can be misleading, as this speed is often discussed when assuming 1G flight at a particular weight, and configuration. Increased load factor directly affects stall speed (as well as do other factors such as gross weight, center of gravity, and flap setting). Therefore, it is possible to stall the wing at any airspeed, at any flight attitude, and at any power setting. For example, if a pilot maintains airspeed and rolls into a coordinated, level 60° banked turn, the load factor is 2Gs, and the airplane will stall at a speed that is 40 percent higher than the straight-and-level stall speed. In that 2G level turn, the pilot must increase AOA to increase the lift required to maintain altitude. At this condition, the pilot is closer to the critical AOA than during level flight and therefore closer to the higher speed that the airplane will stall at. Because "stalling speed" is not a constant number, pilots must understand the underlying factors that affect it to maintain aircraft control in all circumstances. Use of Seatbelts and Shoulder Harnesses According to the CFRs, the regulations give the pilot in command two tasks regarding seat belts and shoulder harnesses. The first is to brief the passengers on how the seat belts work: ...the pilot in command of that aircraft ensures that each person on board is briefed on how to fasten and unfasten that person's seat belt and, if installed, shoulder harness. (14 CFR 91.107(a)(1)). The second is to notify the passengers that seat belts must be fastened: ...the pilot in command of that aircraft ensures that each person on board has been notified to fasten his or her safety belt and, if installed, his or her shoulder harness. (14 CFR 91.107(a)(2).) The POH, also provided guidance under "NORMAL PROCEDURES," on the "BEFORE STARTING ENGINE CHECKLIST.": "Seat Belts and Harness…FASTEN / ADJUST – CHECK inertia reel" It also states Under "BEFORE TAKEOFF": "Belts/Harness…FASTENED/ADJUSTED" On August 7, 2016, the pilot's daughter-in-law, who had been seated in the left seat of the aft row, died. According to the Harris County Institute of Forensic Sciences, Houston, Texas, the daughter-in-law's cause of death was complications of subdural hemorrhage due to blunt force head injuries. The reported weather at CRX, at 0915, included wind 100° at 4 knots, 10 miles visibility, clear skies, temperature 15°C, dew point 11°C, and an altimeter setting of 29.98 inches of mercury. According to Federal Aviation Administration (FAA) airman records, the pilot held a private pilot certificate with ratings for airplane single-engine land, airplane multi-engine land, and instrument airplane. He held an FAA third-class medical certificate dated June 17, 2015, with no limitations. The pilot reported that he had accrued about 1,990 total hours of flight experience, of which 427 hours were in the accident airplane make and model. The airplane came to rest about 1,792 ft from the departure end of runway 18 on a 132° magnetic heading on the front lawn of a residence. Examination of photographs of the wreckage taken at the accident site revealed that the right cowl door was open (see Figure 1). Figure 1 –Right Side Access Door Wreckage Examination Examination of the wreckage revealed that during the impact sequence the nose landing gear was separated from the airframe. The nose gear actuator was found in the down and locked position. The firewall was separated from the forward pressure bulkhead. The tail section of the aircraft from fuselage station 249.60 to station 326.05 was impact-damaged and crushed downward. The pilot's side window was fire damaged, and the window just aft of the pilot's side window was also fire damaged and was partially separated from the window frame. The fuselage was accordion-crushed forward and down between the pilot's side window and the number three window. The bottom of the fuselage was crushed upward into the cabin floor. The top engine cowl had separated from the airframe and was impact-damaged. The top engine cowl mounting points were separated from the cowl on the right side and remained attached to the airframe and bottom cowl. The left access door was found separated from its mounting points. The hinges were found to be bent forward, and the forward clevis keeper was pulled upward deforming its mounting area. The right access door was found open and unlatched with minimal damage noted to the door. The right access door support rod was found lying on top of the battery bay, and the battery charging port cover was not installed over the charging port. A functional check of the right access door latches found them to be functional with no indication of overstress or deformation, and there was no deformation or indication of overstress to the clevis keepers. The rudder and rudder trim tab remained attached to the vertical fin. The rudder was impact damaged on the bottom right side. The rudder skin was crushed down along the entire span of the rudder; the top rudder attach point was partially separated from the vertical fin; and the rudder torque tube remained attached to the rudder bellcrank. The rudder trim actuator was extended about 1.5 inches, which indicated a neutral to slight-nose-right trim setting. The elevator and elevator trim tab remained attached to the horizontal stabilizer. The left and right sides of the horizontal stabilizer had leading edge impact damage. The aft spar of the horizontal stabilizer was separated from the remainder of the structure. The elevator pitch torque tube remained attached to the elevator and to mo