Flight

The twin engine aircraft departed Cali-Alfonso Bonilla Aragón Airport in the morning on a flight to Tolú, carrying seven passengers and one pilot. After takeoff from Tolú, the pilot decided to position to Montería-Los Garzones Airport. Shortly after takeoff, the pilot encountered engine problems and elected to make an emergency landing in a pasture. Upon landing, the right wing collided with obstacles then the nose gear collapsed and the aircraft came to rest near Purísima de la Concepción, about 10 km east of Tolú. The pilot was uninjured and the aircraft was damaged beyond repair.

The pilot was forced to attempt an emergency landing in a wasteland for unknown reason. There were no casualties and the aircraft was damaged beyond repair.

The private pilot, who had recently purchased the airplane, and the flight instructor were conducting an instructional flight in the multi-engine airplane to meet insurance requirements. Radar data for the accident flight, which occurred on the second day of 2 days of training, showed the airplane maneuvering between 1,000 ft and 1,200 ft above ground level (agl) just before the accident. The witness descriptions of the accident were consistent with the airplane transitioning from slow flight into a stall that developed into a spin from which the pilots were unable to recover before the airplane impacted terrain. Examination of the wreckage did not reveal evidence of any preexisting mechanical malfunctions or anomalies that would have precluded normal operation of the airplane. After the first day of training, the pilot told friends and fellow pilots that the instructor provided non-standard training that included stall practice that required emergency recoveries at low airspeed and low altitude. The instructor used techniques that were not in keeping with established flight training standards and were not what would be expected from an individual with his extensive background in general aviation flight instruction. Most critically, the instructor used two techniques that introduced unnecessary risk: increasing power before reducing the angle of attack during a stall recovery and introducing asymmetric power while recovering from a stall in a multi-engine airplane; both techniques are dangerous errors because they can lead to an airplane entering a spin. At one point during the first day of training, the airplane entered a full stall and spun before control was regained at very low altitude. The procedures performed contradicted standard practice and Federal Aviation Administration guidance; yet, despite the pilot's experience in multi-engine airplanes and in the accident airplane make and model, he chose to continue the second day of training with the instructor instead of seeking a replacement to complete the insurance check out. The spin encountered on the accident flight likely resulted from the stall recovery errors advocated by the instructor and practiced on the prior day's flight. Unlike the previous flight, the accident flight did not have sufficient altitude for recovery because of the low altitude it was operating at, which was below the safe altitude required for stall training (one which allows recovery no lower than 3,000 ft agl).

The pilot stated that the engine start and airplane power-up were normal for the air medical flight with two medical crewmembers. The engine ice vanes were lowered (as required for ground operations) and then were subsequently raised before takeoff. Takeoff and climbout were routine, and the pilot leveled off the airplane at the assigned cruise altitude. The air traffic controller informed the pilot of heavy showers near the destination airport, and the pilot "put the ice vanes down." The pilot indicated that, shortly afterward, the airplane experienced two "quick" electrical power fluctuations in which "everything went away and then came back," and "[s]econds later the entire [electrical] system failed." Due to the associated loss of navigation capability while operating in instrument meteorological conditions (IMC), the pilot set a general course for better weather conditions based on information from his preflight weather briefing. While the pilot attempted to find a suitable hole in the clouds to descend through under visual conditions, the left engine lost power. The pilot ultimately located a field through the cloud cover and executed a single-engine off-airport landing, which resulted in substantial damage to the right engine mount and firewall. A postaccident examination of the airplane and systems did not reveal any anomalies consistent with an in-flight electrical system malfunction. The three-position ignition and engine start/starter-only switches were in the ON position, and the engine anti-ice switches were in the ON position. When the airplane battery was initially checked during the examination, the voltmeter indicated 10.7 volts (normal voltage is 12 volts); the battery was charged and appeared to function normally thereafter. The loss of electrical power was likely initiated by the pilot inadvertently selecting the engine start switches instead of the engine anti-ice (ice vane) switches. This resulted in the starter/generators changing to starter operation and taking the generator function offline. Airplane electrical power was then being supplied solely by the battery, which caused it to deplete and led to a subsequent loss of electrical power to the airplane. A postaccident examination revealed that neither wing fuel tank contained any visible fuel. The left nacelle fuel tank did not contain any visible fuel, and the right nacelle fuel tank appeared to contain about 1 quart of fuel. The lack of fuel onboard at the time of the accident is consistent with a loss of engine power due to fuel exhaustion. This was a result of the extended flight time as the pilot attempted to exit instrument conditions after the loss of electrical power to locate a suitable airport. Further, the operator reported that 253 gallons (1,720 lbs) of fuel were on board at takeoff, and the accident flight duration was 3.65 hours. At maximum range power, the expected fuel consumption was about 406 lbs/hour, resulting in an endurance of about 4.2 hours. Thus, the pilot did not have the adequate fuel reserves required for flying in IMC. Both the pilot and medical crewmembers described a lack of communication and coordination among crewmembers as the emergency transpired. This resulted in multiple course adjustments that hindered the pilot's ability to locate visual meteorological conditions before the left engine fuel supply was exhausted.

On 26 January 2017, the pilot of a Grumman American Aviation Corp G-73 amphibian aircraft, registered VH-CQA (CQA), was participating in an air display as part of the City of Perth Australia Day Skyworks event. On board were the pilot and a passenger. The pilot of CQA was flying ‘in company’ with a Cessna Caravan amphibian and was conducting operations over Perth Water on the Swan River, that included low-level passes of the Langley Park foreshore. After conducting two passes in company, both aircraft departed the display area. The pilot of CQA subsequently requested and received approval to conduct a third pass, and returned to the display area without the Cessna Caravan. During positioning for the third pass, the aircraft departed controlled flight and collided with the water. The pilot and passenger were fatally injured.

At approximately 0500 hrs, 12 December 2016, the pilot of ZK-JPU, arrived at Gisborne Aerodrome. The pilot was accompanied by the operator’s recently employed (trainee) loader driver and already at the hangar was a senior loader driver. The pilot conducted the preflight checks of the aircraft for the day’s agricultural aircraft operations. Earlier that morning the Managing Director of the operator had called the pilot of ZK-JPU. The Managing Director requested that after finishing the first aerial topdressing task at Tauwharetoi Station and prior to the next planned task at Waimaha Station, the pilot complete a task at Pembroke Station. This was because the Managing Director was unwell and unable to undertake the Pembroke Station task as planned. The pilot of ZK-JPU agreed to the additional task. The original work plan for the day was for both loader drivers to attend the first task at Tauwharetoi Station, with the senior loader driver providing oversight for the trainee loader driver. The pilot and the senior loader driver were then to proceed to the second task of the day, while the trainee loader driver was scheduled to return to the aerodrome with the loader truck from the first task. The expectation was for the pilot to go straight from the Tauwharetoi Station task to the Pembroke Station task and then proceed to Waimaha Station. ZK-JPU departed Gisborne Aerodrome at approximately 0515 hrs with the pilot and both loader drivers on board. The aircraft was to operate from a nearby private airstrip where the loader truck was already located, as the task had been commenced the previous week. The aircraft landed at the airstrip at approximately 0530 hrs and the pilot assisted the senior loader driver to get the truck ready, double-checking the calibration of the weigh scales and fuel drain, before commencing the task at approximately 0600 hrs. On the day of the accident another pilot from the same operator, who was operating a similar Pacific Aerospace Ltd 750XL, ZK-XLA, was aerial topdressing an area of Bushy Knoll Station, operating off the Tongataha airstrip. Bushy Knoll Station is to the north of Tauwharetoi Station, alongside the route to the next two tasks scheduled for ZK-JPU at Pembroke and Waimaha Stations. The pilot of ZK-XLA commenced operating at approximately 0555 hrs and completed two to three loads before hearing the pilot of ZK-JPU over the radio at approximately 0615 hrs. The brief conversation that followed consisted of an exchange of greetings and description of locations and intentions. Both pilots then continued with their tasks without further direct communication. On completion of the first task the pilot of ZK-JPU landed at the private airstrip and instructed the senior loader driver to pack up the gear and head back to base. The senior loader driver refuelled the aircraft with 100 litres of fuel, packed up the gear and gave the trainee loader driver the radio which had been used to communicate with the pilot. After a 15 minute break the pilot of ZK-JPU was observed by the senior loader driver getting into the left seat of the aircraft and the trainee loader driver into the right seat. The senior loader driver observed ZK-JPU take off, and then departed the airstrip in the loader truck, to return to the aerodrome. At approximately 0850 the pilot of ZK-XLA received a radio call from the pilot of ZKJPU asking “are you breaking left or right?” followed by the pilot of ZK-JPU stating “I am to your left”. ZK-JPU was then observed by the pilot of ZK-XLA flying behind and to the left of ZK-XLA. The pilot of ZK-XLA advised the pilot of ZK-JPU that he was “sowing the boundary of Bushy Knoll Station […] finishing my run and […] turning right to head back to the airstrip”. Spanning the valley near the boundary of Bushy Knoll Station, near to where the pilot of ZK-XLA was operating were a set of 110 kV high voltage power lines (consisting of six wires termed ‘conductors’, supported by towers). These conductors comprised the two circuits supplying electricity to Gisborne and the East Coast region. The span traverses the valley approximately east-west and the height above terrain at the mid-span of the bottom two conductors (the lowest point of the span) was approximately 200 ft. At 0857 hrs the power supply to Gisborne and the East Coast was interrupted. Finishing the topdressing run, the pilot of ZK-XLA commenced a right climbing turn in order to return to the airstrip and sighted ZK-JPU over his right shoulder. At this point the pilot of ZK-XLA noted that something was trailing from the left wing of ZKJPU. Realising that the item trailing from ZK-JPU’s wing was a wire, the pilot of ZKXLA transmitted “you are trailing wire’’, however no response was received from ZK-JPU. The pilot of ZK-XLA witnessed ZK-JPU continue down the valley, slowly rolling to the left before impacting terrain, approximately 700 m further to the south. A postimpact fire ensued with the pilot of ZK-XLA observing “a lot of black smoke”. The pilot of ZK-XLA immediately commenced circling the accident site and attempted to call the operator via cellphone. Unable to make contact the pilot activated the emergency communications facility on the flight following equipment installed in the aircraft and reported the accident to Gisborne Tower. The accident occurred in daylight at 0857 hrs, approximately 24 NM W of Gisborne Aerodrome, at Latitude: S 38° 44' 30.85" Longitude: E 177° 28' 37.41".

On 07 December 2016 morning, after a routine daily inspection at Benazir Bhutto International Airport (BBIAP) Islamabad, Pakistan International Airlines (PIA) aircraft ATR42-500 Reg No AP-BHO operated 05 flights (ie Islamabad to Gilgit and back, Islamabad to Chitral, Chitral to Peshawar and back). As 6th and last flight of that day, it took off from Chitral at time 10:38:50 UTC (15:38:50 PST) with 42 passengers (including 01 engineer) and 05 crew members (03 pilots and 02 cabin crew) aboard for Islamabad. It crashed after 42 minutes of flight at 11:20:38 UTC (16:20:38 PST) about 3.5 Nautical Miles (NM) SSE of Havelian, and 24 NM North of BBIAP Islamabad. All 47 souls aboard were fatally injured. The aircraft remained in air for about 42 minutes before crash (all timings in UTC). These 42 minutes have been split into three stages of flight, described hereunder:

(a) Initial Stage: From 10:38 to 11:04 (~26 minutes) degraded speed governing accuracy of the port propeller was evident in the DFDR data, but was apparently not observed by the cockpit crew. The flight stabilized at an altitude 13,500 feet AMSL and a cruising speed of 186 knots IAS (instead of expected 230 knots IAS). There were two latent pre-existing technical anomalies in the aircraft (a Fractured / dislodged PT-1 blade due to a known quality issue and a fractured pin inside the OSG), and one probable latent pre-existing condition (external contamination) inside the PVM of No 1 Engine. Digital Flight Data Recorder (DFDR) analysis indicates that No 1 Engine was degraded.

(b) Middle Stage (Series of Technical Malfunctions): From 11:04 to 11:13 (~09 minutes), a series of warnings and technical malfunctions occurred to No 1 Engine (left side) and its related propeller control system. These included Propeller Electronic Control (PEC) fault indications, followed by No 1 Engine power loss, and uncontrolled variation of its propeller speed / blade pitch angle abnormal system operation). The propeller speed which was initially at 82% (cruise setting) decreased gradually to 62% and later at the time of engine power loss it increased to 102% (and stayed at that value for about 15 to 18 seconds). It then reduced down to Non Computed Data (NCD) as per DFDR. At this point, (based on simulation results) the blade pitch angle increased (possibly close to feather position). Later, the propeller speed increased to 120% to 125% (probably caused due to unusual technical malfunctions) and stayed around that value for about 40 to 45 seconds. It finally showed an abrupt drop down to NCD again. At this point, (based on simulation results) the blade pitch angle may have settled at a value, different from the expected feathered propeller. During this unusual variation of propeller speed, there were drastic variations in the aircraft aerodynamic behaviour and sounds. The directional control was maintained initially by the Auto-Pilot. A relatively delayed advancement of power (of No 2 Engine) post No 1 Engine power loss, reduction of power (of No 2 Engine) for about 15 seconds during the timeframe when left propeller rpm was in the range of 120% to 125%, and once again a reduction of power towards the end of this part of flight, were incorrect pilot actions, and contributed in the IAS depletion. Auto-Pilot got disengaged. Towards the end of this part of flight, the aircraft was flying close to stall condition. No 1 Engine was already shutdown and No 2 Engine (right side) was operating normal. At this time, IAS was around 120 knots; aircraft started to roll / turn left and descend. Stick shaker and stick pusher activated. Calculated drag on the left side of the aircraft peaked when the recorded propeller speed was in the range of 120% to 125%. During transition of propeller speed to NCD, the additional component of the drag (possibly caused due to abnormal behaviour of left propeller) suddenly reduced. The advancement of power of No 2 Engine was coupled with excessive right rudder input (to counter the asymmetric condition). This coincided with last abrupt drop in the propeller speed. As a combined effect of resultant aerodynamic forces aircraft entered into a stalled / uncontrolled flight condition, went inverted and lost 5,100 feet AMSL altitude (ie from ~13,450 feet to 8,350 feet AMSL).

(c) Final Stage: The final stage of flight from 11:13 to 11:20 (~07 minutes) started with the aircraft recovering from the uncontrolled flight. Although blade pitch position was not recorded (in the DFDR – by design), and it was not possible to directly calculate that from the available data, a complex series of simulations and assumptions estimated that the blade pitch of left propeller may have settled at an angle around low pitch in flight while rotating at an estimated speed of 5%. Aircraft simulations indicated that stable additional drag forces were present on the left side of the aircraft at this time and during the remaining part of flight. Aircraft had an unexpected (high) drag from the left side (almost constant in this last phase); the aircraft behavior was different from that of a typical single engine In Flight Shutdown (IFSD) situation. In this degraded condition it was not possible for the aircraft to maintain a level flight. However, that level of drag did not preclude the lateral control of the aircraft, if a controlled descent was initiated. The aircraft performance was outside the identified performance envelope. It was exceptionally difficult for the pilots to understand the situation and hence possibly control the aircraft. Figure hereunder shows different stages of flight.

The airline transport pilot delayed his scheduled departure for the night cargo flight due to thunderstorms along the route. Before departing, the pilot explained to the flight follower assigned to the flight that if he could not get though the thunderstorms along the planned route, he would divert to the alternate airport. While en route, the pilot was advised by the air traffic controller in contact with the flight of a "ragged line of moderate, heavy, and extreme" precipitation along his planned route. The controller also stated that he did not see any breaks in the weather. The controller cleared the pilot to descend at his discretion from 7,000 ft mean sea level (msl) to 3,000 ft msl, and subsequently, the controller suggested a diversion to the northeast for about 70 nautical miles that would avoid the most severe weather. The pilot responded that he had enough fuel for such a diversion but concluded that he would "see what the radar is painting" after descending to 3,000 ft msl. About 1 minute 30 seconds later, as the airplane was descending through 7,000 ft msl, the controller stated, "I just lost you on radar, I don't show a transponder, it might have to do with the weather." About 40 seconds later, the pilot advised the controller that he intended to deviate to the right of course, and the controller told the pilot that he could turn left and right as needed. Shortly thereafter, the pilot stated that he was going to turn around and proceed to his alternate airport. The controller cleared the pilot direct to his alternate and instructed him to maintain 3,000 ft msl. The pilot acknowledged the instruction, and the controller then stated, "do you want to climb back up? I can offer you any altitude." The pilot responded that he would try to climb back to 3,000 ft msl. The controller then recommended a heading of 180° to "get you clear of the weather quicker," and the pilot responded, "alright 180." There were no further communications from the pilot. Shortly thereafter, radar data showed the airplane enter a right turn that continued through about 540°. During the turn its airspeed varied between 198 and 130 knots, while its estimated bank angles were between 40 and 50°. Examination of the wreckage indicated that airplane experienced an in-flight breakup at relatively low altitude, consistent with radar data that showed the airplane's last recorded altitudes to be around 3,500 ft msl. The symmetrical nature of the breakup, damage to the outboard wings, and damage to the upper fuselage were all signatures indicative that the left and right wings failed in positive overload almost simultaneously. All of the fracture surfaces examined had a dull, grainy appearance consistent with overstress separation. There was no evidence of pre-existing cracking noted at any of the separation points, nor was there evidence of any mechanical anomalies that would have prevented normal operation. Review of base reflectivity weather radar data showed that, while the pilot was maneuvering to divert to the alternate airport, the airplane was operating in an area of light precipitation that rapidly intensified to heavy precipitation, as shown by radar scans completed shortly after the accident. During this time, the flight was likely operating in clouds along the leading edge of the convective line, where the pilot most likely would have encountered updrafts and severe or greater turbulence. The low visibility conditions that existed during the flight, which was conducted at night and in instrument meteorological conditions, coupled with the turbulence the flight likely encountered, were conducive to the development of spatial disorientation. Additionally, the airplane's maneuvering during the final moments of the flight was consistent with a loss of control due to spatial disorientation. The pilot's continued flight into known convective weather conditions and his delayed decision to divert the flight directly contributed to the accident. Although the operator had a system safety-based program, the responsibility for the safe outcome of the flight was left solely to the pilot. Written company policy required completion of a flight risk assessment tool (FRAT) before each flight by the assigned flight follower; however, a FRAT was not completed for the accident flight. The flight followers responsible for completing the FRATs were not trained to complete them for night cargo flights, and the operator's management was not aware that the FRATs were not being completed for night cargo flights. Further, if a FRAT had been completed for the accident flight, the resultant score would have allowed the flight to commence into known hazardous weather conditions without any further review. If greater oversight had been provided by the operator, it is possible that the flight may have been cancelled or re-routed due to the severity of the convective weather conditions present along the planned route of flight.

The twin engine aircraft departed Madrid-Cuatro Vientos Airport on a private flight to Cascais, Portugal, carrying three passengers and one pilot. One of the reasons for the flight was to repair the weather radar at a Portuguese maintenance center that specialized in this equipment. The pilot had to delay the takeoff until 1557LT due to bad weather conditions. The aerodrome of Cuatros Vietnos was in instrument conditions (IMC), which forced its closing from 0900LT until 1444LT. At 1615LT, the aircraft was en route, climbing from flight level 190 to its authorized cruise level of 210. Moments later, according to a detailed analysis of the data taken from the radar, there was a yaw to the left, and the aircraft started to turn in this direction and suddenly lose altitude. After this event, the airspeed fell quickly and gradually until the aircraft stalled. The aircraft went into a spin, which after some time turned into a flat spin. As the airplane descended out of control, and with the spin fully developped, loads were placed on the horizontal tail that exceeded the design loads, causing the tail to break up in flight into five parts before the aircraft impacted the ground. The aircraft was completely destroyed by the impact and sibsequent fire, and its four occupants were killed in the accident.

The twin engine aircraft departed Pangkal Pinang Airport at 0924LT bound for the Hang Nadim Airport located on the Batam Island. En route, the aircraft disappeared from radar screens and crashed in the sea about 74 km southeast of Tanjun Pinang, in the Riau Islands. An hour later, around 1130LT, few debris and bodies were found by fishermen floating on water off Pulau Senayang. All 13 occupants were killed.