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Following an uneventful cargo flight from La Paz (Mexico), the crew was approaching Culiacán Rosales-Federal de Bachigualato Airport. On final, the aircraft crashed onto several houses located less than one km from runway the threshold. Both pilots were killed while there were no casualties on the ground despite several houses were destroyed by fire. For unknown reasons, the crew was completing the approach at an unsafe altitude.

After takeoff from Ocumare del Tuy Airport, while climbing, the pilot encountered engine problems and elected to make an emergency landing in a city center's avenue. Just prior to landing, the single engine aircraft collided with a telephone line and crashed on an autobus. The pilot, the bus driver and a bus passenger were killed. The pilot departed Ocumare del Tuy Airport on a cargo flight to Puerto Ayacucho.

The twin engine aircraft departed Walikale to Goma from an asphalt road connecting Walikale to Mubi and Kisangani as there is no airport in Walikale. Few minutes after takeoff, engines problems forced the crew to return to Walikale but the road was reopened to traffic. On landing, the aircraft collided with several vehicles, veered off road and eventually collided with a house. All four occupant escaped with minor injuries while one people in a car was killed. The aircraft was damaged beyond repair.

On July 29, 2006, about 1345 central daylight time, a de Havilland DHC-6-100, N203E, registered to Adventure Aviation, LLC, and operated by Skydive Quantum Leap as a local parachute operations flight, crashed into trees and terrain after takeoff from Sullivan Regional Airport (UUV), near Sullivan, Missouri. The pilot and five parachutists were killed, and two parachutists were seriously injured. The flight was operated under 14 Code of Federal Regulations (CFR) Part 91 with no flight plan filed. Visual meteorological conditions prevailed. According to photographic evidence provided by a witness, the pilot taxied the airplane onto runway 24 from the intersecting taxiway, which is about 1,700 feet from the runway’s west end, and began a takeoff roll to the west from that location, rather than using the runway’s entire 4,500-foot length. Photographic evidence depicting the airport windsock shows that the airplane departed into a moderate headwind. Witnesses at the airport reported seeing the airplane take off and climb to about treetop height. Several witnesses reported hearing a “poof” or “bang” noise and seeing flames and smoke coming from the right engine. One witness reported that, after the noise and the emergence of flames, the right propeller was “just barely turning.” Photographic evidence shows that, at one point after the flames occurred, the airplane was about one wingspan (about 65 feet) above the runway. One witness estimated that the airplane climbed to about 150 feet. Witnesses reported that the airplane lost some altitude, regained it, and then continued to fly low above the treetops before turning to the right and disappearing from their view behind the tree line. Another witness in the backyard of a residence northwest of the airport reported that she saw the airplane flying straight and level but very low over the trees before it dived nose first to the ground. She and her father called 911, and she said that local emergency medical service personnel arrived within minutes. The airplane impacted trees and terrain and came to rest vertically, nose down against a tree behind a residence about 1/2 mile northwest of the end of runway 24.

The aircraft, owned by the German operator Himmelsschreiber Azur GmbH, was planned to make a sightseeing tour over Hamburg. This was a present from a father for his son aged 12. Less than 2 minutes after takeoff from the Hamburg-Norderelbe Seaplane Base, in the city center, the engine lost power and caught fire. The pilot elected to make an emergency landing when the aircraft lost height, collided with a wagon and crashed on a railway road located in a marshalling yard about 2 km south from the departure point, bursting into flames. The aircraft was totally destroyed by a post crash fire. Four passengers were killed while the pilot and a fifth passenger were seriously injured. The pilot died the following day.

Shortly after takeoff from runway 05 at Cuenca-Mariscal La Mar Airport, while climbing to a height of 300 feet, the engine failed. The airplane lost height, causing the nose wheel to struck the roof of a building. Out of control, the aircraft crashed onto a building occupied by a rubber company. Five passengers were killed while nine other occupants were seriously injured. There were no injuries on the ground. The aircraft was destroyed.

The four engine aircraft departed Tehran-Mehrabad Airport on a flight to Bandar Abbas, carrying 84 passengers and a crew of 10, among them several journalists from local newspapers and the Iranian National TV who were flying to Bandar Abbas to cover important military manoeuvres. Some eight minutes after takeoff, while climbing, the captain informed ATC about technical problems with the engine n°4 and elected to return to Tehran for an emergency landing. After being cleared to return, the crew started the descent when the aircraft stalled and crashed in a residential area located in the district of Yaft Abad, about 2 km south of runway 29L threshold. All 94 occupants were killed as well as 12 people leaving in a 9-floor building that was struck by the airplane. At the time of the accident, the visibility was reduced to 1,500 metres due to haze.

According to the pilot, the airplane took off with a flaps setting of 25 percent, per the operator’s procedures at the time. He stated that, immediately after raising the landing gear after takeoff, he heard an explosion and saw that all gauges for the left engine, a Pratt & Whitney Canada (P&WC) PT6A-34, pointed to zero, indicating a loss of power to the left engine. He also noted that the left propeller had completely stopped so he added full power to the right engine, left the flaps at 25 percent, and left the landing gear up. He further stated that, although he “stood on the right rudder,” he could not stop the airplane’s left turning descent. The pilot later noted that, after the left engine lost power, he “couldn’t hold V speeds” and “the stall warning horn was going off the whole time.” Post accident examination of the accident airplane’s left engine revealed that that it had failed and that the propeller had been feathered. Examination of the trim positions revealed that the rudder was at neutral trim and the aileron was at full left trim. Although these trim positions could have been altered when the wings separated from the fuselage during ground impact, the pilot’s comment that he “stood on the rudder” suggests that he either had not trimmed the airplane after the engine failure or had applied trim opposite the desired direction. The activation of the stall warning horn and the pilot’s statement that he “couldn’t hold V speeds” indicate that he also did not lower the nose sufficiently to maintain best single-engine rate of climb or best single-engine angle of climb airspeed. In addition, a performance calculation conducted during the National Transportation Safety Board’s investigation revealed that the airplane, with flaps set at 25 degrees, would have been able to climb at more than 400 feet per minute if the pilot had maintained best single-engine rate of climb airspeed and if the airplane had been properly trimmed. Post accident examination of the accident airplane’s left engine revealed fatigue fracturing of the first-stage sun gear.[1] According to the airplane’s maintenance records, during an October 1998 engine overhaul, the first-stage planet gear assembly was replaced due to “frosted and pitted gear teeth.” The planet gear assembly’s mating sun gear was also examined during overhaul but was found to be serviceable and was reinstalled with the new planet gear assembly, which was an accepted practice at the time. However, since then, the engine manufacturer determined that if either the sun gear or planet gear assembly needed to be replaced with a zero-time component, the corresponding mating gear/assembly must also be replaced with a zero-time component; otherwise, the different wear patterns on the gears could potentially cause “distress” to one or both of the components. Review of maintenance records showed that the engines were maintained, in part, under a Federal Aviation Administration (FAA)-approved “on-condition” maintenance program;[2] Business Air’s maintenance program was approved in May 1995. In April 2002, P&WC, the engine manufacturer, issued Service Bulletin (SB) 1403 Revision 7, which no longer mentioned on-condition maintenance programs and required, for the first time for other time between overhaul extension options, the replacement of a number of PT6A-34, -35, and -36 life-limited engine components, including the first-stage sun gear at 12,000 hours total time since new. The first-stage sun gear on the accident airplane failed at 22,064.8 hours. In November 2005 (when the Manchester accident occurred), Business Air was operating under an engine on-condition maintenance program that did not incorporate the up-to-date PT6A 34, -35, and -36 reliability standards for the life-limited parts listed in SB 1403R7 because the SB did not address previously approved on-condition maintenance programs. Three months later, in an e-mail message to Business Air, P&WC stated that it would continue to “endorse” Business Air’s engine on-condition maintenance program. Although SB 1403R7 improves PT6A-34, -35, and -36 engine reliability standards, allowing grandfathered on condition maintenance programs for these engines is less restrictive and does not offer the same level of reliability. The National Transportation Safety Board’s review of maintenance records further revealed numerous deficiencies in Business Air’s on-condition engine maintenance program that appear to have gone undetected by the Portland, Maine, Flight Standards District Office (FSDO), which is in charge of monitoring Business Air’s operations. For example, one infraction was that Business Air did not specify which parts were included in its on-condition maintenance program and which would have been removed by other means, such as hard-time scheduling.[3] Also, the operator used engine condition trend monitoring as part of determining engine health; however, review of records revealed missing data, inaccurate data input, a lack of regular trend analyses, and a failure to update trends or reestablish baselines when certain maintenance was performed. Another example showed that, although Business Air had an engine-oil analysis program in place, the time it took to send samples for testing and receive results was lengthy. According to maintenance records, the operator took an oil sample from the accident engine more than 2 weeks before the accident and sent it for testing. The oil sample, which revealed increased iron levels, would have provided valuable information about the engine’s health. However, the results, which indicated a decline in engine health, were not received until days after the accident. If the FAA had been properly monitoring Business Air’s maintenance program, it may have been aware of the operator’s inadequate maintenance practices that allowed, among other things, an engine with a sun gear well beyond what the manufacturer considered to be a reliable operating timeframe to continue operation. It also took more than 2 1/2 years after the accident for the FAA to finally present a consent order[4] to the operator, in which both parties not only acknowledged the operator’s ongoing maintenance inadequacies but also the required corrective actions. [1] A sun gear is the center gear around which an engine’s planet gear assembly revolves; together, the sun gear and planet gear assembly provide a means of reducing the engine’s rpm to the propeller’s rpm. [2] According to FAA Advisory Circular (AC) 120-17A, “Maintenance Control by Reliability Methods,” under on-condition maintenance programs, components are required to be periodically inspected or checked against some appropriate physical standard to determine whether they can continue in service. [3] According to FAA AC 120-17A, “Maintenance Control by Reliability Methods,” under hard time maintenance programs, components are required to be periodically overhauled or be removed from service. [4] A consent order is a voluntary agreement worked out between two or more parties to a dispute. It generally has the same effect as a court order and can be enforced by the court if anyone does not comply with the orders. [4] A consent order is a voluntary agreement worked out between two or more parties to a dispute. It generally has the same effect as a court order and can be enforced by the court if anyone does not comply with the orders.

The pilot purchased the multiengine airplane about 18 months prior to the accident, and was conducting his first flight in the airplane, as he flew it from Georgia to Massachusetts. While en route, the airplane experienced a failure of the left engine. The airplane began maneuvering near an airport, as its groundspeed decreased from 173 miles per hour (mph) to 90 mph, 13 mph below the minimum single engine control speed. A witness reported that the airplane appeared to be attempting to land, when it banked to the left, and descended to the ground. The airplane impacted on a road, about 3 miles east-southeast of the airport. A 3-inch, by 2.5- inch hole was observed on the top of the left engine crankcase, and streaks of oil were present on the left gear door, left flap, and the left side of the fuselage. The number two connecting rod was fractured and heat distressed. The number 2 piston assembly was seized in the cylinder barrel. The airplane had been operated about 30 hours, during the 6 years prior to the accident, and it had not been flown since its most recent annual inspection, which was performed about 16 months prior to the accident. In addition, both engines were being operated beyond the manufacturer's recommended time between overhaul limits. The pilot did not possess a multiengine airplane rating. He attended an airplane type specific training course about 20 months prior to the accident. At that time, he reported 452 hours of total flight experience, with 0 hours of multiengine flight experience.

The airplane was fueled with 65-gallons of jet-A in preparation for the evening's flight. The 6,600-hour pilot stated that no abnormalities were noted during the engine start, and takeoff. However; shortly after departure, and after the pilot had leveled off at 7,000-feet, he reported to air traffic control that he had an engine failure and a total power loss. During the descent, the pilot attempted both an air and battery engine restart, but was not successful. The inspection on the engine was conducted on November 30, 2005. The accessory gearbox had a reddish-brown stain visible beneath the fuel pump/fuel control unit. The accessory gearbox was turned; rotation of the drive splines in the fuel pump (splines for the fuel control unit) was not observed. The fuel pump unit was then removed, the area between the fuel pump and accessory gearbox was stained with a reddish brown color. The fuel pump drive splines were worn. Additionally, the internal splines on the fuel pump drive coupling were worn. The wear on the spline drive and coupling prevented full engagement of the spline drives. Both pieces had evidence of fretting, with a reddish brown material present. The airplane had approximately 130 hours since a maintenance inspection (which included inspection of the fuel pump). The engine had accumulated approximately a total time of 9,852 hours, with 5,574 hours since overhaul.