Preliminary Reports
Caravan Wreck in Kenyan Mountains Claims 10
Cessna 208B, June 5, 2018, Njabini, Kenya—Two days after the FlySAX airplane disappeared from radar at an altitude of 11,000 feet, searchers located the wreckage on the western face of the Aberdares mountain range in central Kenya. There were no survivors. The aircraft, operated by East African Safari Air Express, carried two pilots and eight passengers. Heavy rain and fog were widespread in the area, hampering search-and-rescue efforts by the Civil Aviation Authority, Air Force, Kenya Wildlife Service, and Red Cross. The scheduled flight was en route to Nairobi from the western town of Kitale but went down about 30 miles short of its destination.
President Uhuru Kenyatta promised the victims’ families “every assistance my administration can offer, now and in the days to come” including “a full review of our procedures so that we can all understand how this tragedy happened.” The International Air Transport Association ranks Kenya’s air infrastructure sixth out of the 37 African countries it has reviewed.
Two Injured in Saint Tropez Runway Excursion
Cessna 525A, June 6, 2018, Saint Tropez, France—Both pilots were hurt when a German-registered Citation CJ2+ slid off the runway during a landing at Saint Tropez-La Môle Airport. No passengers were on board the flight, which originated at the Figari-Sud Corse Airport at the southern end of Corsica. The accident took place in early afternoon, and photographs of the scene suggest the weather was clear. The airplane came to rest against a berm in heavy brush.
Three Fatalities in Chinese HEMS Accident
Airbus Helicopters AS350B3e, June 16, 2018, Wuqixincun, China—The pilot and two medical crewmembers were killed when the helicopter crashed into high ground about 10 miles west of Kunming. The air ambulance was en route to pick up a patient at the time.
The helicopter’s wreckage was discovered in a quarry about five hours after its departure. No further details have been released to date.
Two Twin Otters Hit by Gunfire in Indonesia
de Havilland Canada DHC-6, Kenyam Airport, Indonesia, June 22 and June 25, 2018—In the course of four days, two DHC-6 Twin Otters landing at the remote Kenyam airstrip in Papua province were fired on by assailants described as “separatists”; a police spokesman characterized them as “members of an armed criminal gang.” Both aircraft sustained bullet holes to their fuselages but appeared to remain airworthy.
In the attack on June 22, the first officer suffered a wound to the abdomen that was not life-threatening. The airplane’s captain was struck in the back during the June 25 attack. That flight was transporting 18 security personnel being deployed in advance of a gubernatorial election scheduled for June 27.
Five Killed When King Air Crashes in Mumbai
Beech King Air C90B, June 28, 2018, Mumbai, India—A King Air C90B on a post-maintenance test flight crashed into a construction site, killing two pilots and two engineers on board the aircraft and one pedestrian at the scene. The airplane was reportedly on a one-mile final approach to the Chhatrapati Shivaji Mumbai International Airport. Three distinct explosions occurred after impact. The 40 to 50 workers employed at the site were on lunch break at the time, substantially reducing the potential casualty count.
The airplane, originally owned by the Uttar Pradesh government, had been sold to private operator UY Aviation and was being restored to service after several years of inactivity. It was operating on a temporary airworthiness certificate; the flight was intended to be the first step toward obtaining permanent certification. A review of communications with air traffic control showed that two miles from the airport the flight was cleared for a visual approach even though reported visibility was less than one mile (1,500 meters). The last radar contact came one mile from the runway threshold at a height of 400 feet.
Final Reports
Procedural Error Blamed in Russian Airline Disaster
Antonov AN-148-100B, February 11, 2018, Moscow, Russia—The February 11 crash of Saratov Airlines Flight 703 was precipitated by the pilots’ failure to activate the pitot heat before takeoff, according to the final accident report. Ice obstruction of one pitot tube produced erroneous readings on the captain’s airspeed indicator, leading him to misinterpret the airplane’s attitude after it entered the clouds. All 65 passengers and six crewmembers were killed when the jet crashed just seven minutes after taking off from Moscow’s Domodedovo Airport.
The final report of Russia’s Interstate Aviation Committee echoed preliminary findings reported just two days after the accident. The airplane’s flight data recorder (FDR) showed that pitot heat had not been activated on any of its three airspeed probes despite temperatures of -5 Celsius, well below freezing.
Ice blockage of a pitot tube causes two types of indication errors. If the tube’s drain hole is also blocked, trapped ram air pressure will make indicated airspeed increase with altitude as ambient pressure falls. If the drain hole is open, ram pressure bleeds off and indicated airspeed drops to zero. In this case, the indication on the captain’s gauge decreased to zero, leading him to disconnect the autopilot and put the airplane into a steep dive from an altitude of 6,500 feet.
No Warning of EC 225 Main Gearbox Failure
Airbus Helicopters EC 225 LP, April 29, 2016, Turøy, Øygarden, Norway—The 2016 destruction of a Super Puma transporting Statoil ASA workers from the Gulifaks B North Sea platform to Bergen Airport was caused by the fracture of a second-stage planetary gear in the main rotor gearbox. But the fracture did not produce enough debris to activate the system’s chip detector and could not have been discovered by maintenance operations short of a complete overhaul of the assembly. The final report of Norway’s Accident Investigation Board concluded that the failure was not caused by an error by maintenance personnel and gave no warning to the crew. The main rotor separated from the aircraft after the fractured planetary gear caused the gearbox to seize. The fuselage then fell 2,000 feet onto a small island northwest of Bergen, killing all 13 on board. The main rotor assembly was found about 550 meters from the fuselage.
The accident sequence bore strong similarities to that of a 2009 crash that claimed 16 lives off the coast of Scotland from which the crucial section of the failed part was never recovered. The Norwegian investigation found that a fatigue fracture began at a micro-pit in the upper outer race of the gear’s internal bearing which then propagated inwards, producing minimal quantities of metallic particles before “turning towards the gear teeth and fracturing the rim of the gear without being detected.”
The investigators further noted that “the combination of material properties, surface treatment, design, operational loading environment, and debris gave rise to a failure mode which was not previously anticipated or assessed” during aircraft certification. Citing evidence that the vast majority of comparable gears removed during overhaul inspections or unscheduled gearbox removals were rejected for return to service before reaching their nominal service lives, they also issued safety recommendations advocating mandatory manufacturer inspection and analysis of components found unairworthy prior to their nominal service lives and systematic cross-check of design assumptions against the actual wear in use of critical parts.
Montreal Landing Accident Traced to Operator, Crew Inattention
Bombardier BD-700-1A10 Global Express, May 15, 2017, Montréal/St-Hubert Airport, Quebec—Neither company dispatch nor the pilots on board noted the partial closure of Runway 06L despite published Notices to Airmen (Notams) and descriptions broadcast on the current automatic terminal information service (ATIS). The airplane suffered blowouts of both left main tires and puncture damage to the fuselage and left wing after striking temporary runway lights during a daylight landing in visual conditions. The U.S.-registered charter flight had originated in Teterboro, New Jersey, less than an hour before. There were no injuries to the passenger or three crewmembers.
The available landing area had been reduced from 7,801 by 150 to 5,000 by 75 feet due to runway construction; the only instrument approach to that runway was no longer authorized due to a threshold displacement that reduced obstacle clearance below required minimums. In the final report, Canada’s Transportation Safety Board notes that Notams advising of these facts were available to the crew before departure. Cockpit voice recordings also demonstrate that the pilot monitoring copied an ATIS broadcast that included the runway restrictions but did not convey that information to the pilot flying, who tracked the GPS approach via autopilot to an altitude of 500 feet before disconnecting it for the landing. The airplane touched down close to what would have been the runway centerline before the closure.
Transcripts of radio communications also show that the pilot monitoring failed to read back the tower controller’s clearance to land “on the south side” of Runway 06L, and that the controller did not request clarification. The pilot flying later acknowledged having “perceived the temporary edge marking on the left side of the runway as the centreline.”
Although the airplane’s wingspan exceeded that authorized to land on the runway without prior authorization, there is no record of the Singapore-based operator having contacted the airport. Zetta Jet USA subsequently suspended operations on November 30, 2017, and surrendered its operating certificate to the U.S. Federal Aviation Administration.