Preliminary findings from the Sriwijaya Boeing 737-500 crash probe increasingly support an in-flight upset scenario in which the crew was suddenly caught out by the insidious development of an asymmetric thrust condition. No conclusions have been drawn over the 9 January accident. But the highly-unusual retardation of a single throttle lever to idle during a climb – with no immediate indication that the crew was aware – will intensify suspicion of an autothrottle problem, particularly given its history of a repetitive technical malfunction in the week before the accident. Sriwijaya Air has issued an internal safety recommendation reminding pilots to maintain awareness during critical phases of flight and write detailed reports of any aircraft maintenance issues, in order to support engineers’ effort to rectify them. It has also reminded technical personnel to “increase discipline” in regard to following aircraft maintenance processes and procedures. The aircraft had departed Jakarta’s runway 25R on the ABASA 2D departure pattern, requiring a sharp right turn upon reaching 1,000ft to a heading of 081°. Investigation authority KNKT’s initial findings reveal that the left-hand thrust lever, for reasons yet to be determined, started to retard as the jet climbed through 8,150ft. The right-hand lever remained in position. The crew requested a heading of 075°, citing a weather deviation. But while the aircraft subsequently started to turn right, its track suggests it never managed to complete the alignment with the heading. The inquiry has yet to clarify whether this was connected with the developing thrust asymmetry. With the thrust imbalance the autopilot would probably have been trying to compensate for a tendency to yaw and roll left by commanding right-aileron input. Although the crew was instructed to level off at 11,000ft, to avoid a traffic conflict, the aircraft had not even reached this altitude before it started to turn to the left, as the left-hand thrust lever continued to retreat. At 10,900ft and a heading of 016° the autopilot disengaged and the aircraft rolled steeply to the left, with a bank of 45°, and entered a rapid descent. Full circumstances of the upset have still to become clear, particularly given that the cockpit-voice recorder remains unrecovered. But the initial findings suggest parallels with a fatal China Southern Airlines 737-300 accident near Guilin in November 1992. The aircraft had been experiencing an autothrottle problem affecting its right-hand engine and, during the descent to Guilin, the left-hand throttle lever advanced as the aircraft transitioned to level flight but the right-hand lever did not. This led to a thrust asymmetry under which the aircraft tended to yaw and roll to the right, corrected by the autopilot with left aileron input. But a limit to the aileron deflection meant the autopilot eventually was unable to overcome the effect of the thrust imbalance, and the aircraft started to roll slowly to the right. Control-column input suddenly cut off the autopilot’s counteraction, the jet’s right roll rapidly accelerated, and the upset resulted in the crew’s losing control. KNKT has not provided details of the Sriwijaya 737’s airspeed, nor has it disclosed the readings from instruments including the engine indicators. It says that it will review the history of the autothrottle maintenance, examine the pilots’ training for upset prevention and recovery, and analyse the split in the thrust levers to identify its cause. Boeing 737-300s, -400s and -500s were the subject of an airworthiness directive in 2001 which focused on upgrading autothrottle computers following incidents of asymmetric thrust conditions in flight caused by the thrust levers’ slowly moving apart, causing the aircraft to bank excessively and enter a roll. But the US FAA set a compliance time of 18 months for carriers to implement the change, suggesting this upgrade had taken place while the Sriwijaya aircraft – manufactured in 1994 – was still in operation with US carrier Continental Airlines.

Ethiopian Airlines is making slow progress with talks regarding co-operation with South African Airways (SAA), according to the former’s chief executive Tewolde Gebremariam. The Addis Ababa-based carrier said in October last year that it was willing to provide “planes, pilots and maintenance services” to ailing SAA as part of a “joint venture” with the country’s government, but noted that it did not wish to take on legacy issues such as debts. Speaking during a CAPA Live session today, Gebremariam says that talks with South Africa’s government “have been a challenge so far”. “We are still discussing, but I would say it has not made the expected progress,” he states. Explaining Ethiopian’s strategic thinking regarding a potential SAA tie-up, Gebremariam notes that South Africa’s origin and destination-focused traffic means its is a very different proposition to the hub-based model at Addis Ababa. That dominance means South Africa is “very, very competitive… because every mega-carrier in the world is there”, Gebremariam observes. “To succeed in that market, one has to be inside South Africa,” he states. Ethiopian, which has a history of investments in other African carriers, therefore believes that “the only way we can look at opportunities, is if we cooperate with South African Airways”, says Gebremariam. SAA is being restructured as part of a rescue plan that also sets out ambitions to find a strategic equity partner for the carrier.

The UK is to launch mandatory hotel quarantines for UK and Irish residents returning from "red list" states where transmission rates of Covid-19 are high. "In short, this means that any returning residents from these countries will have to quarantine in an assigned hotel room for 10 days from the time of arrival," health secretary Matt Hancock has told parliament. UK or Irish residents travelling from the 32 travel red-list countries are currently required to self-isolate at home, with non-resident travellers being banned from entry altogether. Returning residents will be required to book through an online platform and pay for a quarantine package costing £1,750 ($2,410) per person, which includes the hotel, transport and testing. The booking system will be online from 11 February, when the government will publish further details. "Passengers will only be allowed to enter the UK through a small number of ports that currently account for the vast majority of passenger arrivals. When they arrive they will be escorted to a designated hotel which will be closed to guests that aren't quarantining for 10 days, or for longer if they test positive for Covid-19," says Hancock. The UK has contracted 16 hotels for an initial 4,600 rooms "and we will secure more as they are needed", he adds. All travellers entering the country will be required to take Covid-19 tests on days two and eight of their return to the country, regardless of whether they are isolating at home or in a hotel. Passengers arriving in the UK are already required to isolate on their return, as well as to have a negative Covid-19 test result taken within 72h before travelling. Travellers that do not comply with the new rules face fines of £10,000 and possible jail sentences. The use of hotels to enforce quarantine on returning travellers has worked successfully in territories such as Singapore, Taiwan, Australia and New Zealand.