Investigators probing the fatal Ethiopian Airlines Boeing 737 Max accident have given additional insight into a crucial period during which the crew, having temporarily stopped the aircraft from automatically nosing down, struggled vainly to regain pitch and trim control. In an interim update into the 10 March 2019 crash near Addis Ababa, the Ethiopian accident investigation bureau says the differences training provided by Boeing – to convert 737 pilots to the 737 Max – was “inadequate”. It adds that the reliance of the controversial Manoeuvring Characteristics Augmentation System (MCAS) on a single angle-of-attack sensor input left it “vulnerable to undesired activation”. When the sensor, on the left-hand side of the jet, started transmitting bad angle-of-attack data, MCAS responded by repeatedly triggering the stabiliser trim to force the aircraft’s nose down, and causing the pilots to counter by pulling on their control columns. But while MCAS triggered on four occasions, the third of these had no effect on the aircraft’s pitch because – for a period of 2min 33s – the crew had been flying the jet with the stabiliser trim cut-out engaged. Engaging the trim cut-out de-activates MCAS and, for this critical period, the crew would not have been battling directly against MCAS to control the aircraft’s pitch. The inquiry says the captain, at this point, succeeded in increasing the aircraft’s pitch, and the 737 started climbing at 1,800ft/min. He asked for the first officer to “pull with me” and, over the 2min 33s interval, the crew was applying an average of 94lb force to the control column. Pitch varied between 7° nose-up and 2° nose-down, increasing when both pilots pulled and falling when only a single pilot pulled, and this resulted in the vertical speed swinging between a 4,400ft/min climb and a 2,500ft/min descent. Air traffic control approved a request from the crew to climb to 14,000ft in order to troubleshoot their flight-control problems. The aircraft was travelling at excessive speed, some 360-375kt, and the captain made a “speed” call-out, which was acknowledged by the first officer. The captain again sought the first officer’s help to pitch the aircraft nose-up, and then asked him whether the trim was functional. The first officer replied that the trim was not functioning, and asked if he could try to activate it manually, but subsequently stated: “It is not working.” At the time of the first officer’s comment, the aircraft was mis-trimmed and flying at 340kt. Simulations of the flight, with the thrust and trim settings at the time, aimed to evaluate the control column forces required for the climb and to turn the trim wheel. With both simulator pilots pulling they achieved a nose-up pitch of 5-10°. But the inquiry says: “The forces needed from both pilots to achieve this were considered significantly very high and unbearable for the duration held.” The simulations also revealed that, for the trim setting, the pilots could not move the trim wheel manually at speeds above 220kt. Several times the Ethiopian aircraft’s captain remarked “keep with me”, stating that they should continue climbing to 14,000ft. But the crew then decided instead to return to the airport. The inquiry states that, shortly afterwards, manual electric trim-up inputs were recorded, indicating that the stabiliser cut-out had been disengaged – enabling MCAS to continue triggering nose-down stabiliser trim. Investigators have not specifically stated why, having been engaged, the cut-out was subsequently disengaged, and whether this related to the difficulties with pulling the control column or turning the trim wheel. But the inquiry states that, with MCAS again active, the remainder of the flight lasted just 33s as it pushed the aircraft into its final fatal descent.

Source: Cirium

Investigators have revealed a fourth incident involving a Boeing 787 deviation from the localiser path, during an ILS approach to runway 25R at Hong Kong last year. The incident occurred to an Ethiopian Airlines 787-8 which had been arriving on 18 July. It had been cleared for the ILS approach to 25R but, shortly after passing the RIVER waypoint, the aircraft “kept diverging” to around 1nm north of the approach path, says the Hong Kong Air Accident Investigation Authority. The twinjet (ET-ASG) also descended to an altitude of 3,700ft, coming within 570m horizontally of terrain rising to 3,277ft. Air traffic controllers transmitted a warning to the crew and instructed the flight to climb to 4,500ft, after which the aircraft positioned for another ILS approach and a safe landing. While none of the 235 occupants was injured, the incident bears a remarkable similarity to three other events – all involving 787s – which took place over the following three months, all in the vicinity of the RIVER waypoint during approaches to 25R. The RIVER waypoint is about 16nm from runway 25R and close to the Tai Mo Shan peak. Two of the three subsequent incidents occurred to Virgin Atlantic 787-9s while the other involved an Etihad Airways 787-9. Ethiopian’s service had been arriving from Manila, in darkness, at the time of its deviation. Weather conditions and visibility were good, according to meteorological data from Hong Kong airport. All of the events are under investigation.

Source: Cirium

Lufthansa is evaluating a temporary grounding of its entire Airbus A380 fleet as part of capacity cuts in response to the coronavirus outbreak. The airline says it may reduce capacity by up to 50% over the coming weeks – more than previously planned – as a result of a "drastic decline" in bookings amid "exceptional circumstances" Capacity cuts will be made at all passenger airlines across the group, it indicates. Lufthansa has 14 A380s, stationed in Frankfurt and Munich. The aim of any temporary grounding would be "to reduce the financial consequences of the slump in demand", says the carrier. "The company is in talks with its operating partners and trade unions in order to avoid dismissals… by means of various part-time models," adds Lufthansa, which in February introduced a recruitment freeze and multiple other cost-saving measures, including voluntary unpaid leave. Lufthansa has for a limited period waived change fees on existing and future bookings in a bid to stoke demand by offering passengers flexibility.

Source: Cirium