Science

Boeing 737MAX: Automated Crashes

Underestimating the dangers of designing a protection system
Ada
Bernd Sieker
Everybody knows about the Boeing 737 MAX crashes and the type's continued grounding. I will try to give some technical background information on the causes of the crash, technical, sociological and organisational, covering pilot proficiency, botched maintenance, system design and risk assessment, as well as a deeply flawed certification processes.
On the surface of it, the accidents to two aircraft of the same type (Boeing 737 MAX), which eventually led to the suspension of airworthiness of the type, was caused by faulty data from one of the angle-of-attack sensors. This in turn led to automatic nose-down trim movements, which could not be countered effectively by the flight crew. Eventually, in both cases, the aircraft became uncontrollable and entered a steep accelerated dive into terrain, killing all people on board on impact. In the course of the investigation, a new type of flight assistance system known as the Maneuvering Characteristics Augmentation System (MCAS) came to light. It was intended to bring the flight characteristics of the latest (and fourth) generation of Boeing's best-selling 737 airliner, the "MAX", in line with certification criteria. The issue that the system was designed to address was relatively mild. A little software routine was added to an existing computer to add nose-down trim in situations of higher angles of attack, to counteract the nose-up aerodynamic moment of the new, much larger, and forward-mounted engine nacelles. Apparently the risk assessment for this system was not commensurate with its possible effects on aircraft behaviour and subsequently a very odd (to a safety engineer's eyes) system design was chosen, using a single non-redundant sensor input to initiate movement of the horizontal stabiliser, the largest and most powerful flight control surface. At extreme deflections, the effects of this flight control surface cannot be overcome by the primary flight controls (elevators) or the manual actuation of the trim system. In consequence, the aircraft enters an accelerated nose-down dive, which further increases the control forces required to overcome its effects. Finally I will take a look at certification processes where a large part of the work and evaluation is not performed by an independent authority (FAA, EASA, ...) but by the manufacturer, and in many cases is then simply signed off by the certification authority. In a deviation from common practice in the past, EASA has announced that it may not follow the FAA (re-) certification, but will require additional analyses and evidence. China, which was the first country to ground the "MAX", will also not simply adopt the FAA paperwork.

Additional information

Type lecture
Language English

More sessions

12/27/19
Science
Sebastian Pischel
Clarke
Wir verlassen uns in unserem Alltag permanent auf die Verfügbarkeit von elektrischer Energie. Aber wenn wir vom dauerhaften Betrieb von Kraftwerke, die fossile Energieträger verbrennen, wie stellen wir die Versorgung sicher, wenn nachts kein Wind weht? Elektrolyse oder Pumpspeicherkraftwerk? Superkondensatoren oder mechanische Speicher? Was geht heute überhaupt schon? Ähnlich unklar ist die Zukunft der Mobilität, wenn Verbrennungsmotoren von unseren Straßen verschwinden sollen. ...
12/27/19
Science
Clarke
The Large Hadron Collider (LHC) is the biggest particle accelerator on Earth. It was built to study matter in more detail than ever before and prove physical theories like the Standard Model of Particle Physics. This talk will focus on the engineering aspects of LHC. How was it built? What makes it tick? Which technologies are needed to create a such powerful machine? This talk will take you on a journey to explore how the most complex machine ever built by humans works.
12/27/19
Science
karlabyrinth
Dijkstra
When climate activists say you should listen to the science they usually refer to reports by the Intergovernmental Panel on Climate Change (IPCC). The IPCC is an Intergovernmental organization (IGO) providing an objective summary of scienctific results regarding climate change, its impacts and its reasons. The simulation of future climate is one fundamental pillar within climate research. But what is behind it? How does the science sector look like? How do we gain these insights, what does it ...
12/27/19
Science
Dijkstra
Making climate predictions is extremely difficult because climate models cannot simulate every cloud particle in the atmosphere and every wave in the ocean, and the model has no idea what humans will do in the future. I will discuss how we are using the Julia programming language and GPUs in our attempt to build a fast and user-friendly climate model, and improve the accuracy of climate predictions by learning the small-scale physics from observations.
12/27/19
Science
Bernhard Stoevesandt
Dijkstra
This talk is to show the current state of the discussion on climate change and the necessary and possible changes from a scientific perpesctive. It is to give some typical relevant answers and to foster the resiliance against climate sceptic questioning. This is one of the main tasks the scientist for future are trying to tackle.
12/27/19
Science
Martin Hillenbrand
Eliza
Einführung in das Forschungsfeld der Kritikalitätsanalysen. Anhand der Rohstoffe Tantal, Wolfram, Zinn und Gold werden exemplarisch die quantitativen und qualitativen Indikatoren für eine Versorgungsengpassanalyse vorgestellt.
12/28/19
Science
Ada
Mit 4G wurde gegenüber früheren Mobilfunktechnologien das Air-Interface komplett neu gestaltet. Mit 5G wird dieses nun auf mögliche Zukunftstechnologien erweitert. Wir stellen die Neuerungen und die Möglichkeiten auf dem 5G-Air-Interface und im Core-Netz gegenüber 4G vor.