Conceptual Design of a Hybrid Electric Regional Turboprop Aircraft, The Failure of Boeing’s MCAS System: How an Autonomous Flight Control Program Crashed Two Aircraft

Vu, Nathan, School of Engineering and Applied Science, University of Virginia
Stafford, William, EN, University of Virginia
Quinlan, Jesse, EN-Mech & Aero Engr Dept, University of Virginia

The design of aircraft is a critical part of developing new concepts especially in regards to new technologies such as more environmentally friendly aircraft and advanced autonomous drones. Aircraft design is a complex task, requiring multidisciplinary analysis and optimization of several diverse areas of study. It combines structural loads analysis, mechanical design, aerodynamics, propulsion, materials analysis, fuel systems, electrical controls, sensor fusion, flight computation, stability analysis, and many other disciplines. The highly coupled nature of aircraft design also means that changes in one area of design often affects several other aspects of the concept aircraft, which often requires additional work to rectify. This design process is required for the development of new aircraft, which was the focus of the technical report. The technical report details the design of a hybrid-electric regional turboprop aircraft to serve the 50 passenger market for the AIAA design competition. However, the complex nature of design means that there are a lot of possible design decisions that need to be made throughout the design process. This process of developing a new aircraft can lead to catastrophic failure, such as the Boeing 737 MAX crashes that are the subject of the STS research paper. It will analyze the factors that led up to the crashes through the social-technological framework of Thomas Hughes’ theory of technological momentum, which describes the effect of time on the relationship between society and technology.

The technical report describes the design process and final configuration for the AIAA design competition for a hybrid-electric turboprop aircraft. One of the key issues facing the commercial aerospace industry is the difficulty in making more environmentally friendly aircraft, especially since jet fuel is extremely energy dense, meaning that much less fuel is required compared to other sources of energy. One key push in the smaller aircraft market is the utilization of electrical power sources since they offer a variety of advantages such as the ability to recharge from renewable sources of electricity, the efficient conversion between energy source and propulsion architecture, and the ability to utilize energy recovery methods such as regenerative braking. The markets for an aircraft of this type makes it ideal for island destinations where large airline hubs are infeasible and maintenance support might be limited and fuel more difficult to logistically transport. Electrical energy can be renewably sourced and might present a more viable way of powering shorter flight aircraft between these smaller regional hubs.

The STS research paper will focus on the two Boeing 737 MAX crashes caused by a cascading effect of failures in the MCAS system of the aircraft, or Maneuvering Characteristics Augmentation System. The two crashes happened when the system was fed faulty data from an incorrectly calibrated sensor, causing the MCAS system to pitch the nose of the aircraft down despite the pilots’ attempts to control the aircraft. The subsequent investigations into the incident revealed a large host of issues that eventually culminated in the two catastrophic events. Using the framework of technological momentum by Thomas Hughes, the STS research paper will use this framework to analyze how time plays an effect into the problems that manifested in the Boeing 737 development. While improvements were made over time to the original aircraft, eventually the limitations of the design presented a significant challenge to Boeing in the present day. The effect of time amplifying the problems in the Boeing 737 illustrates the societal effects of technological momentum and how these technologies can have disastrous effects if not properly addressed, affecting many different aspects of society that have become intertwined with the technology’s proliferation over time. The STS research paper will ultimately discuss mitigation strategies to deal with the multifaceted problem that became the Boeing 737 MAX and the MCAS system.

Lessons from the STS research paper has a direct connection to the technical paper due to the importance of understanding potential problem areas in aircraft design. These technologies can have lasting impacts on society, so it is critical to design these systems well to avoid the potential for catastrophic events like the Boeing 737 MAX crashes. Understanding how the STS research paper plays into the technical report is critical for developing ethical and responsible innovations that can help benefit society.

BS (Bachelor of Science)
Aircraft Design, Electric Aircraft, Aerospace Engineering, Turboprop Aircraft

School of Engineering and Applied Science

Bachelor of Science in Aerospace Engineering

Technical Advisor: Jesse Quinlan

STS Advisor: William Stafford

Technical Team Members: Nathan Vu, Robert Taylor, Christian Prestegard, Catherine DeScisciolo, Vincent Fimiani, Kyle Hunter, Daniel Lattari, Kazi Nafis, Michael Richwine

All rights reserved (no additional license for public reuse)
Issued Date: