From Flying and Handling Qualities towards Pilot-in-the-Loop Oscillations (PIO)

The Institute of Flight System Dynamics mourns the loss of Prof. Dr.-Ing. Matthias Heller, who passed away on 02. April 2020. He was a brilliant lecturer, a great researcher and a wonderful friend. Our thoughts are now with his family and his loved ones. Matthias leaves behind four wonderful girls – his wife and three daughters.

In order to support his family, a donation page has been established:
Every small amount is welcome. More information can be found here.

Due to the circumstances, the lecture “From Flying and Handling Qualities towards Pilot-in-the-Loop Oscillations (PIO)” has been canceled in the summer semester 2020.

Key Facts
Contact Prof. Dr.-Ing. Matthias Heller
David Seiferth, M. Sc.
Language of Instructions German
Language of Materials German
Type / ECTS Lecture, Exercise / 3 (Elective Lecture Module)
Semester Summer Semester
Time and Place Lecture:
Related Links Poster, Flyer
Prerequisites The interdisciplinary module is aimed for students as well as PhD students of different study degree programs (e.g. aerospace and mechanical engineering, physics, electrical engineering, informatics, ergonomics, … ) who like to gain well-founded knowledge in the field of “Flying and Handling Qualities as well as the PIO problem” of modern flying systems.
Prerequisites are interest in the field of flight system dynamics, flight control Systems and/or flying/handling qualities as well as the willingness of gaining (background) knowledge in the associated technical areas as control/stabilization theory, system dynamics, pilot model identification. Attendance of the course “Introduction to Flight System Dynamics and Flight Control” is recommended, but not necessary.
Content / Educational Objectives It is the objective of the one-semester lecture to impart basic knowledge up to the state-of-the-art concerning the important interdisciplinary field “Flying / Handling Qualities and Pilot-in-the-Loop Oscillations (PIO)”.
Looking back on the earliest definition given by the “Wright Brothers” [1901], the discipline “Flying Qualities” is concerned with the “ability of balancing and steering an aircraft”. More generalized and up-to-date, Flying and Handling qualities relate directly to the ease or effort with which a flight task can be performed by the pilot. Thus, they describe the manner in which the aircraft responds to both, the control inputs of the pilot and to the effect of disturbances (turbulence, gusts, engine failures, flaps / landing gear operation, damage, etc.).
In particular, the emerge of the “high order Pilot-in-the-Loop Oscillations” (PIO), owing to the substantial couplings of the dynamic regulator “pilot” with the aircraft dynamics, afflicted the majority of fly-by-wire aircraft and has to be considered as the most intractable key problem.

Lecture contents and breakdown

  • Flying and Handling Qualities: What – How – when and in particular Why?
  • Relevant Specifications, Standards and Regulations, Rating Scales, motivation of applied methods
  • Stability Analyses of the “Pilot-Vehicle Closed Loop System”
  • Pilot Behavior and typical forms: Compensatory (lead/lag), proportional,
    or Open-Loop Control Chain
  • Review on fundamental Flying Qualities Requirements w.r.t. Pitch and Roll Axis
  • PIO – Pilot-in-the-Loop Oscillations: Categories, causes, effects and PIO prediction
  • Design for excellent Handling: The Prevention of PIO’s
  • Pilot’s modeling and pilot model involved criteria
  • Nonlinear (Cat. II) PIO phenomena: Rate and deflection limits within the FCS;
    the OLOP Criterion
  • “The Test Pilot’s View”: In-Flight Handling Qualities Verification against the background of subjective perception and evaluation

Learning Objectives
Upon successful completion of the module, students are able to:

  • understand the fundamental problem and relationships of Flying / Handling Qualities Analysis and Design as well as „Pilot-in-the-Loop Stability”
  • to constitute and reflect the associated „state-of-the art“
  • apply independently the analysis methods and criteria taught on current industrial flying qualities problems and tasks
  • analyze and evaluate the Flying / Handling Qualities as well as the PIO suceptibility of existing and future Aircraft / Flight Control System designs
  • implement measures for effective PIO prediction and prevention
  • work out a Flight Control System design for „Excellent Handling“ independently
Teaching Methods / Materials Integrated Lecture / Course:
The individual course units comprise each of the basic elements: lecture, interactive talk, exercises and computer practice (tutorial), in an integrative manner.
Within the lecture, the theoretical principles of Flying / Handlin Qualities Analysis and “Pilot-in-the-Loop Stability” will be derived and presented via Power Point slides and writing on the board. Comprehensive Lecture Notes (script) will be provided to the students which they should supplement with their own notes and remarks. In the course of an interactive talk the students are asked targeted questions or they may ask questions, respectively, in order to deepen the understanding and the proper application of stability analysis, flying qualities evaluation, PIO prediction and prevention.
In the course of the exercise together with the supplementing computer practice (tutorial) the contents imparted in the lectures will be applied to typical practical problems, e.g. the evaluation of PIO criticality of a modern high performance aircraft design, supported by simulations and calculations using modern analysis tools (MATLAB / Simulink). Furthermore, additional problem sheets will be provided to the attendees which can be solved during the exercises or voluntary at home in order to deepen the insight and practice of the techniques taught. The elaborated functions/scripts together with the provided program listings / algorithms will be collected together with the students into a fundamental “Handling Qualities Evaluation Toolbox”, which should serve as solid basis for their own (future) flying / handling qualities analyses and evaluations of new Aircraft / Flight Control System designs.
Additionally, each term a highly topical guest lecture given by an active jet experimental test pilot will be provided highlighting the practical aspects of “in-flight handling verification” at first hand. Through this, the students will be to recognize and prevent typical fallacies and pitfalls of handling qualities verification in practice from test scheduling, realization up to analysis and evaluation.
Exam Exam type: oral
Reference Literature List of recommended literature provided with first chapter of lecture notes.

This lecture is part of the Munich Aerospace Teaching Collaboration.