Mini lecture notes, class 3

1. Mini lecture notes, class 3 • Course organization [3 min] • got group members? (put group number on hwk) • got the book? • Lego exercise [5+5] • Reprise Kegworth [15min] • How to read a book, 5.2.3 (PQ4R) [10min] • So, preview preface, and preview conclusions soon • Chapter 1 [10] • why study the user? • risk • better design • help you be a team member/user • ABCS • not covered: emotions, esthetics • when? • How much do you have to study the user? • Chapter 2 [5] • CHI, HCI, HF, cog. Ergonomics, systems, user-centered design • Course project reminder [20 min.]

2. What causes a plane to crash? • A laundry list is required, or, a swiss cheese loaf lined up • A lot, in safety critical systems

3. Kegworth Air Disaster • Why? • Near Ritter, Baxter & Churchill • A lovely example • Often used

4. Storyline • Flight, jan 1989, Heathrow to Belfast, Midland 192 • Experienced pilots, new plane (737) • Part of one of the safest systems in the world • Upon take-off, no problems • Shuddering, fire in an engine at ~10 min. • Shut off #2 engine, RHS (the good one!) • This is the pilot error

5. Hardware and Mischance badly designed new engine, failure at 3 months, approx. t=300 h, should be t=500,000 h, not tested at altitude /unlucky choice of diversion airport [BMI hub]

6. Auto throttle problem poor mental model of plane [system](turned off good engine, which disengaged autothrottle, solving the judder problem) lack of engine feedback [interface design]

7. Vibration Dial 1 vibration dial harder to read [design] vibration dial not required to fly [regulation] dial and plane not trained with simulator technology updated but not announced

8. Vibration Dial 2 • vibration dial small [design] • Without range marking [design]

9. During descent lots of interruptions pilots can’t see the engines no protocol: no checking/confirmation visually from cabin • Passengers could see fire but explained it away, perhaps also flight attendants diffusion of social responsibilities Social distance between aircrew and pilots

10. crash • 900 m short • 43+4 out of 118+8 die +1 in 2012 (PTSD)

11. At crash • Not documented: noise abatement hillocks

12. Afterwards • If any 13or 3 missing, no loss of life • What was the pilot error? • Thus, systems require understanding people, technology, and systems and environment

13. References • Wikipedia on kegworth • BBC. (1991). Fatal error: Taking liberties [television series]. • Youtube has videos as well

14. How to read a book, 5.2.3 (PQ4R) • So, preview preface, and preview conclusions soon

15. 1.3 So, when to study the user? • Fundamental attribution error of design • More usable • $$ • Safer • Risk driven • Not like you • Lives at risk • Know enough given cost of knowing more(satisficing)

16. The ABCS • Anthropometrics • Behavioral • The senses • Motivation • Cognition • Social • System • The system(pre-HCI) • The system and user(early HCI) • The system and what we know about the user(U-CS)

17. Another way to organize the user • The system(pre-HCI) • The system and user(early HCI) • The system and what we know about the user(U-CS)

18. Chapter 2