1. Mini lecture notes, class 3
Course organization
got group members?
got the book?
Lego exercise
Reprise Kegworth
How to read a book, (PQ4R)
So, preview preface, and preview conclusions soon
Chapter 1
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
CHI, HCI, HF, cog. Ergonomics, systems, user-centered design
Course project reminder
Allow chance to talk in group before talking in cybertorium

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
Survey on how it’s going every three weeks

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

4. Storyline Shut off #2 engine, RHS (the good one!)
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]
Pipedream

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]
Pipedream

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
Pipedream

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

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 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. So, when to study the user?
Fundamental attribution error of design
More usable $$
Safer
Risk driven
Not like you
Lives at risk

15. The ABCS Anthropometrics Behavioral Cognition Social System
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)

16. Chapter 2