16.400/453J
Human Factors Engineering
Introduction
Professor Larry Young
Professor Divya Chandra
Caroline Lowenthal
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Outline
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Introductions
Human Factors Evaluation
Syllabus
Overview of Human Factors
Case study presentation
Questions
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Human Factors Evaluation
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• Each Student is to choose a Human Factors example and write down:
– Some HF Issue (what is difficult or dangerous)
– A potential solution to the problem
– And what you would need to know to design a good solution.
–Put YOUR NAME and contact info on the card
– They will be collected at the end of the case study presentation
Syllabus
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• Books
– Proctor, R. W., & Van Zandt, Dismukes, et al., Bluman, A.G
• Readings
• Case studies
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– Presentations
Online surveys (Daily Quizzes)
P‐sets (2) & Projects (3 UG +1 G)
Quizzes
Grad students
Overview of Human Factors
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Work Environment
Information
Processing
Controlling
Sensing
Human Being
Machine
Display
Controls
Output
Input
Operation
Schematic representation of a human-machine system.
Image by MIT OpenCourseWare.
Case Study Presentation
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Eastern Airlines Flight 401
Larry Young
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Flight Summary
• Lockheed L‐1011 Tristar
• Departed NY(JFK) ‐> Florida(MIA) 9:20pm, Dec29th, 1972
• Crashed 11:42pm ~18 miles from MIA
• 103/176 People on board died in the crash.
• Cause of the accident (NTSB):
– Failure of crew to monitor instruments during final 4 minutes of flight, leading to CFIT
– Distraction while dealing with failure of nose landing gear position light is a contributing factor
Lockheed L‐1011 Tristar
• Competitor of the DC‐10
• Triple‐engine configuration, 400 passengers max. • Between 1968 and 1984, Lockheed manufactured a total of 250 TriStars. • The L‐1011 was advertised technologically largely ahead of its time.
• First widebody to receive FAA certification for Cat‐IIIc
autolanding (no decision height, zero visibility).
This image is in the public domain. Source: NASA
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L‐1011 Overview
• Direct Lift Control (DLC) system which allowed for smooth approaches when landing.
• Four redundant hydraulic systems (the DC10 and MD11 had only three).
• As of September 2006, 33 are in service with ad hoc charter and military carriers, as well as Hewa Bora Airways of the Democratic Republic of Congo, the sole remaining operator of scheduled TriStar flights.
• Most remaining L‐1011’s are now being sold for scrap.
• There has never been a crash of an L‐1011 due to mechanical failure. 10
Flight Narrative
• The flight crew was qualified, with >40,000 flight hours between the Captain and the First Officer.
• There was an experienced Flight Engineer, and a maintenance officer in the cockpit as well. • The flight was essentially uneventful leading up to the approach to MIA.
• During the approach, the landing gear handle was lowered, but only 2/3 gear could be confirmed to be in the down position (via the cockpit indicator lights). 11
L‐1011 Cockpit
Images of Lockheed L-1011 cockpit removed due to copyright restrictions.
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Images of Lockheed L-1011 cockpit removed due to copyright restrictions.
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Flight Narrative
• Unsure of whether the gear or the indicator was at fault, the Captain elected to abort the landing.
• The flight was directed by ATC to 2000ft and was given a course to hold while diagnosing the problem.
• The autopilot was engaged to hold course and altitude.
• The Captain ordered the F/O to fly the plane while he communicated with ATC and coordinated with the Flight Engineer to diagnose the problem. 14
Flight Narrative
• Upon reporting that the hydraulics were online, the Flight Engineer was ordered down into the “hell hole”.
• The copilot pulled out the suspect light, inspected it, and jammed it back in the panel incorrectly.
• Captain: You got it sideways, then.
Co-pilot: Naw, I don't think it'll fit.
Captain: You gotta turn it one quarter turn to the left.
Captain: Hey, hey, get down there and see if that damn nose
wheel's down. You better do that.
Co-pilot: You got a handkerchief or something so I can get a
little better grip on this? Anything I can do with it?
Captain: Get down there and see.
Co-pilot: This won't come out, Bob. If I had a pair of pliers, I
could cushion it with that Kleenex.
Flight Engineer: I can give you pliers but if you force it, you'll
break it, just believe me
Co-pilot: Yeah, I'll cushion it with Kleenex
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Flight Narrative
• At 11:40:38 a C‐chord was heard in the CVR, indicating a 250ft deviation from the selected altitude. This was apparently missed by the flight crew.
• Co-pilot: Naw that's right, we're about to cross Krome Avenue
right now.
[Sound of click]
Co-pilot: I don't know what the # holding that # # # # in'
Co-pilot: Always something, we coulda make schedule'
[Sound of altitude alert]
Captain: We can tell if that # # # # is down by looking down at
our indices
Captain: I'm sure it's down, there's no way it couldnt help but be
Co-pilot: I'm sure it is
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Flight Narrative
• The Flight Engineer in the hole reported that he couldn’t see the gear through the viewing periscope, as it was too dark. • The maintenance officer riding in the jumpseat attempted to help, but also couldn’t see anything.
• The problem was discussed for another 30s before it was decided to turn back to the airport.
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Flight Narrative
• Air traffic controller: Eastern, ah 401 how are things comin'
along out there?
Capt to air traffic controller: Okay, we'd like to turn around and
come, come back in.
Captain: Clear on left?
Co-pilot: Okay
Air traffic controller: Eastern 401 turn left heading one eight
zero
Co-pilot: We did something to the altitude '
Captain: What? '
Co-pilot: We're still at two thousand right?'
Captain: Hey, what's happening here? '
[Sound of click]
[Sound of six beeps similar to radio altimeter increasing in rate]
[Sound of impact]
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Flightpath, 29 DEC 1972, Eastern Tristar
Everglades, FL
180 kts
KROME AVE
Pitch CWS
Roll CWS or
head sel.
Pitch CWS
Roll CWS or
head sel.
176 kts
1
170 kts
.
FT
0
0
9
240o
Glide slope
176 kts
179 kts
0
0
0
2
182 kts
.
FT
RWY 09L
Miami
International
Airport
Image by MIT OpenCourseWare.
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Investigation
• Examination of the wreckage showed that the indicator bulb had been burned out, and that the gear was operational
• It was speculated that the pilot may have inadvertently bumped the control column, disengaging the autopilot from its altitude‐
hold mode, and that this went undetected by the flight crew
• The altitude had gradually decayed over a period of minutes before impact
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HF Issues
• Poor Crew Resource Management (CRM)
• Failure to maintain task priority: “Aviate, Navigate, Communicate”
• Overreliance on Automation, leading to loss of situational awareness
• Excessively cluttered and complicated cockpit layout
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Possible Solutions
• CRM training
• Simplified cockpit design (glass?)
• Improve training emphasizing aviate first
• More intelligent automation:
– Better alarm for autopilot disengage
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References
• NTSB:AAR 73‐14. 14 JUN, 1973. Retrieved 5 Sep, 2006, from http://www.ntsb.gov/
• “Eastern Airlines Flight 401 Memorial”. Retrieved 5 Sep, 2006, from http://eastern401.googlepages.com/
Questions?
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Syllabus Overview
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Introduction and Vision I Vision II
Space Bioastronautics
Research Methods I
Research Methods II
Vestibular/Spatial Disorientation Displays
Space Human Factors
Auditory
Attention/Workload
PIO and Cooper Harper
Handling Qualities
Space Physiology
• Automation, Situation Awareness • Decision Making
• Flight Deck Automation Working Group
• Manual Control I
• Manual Control II, FAA Regulations
• Fatigue/Circadian Rhythms
• Automobile HF
• Response Selection & Control of Movement
• Anthropometry/Environmental Ergonomics
• Volpe HF Lab Tour 24
Human Vision and
Aircraft Displays
Part 1
The Eye
16.400/16.453J
Prof. L. R. Young
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Impact
θ
g
rin
ea
eb
tiv
la
Re
Aircraft B
θ
Aircraft A
Aircraft about to collide will remain at constant relative bearings.
(i.e there will be no movement across the windshield)
Image by MIT OpenCourseWare.
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3 s/1/2o
o
1.5 s/1
0.75 s/2o
0.38 s/4o
0.1 s/very big indeed
The retinal size of an approaching aircraft before impact.
Image by MIT OpenCourseWare.
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Conjunctiva
Vitreous
Ora serrata
Sclera
Ciliary body
Choroid
Aqueous
Retina
Iris
Macula
Anterior chamber
Cornea
Pupil
Lens
Artery (central retinal)
Posterior chamber
Vein (central retinal)
Canal of schlemm
Optic nerve
Conjunctiva
Rectus medialis
Image by MIT OpenCourseWare.
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Eye Movements
• Tracking (Versional)
– Saccades
– Pursuit
• Vergence
• Compensatory (VOR)
• Nystagmus
• Miniature
Drift
Flicks
Tremor
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Image by MIT OpenCourseWare.
Retina Organization
Pigment epithelium
Rods
Cones
Outer limiting membrane
Muller cells
Horizontal cells
Bipolar cells
Amacrine cells
Ganglion cells
Nerve fiber layer
Inner limiting membrane
Image by MIT OpenCourseWare.
Light - Sensitive Transducers :
Rods (Color insensitive, Max. concentration at 20o)
Cones (Color sensitive, Max. concentration at 0o)
Foveal Acuity ~ 1 Min. of arc
Max. Lumens - Sun (threshold of damage)
Min. Lumens - A few photons (Min. threshold)
Ratio of above ~ 1013
Rods
Cones
Wavelength
Threshold
Threshold
Frequency range 340 - 760 nm wavelength
Color adaption - "Visual purple"
Temporal adaption - Flicker fusion 20 Hz
- 20 Min. in dark.
Time in Dark
Image by MIT OpenCourseWare.
150
100
Blind Spot
Number of Rods or Cones - Thousands / mm2
200
50
0
100
80
60
40
20
Nasal Retina (Temporal Field)
0
20
Fovea
40
60
80
Temporal Retina (Nasal Field)
Angular Eccentricity - Degree
Cones
Rods
Image by MIT OpenCourseWare.
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10
5.0
Visual angle
Target Visual Angle - minutes
Visual angle
(minutes of arc)
1.0
Minimum separable acuity
.5
.1
Vernier acuity
.05
Stereoscopic acuity
Targets
Minimum perceptible acuity
.01
Visual angles
.005
.001
.01
0.1
1
10
100
1000 10000
Background Luminance - mL
Image by MIT OpenCourseWare.
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B/B
10000
1000
0.595 - Target Size in minutes of arc
Threshold Contrast -
100
3.60
10
5
2
1
10.2
9.65
121
.1
55.2
340
.01
.001
.00001
.0001
.001
.01
1 2 5 10
.1
100
1000
2.6
2.1
Background Luminance - mL
7.0
6.8
6.4
5.8
5.1
4.4
3.6
Pupil Diameter - mm
Luminance contrast is a measure of how much target luminance (Bt) differs
from background luminance (Bb). The equation for obtaining contrast is:
CB =
Bt - Bb
Bh
or CB
X
100 = 50 CB
Image by MIT OpenCourseWare.
.10
.010
0.5 .00
.005
.000
100
Target Size - minutes
00
1.0 - Target contrast
10
1
10.0
100
1000
0.1
.01
.00001
.0001
.010
.01
.1
1
10
100
1000
Background Luminance - mL
Image by MIT OpenCourseWare.
Luminance Threshold - mL
.1
.01
.001
4700 ml
447 ml
.0001
44 ml
4 ml
.00001
0
10
20
30
Time in Darkness - min
Numbers on curves indicate brightness of pre-exposure white light.
Image by MIT OpenCourseWare.
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Luminance Threashold - mL
.0001
.00001
0
5
10
15
20
Time in Darkness - min
Pre-exposure brightness of 1.1 - mL Light of the following Colors,
Violet
White
Red
Yellow
Image by MIT OpenCourseWare.
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Flicker Frequency %
60
50
40
Perceived as Steady
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Perceived as Flickering
20
10
0
0.001
0.01
.1
1
10
100
1000
Luminance of Target - mL
Image by MIT OpenCourseWare.
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Critical detail - Min of arc
20
16
1.0 ft.c
.20 ft.c
.04 ft.c
12
8
125.0 ft.c
4
.
2.0 ft.c 25.0 ft c
0
20
40
60
80
100
210
140
Angular velocity - deg/sec
Image by MIT OpenCourseWare.
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Fall 2011
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