1
Creating the
Somatogravic Illusion in
Your Simulator –
Early Research Results
Federal AviationAdministration
Federal AviationAdministration
Flight Safety Foundation
International Air Safety Summit
November 16, 2016
Jeffery Schroeder
2
Pitching illusion
• Forward accelerations create illusion of pitching
Go around with T/W=0.35
g
0.35g
Apparent direction
of gravity
Reality
3
Pitching illusion
Go around with T/W=0.35 19 degs pitch up
g
0.35g
Apparent direction
of gravity
Reality
• Forward accelerations create illusion of pitching
Perception
4
Pitching illusion
• So what?
• Illusion believed to be a factor in following:
– Skylink Airlines #70 accident, SA 227, Sept. 1989
– Air Transport Intl #805 accident, DC-8, Feb. 1992
– USAir #1016 accident, DC-9, July 1994
– Gulf Air #72 accident, A320, Aug. 2000
– Armavia #967 accident, A320, May 2006
– Afriqiyah Airways #771 accident, A330, May 2010
5
Pitching illusion
• Illusion training recommendations now in:
– “Aeroplane State Awareness during Go Around”
• BEA Study, Aug 2013
– “Manual on Aeroplane Upset Prevention and
Recovery Training”
• ICAO Doc 10011, 2014
– “Scenario-Based Go-Around Training”
• FAA Safety Alert for Operators #15004, March 2015
– “Upset Prevention and Recovery Training”
• FAA Advisory Circular 120-111, April 2015
6
Pitching illusion
• What to do?
– Pure illusion takes too much fore/aft travel
– Takes 10 secs to create 0.35g with cab tilt below
sensory threshold
7
Pitching illusion
• What to do?
– Pure illusion takes too much fore/aft travel
– Takes 10 secs to create 0.35g with cab tilt below
sensory threshold
• Maybe we can temporarily “fake it” and still
provide training value
8
Pitching illusion
Time, sec
0 20 40
Aircraft model
Pitch,
deg
20
10
0
9
Pitching illusion
Time, sec Time, sec
0 20 4020 40
Aircraft model Simulator cab
Pitch,
deg
20
10
00
Old motion
New motion
10
Pilot brief, Task, Method
– Brief: Told it was a degraded visual environment study, reviewed
go-around maneuver…intention was to create a little surprise
– Task: ILS 28R SFO. Flight directors used throughout.
“ATC” calls go around at 200 ft AGL:
• TO/GA switch, flaps 20, rotate to ~15 deg pitch
• Gear up
• LNAV at 400 ft
• VNAV and desired speed at 800 ft
• Flaps retract
• Level off
– Method: (1) Go-around with unmodified motion, night VMC
(2) Go-around with modified motion, night IMC (400/1.5 mi)
11
12
13
Pitching illusion
Column
position,
inches
Time, secs
Old motion
New motion
14Strongly
Disagree
Disagree Neither Agree
Nor Disagree
Agree Strongly Agree0
5
10
15
Nu
mb
er
of
Pilo
ts
Q5: The DVE scenario gave an effective demonstration of the “pitch up” illusion.
Pitching illusion
Number
of
pilots
10
5
0
15
“The scenario was an effective demonstration of the pitch up illusion”
15
Conclusions
• Illusion training justified by accidents
• Study examined value of “faking” the illusion
• Illusion affected some pilot responses, and
majority felt illusion demo was effective
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