Recent Transport Canada safety research at Cranfield University

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• Recent Transport Canada safety research at
  Cranfield University
• Rebecca L. Wilson, Lauren J. Thomas
• Helen C. Muir
• Human Factors Group
• School of Engineering
• Cranfield University, UK

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Recent Research

• Considerable research has been conducted into the
  operation of the Type III exit, however much of
  this work has been conducted in a 3x3
  configuration.
• Relatively little is known about whether the
  research findings generalise to a 2x2
  configuration.
• Transport Canada have commissioned three
  preliminary studies into the operation of the
  Type III exit in a 2x2 configuration.

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Study 1- 2x2 and 3x3 cabin configuration

• Test facility was a Boeing 737 cabin simulator
  configured in either
• 3x3 or 2x2 configuration
• 10 or 13 VP in Type III exit row
• Participants
• 24 independent groups of up to 20 participants,
  six groups per condition.
• Dependent variable
• Egress time
• Exit availability time

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Boeing 737 cabin simulator 3x3
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Boeing 737 cabin simulator 2x2
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Procedure

• Participants were greeted by a researcher trained
  and dressed as cabin crew. After check-in,
  participants boarded the cabin simulator.
• Seats for each group were pre-allocated according
  to a random seating plan.
• Each group of participants were given a typical
  pre-flight safety briefing.
• A minimal briefing was also provided to the
  passenger seated at the Type III exit (Cobbett,
  Liston Muir, 2001).

2x2 and 3x3
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Evacuations

• On completion of the safety briefing, passengers
  heard a recording of engine noise, followed by an
  announcement from the Captain to Undo your
  seatbelts and get out!
• The cabin crew member then instructed passengers
  to open and move towards the Type III exit.
• Throughout the evacuation, the cabin crew used
  assertive, positive and concise commands to
  encourage passengers to move as quickly as
  possible (Muir Cobbett, 1996).

2x2 and 3x3
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Results

• Data on evacuation times was extracted from video
  footage recorded outside the Type III exit. Each
  participant was deemed to have evacuated when
  both feet were on the wing.
• Data were available from a total of 24
  evacuations six trials within each condition.
• Since the group size varied due to non
  attendance, all evacuation time analyses used
  only the times for the first 15 people to
  evacuate through the exit.

2x2 and 3x3
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Mean evacuation times 1st 15 (in secs)
Seating configuration Seating configuration Total
Vertical projection 3x3 2x2
10 19.0 (sd 5.8) 18.1 (sd 5.3) 18.6 (sd 5.6)
13 18.8 (sd 5.7) 17.3 (sd 4.9) 18.1 (sd 5.3)
Total 18.9 (sd 5.7) 17.7 (sd 5.1)
2x2 and 3x3
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Evacuation results

• Inferential statistical analysis showed that
  there were statistically significant differences
  due to the seating configuration.
• Participants evacuated quicker in the 2x2
  configuration than the 3x3 configuration. This
  effect may be due to passageway length. The
  result was unlikely to have arisen by chance.
• There were no statistically significant
  differences in evacuation times due to vertical
  projection, nor an interaction between seating
  configuration and vertical projection.

2x2 and 3x3
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Mean exit availability times (in secs)
Seating configuration Seating configuration Total
Vertical projection 3x3 2x2
10 10.2 (sd 3.0) 8.1 (sd 1.6) 9.1 (sd 2.5)
13 9.4 (sd 2.1) 8.6 (sd 0.8) 9.0 (sd 1.6)
Total 9.8 (sd 2.5) 8.4 (sd 1.2)
2x2 and 3x3
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Exit availability results

• Inferential statistical analysis indicated no
  significant differences in the time taken to make
  the exit available due to seating configuration
  or vertical projection.

2x2 and 3x3
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Study 2- Modification to operating handle

• Test facility was a Boeing 737 cabin simulator
  configured in either
• 3x3 configuration or 2x2 configuration
• Exit operating handle configured in either
• Retracted (conventional) mechanism or fixed
  (modified) mechanism
• 40 participants
• Tested individually.
• Repeated and counterbalanced on handle type
• This paper reports data from naïve participants
  only
• Dependent variables
• Egress time and exit availability time

Handle mods
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Exit handle modifications
Handle mods
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Procedure

• Participants were greeted by a researcher trained
  and dressed as cabin crew. After check-in,
  participants boarded the cabin simulator.
• Each participant sat in the seat adjacent to the
  Type III exit.
• Participant was given a typical pre-flight safety
  briefing.
• In addition, participants received an in-depth
  individual briefing on their emergency duties
  (i.e. checking outside, heavy hatch, mode of
  operation).

Handle mods
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Evacuations

• On completion of the safety briefing, passengers
  heard a recording of engine noise, followed by an
  announcement from the Captain to Undo your
  seatbelts and get out!
• The cabin crew member then instructed the
  passenger to open and move towards the Type III
  exit.
• Throughout the evacuation, cabin crew used
  assertive, positive and concise commands to
  encourage the passenger to move as quickly as
  possible (Muir Cobbett, 1996).

Handle mods
17
Results

• Data on evacuation times was extracted from video
  footage recorded outside the Type III exit. A
  participant was deemed to have evacuated when
  both feet were on the wing.
• Only the results from the first trial with
  naïve participants - are reported here.
• Data were available from a total of 40
  evacuations 10 evacuations within each
  condition.

Handle mods
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Mean evacuation times ppn (in secs)
Handle modification Handle modification Total
Seating configuration Retracted Modified
3x3 12.8 (sd 3.8) 12.3 (sd 3.1) 12.5 (sd 3.4)
2x2 15.4 (sd 4.2) 17.9 (sd 6.1) 16.7 (sd 5.2)
Total 14.1 (sd 4.1) 15.1 (sd 5.5)
Handle mods
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Evacuation results

• Inferential statistical analysis showed that
  there were statistically significant differences
  due to the seating configuration.
• Individual participants evacuated quicker in the
  3x3 configuration than the 2x2 configuration.
  This effect was unlikely to have arisen by
  chance.
• There were no statistically significant
  differences in evacuation times due to handle
  modification, and no interaction between handle
  modification and seating configuration.

Handle mods
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Mean exit availability times (in secs)
Handle modification Handle modification Total
Seating configuration Retracted Modified
3x3 11.0 (sd 3.6) 10.3 (sd 2.9) 10.6 (sd 3.2)
2x2 13.3 (sd 2.8) 15.7 (sd 5.8) 14.5 (sd 4.6)
Total 12.1 (sd 3.4) 13.0 (sd 5.2)
Handle mods
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Exit availability results

• Inferential statistical analysis showed that
  there were statistically significant differences
  due to the seating configuration.
• Participants made the exit available more quickly
  in the 3x3 configuration than the 2x2
  configuration. This effect was unlikely to have
  arisen by chance.
• There were no statistically significant
  differences in exit availability times due to
  handle modification, nor an interaction between
  handle modification and seating configuration.

Handle mods
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Study 3 - Type III hatch disposal

• Test facility - Boeing 737 cabin simulator in a
  2x2 configuration.
• Type III exit hatch configured as either
• Conventional plug style hatch or up and over
  ADH
• 80 participants, tested individually.
• Three stooge passengers around the exit row to
  add a degree of pressure on participants to
  evacuate quickly.
• Dependent variable egress times and exit
  availability times

Hatch disp
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Type III exit hatch with plug design
Hatch disp
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Type III exit hatch with ADH mechanism
Hatch disp
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Procedure

• Participants were greeted by a researcher trained
  and dressed as cabin crew. After check-in,
  participants boarded the cabin simulator.
• Each participant sat in the seat adjacent to the
  Type III exit.
• Participants were given a typical pre-flight
  safety briefing.
• A minimal briefing was also provided to the
  passenger seated at the Type III exit (Cobbett,
  Liston Muir, 2001).

Hatch disp
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Evacuations

• On completion of the safety briefing, passengers
  heard a recording of engine noise, followed by an
  announcement from the Captain to Undo your
  seatbelts and get out!
• The cabin crew member then instructed passengers
  to open and move towards the Type III exit.
• Throughout the evacuation, cabin crew used
  assertive, positive and concise commands to
  encourage the passenger to move as quickly as
  possible (Cobbett Muir, 1996).

Hatch disp
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Results

• Data on evacuation times was extracted from video
  footage recorded outside the Type III exit. The
  participant was deemed to have evacuated when
  both feet were on the wing.
• Data were available from a total of 40
  evacuations 10 evacuations within each
  condition.

Hatch disp
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Mean evacuation times ppn (in secs)
Exit design Exit design
Conventional plug hatch Modified up and over ADH
13.5 (sd 4.0) 8.6 (sd 2.6)
Hatch disp
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Evacuation results

• Inferential statistical analysis showed that
  there were statistically significant differences
  between hatch designs.
• Participants evacuated significantly faster when
  the hatch had an ADH mechanism than when it was a
  conventional plug design. This effect was
  unlikely to have arisen by chance.

Hatch disp
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Mean exit availability times (in secs)
Exit design Exit design
Conventional plug hatch Modified up and over ADH
12.2 (sd 4.3) 5.8 (sd 2.1)
Hatch disp
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Exit availability results

• Inferential statistical analysis showed that
  there were statistically significant differences
  between hatch designs.
• Participants made the exit available more quickly
  when the hatch had an ADH mechanism than when it
  was a conventional plug design. This effect was
  unlikely to have arisen by chance.

Hatch disp
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Conclusions

• All results relate to preliminary experimental
  work, but raise interesting issues regarding
  Type III exits in smaller airframes.
• Findings from the second study directly
  contradict results in first study. With small
  groups, overall evac time in 2x2 configurations
  were quicker. With individuals, 3x3 was quicker.
• It may be that for small groups, the shortened
  passageway length in 2x2 configuration offset the
  lack of headroom.
• With individual tests, pax were already in exit
  row, therefore headroom a more important factor.

Hatch des
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Conclusions

• The modification to the operating handle had no
  effect on the time taken to operate the exit,
  although this may be a function of the in-depth
  exit briefing that was provided to passengers.
• However, there was an effect for configuration,
  such that participants were able to make the exit
  available more quickly in a 3x3 configuration.
  This again may be due to the additional headroom
  available for the exit operator.
• ADH results replicate previous research on the up
  and over mechanism in 3x3 configurations.