VLTA Emergency Requirements

1

• VLTA Emergency Requirements
• Research Evacuation Study
• Rebecca L. Wilson, Lauren J. Thomas
• Helen C. Muir
• Human Factors Group
• School of Engineering
• Cranfield University, UK

2
Consortium funding

• The VERRES programme was a European Commission
  DG Tren funded project.
• The aim of the project was to examine some of the
  issues relevant to evacuation from next
  generation VLTA.
• The study was general in nature, and not related
  to any specific VLTA type.
• The consortium included Sofréavia, CAA/SRG, JAA,
  Airbus, University of Greenwich, Cranfield
  University, Virgin Atlantic Airways and SNPNC.

3
Programme of study

• The study covered three major domains
• The configurational aspects of aircraft cabin
  design and the evacuation implications.
• The use of analysis supported by relevant
  small-scale evacuation tests and evacuation
  modelling software.
• The human aspects such as cabin crew
  co-ordination and training and the mental
  representation layout of the aircraft for the
  passenger.

4
Scope of project

• Analyses on the trial data were conducted
  independently by three VERRES partners, each
  using a different approach and reaching their own
  conclusions.
• The Cranfield University analysis focussed on
  passenger evacuation times and data from post
  evacuation questionnaire.
• A summary report, providing an overview of the
  whole programme, has been published by the JAA on
  behalf of the consortium (Greene Friedrich,
  2003).

5
Potential research areas

• During the development of the test plan for the
  experimental tests, the VERRES consortium
  identified a large number of areas of interest.
• Areas were classified into high or low priority
  within the specification of the project.
• High priority issues included staircase size,
  staircase configuration, staircase flow
  management, upper deck slides and crew
  co-ordination.

6
Research areas for testing

• However, it became evident that consortium
  members were unable to limit the number of
  variables for testing.
• Therefore, instead of an experiment, it was
  proposed to conduct the evacuation trials as a
  series of demonstration evacuations.
• It was accepted that because of the lack of
  experimental control, trials would only be used
  to explore possibilities for future research, and
  no conclusions could be drawn from the work.

7
Design of demonstrations

• Three variables related to passenger movement in
  three types of situations
• Free choice of exits between decks
• Lower deck exits unavailable
• Upper deck exits unavailable
• Variables related to the cabin crew at the
  staircase
• Additional cabin crew at staircase
• Cabin crew at exits only

8
Test facility

• Test facility Large Cabin Evacuation Simulator
  located at Cranfield University, United Kingdom.
• Both decks of the simulator were to be used
  during the trials, all seats were at 31 pitch.
• Lower deck had 172 seats, with three fitted exits
  (LL1, LL2 LR2), with platforms available
  outside for evacuation.
• Upper deck had 88 seats, two fitted exits (UL1
  UR1). UL1 had a platform for evacuation and UR1
  was fitted with a dual lane evacuation slide.

9
Lower deck of LCES
10
Upper deck of LCES
11
Internal staircase
12
Volunteers

• Up to 168 volunteers were recruited for each day,
  with four demonstrations held on each day.
• Volunteers were split into two groups of 84, to
  manipulate staircase naiveté.
• Volunteers were members of the public who were
  recruited using either the HFG aviation research
  database or via local and regional advertising.
• All demonstrations were video recorded, to allow
  data relating to passenger and cabin crew
  behaviour to be extracted.

13
Demonstration scenarios

• Movement between decks was of interest, as was
  the presence or absence of additional cabin crew
  at the internal staircase.
• Four demonstrations were the moving downwards
  scenario, two with additional crew at internal
  staircase.
• Two demonstrations utilised the moving upwards
  scenario, one with and one without additional
  crew.
• Two demonstrations were free choice scenarios,
  neither with additional crew at the internal
  staircase.

14
Order of demonstrations
Trial number Day 1 (25 Jan 03) Day 2 (1 Feb 03)
1 Free choice Moving downwards with additional crew at staircase
2 Moving downwards, no additional crew at staircase Moving upwards, no additional crew at staircase
3 Moving upwards, additional crew at staircase Moving downwards without additional crew at staircase
4 Moving downwards, with additional crew at staircase Free choice
15
Conduct of demonstrations

• After pre-trial paperwork and briefing,
  volunteers boarded simulator via external
  staircases to ensure naïve use of internall
  staircase.
• Seats allocated according to a pre-defined
  seating plan on a random basis, with each
  volunteer sitting on each deck twice.
• Ten members of cabin crew were involved in the
  evacuations.
• Prior to the evacuation all cabin crew (except
  those located at UR1) were unaware of which exits
  were available for evacuation.

16
Results

• Data were available from 8 demonstrations, with a
  total of 336 volunteers.
• A person was deemed to have evacuated when they
  placed their 1st foot over the exit threshold.
• Inferential statistical analyses between
  different scenarios could not be conducted, since
  insufficient data were available for comparison.
• Differences between additional/no additional
  cabin crew scenarios may not be clear due to crew
  behaviours.

17
Free choice demonstrations
Free choice N Mean evac time (secs) Evac rate (pax per min) Overall exit time (secs)
25 Jan 03 Trial 1
UR1 33 42.4 25.4 75.6
LL2 62 31.2 56.7 64.5
LR2 74 33.4 63.3 69.2

1 Feb 03 Trial 4
UR1 36 29.9 46.4 45.3
LL2 65 22.9 92.3 41.6
LR2 68 25.3 79.4 50.6
18
Free choice results

• Differences are apparent between demonstrations.
  Faster evacuation rates, lower evacuation times
  and lower overall evacuation times were obtained
  on the last trial of programme.
• Inferential statistical analysis cannot be
  conducted, since insufficient data are available
  for comparison.
• The observed differences are likely to be a
  function of passenger and cabin crew learning.

19
Moving upwards demonstrations
Moving upwards N Mean evac time (secs) Evac rate (pax per min) Overall exit time (secs)
1 Feb 03 Trial 2
No additional crew
UL1 112 43.9 78.9 84.4
UR1 (slide) 57 47.5 38.8 86.5

25 Jan 03 Trial 3
Additional crew
UL1 119 45.3 91.1 77.7
UR1 49 45.4 36.8 78.2
20
Moving upwards results

• Two demonstrations were conducted within this
  scenario, one with and one without additional
  crew.
• Marked differences are apparent in evacuation
  rates between UR1 and UL1.
• Inferential statistical analysis cannot be
  conducted, since insufficient data are available
  for comparison.
• Observed differences are likely to be a function
  of the extreme caution exercised by cabin crew at
  UR1

21
Moving downwards demonstrations without
additional crew
Moving downwards Without additional crew N Mean evac time (secs) Evac rate (pax per min) Overall exit time (secs)
25 Jan 03 Trial 2
LL2 80 28.3 83.0 57.1
LR2 88 29.4 92.9 56.2

1 Feb 03 Trial 3
LL2 81 27.5 90.7 52.9
LR2 88 28.1 98.3 53.1
22
Moving downwards demonstrations with additional
crew at staircase
Moving downwards With additional crew N Mean evac time (secs) Evac rate (pax per min) Overall exit time (secs)
25 Jan 03 Trial 4
LL2 81 28.8 90.2 53.2
LR2 87 28.2 99.0 52.1

1 Feb 03 Trial 1
LL2 86 29.9 89.9 56.7
LR2 83 31.1 83.5 58.9
23
Moving downwards evacuations

• Four demonstrations were conducted within this
  scenario two with and two without additional
  crew.
• Mean evacuation times, evacuation rates and
  overall evacuation times do appear to be broadly
  similar across the different demonstrations.
• Inferential statistical analysis cannot be
  conducted, since insufficient data are available
  for comparison.

24
Conclusions

• Post demonstration questionnaires revealed that
  cabin crew had a major influence on passenger
  exit choice.
• Cabin crew variable was uncontrolled as crew
  moved to give additional assistance at staircase.
  Reasons may be highlighted in Sofréavia analysis
  - research crew can be more flexible.
• As demonstrations were not scientifically
  controlled, no firm conclusions can be drawn.
• Future research could include passenger exit
  choice behaviours, interaction between passengers
  and crew, and investigation of internal features
  e.g. staircases.