VLTA Emergency Requirements

Research Evacuation Study

Rebecca L. Wilson, Lauren J. Thomas

& Helen C. Muir

Human Factors Group

School of Engineering

Cranfield University, UK

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.

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.

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).

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.

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.

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

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.

Lower deck of LCES

Upper deck of LCES

Internal staircase

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.

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.

Order of demonstrations

Trial number Day 1 (25 Jan 03) Day 2 (1 Feb 03)

1Free choice Moving downwards with

additional crew at staircase

2Moving downwards, no

additional crew at staircaseMoving upwards, no

additional crew at staircase

3Moving upwards, additional

crew at staircaseMoving downwards without additional crew at staircase

4Moving downwards, with

additional crew at staircaseFree choice

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.

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.

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

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.

Moving upwards demonstrationsMoving 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

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

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

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

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.

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.