Presentation on theme: "VLTA Emergency Requirements Research Evacuation Study Rebecca L. Wilson, Lauren J. Thomas & Helen C. Muir Human Factors Group School of Engineering Cranfield."— Presentation transcript:
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.
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 numberDay 1 (25 Jan 03)Day 2 (1 Feb 03) 1 Free choiceMoving 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
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 1 st 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 choiceNMean evac time (secs) Evac rate (pax per min) Overall exit time (secs) 25 Jan 03 Trial 1 UR13342.425.475.6 LL26231.256.764.5 LR27433.463.369.2 1 Feb 03 Trial 4 UR13629.946.445.3 LL26522.992.341.6 LR26825.379.450.6
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 demonstrations Moving upwardsNMean evac time (secs) Evac rate (pax per min) Overall exit time (secs) 1 Feb 03 Trial 2 No additional crew UL111243.978.984.4 UR1 (slide)5747.538.886.5 25 Jan 03 Trial 3 Additional crew UL111945.391.177.7 UR14945.436.878.2
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 NMean evac time (secs) Evac rate (pax per min) Overall exit time (secs) 25 Jan 03 Trial 2 LL28028.383.057.1 LR28829.492.956.2 1 Feb 03 Trial 3 LL28127.590.752.9 LR28828.198.353.1
Moving downwards demonstrations – with additional crew at staircase Moving downwards With additional crew NMean evac time (secs) Evac rate (pax per min) Overall exit time (secs) 25 Jan 03 Trial 4 LL28128.890.253.2 LR28728.299.052.1 1 Feb 03 Trial 1 LL28629.989.956.7 LR28331.183.558.9
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.