This study, funded by the European Commission and undertaken by a European consortium has been able to investigate a wide variety of issues related to the evacuation of Very Large Transport Aircraft (VLTA). Some exploratory evacuation trials have been carried out and areas for future research have been identified.
The purpose of Very Large Transport Aircraft (VLTA) Emergency Requirements Research Evacuation Study (VERRES) is to investigate many issues relating to post-accident survivability of larger aircraft in the future. A particular focus is on evacuation issues with detailed investigation of the role of computer models.
The use of computer models
The value of computer models of evacuation have been assessed as a major part of the study with a particular focus on VLTA. Computer based analysis techniques coupled with partial testing have been shown to assist in the design and development of safer aircraft, particularly significant for the more complex interiors that may be offered in VLTA.
VERRES includes results of the first evacuation research trials of a large double-deck aircraft. These were intended to provide data for evacuation models, particularly related to the use of stairs in addition to exploring wider issues of VLTA evacuation. These exploratory trials were able to provide an indication of the many issues involved and provided useful pointers for future, more detailed investigations. It should be noted that a more complex interior allows more crew procedural options and passenger behaviour may be less predictable with implications for crew training.
Managing large numbers of passengers A major VLTA evacuation issue would be more passengers for cabin crew to manage (although in total, the proportion of cabin crew to passengers would be expected to stay the
same), possibly with large slides and crowd management at the foot of the slides becoming more significant in importance. Concerning the passenger exit hesitation times for the high sill height, the trials produced inconclusive results. Whilst the measured exit flow rates are lower and the passenger exit delay times are longer than would be expected for a normal Type-A exit, it was clear that the extreme caution of the cabin crew positioned at the exits and the lack of (panic) motivation of the passengers exerted a strong influence on the data produced.
The management of large numbers of passengers in a more complex cabin interior than current aircraft is an issue. The need for improved situational awareness for cabin crew has been considered and improved communication systems for them may be worthy of further investigation. These could be visual information display systems perhaps placed at exits or portable systems to allow crew to share information regardless of location. These tools may enable better command and control procedures to be developed for the cabin crew.
The communication of safety information to passengers is likely to continue to be difficult to successfully achieve. Providing situational awareness to passengers in a more complex VLTA interior will be a challenge and improved techniques may be required.
Research recommendations are made to:
- Conduct further experimentation and computer simulation on the use of stairs (and handrails) in the evacuation process for accident/incidents and precautionary evacuations. The VERRES trials provide an indication of some of the passenger movement issues but more trials would be required to establish conclusive results. The purpose would be to formalise the use of stairs and stair management.
- Continue to develop and eventually demonstrate (through parallel application with certification trials – both historic and new) a framework for the use of aircraft evacuation simulation for certification purposes.
- Continue the development of aircraft evacuation modelling technology to enhance
existing behavioural capabilities, in particular in the area of crew-passenger interaction and passenger behaviour in real accident scenarios; e.g. ability for passengers to climb over seats and their behaviour in fire/smoke environments.
- Collect data on the passenger exit hesitation time distribution associated with representative VLTA upper deck exits to better characterise the performance of these exits and for use in computer simulation.
- Gain a greater knowledge of passenger behaviour and passenger- crew interaction in an emergency within a VLTA through experiments (plus the use of software models noted in recommendation 3) in order to maximise evacuation efficiency.
- Assess the importance of exit visibility. This should include the evaluation of new materials and intelligent systems to make the location and status of the exit more apparent to passengers (and crew).
- Review the use of upper-deck slides for large numbers of passengers in accident/incidents and precautionary evacuations with the purpose of maximising evacuation efficiency and minimising injuries.
European Commission DG TREN Final Report for Publication
- Conduct experimentation on enhanced crew communication (with the flight crew and between cabin crew) in accident/incidents and precautionary situations (attention should be paid to the crew organisation and communication means).
- Conduct research work on the improvement of the passenger safety information delivery process (safety objectives, media and timing).
- Conduct experimentation on cabin crew location significance (special attention should be paid to panic mitigation and passenger flow redirection).