Agreement re Energy-Absorbing Crashworthy Seats

ABBS have an agreement with a world-leading Israeli supplier of energy-absorbing seats for armoured vehicles and offshore racing power boats. Following our approach to them, they are now developing seats for Crashworthy Urban Air Mobility aircraft (UAMs) and other light aircraft/helicopters for ABBS to sell.

The company has many years of experience in designing energy-absorbing seats with a focus on ergonomic designs and the very best protection levels against high-G loading scenarios which can cause spinal injuries.

The crashworthy seat for the UAM aircraft will weigh less than 6.5 kg with an exceptional patented energy absorbing mechanism to protect against the rapid deceleration created during a hard landing or crash. The seat will be manufactured from advanced materials using a unique manufacturing process that the company developed in-house.

Design and appearance are just as important to the company as the effectiveness of the technology so it has partnered with a world-renowned designer for BMW, Fiat, Ferrari, Maserati, and McLaren to combine his deep understanding of the mobility industry with their unmatched technology for energy and impact absorption.

ABBS will be able to offer these seats both as part of our Advanced Blast protection system for vehicles, and as part of our Zero-Zero Safety System for eVTOL aircraft.

AVCP - Zero-Zero Safety System Stroking Seats

 

This arrangement was instigated by ABBS following our involvement with the EUROCAE/EASA eVTOL Safety Committee, where ABBS personnel are currently responsible for drafting the Certification Standards for the Crashworthy Seats which will probably become a standard fit for these aircraft in due course.

In recent webinars both NASA and the FAA representatives have all been assuming that Stroking Crashworthy Seats will be an essential part of the whole aircraft safety systems, although they may not be mandated. We have proposed mandating stroking seats for these aircraft to EASA because they are the very best and simplest means of protecting the occupants from spinal injuries but the CAA, EASA and the FAA are all reluctant to tell the aircraft designers how to achieve the required results because they say it could inhibit innovation. This is a potentially valid point in some areas of technology but it becomes a strange position in our view when passenger safety is critical to the success of these eVTOL aircraft.

One issue is that stroking seats have previously been used primarily in military helicopters and are therefore designed to work with the normal range of ‘standard military adults’ weighing from about 60kg to 110kg. The fact that children and smaller adults, plus obese adults heavier than 110kg will be using these aircraft means that a wider range capability is ideally required. This is where the unique and patented energy absorbing mechanism developed by the Israeli company will pay dividends in due course, especially as we can guide the certification standard draft towards the ultimate capability of the mechanism. This is not to say that other mechanisms cannot provide the same performance, but they will probably be heavier and more complex than our solution.

This is going to be a medium to long term contributor to the development of the ABBS business, but it is an important niche to be in as it goes very well with the AVCP Zero-Zero systems as another part of the whole eVTOL Aircraft Safety Suite.


eVTOLS - EASA Publish Study on the Societal Acceptance of Urban Air Mobility in Europe

EASA (the European Union Aviation Safety Agency) has now published the outcome of a study into how acceptable Urban Air Mobility (UAMs) will be to members of Society across Europe.

The study focussed on 4 cities across the EU which had been identified as the potential target markets for Urban Air Mobility; focussing on drones and manned eVTOL aircraft; specifically looking at five different groups of vehicles:

  • Passenger transport (such as air taxis and flying an emergency doctor to the site of an accident)
  • Delivery drones
  • Civil surveillance and monitoring (such as assessing the extent of fires and accidents)
  • Police surveillance
  • Use for providing signal emitters for multimedia applications or intenet access

Whilst infrastructure was seen as the main challenge for the industry, safety was the next biggest perceived challenge.

Challenges faced by eVTOLs and other UAMs

From the point of view of how acceptable eVTOL aircraft would be in an urban environment, safety was also seen as a major concern and came out just slightly behind the issue of noise from the aircraft. Indeed the main concern for potential users was noise and safety.

Socially Acceptability Challenges

The report also considers the views of governments, public institutions and regulators; where the focus was said to be the public good, and safety of the public above other factors.

Interestingly, the report suggests that eVTOLs could achieve the same level of safety as aviation did within the EU during 2018 (0.01 fatalities per billion passenger kilometers).  It was however, recognised that air taxis pose a potential safety threat not only to the passengers using them. Pedestrians will be affected by drones and air taxis, despite not necessarily choosing to use them themselves, and so the hypothesis was that the perceived safety of pedestrians will have a significant impact on the societal acceptance of drones and air taxi operations.

To some extent, the concerns over safety are reduced in the report, as it recognises that “Respondents often took for granted that safety would be guaranteed by authorities that authorise them to fly. Therefore, safety was not mentioned very often as a key concern”.  The report also goes on to say that “One reason for this is that the perception of the safety dimension might be underrated in this survey as people are used to and expect high safety standards when it comes to aircraft.”

The report later concludes that whilst a high safety bar may lead to significantly higher costs for the business cases of the companies in the eVTOL field, safety is not a dimension where a business trade-off is acceptable in society.  “Even a low number of accidents such as seen for autonomous cars can quickly cause a deterioration of public perception, thus the highest standards should be applied to UAM to foster its acceptance”.

The full report can be read on the EASA website.

How can ABBS provide eVTOL Companies with the Necessary Solution

ABBS offers a full Zero-Zero Safety System for eVTOL Aircraft which uses a series of parachutes, rockets, crashworthy seats and airbags to ensure that in an emergency eVTOL Aircraft can be landed without serious injury to the passengers or pilot.

This will ensure the highest standards for UAMs / eVTOL aircraft, as it means that crashes are survivable, even during the vertical take-off and landing stage; when the aircraft are most at risk from engine failure and/or bird strike.


Crowdcube Funding Pitch 2021

The Crowdcube Funding Pitch is now open and investment at the link below:-

https://www.crowdcube.com/companies/abbs-1/pitches/qD0KEq

There have been quite a few updates and progress since the last round in October, so we hope to welcome you onboard this exciting journey.  There is plenty to read about on the pitch deck and updates to whet your appetites and show how ABBS aims to make a real difference in protection for occupants of both land vehicles and eVTOL aircraft.

So why not Join Us and Save Lives

Investments of this nature carry risks to your capital. Please Invest Aware.


Forthcoming Funding Round Update

As a reminder, we will soon be launching a new funding round on Crowdcube as we move towards commercialisation of our offerings.  If you are interested in finding out more, then you can pre-register your interest via the dedicated Crowdcube page (capital at risk as always)

Crowdcube are still coming back with final questions on the due diligence before the new pitch can go live but we are nearly there I think. Part of the problem is that there has been a succession of new developments that we want to get into the pitch so we have had to update it twice, which means new questions from Crowdcube each time. Hopefully we should be able to get the pitch live next week.

Brief Update on Progress Since Last Fundraising Round

Blast Test on the Hilux Belly Plate Design

Following the complete failure of the first test using the 6mm thick main belly plate last year we have now successfully tested a modified version using exactly the same 6mm plates which failed last time. A very heavy 6kg test on a jig (heavy because of the ground conditions) gave about 230mm deformation without penetration, whilst a 4kg test gave only 50mm permanent deformation at the back face, with a jump height within the performance limits of stroking blast seats.

The jump height of the 6kg test was far more than blast seats could mitigate so whilst we could deal with the penetration threat with 6kg it would need the active Linear Rocket Motors to control the jump height which could make the system too expensive for many light vehicle applications.

So the emerging conclusion is that we have a 4kg capable solution, which we believe is considerably better than current options, probably twice what anyone else has achieved on such a light vehicle.

Furthermore, we now have good data on the novel combination of elements we have used in this belly plate design, which will be further elucidated during the current UK MOD DSTL/DASA test programme which will be completed over the next 2 or 3 months.

We think that we have discovered a potentially patentable combination of design elements that have not been used together before and they may provide a desirable mixture of both shock attenuation and reduced deformation/weight, albeit in a more complicated structure than a plain sheet of armour steel.

This may prove ideal for use with larger armoured vehicle designs, particularly combined with the active Linear Rocket Motors.  We will see what the market thinks about it.

Global Marketing Channel Development

There has been extensive development of the global marketing channel and strengthening of the ABBS team since the first Crowdcube round nine months ago. We now have strong representation covering the whole Asia-Pacific region via a new recruit to the Team, Steve O’Connor (based in Singapore), with specific agreements either in place or being discussed for Japan, South Korea, India, Pakistan, Turkey, South Africa, many ex-French Colonial countries in North, West and East Africa, and options for the UAE and maybe Saudi Arabia. There is  already our existing operation in the USA of course.

Our new agents in India and Turkey are being very pro-active and have had good responses from their key targets which we are following up and there are potential joint manufacturing operation opportunities in both these locations, as there is in the Middle East.

The eVTOL Zero-Zero Safety System

There has been a real, game-changing breakthrough in this market via a proposed agreement with another major US player in the market. No more information to release at this time but the deal should be signed and sealed within the next two weeks.

We have also been approached by a local UK eVTOL project looking to start a programme to demonstrate the effectiveness of a Zero-Zero safety system on their aircraft if their funding from a Stock Exchange listing comes through.

These two items match beautifully together.

US Army/Pentagon Project Proposal

Again, we can’t say much, only that a major proposal has been made (not by us) for a significant, long term development programme relating to the land vehicle protection system.

New Enquiry for Blast Protected Containers

We have received an un-solicited proposal for blast proof containers.  This is something we know well in terms of the technology used currently, and there is direct read-across from the vehicle belly plate design described above. This could either come to nothing or it could become a major new development line for a standard, high volume product using our existing technology, so it will be interesting to see how it develops.

BFBS Video on You Tube

In case you haven’t picked it up yet, the British Forces Broadcasting Service video at https://www.youtube.com/watch?v=R5sbBKdftNQ has now had over 768,000 views since 11th January, and has raised a lot of interest, including that from the Pentagon. Excellent free publicity potentially leading to major funding for development, which can’t be bad.

New Products From Other Suppliers Added to Our Product Portfolio.

  • We have an agreement with an Israeli supplier of armoured vehicle blast seats to develop at their own cost crashworthy stroking seats for use in eVTOL aircraft and they have now appointed someone to oversee the design and development of this product specifically for the eVTOL industry. These seats will be offered to the market as an integral part of our safety package.
  • We are in the midst of agreeing heads of terms for the supply of a novel fire resistant prepreg for battery boxes for eVTOL’s and other fire-resistant applications on the aircraft from an associated UK prepreg manufacturer.This new prepreg type is much better than the current standard phenolic prepreg systems which are unpleasant to use due to the toxic ingredients in the material.Containing fires in the very large battery boxes used in the eVTOL’s is a serious issue, and this material has already been certified for use in the application. We may also supply other products in the supplier’s prepreg range for other applications in other markets.


Importance of an Emergency Descent Arrest System for eVTOL Aircraft

Emergency Descent Arrest Systems (also known as Ballistic Parachute Recovery Systems) are an essential element when it comes to aircraft safety.

In the event of an emergency, such as a bird strike or power failure, a parachute system can be deployed which helps to land the aircraft safely.

The large parachute required to provide a 10m/s landing cannot be opened fully at cruising speed because it would tear the aircraft apart.

Hence a ‘slider’ is used to slow the parachute opening.

The second video shows the slider being operated in more detail.

As you can see from these videos, the result is a rapid drop of the aircraft of at least 300 feet for about 12 seconds before the parachute is fully deployed and can provide a survivable landing.

This provides a 300ft “Safety Gap” where the system doesn’t provide protection.  This is literally a fatal flaw in the concept when it comes to eVTOL aircraft where the greatest risk is during the vertical take-off and landing phases of the flight; where the aircraft – are very vulnerable to any power or control problem, or any Foreign Object Damage from anything thrown up by the downwash during landing.

Why is the Vertical Take-Off and Landing Stage so Dangerous?

The lack of forward momentum substantially reduces any lift effect provided by fixed wings; as well as the additional stress and strain on the pilot and engines alike caused by the vertical phase.

By way of illustration, the Harrier accident rate is 10X that of conventional fighter aircraft.  The following videos show how dangerous an emergency during the vertical take-off or landing phase can be.

 

The AVCP solution to the Safety Gap Problem

The AVCP Zero-Zero system provides a solution to the Safety Gap by using retro-rockets to control the descent rate.

  • The worst case potential descent rate is 25m/s, controlled by a small drogue parachute which can be deployed at maximum aircraft speed.
  • The retro-rockets are designed to reduce the descent rate by 15m/s.
  • The crashworthy stroking seat plus airframe compliance can deal with the remaining 10m/s descent rate in the worst case scenario

A more detailed analysis of competing Emergency Descent Arrest Systems and the issues surrounding them appears in our White Paper which we submitted to EASA / EUROCAE

More details on the AVCP solution appear on our website


CrowdCube Funding Pitch Coming Soon

Why are we launching a new crowdfunding round?

We will soon be launching a second funding round on CrowdCube.

Whilst the focus for the original funding was on continuing the development and marketing of our unique solutions for mine and IED threats to vehicles, there have been a number of significant technical, product, and marketing developments which provide real opportunities for bringing other ABBS group products to market.

These new opportunities are all related to our basic mission to save lives and prevent serious injuries in situations where to date fatalities have been considered inevitable.

Wider Global Marketing of the Armoured Vehicle Technology

As a result of the previous interest through CrowdCube and also our appearance on Forces TV (which had over 700,000 views); we have received a substantial number of new contacts globally interested in either using or marketing our technology in the armoured vehicle sector.

This has enabled us to establish good coverage of immediate potential in Africa, the Middle East,India, Pakistan and the Asia Pacific regions where current conflicts mean that mine and IED threats regularly cause casualties.

Hence, the belly plate programme for the Toyota Hilux, which is expected to lead to first sales later this year, is already demanding increased marketing and technical support in these regions. Marketing to a number of interested operations in Africa and the Middle East is only awaiting the results of our final Hilux proof-of-concept test which is now expected to be in early April.

The Hilux belly-plate design has become more sophisticated than originally envisaged in order to optimise both the performance and weight. Much FEA (Finite Element Analysis) of the structure has been undertaken to optimise the design, prior to multiple jig testing (due at the end of March) to prove the design, followed by the full Hilux test in April.This has been a complex design to optimise, especially as the FEA cannot be completely relied upon to give 100% correct results under the extreme blast conditions. Therefore, multiple series of tests are required to demonstrate the suitability of the different options. These include both static and drop testing of various reinforcing beam constructions to identify their relative effectiveness, followed by finally proving the optimal solution by the more expensive full scale blast tests.

Increased eVTOL Market Products and Activity

The development of the Active VTOL Crash Prevention Limited (AVCP) Active Zero-Zero Safety System which was originally designed to use a combination of a large parachute and retro-rockets has been on the back burner for the last 18 months because of the lack of funding to pursue it.

However, a new development has simplified the system concept and new products becoming available has brought forward the need to re-start marketing of the concept, and the new products, as follows:

Stroking Crashworthy Seat Supply and Simplification of the Zero-Zero System.
AVCP has obtained a supply of stroking crashworthy aircraft seats which provide protection from spinal injuries in a crash. The availability of stroking seats has enabled the simplification of the eVTOL Safety System by removing the large parachute and replacing it with a small drogue which can be deployed at any aircraft speed.

The aviation regulators are insisting that these aircraft must be crashworthy by themselves, and hence must be designed to take a 10m/s landing without serious injury to the occupants, and stroking seats are a normal part of the design to achieve this.

Hence, we can now change our concept by:

  • Reducing the size of the parachute to a small drogue which can be opened fully at any aircraft speed, and which controls the aircraft descent rate to 25m/s and also maintains a level aircraft attitude during the descent.
  • Using the retro-rockets to reduce the aircraft descent rate from a maximum of 25m/s to 10m/s on landing, which is then dealt with mainly by the stroking crashworthy seats.

The result of these changes is that the whole system becomes lighter, cheaper, and simpler to design and install on aircraft and certify for service.

This development on its own is enough to justify renewed marketing activity for the concept, but the addition of the stroking seats to the product portfolio can potentially provide earlier sales than the main system itself, and there is also another product that may generate short term revenue whilst requiring no significant investment in R&D.

Fire Resistant Prepreg System for Battery Box Fire Containment and Cabin Components.
ABBS is has entered an agreement to distribute a novel prepreg composite system which has exceptional fire resistance. This has already been certified for use as a battery fire containment system for eVTOL aircraft and is being evaluated for similar use in road vehicles. It can also be used for aircraft/rail/road transport cabin interior and firewall applications.

This composite material has excellent Health and Safety and ‘green’ credentials, unlike the phenolic resin system generally used for these applications to date, which has serious toxicity and skin irritation problems and is currently being phased out of use where possible.  The resin is made from a waste product from processing sugar or other organic materials.

The UK-based manufacturer of this prepreg is owned by ex-Advanced Composite Group personnel with whom Roger Sloman has a strong relationship; and an agreement has been reached to allow ABBS to develop a joint global marketing exercise to maximise the exploitation of the potential that exists, based initially on the strong position that AVCP has in the worldwide eVTOL market.

EASA/CAA and FAA Philosophy on Aircraft Safety
It may come as a surprise to the un-initiated that the regulations on crashworthiness of aircraft only deal with ‘survivable’ crashes, and no attention is given to ‘un-survivable’ accidents, which for helicopters is anything over a descent rate of 9.1m/s (30ft/s). This 9.1m/s descent rate is chosen arbitrarily as being the design criterion that the aircraft must meet and keep the G levels experienced by the occupants to safe levels. Any descent rate higher than this is deemed ‘un-survivable’ although there are many examples of higher descent rate helicopter accidents where occupants have survived with only relatively minor injuries due to the use of stroking crashworthy seats.

Hence you might imagine that the regulatory bodies would mandate the use of stroking seats, and we have proposed this to EASA, but as a matter of principle they prefer to leave the aircraft designers to adopt whatever solutions they want to meet the overall G-level targets.

So, by limiting the crashworthiness design criterion to a 9.1m/s Ground Impact Velocity (GIV) the authorities currently ignore the potential to provide protection above this 9.1m/s rate, which we strongly reject as a limit, and we are pushing EASA to re-consider this position.The whole point of our Zero-Zero system is that it is the only physically possible concept that is capable of providing full protection from any descent rate up to 25m/s, which we plan is the maximum that any aircraft will attain under the small drogue parachute in our system. Hence as far as eVTOL’s are concerned we believe that adopting our Zero-Zero system means that essentially there should be NO LOSS OF CONTROL OR POWER LOSS eVTOL ACCIDENTS THAT ARE NOT SURVIVABLE.

In due course we will propose to EASA a new standard based on our system which will provide full protection in a 25m/s descent rate scenario. Since safety is universally agreed to be critical if the eVTOL market is going to attain its full potential, we believe that in due course the validity of the AVCP approach will eventually be recognised, but it may take a few serious accidents that kill or injure people for the industry and the certification authorities to accept it. In practice it may actually be the insurers and relevant city authorities who bear some financial responsibility for the risks that drive the market to this conclusion.

AVCP is currently the only company proposing ‘another way down’ that realistically deals with essentially all the emergency loss-of control scenarios that eVTOL’s will experience that result in an excessive GIV.

The EASA (European Aviation Safety Agency) is soon to publish its first guidance on the use of parachute recovery systems for aircraft.  This will tie in with the forthcoming EUROCAE guidance for Installation of Emergency Descent Arrest Systems on eVTOL Aircraft, which AVCP is responsible for drafting.

As such, now is the key time for ABBS to promote its safety solutions for eVTOL aircraft to the industry and get buy-in from the designers and manufacturers of the aircraft, showing how we can help ensure that practically almost all crashes are survivable.

Both the updated eVTOL Safety System and the new prepreg composite system offer excellent opportunities to establish these products in those parts of the global marketplace currently unaware of them, based on our existing eVTOL market contacts and presence.  We therefore need to ramp up the global marketing of our eVTOL Safety Systems to take advantage of these major opportunities.

Bringing Products to Market

The prepreg composite system has already been certified for use as a battery fire containment system for eVTOL aircraft and is ready to be marketed to eVTOL aircraft designers both as an improved means of protecting the aircraft from battery fires, and for interior panels and components.

Given satisfactory results from the forthcoming Hilux blast testing it is expected that current interest in the solution will result in specific enquiries and sales starting in 2021. Some further development may be required to produce a complete kit for the vehicle which is likely initially to include stroking blast seats, while an active floor system could be a later addition. Also, if required by the customers a form of active impulse counteraction to reduce the jump height/global acceleration level could be developed based on current ABBS knowledge.

The stroking crashworthy aircraft seats will require specific design by our seat supplier to take account of the characteristics demanded by the eVTOL aircraft manufacturers.  These will therefore take a while to bring to market, dependent on the design considerations and regulatory pressure. Again, AVCP is responsible within the EASA/EUROCAE committee framework for drafting a new certification standard for stroking seats for eVTOL’s.

Appointment of KBS Corporate to Pursue Deals with Major Industry Players

Finally, the ABBS Board has decided that the operation has reached the stage where it is deemed appropriate to explore the potential for deals with major aerospace or defence Groups.

  • Specifically, the AVCP Ltd. eVTOL Safety System may be good candidate for a JV or a partial buyout/buy-in by a large aerospace company which has a stroking seat manufacturing operation, and this will be the early focus of the activity with a handful of the obvious potentially interested parties.
  • Equally, given the successful testing of a 6kg-capable belly plate system for the Toyota Hilux there is expected to be a surge of interest later this year from major defence-related operations, and we need to be prepared with options identified and evaluated if this happens.

Hence, we have decided to engage KBS Corporate to prepare fully professional approaches to identified major industry players and assist ABBS in considering any resulting options. Our emphasis will be on generating potential buy-in scenarios, initially for the full Zero-Zero eVTOL safety system, and then later for the armoured vehicle technologies rather than any full buy-out scenarios which would compromise any recent investments under the EIS scheme. Maximising the longer-term returns for our shareholders is always our primary objective.

Join Us to Save Lives

Please sign up to express your interest in investing in this round.  Investments of this nature carry risks to your capital. Please Invest Aware.


Emergency Descent Arrest Systems (EDAS) for VTOL Aircraft (Draft White Paper)

Introduction:

Whole airframe recovery parachute systems have made impressive advances in safety for general aviation aircraft for nearly four decades: thousands of systems have been put into service, and over 500 lives saved with this technology. The problem is that a conventional ballistically deployed airframe recovery parachute system will not work effectively in a VTOL environment due to lack of forward speed and dependence on altitude-loss to inflate the large parachute canopy required to provide a maximum 9.1 metres per second. Ground Impact Velocity. Only recently have new technologies been developed to address the typical shortcomings of traditional recovery systems (particularly the low-altitude limitation) and several new options now exist which deliver enhanced Emergency Descent Arrest Systems (EDAS) performance, reducing ultimate ground impact velocities (GIV), potentially to the level of a soft landing (1-2 metres per second) and improving overall occupant safety, even in the vulnerable VTOL phase of flight.

Typical flight operations for rotorcraft (such as helicopters and multi-rotor electric VTOL aircraft), especially in an advanced or urban mobility context, can involve significant flight-time in hover (with little or no forward velocity), quite unlike general aviation aircraft which require a traditional runway for take-off and landing. Moreover, electric VTOL platforms (often with high-velocity / low-mass / low-momentum lift fans) can lack the capability to flare, autorotate and arrest an emergency (vertical) descent: for example, a ducted fan is incapable of producing the necessary lift during an attempted autorotation. Without an EDAS, critical loss of thrust or control results in occupant protection within the descending rotorcraft (in common with all aircraft types) being entirely dependent on the Landing Gear/Skids, fuselage Sub-Floor and the Seats, working together as a system to mitigate the landing effects on the occupants. Collectively these elements are designed to dissipate energy from a crash event and reduce some of the significant G loads on the occupants. Whole airframe parachute recovery systems are designed to reduce loads at touchdown to below the aircraft certification limits: this level may be injurious but should allow the occupant to self-extract from the aircraft to safety.

There are several considerations in the design of today’s rotorcraft including the emerging VTOL vehicles designed for advanced/urban air mobility (AAM/UAM). With UAM aircraft designed for predominantly multiple short-hop flights, this means a higher number of take-offs and landings per day than traditional rotorcraft or aircraft, and increased workload for crew, the airframe and the lift/propulsion systems. Typically, low-altitude operation exposes the VTOL aircraft to greater bird density (compared with general aviation) and therefore higher risk of bird strike to the VTOL aircraft. Any of today’s VTOL aircraft may consider the following measures to arrest the emergency descent of an aircraft:

1. Reserve Power

Reserve Power supply and lift/thrust options can be designed into the aircraft to enhance reliability during all phases of operation, and especially to cater for a controlled emergency landing if the main power supply/propulsion system fails.

Whilst this architecture can address a main engine failure and enable a controlled landing, reserve power does not overcome loss-of-lift (for example from a catastrophic bird strike event and/or rotor blade damage), and can add significant additional weight (motor + power source) to the airframe.

2. Emergency Descent Arrest System (EDAS)

 

Deployment of a Ballistic Parachute Recovery System from a light aircraft

EDAS solutions can mitigate a loss of main lift propulsion on the aircraft, reducing Ground Impact Velocity (GIV) in a crash, and enable a survivable emergency landing (in terms of GIV). Single lift/thrust unit failure/malfunction should not affect the continued safe flight and landing of the VTOL aircraft [VTOL.2510], and EDAS activation and deployment would not be anticipated to result from a single lift/thrust unit failure/malfunction. Multiple lift/thrust unit failures/malfunctions could affect the continued safe flight and landing of the VTOL aircraft, and so EDAS activation and deployment could be anticipated to result from multiple  lift/thrust unit failures/malfunctions.

From a brief consideration of emergency/crash landing scenarios, deployment of the EDAS should not impede operation and control of the installed lift/thrust system [VTOL.2430]. Descent and landing under EDAS should remain within Limit Loads for the VTOL aircraft structure [VTOL.2230]. EDAS should not impede conduct of a controlled emergency landing (Category Basic) nor continued safe flight and landing (Category Enhanced) following bird impact(s) [VTOL.2250]. Following an emergency landing, the EDAS (whether activated or not activated) should not obstruct means of egress/exits [VTOL.2315] nor present an injury hazard to occupants during their egress from the aircraft [VTOL.2270].

Considering aircraft design performance, single-mode failures in the EDAS should not result in catastrophic failure of the VTOL aircraft
[VTOL.2510], and in-service monitoring (built-in-test) in the EDAS sub-system can contribute to functional reliability of the aircraft [VTOL.2510(c)]. Reliability and the expected Functional Performance of the EDAS should be included in determining the Function Development Assurance Levels (FDAL) for a VTOL aircraft with flight crew on board [VTOL.2510].

EDAS maintenance should support the ensured Continued Airworthiness of the VTOL aircraft [VTOL.2625] Limit and Ultimate Loads on the VTOL airframe induced by the deployment of an EDAS system shall be determined [VTOL.2225, VTOL.2230]. Operation (intended or fault) of the EDAS should not generate high-energy fragments [VTOL.2240]. The EDAS should not present a risk of fire to the VTOL aircraft, with the EDAS sub-system designed to withstand crash load factors per MOC SC-VTOL, and its crash resistance demonstrated by drop testing [MOC VTOL.2325(a)(4)].

What Emergency Descent Arrest Systems Exist?

There are multiple EDAS solution pathways. Each of these EDAS concepts add weight to the airframe, and can recover the entire aircraft to the ground with a survivable touch-down condition. Some of these EDAS solution
pathways are outlined below:

Whole-Aircraft Emergency Recovery Parachute systems can deliver a survivable landing, usually at 7 to 10metres per second GIV, following critical loss of thrust and/or loss of control; these parachute systems are designed to recover the entire aircraft, including airframe and occupants, to the ground in an emergency. Attached by harness straps to hard-points on the aircraft fuselage, the parachute is usually deployed by the action of a manual emergency handle in the cockpit, which triggers the parachute extraction sequence.

Ballistic Parachute Recovery Systems applied to Light Aircraft and Rotorcraft, reported for Ballistic Recovery Systems Inc. (BRS) (left), Galaxy Rescue Systems (GRS) (centre) and Curti Costruzioni Meccaniche S.p.A. (right)

Ejection of the parachute can be accelerated with the release of stored-energy, for example using compressed gas or a (chemical propellant) tractor rocket: these Ballistic Parachute Recovery Systems are in manufacture and in service on light aircraft worldwide (for example the one from Ballistic Recovery Systems Inc and another from Galaxy GRS).

Ballistic Parachute system weights (for light aircraft) are typically 75-100lbs (35-45kg), some achieving a descent velocity of c.7.0 to 7.5 metres per second. Given the time required for the ballistically-ejected parachute canopy to inflate (often constrained by a Slider to limit the shock loading on the airframe structure), parachute-based recovery systems can have a low-altitude limitation ranging from at least 100-feet (33-meters) through 450-feet (150 meters) to 600-feet (200 meters) in the case of aircraft engine failure.

Recovery Parachute deployment can be further accelerated through the use of multiple small parachutes, reducing the inflation time (and reducing low-altitude limitation). Developing multi-parachute systems include the Galaxy GRS Robur system, with distributed small parachutes achieving unmanned platform descent rate of c.7.5 metres per second.

Aviation Safety Resources (ASR) combine multiple ballistically-extrcted recovery parachutes with a retro-rocket effector to slow the descent in its Xtreme Rapid Deployment (XRD) vehicle recovery system. Having been deployed on a tether from the airframe with the parachutes, the XRD retro-rocket continues to produce thrust and deliver lift to the aircraft to prevent it acquiring a high descent rate whilst the parachutes inflate: this reduces the minimum deployment altitude c.100ft/33m.

Multi-Parachute Ballistic Recovery System with Retro-Rocket System from Aviation Safety Resources

The EDAS concept from Active VTOL Crash Prevention (AVCP) Ltd. further extends the role of a Retro-Rocket system, with an actively-ejected small drogue parachute (which can be launched over a broad aircraft speed range) stabilising the aircraft attitude and limiting the maximum descent rate to 25 metres per second, with a twinned, rotating, self-extinguishing solid rocket motor system delivering emergency lift during the final 15m to 5m of the descent to the ground. The altitude at which the motors are fired is dependent on the weight and the current descent rate of the aircraft.

 

On landing, the AVCP system rotates the rocket motors so that the initial vertical thrust switches to a horizontallyopposed orientation: this prevents excess thrust lifting the aircraft off the ground again, especially in the case of lower descent-rate incidents where only a proportion of the total motor impulse is required. An automatic carbondioxide quench system ensures the rocket motors are fully extinguished on landing, and cools the motor casings to prevent fire and avoid a hazard to egress from the aircraft.

Emergency Descent Arrest System using Rocket Motor Lift Effector cassette, from Active VTOL Crash Prevention Ltd.

Basic airframe crashworthiness standards (FAA and EASA) of either 9.1 metres per second or 10 metres per second are expected, effectively including a free unpowered fall from 5m altitude (resulting in a 9.9 metres per second GIV): with a qualified (stroking) energyabsorbing seat system in the airframe, a worst-case free-fall emergency from up to 5m altitude could be addressed if a 10 metres per second criterion is adopted for basic airframe crashworthiness.

The AVCP system is designed for activation at any operational altitude above 5m for launching the drogue parachute and extracting the rocket motor system, with the rocket motors only fired within a 5m-15m altitude initiation zone if the descent rate (possibly still influenced by the aircraft rotors providing partial lift) is greater than 9.1 metres per second. Once the rocket motors are initiated and full thrust confirmed, power to the aircraft rotors is cut to avoid the combined upward thrust lifting the aircraft again.

In a worst-case design scenario of a 25 metres per second descent rate, when the motors are fired the baseline-weight version AVCP system (which is designed to reduce the descent rate by 15 metres per second) will reduce the GIV to less than 10 metres per second.

If residual aircraft rotor lift is available (so that the stable descent rate is less than 25 metres per second) the baseline motor system will reduce the GIV to a level below 10 metres per second by reducing the descent rate by 15 metres per second.

With a descent rate of 15 metres per second (or lower) the baseline AVCP system will enable a soft landing (1-2 metres per second) by selecting the correct height for firing the rocket motors, dependent on the aircraft weight and current descent rate.

The AVCP system is designed to eliminate the altitude limitation Safety Gap, and ensure (as far as possible) that there is no ‘un-survivable’ descent rate for a (essentially) vertical emergency descent situation, where additional lift is not provided by fixed wings or other means.

A further development could use retrorockets capable of providing a soft landing (1-2 metres per second) from an assumed worst-case aircraft descent rate of c.25 metres per second and zero lift from the aircraft rotor(s), albeit with additional rocket motor size & weight.

Consideration of survivable landing loads / GIV data

EDAS arrest of the VTOL emergency descent should contribute additional margin to the currently-defined acceptable aircraft loads during Emergency Landing conditions [MOC VTOL.2270(a) and (c)], through the reduction in ground impact velocity (GIV) on landing.

Likewise, EDAS arrest of the VTOL emergency descent should contribute additional margin to the loads experienced by aircraft occupants during Emergency Landing conditions [MOC VTOL.2270(b)(1)]. From a rotorcraft basis, CS 27.562(b)(1) Amdt. 6 also notes downward velocity of not less than 9.1 metres per second (30 feet per second) and deceleration of 30g within 31 metres per second at seat attachment level, based upon the typical underfloor structure of a conventional rotorcraft.

CS 27.561(b)(3) Amdt. 6 notes ultimate inertial load factors on the occupant relative to the surrounding structure: Upward 4g / Forward 16g / Sideward 8g / Rearward 1.5g / Downward 20g (after intended displacement of an energy-absorbing seat device). From a normal aircraft basis, CS 23.2270 Amdt. 5 simply requires the aircraft, even when damaged in an emergency landing, must protect each occupant against injury that would preclude egress. Emergency landing conditions must include dynamic conditions that are likely to occur in an emergency landing; and must not generate loads experienced by the occupants, which exceed established human-injury criteria for human tolerance.

Analysis of civil and military rotorcraft incidents shows vertical impact velocities up to 70 feet per second (21.2 metres per second) with mortality rates showing a marked increase from GIV levels of 9.1 metres per second (30 feet per second) for conventional rotorcraft, and from GIV of 12.1 metres per second (40 feet per second) for crashworthy military rotorcraft18, 19. Modern military rotorcraft have demonstrated hard landing impacts up to 6.1 metres per second (20 feet per second) with no injury to occupants, and little or no damage to the aircraft; similar impacts for civilian helicopters routinely resulting in serious occupant injuries and significant airframe damage.

Cumulative frequency plot of mortality rate vs. vertical impact velocity for conventional (UH-1) and crashworthy (UH-60) helicopter designs [from Shanahan]

FAA analysis of Rotorcraft accident data, US military& US civilian operations [from Pellettiere & Taylor]
EDAS arrest of the VTOL emergency descent should also contribute additional margin to the baggage compartment design [MOC VTOL.2270(e)].

Addressing the EDAS Safety Gap

These three EDAS concepts (reserve power, whole-aircraft recovery ballistic parachute systems, and parachute ballistic recovery with retro-rocket systems) clearly have differing design approaches and performance capabilities, which complicates the definition of a single objective EDAS standard for the VTOL Urban Air Mobility / Advanced Air Mobility (and light aircraft/helicopter/gyrocopter) industries to work towards.

The first differentiation factor is the altitude at which the EDAS system becomes effective, the ‘Safety Gap’ inherent in a descent-arrest system concept. This Safety Gap is a clear concern, and can discount the use of conventional ‘Ballistic Parachute Recovery Systems’ where they are not fully effective during the VTOL aircraft flight envelope when they are most vulnerable to any loss of power or control, i.e. the VTOL phase.

The Safety Gap aspect is a primary discriminator between the three EDAS system concepts currently identified.

Actual ground impact velocity (GIV) that any system delivers could be used as a secondary discriminator. Clearly there is some advantage if all emergency descents could result in a soft landing, minimising injury to occupants and damage to the aircraft. Currently, any integrated engineering design must only meet current ASTM requirements in order to produce a survivable touchdown condition.

Categorization of Emergency Descent Arrest System (EDAS) solutions

In conclusion, there are four EDAS categories that could be considered:

  1. current conventional Ballistic Parachute Recovery System types, with a c.300+ feet Safety Gap and GIV controlled to a maximum of 10 metres per second
  2. rapid Deployment Vehicle Recovery System such as the ASR system, with a c.100 feet Safety Gap and GIV controlled to a maximum of 9.14 metres per second (30 feet per second)
  3. such as the AVCP and ASR systems with no Safety Gap due to operation from >5m altitude (integrated with the airframe/seat system, for aircraft crashworthiness addressing a 9.14 metres per second GIV)
  4. such as the ASR and AVCP systems with no Safety Gap due to operation from >5m altitude, and sufficient retro-rocket total-impulse to provide a soft landing from a maximum descent rate of 25 metres per second, with additional weight penalty from the increased total-impulse from the retro-rocket(s) required to achieve this.

As an airframe system to arrest an emergency descent, and the range of different EDAS approaches and design safety performance levels, it is appropriate that the VTOL aircraft designer/manufacturer/operator/insurer able to specify their EDAS system type / category choice, supported by an objective standard to which the EDAS can be certified. The capabilities and categories of EDAS system could follow a taxonomy as below:

Categorization of Emergency Descent Arrest System (EDAS) solutions, by airframe effects and deployment mechanism

 

Alongside the aircraft Altitude and ultimate GIV performances of a given EDAS solution, the Safety & Initiation Architecture of the EDAS is also considered. This EDAS Architecture category will inform the aircraft designer on the avionic & crew interface(s), functional reliability, and functional failure mode(s) of an EDAS system.

Finally, consideration is given to any energetic material content within the EDAS (for example, the tractor rocket used to eject a ballistic parachute), and its sensitivity to environmental stimuli. Energetic / pyrotechnic components are routinely fitted in military aircraft systems, and are already used in several Whole-Aircraft Emergency Recovery Parachute systems as shown above.

It remains important to consider measures to minimise or eliminate all the potential risks that an energetic system can present. Safety Design principles can mitigate un-commanded initiation of the EDAS interface, whilst insensitive munition (IM) design principles can mitigate hazards such as fragment impact and un-commanded ignition (cook-off) of an energetic/pyrotechnic component such as tractor rocket propellant.

Each category of EDAS system can then be assessed objectively within a VTOL aircraft design, both in terms of (i) operational function, safety and reliability, and (ii) in assessing the emergency landing capability (and resulting occupant loads) of the EDAS-equipped VTOL aircraft.


What are eVTOL Aircraft: Electric Vertical Take-off and Landing Aircraft

Vertical Take-Off and Landing (VTOL) Aircraft have always been seen as an ideal for military applications - they do not require a specialist runway and use less physical space and infrastructure to get into the air and land.  There is a history of various attempts to create a successful VTOL aircraft; but perhaps the most recognisable and infamous example is the Hawker Siddeley Harrier Jump Jet which first entered service with the RAF as long ago as 1969.

Of course, rotorcraft such as helicopters and many modern drones are also part of the wide range of VTOL aircraft.

In recent years, there has been a wide range of interest from aircraft manufacturers, automobile manufacturers and small start up companies in creating electric VTOL aircraft (eVTOLs) which can be used to provide a range of personal transport solutions, from air-taxis and flying cars, to emergency response vehicles.  The benefits of these eVTOL aircraft is that they are quiet, can operate with a minimum of infrastructure, and will help avoid the highly congested roadways by adding a third dimension to the daily commute.

As a result there were over 200 eVTOL projects in development in June 2019, and as of February 2021, there is growing interest, with United Airlines placing over $1 billion worth of orders for eVTOL aircraft.  Some of these projects are aiming to use autonomous technology to assist the pilot (or even remote piloting).

Whilst any autonomous vehicle will have to undergo legal regulation before it can be released to the public; the complexities in creating and regulating autonomous vehicles are numerous and it is already proving difficult to obtain proper regulation for  autonomous cars, let alone autonomous aircraft where there are fewer cues that the aircraft can use.  Further, eVTOL’s will have to develop flight plans and communicate with other aircraft, as well as take account of not only pedestrians and animals on the ground (when taking off or landing), but also complications such as overhead cables; birds; cranes and other man made structures which may appear above or below the aircraft.

Advanced VTOL Crash Prevention Limited have already identified that there is an issue over safety regulation for eVTOLs and we are already taking a key part in the formation of the EASA safety standards for Emergency Descent Arrest Systems.  To fit alongside this, we have developed our own innovative Zero-Zero Safety Systen for eVTOL aircraft to help ensure that crashes are survivable.


eVTOL Safety Standards - a Pressing Need

As the eVTOL aircraft industry moves forwards towards offering commercial air-taxi services and first responder services, there is a growing need to define how these aircraft will be safe for use within an urban environment.

Visual representation of the Air-One® site with a Hyundai Motor Group eVTOL in the centre of Coventry. Image Copyright © Urban Air Port Ltd

We are already seeing announcements of planned mini airports for electric aircraft - with Lilium currently planning to launch 10 "Vertiports" in Florida (USA) and the first UK airport for electric aircraft now announced for Coventry, but on top of this there are various companies such as General Motors, Hyundai, Airbus and Aston-Martin currently looking at personal air taxis which could take-off and land from a roof top, or even your own driveway.

Taking accident data for helicopters as a starting point, the two highest causes of accidents are Loss of Control-Inflight and System (Powerplant) malfunction, with Low Altitude Operations and Collision cited as two additional causes for accidents.

eVTOL aircraft are designed to be flown at low altitude and the lack of any (or minimal) forward momentum during the vertical take-off and landing phases means that there will be no normal lift under any wings; and no rotational effect which is used by helicopters to control emergency descents.

The strain on pilots and motors may also be much higher than for normal aircraft, due to the use of the aircraft for short-hop journeys, with many take-offs and landings per day.  Bird-strike (where the aircraft collides with a bird) is also much more common at low altitude due to the greater nuimbers of birds in flight at lower levels.

At present there is no specific certification and safety requirements for eVTOL aircraft.  As with any aircraft, before they can be used in public service, they will need an airworthiness certificate to show how they meet the relevent safety standards.

The European Union Aviation Safety Agency (EASA) has been working on the certification of such aircraft since 2018 and Active VTOL Crash Prevention Limited is part of the team formulating the EUROCAE/EASA safety standards for eVTOL aircraft with specific responsibility for drafting new standards for both eVTOL Active Safety Systems and for Stroking Crashworthy seats.

As part of this, it has become apparent that current Emergency Descent Arrest Systems designed for fixed wing and rotary aircraft will not work when it comes to eVTOL aircraft and a new approach is required.

In particular, in the NASA Langley Research Center's paper on "Challenges in Vehicle Safety and Occupant Protection for Autonomoud electric Vertical Take-Off and Landing (eVTOL) Vehicles" by Justin Littell; the author concluded that a Ballistic Recovery System should be a required piece of equipment but notes that existing systems do not advertise operation below 400 feet.

This is where the AVCP Zero-Zero Safety System comes to the rescue.


New Seedrs Fund-Raising Round

The fund-raising round on Seedrs has now been cancelled.  During the round, it became clear that many would prefer an equity fund-raising, particularly as they would still be eligible for EIS relief on monies invested.

Why not the Future Fund?

The round was a convertible loan note, fund matched by the UK Future Fund.  Unfortunately, it became apparent after launching the round that anyone who invested via a Future Fund round would not be able to claim EIS on any further investment rounds (even if they were equity rounds).

As a result, we regret that we decided to cancel this fund raising and ensure that our shareholders can continue to benefit from EIS relief.

We still require funding to maximise the new opportunities, especially for products that can provide short/mid-term revenue without any significant investment by ABBS, except in marketing costs.

1) We have a number of new contacts globally interested in using or marketing our technology which all require support.

2) The stroking seat supply has enabled the simplification of the eVTOL Safety System which also makes it much cheaper, and easier to install on the aircraft, bringing forward the need for marketing activity in the USA.

3) The belly plate programme for the Toyota Hilux is leading towards early sales which need increased marketing and technical support globally.

We therefore intend to run an equity fund raising round in the coming months; so watch out for news of this round.

You can also pre-register your interest on CrowdCube so that you will hear as soon as the new round is launched.