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