EUROCAE ED‐300 PDF

Assessment

The assessment is as generic as possible in order to remain valid and useful for as much of the industry as possible. However, a balance has to be struck because a certain level of detail is required to conduct a sensible analysis. This has meant that certain details of the VTOL aircraft architecture and its operations will be specified in order to allow the analysis to be produced.

Generic VTOL Type

Based on information from the Vertical Flight Society, the generic types of VTOL aircraft can be broken down into the following three types:

• Vectored Thrust (tilt-wing or propeller, same propulsion system for hover and cruise)

• Lift & Cruise (wing but two different propulsion systems for hover and cruise)

• Multicopter

For this first issue of the guidance, a generic example of a vectored-thrust type VTOL aircraft with an Electric / Hybrid Propulsion Systems (EHPS) has been considered. It is expected that at a later date this document can be expanded to highlight key differences when considering the other two types.

Certification Baseline

The certification baseline defines some key inputs for the VTOL safety analysis. This document is based on the following:

• VTOL will be certified to SC-VTOL-01 Issue 1 (ref.2) (i.e., no remote piloting capability, so including onboard flight crew)

• VTOL aircraft category is “Category Enhanced”

o Aircraft is intended for operation over congested areas or for Commercial Air Transport operations of passengers.

o This drives the most stringent requirements. Future versions of this document could highlight the differences for Category Basic.

This means that EASA’s MOC SC-VTOL (ref.3) is also applicable and particular attention is paid to MOC VTOL.2510. A full list of extracted requirements from SC-VTOL and its MOCs that have been deemed key for the complete VTOL Safety Assessment can be found in Appendix A. It should be remembered that MOC VTOL.2510 (ref.3) is the methodology for all safety assessments regardless of whether they are for direct compliance or for the determination of system configuration/conditions to be used for compliance to other requirements in SC-VTOL (ref.2).

The following requirements are also considered for establishing this document:

• SC E-19 EHPS - EHPS.80 (ref.7) about the consideration of the intended aircraft application for the evaluation of the EHPS failure conditions, the assumed aircraft-level devices and procedures, the consequential secondary failures and dormant failures, and multiple failures in the safety analysis to assess all failure conditions that can reasonably be expected to occur.

• SC E-19 EHPS - EHPS 350(e) (ref.7) requiring the EHPS control system in particular not to have any single failures or foreseeable failures that result in hazardous EHPS effect of catastrophic aircraft effect.

More-detailed specific inputs resulting from the above have been defined where required.

Considerations For Future Versions

The next version of this document will include the second part of the scope, i.e., the PASA, as well as checking for correctness with the references that are still draft (e.g., ED-135/ARP4761A (ref.1)).

The following list summarises the key areas identified during the creation of this version of the document that are recommended for future analysis and inclusion in updated versions:

• Same approach extended to other generic types of VTOL, particularly focusing on any key differences.

• Specify differences considering VTOL aircraft Category Basic. These will be limited to different failure severity classification.

• The hover phase which might constitute a significant part of the flight due to operational constraints.

• Further consideration of different VTOL dynamic configurations (e.g., the orientation of rotors, the active rotors).

• Extend analysis to cover other main A/C functions

• Further work on examples of detailed considerations of the Failure Conditions (FC) effects in the AFHA (e.g., crew awareness, operational & environmental conditions).