Many new aircraft are fitted with ‘Enhanced Vision Systems’. These systems use infra-red cameras and other technology to see through atmospheric obscuration such as fog, snow or dust so that pilots can have a view of their surroundings that isn’t available with the naked eye. Enhanced vision systems have the potential to allow pilots to make approaches in low visibility even at relatively unsophisticated airports that do not have the radio aids and infrastructure of the major international airports. This could be a particular benefit to business aviation and regional airlines. Many new business jets have the equipment installed.
One business jet manufacturer stated that 80% of the aircraft they deliver have enhanced vision systems installed but less than 1% of their aircraft operators have the necessary operational approval to take advantage of lower landing minima. EASA have now published a ‘notice of proposed amendment’ (NPA) that proposes simplified rules that would allow operators to take advantage of the capabilities of this new equipment without a complex approval process [NPA 2018-06].
The NPA introduces new terminology, aligned with terminology used by the American FAA. An ‘Enhanced Flight Vision System’ (‘EFVS’) will be an Enhanced Vision System (‘EVS’) which is certified to allow ‘operational credits’, i.e. operation to lower minima. EFVS will use a Head-Up Display so that the pilot can simultaneously view the ‘enhanced’ image and the ‘natural’ image of the environment in front of the aircraft. As well as presenting the enhanced image EFVS will display aircraft instruments, a flight path vector and cues that the pilot can use to set the required approach angle. There will be two classifications of EFVS. EFVS-A systems may be used for approach operations down to a height of 100 feet above the runway and EFVS-L systems may be used all the way to landing. EFVS-L systems will additionally provide flare cueing and height information from a radio altimeter.
EFVS Operations without approval
Aircraft operators using EFVS will be allowed to continue an instrument approach below decision height without having ‘natural’ view of the runway provided that the runway is visible on the EFVS image. For ‘EFVS 200’ operations the pilot must have a ‘natural’ view of the runway by a height of 200 feet. These ‘EFVS 200’ operations will not require a specific approval from the Competent Authority. The aircraft operator will be responsible for operating procedures and crew training, but it is expected that the aircraft manufacturers will develop suitable procedures and ensure that training is available through their training organisations. EFVS 200 operations could use both precision and non-precision approach procedures but they are expected to be most valuable at airports without ILS. EFVS 200 operations will be allowed for both Commercial Air Transport (CAT) operators and Non-Commercial (NCC) operators. Regulations for specialised operators (aka ‘aerial work’) and non-complex aircraft are still under development.
EFVS Operations Requiring Approval
In order to take full advantage of the capabilities of EFVS, operators will need to have specific approval for an ‘operational credit’ issued by the Competent Authority. An operational credit could allow pilots to use an EFVS-A system down to 100 feet above the runway without natural visual reference and to use an EFVS-L system all the way to touchdown. The visibility required will depend on the capabilities of the system. Current systems can be used in a runway visual range (RVR) of as little as 300m. Future sensor technologies may allow use in even lower visibilities. In order to obtain ‘operational credit’ each operator will need to conduct a safety assessment and develop performance indicators that can be used to demonstrate that their operation achieves the required level of safety.
Benefits of EFVS
There are currently very few operators taking advantage of EFVS but the technology has the potential to make a big difference. Airports that are constrained by runway length or surrounding terrain, or which don’t have the resources to install the infrastructure usually required for low-visibility operations, can be accessible in all weather for suitably equipped aircraft. This will be beneficial to business aircraft operators and could make regional airline services viable to new destinations. It is expected that innovations in sensor and display technology will continue to improve the capability of EFVS systems. The proposed regulations have been drafted so that the introduction of new technology doesn’t require major changes to regulation. Innovations in EFVS could be implemented quickly provided that there is a robust safety case.
Who wrote this?
Andrew McKechnie is an expert in Air Operations and Director of McKechnie Aviation LTD. Since 2015 Andrew has been working as a consultant to EASA RMT.0379 developing new regulations for All Weather Operations. Andrew is available to provide training and consultancy to Aviation Authorities and Aircraft Operators.