The world’s four leading helicopter manufacturers have agreed plans for the implementation of enhancements to their Helicopter Terrain Avoidance and Warning Systems (HTAWS). At a recent meeting organised by HeliOffshore, senior representatives from Airbus Helicopters, Bell, Leonardo Helicopters, Sikorsky and avionics manufacturer Honeywell met with officials from the European Aviation Safety Agency and the UK Civil Aviation Authority to agree the next steps for HTAWS upgrades that promise significant safety benefits.

The agreed plans call for equipment to be enhanced by adjusting alert envelopes on existing aircraft types, beginning with those equipped with Honeywell’s EGPWS MK XXII HTAWS. This will give earlier notifications that increase the time available for pilots to avoid a possible unsafe aircraft flight condition.

A HeliOffshore work group has brought together manufacturers, operators and regulators to agree the best way to deliver clear safety benefits of HTAWS. Simulator trials conducted by Honeywell in late 2017 with offshore operators CHC Helicopter and Bristow Group demonstrated the use of the UK Civil Aviation Authority’s CAP 1519 protection envelopes and how these can reduce the risk of controlled fight into terrain/surface accidents.

The protection envelopes defined in CAP 1519 have resulted from several years of work led by the UK CAA. The CAA research was initially sponsored by IOGP, Shell, Bristow and BP, and has also been supported by HeliOffshore and Oil & Gas UK. The work has used Flight Data Monitoring (FDM) data and simulator trials to provide the evidence to establish the enhanced envelopes.

Now in the implementation phase of work, aircraft manufacturers will focus on implementing Modes 1 through 6 of the enhanced HTAWS software, which between them will deliver approximately 60 percent of the safety benefits from the proposed upgrade. The meeting agreed that Mode 7, which would deliver the remaining 40 percent of benefits, will be implemented later after further flight trials are complete.

Leonardo Helicopters has committed to implementing the first phase of the upgrade during 2019 for its AW139 and AW189 fleets. Mode 7 is set to be added after further flight testing.

Sikorsky agreed to introduce Modes 1-6 in Revision 11 of its Avionics Management System (AMS-11) for the S-92, which is due in 2021. In the meantime, it will continue to flight test Mode 7 and hopes to be able to add this to the upgrade at the same time.

Airbus Helicopters is also continuing to test all the modes and intends to implement the upgrade of mode 1 through 6 for the H175 models in 2021 and on the H160 in the same year. The mode 7 upgrade requires additional design work and flight testing before implementation in the HTAWS or flight control system.

Bell has agreed to implement enhanced capabilities in its new B525 aircraft. The manufacturer is considering implementation options including embedding these functions within the aircraft’s avionics suite or fly-by-wire flight control system.

HeliOffshore’s Operational Effectiveness workstream also is working to incorporate HTAWS into Flight Crew Operating Manuals (FCOMs) developed to give pilots a complete understanding of how their aircraft are designed to be operated safely and how they can make the best possible use of all systems.

“Effective collision avoidance is fundamental to helicopter safety, and this collaborative project involving multiple stakeholders is working to give pilots earlier alerts through the widespread adoption of upgraded HTAWS in the offshore helicopter sector,” commented HeliOffshore CEO Gretchen Haskins.