News: New CAP 1747 Report Identifies Optimum Strategy for Flight Crew HTAWS Alerts
The UK Civil Aviation Authority has published its CAP 1747 report on research into the optimum means of alerting helicopter flight crews to alerts for Class A Helicopter Terrain Awareness and Warning Systems (HTAWS). The report’s findings will provide input for the EUROCAE WG110 working group as part of the aviation standards organisation’s efforts to develop Minimum Operational Performance Standards for HTAWS use in offshore helicopter operations.
Addressing the need to avoid alerts being missed by flight crew, the CAP 1747 report–which can be downloaded here–concluded that aural alerting should remain the primary means of delivering HTAWS alerts. The report added that the use of an attenson tone before each aural alert could improve their effectiveness. It further recommended that visual alerts serve as a supplementary reminder to pilots, with tactile alerts viewed as a useful addition. One of the main recommendations from the research is that HTAWS should be considered as part of the wider helicopter system, with multiple factors having significance in the effectiveness of alerts, including: ambient noise, communication levels, other auditory alerts, existing displays, headsets, use of ear plugs and nuisance alerts.
The human factors/human machine interface research work team consisted of the following experts: Professor Polly Dalton (Professor of Psychology with Royal Holloway, University of London), Dr Matthew Greaves (then Senior Lecturer in Accident Investigation at Cranfield University and now Safety Intelligence Programme Manager for HeliOffshore), Mark Prior (former test pilot and helicopter safety consultant) and Dave Howson (Research Project Manager with the CAA’s Safety and Airspace Regulation Group). The work was supported by HeliOffshore and pilots from member companies Babcock International, Bristow Group and CHC Helicopters were involved in the flight trials, surveys and interviews. The research also considered accident investigation findings.
The CAP 1747 report recommended that Flight Data Monitoring should be used to measure the current rate of HTAWS alert activation to inform ongoing work to introduce new HTAWS algorithms. HeliOffshore is currently coordinating a collaborative effort between aircraft operators, manufacturers and regulators to advance the implementation of HTAWS upgrades.
The report recommended further development work on tactile alerting systems, such as wearable items for pilots or incorporating tactile transducers into flight suits. It also proposed further investigation to understand pilots’ visual responses to aural HTAWS alerts and the development of a protocol for simulator testing the effectiveness of alerting strategies.