Advanced VTOL Technologies - Ship-Helicopter Operational Limits Assessment and Ship Motion Analysis

Advanced VTOL Technologies (AVT) has specialised in the assessment of Ship Helicopter Operational Limits (SHOL's) and other helicopter - ship interface related problems since 1997. AVT also develops ship motion models for seakeeping assessment and helicopter - ship dynamic simulation purposes.

Helicopter-ship dynamic interface software

Ondeck helicopter-ship dynamic interface software was initially developed by the Australian Defence Science and Technology Organisation (DSTO) in 1988.

Since then it has been extensively modified to improve fidelity and permit the analysis of a wide range of helicopters and ships. AVT has been primarily responsible for developing the code since 1997.

The OnDeck software is a non-linear time domain code specifically optimised for the development of operational limits and the analysis of on-deck interface issues. It incorporates detailed non-linear representations of the helicopters including accurate representations of the undercarriage and tyres. The code can model wheel sliding and lift off, the interaction with multi-contact surfaces, undercarriage loads, lashing loads, rotor and wind loads as well as the effect of restraint systems like RAST, ASIST, Decklock and the MacTaggart Scott TRIGON system.

Helicopter models developed include:

• S70B-2 / MH60-R Seahawk
• S70A Black Hawk
• SK 50/50A Sea King
• MRH90 / NFH90
• ARH Tiger
• Squirrel (ADF)
• Lynx Mk90b
• SH-2G Seasprite
• CH-47 Chinook
• S92
• Bell 222
• A109

On-deck operational analysis capabilities

AVT can conduct the following analysis:

Predict safe ship motion limits including:

• Toppling / sliding limits
• Lashed limits
• Restraint system limits
• Clearance limits
• Ship motion analysis
• Estimate sea state capability
• Assess landing loads
• Airframe clearance
• Optimise lashing scheme layouts
• Produce gear and airframe load data for structural and fatigue analysis
• Assess restraint and ground handling systems
• At sea OnDeck modelling validation using the MHA system
• UAV operational guidance

As part of a Commonwealth supported Capability Technology Program (CTD) the software has been modified to provide real time operational guidance and usage monitoring on ships. The maritime helicopter aid (MHA) has recently been successfully conducted prototype trials on the RAN LPA HMAS Manoora, demonstrating potential increased on-deck operational capability, improving safety, airframe usage monitoring and improved situational awareness. Ondeck validation trials were also successfully performed on HMNZS Canterbury.