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6 major problems with military helicopters (and how to solve them)

Defence IQ takes a look into some of the most common problems for military helicopters, and what is being done about them. By no means a definitive list, the following aims to provide a broad overview ahead of the 2013 International Military Helicopter event

1. Brownout

The problem

Degraded Visual Environment (DVE) is cited by some as the biggest ongoing problem operating modern rotary-wing assets – particularly for those in deployment in dry, dusty regions. Reports suggest that it costs US forces $100m a year for Middle East operations, and has been responsible for 3 of every 4 accidents. Hundreds of helicopters have been lost in the past ten years to brownout, along with hundreds more lives.

Adding to the difficulty, brownout tends to be caused by a combination of factors, including wind speed and rotor configuration, while most of the aircraft in combat do not have the luxury of preparing or analysing the landing site.

In essence, this isn’t just a case of having a clouded visual field – dust clouds can play optical games on a pilot, skewing his or her sense of motion (i.e. ‘vector illusion’) and of the horizon angle. More odd is the relatively recent discovery of the ‘Kopp-Etchells Effect’ wherein landing in a dust cloud at night has been observed to spark sand on blades, creating a bright halo around the rotor and potentially resulting in disorientation.

Worse still is the long-term sand erosion of nickel or tin based rotor blades, driving up maintenance requirements and costs. It’s nature versus machine… and to date, nature is winning.

What can be done about it?

There have been recommendations for operational variances that can offset the probability of being caught up in the storm, such as landing at higher speed to stay ahead of recirculating dust, but these are largely reliant on specific surfaces and platform capabilities.

Effective and intense training is vital, requiring simulators that can accurately replicate a brownout experience. AgustaWestland has spent time on developing this type of visualisation with the British MoD, while other private firms such as Quantum3D, have attempted to tackle this specific issue, as seen here.

More recently, machine is making a comeback, with a range of technologies being touted as potential solutions to the problem.

Sierra Nevada’s Helicopter Autonomous Landing System (HALS) uses sensors on a 94 GHz radar, which is barely impacted by dust, sand or smoke. Integrating this with broader 3d mapping and satellite technology, the pilot is provided a detailed colour display in the cockpit with which to navigate the descent. US forces will trial it in Afghanistan from the beginning of 2013. Meanwhile, BAE Systems unveiled its similar Brownout Landing Aid System Technology (BLAST) in 2011, based on off-the-shelf technology and apparently ready for full-scale production.

DARPA began to test its own solution programme in 2009, termed Multifunction Radio Frequency (MFRF) – formerly “Sandblaster”, exploring millimetre wave (MMW) radar to update a stored terrain database and create a display for the pilot. The programme remains in development with plans to see it complete laboratory testing of key subsystem technologies for waveforms and arrays by 2013. BAE also won this development contract earlier in the year.

The US Army has also spent resources on the development of the Tactile Situational Awareness System (TSAS) by Chesapeake Technology International, which as the name suggests, is designed with a number of aims including a capacity to help pilots ‘feel’ their flight manoeuvres with touch and vibration indicators, removing dependency on pure vision.

Other ideas suggest a reconfiguration of the blades to reduce downwash, which may well be considered on future rotary-wing programmes…

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To read the rest of the article, click here. We’re also keen to hear your opinion on these issues! Email us with your thoughts at haveyoursay@defenceiq.com.

Discussion of these topics and other solutions will be on the agenda at International Military Helicopter, 23-24 January 2013, London, UK. Book your place today.

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