Helicopter Ballistic Protection - users should demand better!

Having spent 20+ years working on ballistic protection and composite armour projects for land, sea and air platforms, it remains surprising the extent to which helicopter ballistic protection solutions for transport helicopters remain unoptimised and treated as an afterthought. This is despite the trend towards using air mobility in place of ground vehicle movements to avoid IEDs and roadside bomb attacks.

I believe there are several reasons for this – firstly, with the exception of attack helicopters like the AH-64 Apache, installing armour on helicopters remains a relatively recent innovation. With the exception of pilot and crew seats, transport helicopters were not designed to integrate extensive armour protection and there is a lack of knowledge and experience within the teams that write the requirements and buy the platforms. Coupled with a lack of “loop closure” with intelligence, tactics and mission planning to properly consider threats and enemy engagement scenarios, this results in overly simplistic ballistic protection specifications.

To some extent this is true within the airframe OEMs too, where there are often in-house experts but their focus is naturally on complying with customer specifications rather than exceeding them, with the weight and cost penalities that implies.

Secondly, there is also a lack of knowledge of the subject within the user community, where the aircrew and their passengers are often grateful for “some” ballistic protection when they previously had none.

Helicopter platforms are perhaps the most challenging to protect. They are of course highly weight sensitive, but the nature of the lightweight airframe construction and the need to work around various items of role equipment (some of which has been installed post-delivery as a modification) adds to the complexity of integrating ballistic protection solutions and often results in limitations and ballistic weaknesses. Those limitations and weaknesses have been accepted too readily.

The contrast with the specification of protection for military vehicles is telling. Even patrol and logistics vehicles that may have been lightly-armoured or even completely unarmoured in the past now have detailed ballistic protection specifications to inform the procurement process. The specification is derived from detailed threat assessments, taking into account types of weapons and rounds, expected range when engaged and even angles of attack. There will be high standards set for the percentage coverage for the protection, with suppliers expected to demonstrate how they have addressed ballistic weaknesses and gaps between panels. There will also be an extensive qualification testing programme to prove the ballistic protection solutions meet the requirements across the range of operating environments. The solutions offered by suppliers will have been optimised, taking into account the threat specifications from different directions, the underlying vehicle structure, and often the angles presented by the various facets of the vehicle.

Helicopter ballistic protection specifications are often simply condensed into one or two round types with a range or velocity, with the same specification applicable to both floor and sidewall armour. It is rare to see a full assessment of the likely engagement scenarios, taking into account the range and angle of attack, considering the altitude of the aircraft and whether it is likely to be banking or flaring at the time it is engaged by a ground-based enemy.

Most types of armour material perform better when rounds strike at an oblique angle, with the worst-case being an impact at or close to perpendicular to the strike face of the armour panel. The scenarios in which rounds will strike perpendicular to a helicopter armour panel and at close range are very limited, particularly for floor panels. And while a typical aircraft fuselage skin will not provide any significant contribution to protecting against bullets, the fuel tanks might, particularly when a round enters them at an oblique angle.

Another proven way to gain an increase in ballistic performance in some situations is to use a “spaced array” with layers of different materials with an air gap between in a "disruptor/absorber" combination. Many helicopters have voids in their structure as a function of their design which could be exploited to provide protection in this way.

Detailed consideration of threats and engagement scenarios leading to more comprehensive protection specifications, and better collaboration between the ballistic protection experts and aircraft engineers could lead to better protection for aircrew and their passengers without significant weight penalty.

Transport helicopters are battlefield assets deserving at least as much effort to protect them from small arms attack as logistics vehicles. The users should be demanding better, and we should be giving it to them.

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