I read with interest your article on helicopter safety ("Lessons learned", Flight International, 4-10 November).

On the one hand, Bristow Helicopters sees pilot instrument rating and fully instrument meteorological conditions (IMC)-capable helicopters as fundamentals. In addition, in the UK, helicopters used for public transport have to be twin-engine, IMC-capable and either crewed with two pilots or equipped with an autopilot.

The report highlights the danger at night of visual-meteorological-conditions pilots suddenly finding themselves in cloud, becoming disorientated and losing control. And yet, for some of the most demanding roles - air ambulance and police work, for example - an exemption to the rules permits these operations to take place at night in a helicopter that is not IMC capable, flown by a pilot without an instrument rating.

The Australian Transport Safety Board has identified a safety deficiency relating to visual operations at night following the loss of three rescue helicopters in Queensland in as many years (Flight International, 25 November-1 December).

Put together, these reports question the safety of visual operations at night in the UK by the emergency services using helicopters that are not IMC capable, flown by pilots without instrument ratings.

Robert Brown Leyburn, Yorkshire, UK

Source: Flight International