Contents Continued

The cockpit of BBMF Spitfire Mk IX MK356 with the PFLARM ‘Butterfly’ collision warning display at top centre. (photo: Clive Rowley)


Keeping ’em Flying

Collision alerting system


This series looks ‘behind the scenes’ at the engineering that keeps

the RAF BBMF historic aircraft where they belong, in the air.

In this issue we look at a modern piece of avionic ‘wizardry’,

which has been fitted to the BBMF aircraft to assist the pilots in

spotting other aircraft and to reduce the risk of mid-air collision.

R A depiction of the aerial traffic (shown as light trails) over Eastern England,

in just one hour of one day, shows how congested the airspace is. (photo: NATS)

This series looks ‘behind the scenes’ at the engineering that keeps the RAF BBMF historic aircraft where they belong, in the air. In this issue we look at a modern piece of avionic ‘wizardry’, which has been fitted to the BBMF aircraft to assist the pilots in spotting other aircraft and to reduce the risk of mid-air collision.

Airspace: The vast majority of the BBMF’s flying takes place in uncontrolled airspace – known as ‘Class G’ airspace – which covers more than half of the UK. In ‘Class G’ airspace aircraft of all sorts can fly, uncontrolled, under both ‘Visual Flight Rules’ (VFR) or ‘Instrument Flight Rules’ (IFR). Air Traffic Control has no authority over aircraft in this free airspace, but may be able to provide a Traffic Information Service. The BBMF aircraft operate only under VFR, always in sight of the surface. Much of the BBMF flying takes place at weekends during the summer months and in busy areas of the country, when the congested lower airspace is shared by an increasing number of General Aviation light aircraft, gliders, para-gliders, para-motors and micro-lights.

Mid-air collision risk: The mid-air collision risk is currently one of the highest Air Safety priorities for the Military Aviation Authority and for the RAF. Statistics show that, perhaps surprisingly, most mid-air collisions occur in daylight and in excellent visual meteorological conditions.

By Sqn Ldr Clive Rowley MBE RAF (Retd)

 this article originally appeared in the RAF Memorial Flight Club's Yearbook.

BBMF