Aerial Colision
So, what can we do about this problem, without taking the fun out of gliding?
BGA and the UK military gliding organisations have agreed a protocol to improve safety in
thermalling. Competition startline procedures have been modified to give better
separation. Much thought is being given to improving the positioning of GPS installations
to improve lookout, possibly including head-up displays. Most clubs are tightening up on
landing pattern discipline and, where thought necessary, introducing traffic information
circuit joining radio calls from gliders and tugs so that everyone flying in the vicinity
will be alerted to what is happening.
I understand that competition thermalling can still present problems, with some
"macho" pilots taking undue risks to beat the others. Talking to a senior BGA
person (who shall remain forever nameless) he said "I know that we take higher risks
in competitions, but we accept them". It can be argued that you should be allowed to
risk your own life and the effects on your
family of losing a husband, father and breadwinner, but collisions involve more than one
aircraft. Should you be allowed to take additional risks with other pilot's lives, with
the consequent tragedy and hardship for their families?
In my opinion, definitely not. I believe that competition pilots should also follow the
thermalling protocol, with sanctions taken against those who consistently present a hazard
to fellow competitors. Gliding is a sport, not a war.
When the head is in motion, vision is blurred and the mind will not register potential
targets. So scan in blocks of no more than ten degrees, pausing each time for at least a
second to enable detection. If you fly over water or under hazy conditions with the
horizon obscured, your distance focus relaxes after 60-80 seconds and your eyes revert to
an intermediate focal distance, only a few feet in front of your aircraft. In those
circumstances, before scanning condition your eyes by focusing on the most distant object
you can see. A dirty, scratched or flyspecked windscreen makes this problem worse.
Each eye has a blind spot. Under normal binocular vision conditions this is not a problem,
because an object cannot be in the blind spot of both eyes at the same time. On the other
hand, where the field of vision is obstructed by, say, a canopy fitting, a conflicting
aircraft could fall in the blind spot of the other eye and remain undetected.
An FM study has shown that only 8% of mid-air collisions were head-on. However, 42% were
between aircraft heading in the same direction. So, compared with opposite direction
traffic, your chances of having a mid-air are more than five times greater with an
aircraft you are overtaking, or one that is overtaking you. The eye needs motion to
attract attention. So the aircraft on a constant bearing - the one that will hit you - is
the one you are least likely to see.
An experienced pilot is just as likely to have a mid-air collision as a student. The
above points - and many others - are developed and fully explained in the pamphlets, so
get one now - they are free !
A final little story. A few years ago, I was training Glyn Yates on the BGA Super Falke
for his private licence. We had reached the stage of forced landings without power, and I
briefed him of the dangers of over-concentrating on his field and landing pattern at the
expense of lookout.
On one of his practices, Glyn chose a good field and quickly planned his circuit. By this time we were descending through 800ft agl and Glyn said "maintain lookout". We both scanned and there on the port quarter was a Piper Warrior, 150 yards away, at our height and heading straight for us on a direct collision course. Glyn pitched our aircraft hard down and we passed below the Piper, which maintained its course and heading, having probably not seen us at all. But for our proper emphasis on lookout, it is likely that neither Glyn nor I would be here today to tell the tale.