[aus-soaring] Tow height when launching

[Harry Medlicott]

I am somewhat disappointed, but not surprised that my effort( 24th April ) to contribute to safety by reporting an accident resulted in more nitpicking comments than useful discussion.  It is not pleasant referring back to incidents involving oneself but it is only by analysing accidents that we can learn from them.  A few comments on my original notes and associated replies;   I was in high tow, which for me meant just above the slip stream, but then went about 1 or 2 metres higher.  Perhaps the height above the ground was as much as 5 metres but as I did not have a leadline to measure the height and am relying on a memory of eight years ago cannot be precise.   Comments re entry of the non-manoeuvring area are either an example of ignorance of wishful thinking.  When winch launching, respect and avoidance of the n.m.a. are both possible and highly desirable, but on aerotow it is a different kettle of fish.  Probably at lease 10% of aerotows spend time in an n.m.a. and on some airfields every flight is in the n.m.a. for from a few seconds to upwards of a minute.  If we were to release when we anticipated entering the n.m.a., (not much use releasing when we are in it!) then imagine the consequences, not least for those who had already entered to n.m.a.  Except in obvious cases I believe that not many pilots are aware of when they are approaching a marginal situation.  Surely it is primarily the tug pilots responsibility to release us, depending on his evaluation of power available and conditions ahead.  He must have a very good idea of his ability to safely clear obstacles and usually has many times the experience of the pilot he is towing.   Fortunately the GFA by setting standards and providing release testers has largely eliminated part of the problem of premature releases.  A new 60m length of 12mm 1400kg breaking strain poly. rope costs  $25.00 so please scrap and cut up tow ropes when they become frayed.   There are also situations when it is most prudent to stay close to the ground until a speed of 10 or 15kts above stall speed has been reached.  Certainly under windy and turbulent conditions this applies, unless you wish to be unceremoniously dumped back on the ground, and also with heavily ballasted gliders.  A tug will almost always be airborne well before a standard class glider ballasted to 50kg wing loading.  At this weight severe damage will result in stalling from 1metre.  I have seen it happen twice.  A heavily ballasted glider must exercise extreme care when launching, the tug has less acceleration, and any idea about transiting immediately to high tow after lift off may well have a disastrous result.