I am generally not a fan of the double top or double bottom formation because its has such a high faliure rate. If you have read Thomas Bulkowski's - "Enclyopedia of Chart Patterns", you'll know exactly what I mean.
If we make a small adjustment to the rule, only sell lower double tops and only buy higher double bottoms, our success rate is generally much higher. In this case Qantas has made a new low in late 2013 and now we appear to have a 1st higher low in place and now a retest of that higher low. (referred to as higher double bottom).
Our success rate is much higher and our stop level is obviously at a tight level also. So low risk high reward trading opportunities are generally viewed favoubly by traders as your generally risking less with a tighter stop. A break below the February low would be a negative sign. A strong week up with strong committed volume would be ideal for the bulls.