[P7_TOM]

Frustrating and Tedious.

The frustration stems from not being able to source the data; not the 'happy-clappy' stuff; but the results of test flight and performance data. The little Cirrus is a good little rocket, no doubt about it – provided the recommendations and factory data is applied, it will 'perform design function' quite nicely. Yes, this is the however bit:-

Strictly related to the 'Gundaroo' event; critical elements in no specific order:-

Centre of Gravity – much depends on the estimated location of this datum; as does the estimated TOW. No point in guesstimating it; ATSB will do their best on that. It matters though; the weight and the C of G location could (and I did say could/ maybe) have some bearing on events subsequent. For consideration.

Resistance to Spin; certification and flight tests results for same. These are proving to be deuced difficult to locate, access and consider. Given the paucity of evidence for ATSB to work with, we can only hope that resources, time and money will be invested taking a long, educated read of the data. Why? Well; there are questions which need answers.

For instance; given the known data that there are some 'situations' in which the Cirrus is unable to affect a spin recovery; this led to certification as 'resistant' to spin and the CAPS were developed to alleviate this small area of 'difficulty'.

For instance; the 'wing cuff' was an 'add-on' to assist the laminar wing when critical angles were approaching. Good idea; cheap, cheerful and it works. Bravo – However; trying to find data related to flight test of the performance of 'the cuff' in icing conditions, at a critical speed/angle of attack., on climb, possibly through icing layers,  is proving to be a bit like Hen's teeth – bloody tough to find.

Now the 'If's' part: with great scope for 'Yeah-but'. The perennial problems of thinking aloud: consider some of the data available.

Met forecast – short odds on icing in one form or another.
Increased 'work load' on the lift/ drag ratio and airflow;
Add ice to the cuffed wing section;
Add ice to the aircraft weight;
add in an aft C of G;
consider the spin 'limitations' on the aircraft and;
consider the chances of a 'flat-spin'.

Still leaves a lot of questions unanswered I know this; but we must begin somewhere and these are obvious questions to be seriously considered and eliminated – even if just to clear away some 'grey' areas. Something went terribly wrong; can't do too much about that which is history; but we must at least try to prevent a repeat performance.