My tailwheel training course in the Super Decathlon does not conform to CASA’s Part 61 Manual of Standards for the reasons explained below.
- CASA requires take-off power to be fully applied before releasing the brakes – this is contrary to the Manual and is a common cause of nosing over.
- CASA requires rotation at the manufacturer’s recommended speed and climb at speed for obstacle clearance – rotate speed in the Manual is 43 kts – less than the stall speed and the climb speed in the Manual is 50 kts – very close to the stall speed. The Manual warns of risk of injury or fatality in the event of an engine failure in this situation.
- CASA requires application of maximum braking after touchdown at minimum speed – this is contrary to the Manual where the instruction is “brake as required” with a warning of injury or fatality due to the risk of nosing over.
- CASA requires the trainee to calculate the landing distance and promotes the falsehood that the short field performance can be easily achieved by an average pilot – this is not true of aircraft certified many years ago. The Manual states that the landing distance data represents “maximum airplane capability at speeds shown and requires aircraft in good operating condition and a proficient pilot”.
- CASA requires that the trainee stops the aeroplane within the calculated distance. Landing approach speed in the Manual is 52 kts which is very close to the stall speed. The Manual warns of risk of injury or fatality with this technique and I repeat the above statement – the landing distances in the Manual will only be achieved using exactly those speeds specified with the various risks of damage to the aeroplane and injury or death to the crew must be highlighted.
It is interesting to note that when Decathlons first arrived in Australia they were provided with new take-off and landing charts – so-called P charts. There was a take-off safety speed (that is a very informative term) of 58 kts. The landing approach speed was also 58 kts – about 1.3Vs. Those charts applied to the earlier model Decathlons with a lower maximum weight and have since been withdrawn.
I see that the Manual for the new Xtreme Decathlon is differs from that of the Super Decathlon by specifying more reasonable speeds – similar to these P charts.
Incidentally, there is another consideration with those old P charts:
When CASA changed the rules on Flight Manuals around 2002 they also withdrew their own P charts however recommended that operators retaining them for older aircraft – but the operator took responsibility for them, not CASA. The P charts were derived from accurate flight testing in Australia so generally could be relied upon except for one thing.
The 8KCAB series has a variety of engine and propeller combinations but the P charts are simply labelled “Bellanca 8KCAB” with no indication as to whether they tested a Standard Decathlon, Decathlon CS or a Super Decathlon. Being a flight performance engineer I did some analysis of the information in the Pilot Operating Manual and these P charts. Guess what, I worked out that they would’ve tested a Super Decathlon (180 hp with C/S prop) whereas I had a 150 hp fixed pitch prop version. I queried CASA and said that I wanted to review the original test data if I am to take responsibility for them. Of course, it is take-off distance which was going to be critical. CASA didn’t try to find them in the archives from 1974 so I declined to use them – instead I advised my pilots to use the POM data with a generous margin (plus the usual 15% factor which is missing from USA manuals of that era).
Now that I have a Super Decathlon I am confident with the use of the P charts however they only go up to a weight of 816 kg whereas the maximum weight of the new aeroplane is 884 kg.
If you ever hear of a Decathlon hitting trees on take-off then think back to this story. Not a big risk as there are only a handful of those aeroplanes around and generally not used for short strip work ….. but, one day, maybe ………