Transitioning to a Decathlon

The 8KCAB series are fairly simple airplanes, mostly 1940 technology with a few bells and whistles. Pilots seem to cope with the fancy bells and whistles fairly well but my observation is that there needs to be more effort by pilots new to the type into learning some very basic stuff.

The park brake. There is a placard adjacent to the park brake knob which clearly explains how to operate it. There are instructions in the Airplane Flight Manual and the Pilot Operating Manual. So, why do so many pilots tell me that they have set the park brake yet the airplane moves freely when given a gentle tug.

Weight and balance is a fairly important topic, not really critical in the Decathlon as on a typical training flight with the usual weights of pilots then it is generally within the permitted envelope – just follow maximum weight limitations. Yet, pilots seem unable to actually determine the weight and balance for a particular loading. The method in the Airplane Flight Manual is expanded upon in the Pilot Operating Manual with a sample calculation which is easy to follow. So simple that it can be done on the back of envelope.


The thing that catches most people out is that the Manuals use Imperial units whereas stuff generated in Australia is mostly metric and if a new approved loading system is not provided then pilots need to work with the system in the Manual. There is plenty of help online to convert from one set of units to another. Some people use a simple Excel spreadsheet. Compare your calculations with the sample then proceed with your own – if it looks inexplicably different from the sample then it is probably wrong.

There is some good advice on transition to a new type here:

“You begin by studying and learning the new aircraft’s systems and operating procedures since the bottom line to all flying is knowing everything that we can about the aircraft so we can operate it safely. You will find this information in the aircraft’s flight manual (AFM), owner’s manual, or pilot’s operating handbook (POH). If the aircraft is an older model, it might have a very basic owner’s manual. If so, you need to be aware that the older manuals may not have the same information as some of the newer manuals, nor are the older manuals organized like the newer POH’s or AFM’s. Although the older manuals have less information than the new manuals, they still provide the basic information.


Once you have done your homework and thoroughly understand the new aircraft, you should take the aircraft’s manual and checklist out to the aircraft and spend time sitting in the cock-pit to learn the locations of the various controls, instruments, and checklist procedures. Your goal is be become familiar enough with the aircraft to be able to fly it before you ever start the engine. If you are renting the aircraft, this procedure also will save you valuable training dollars.”

Very good advice indeed.

I encounter some pilots who have flown Decathlons for some time but they have never even opened up the Airplane Flight Manual. They tell me that it is in the airplane so at least they know where it is. Perhaps. I know of some airplanes which do not have the FAA Approved Airplane Flight Manual in it – instead they have just that other Pilot Operating Manual – not quite the same with some conflicting information.

Myths of Manoeuvring Speed

“It turns out that our early training on maneuvering speed was badly over-simplified. The truth is that you can’t move all the controls to the stop and it isn’t the same as gust penetration speed. Here’s the unvarnished truth about Va.”

Avweb recently started this topic at

I explained this further with three articles in the first three volumes of the Australian Aerobatic Club’s Vitamin G magazine.

You may have been told something like the definition quoted in Avweb’s article:

“The maximum speed at which the limit load can be imposed (either by gusts or full deflection of the control surfaces) without causing structural damage.”

Another one that I have seen is:

“Maneuvering Speed is the maximum speed at which you may use abrupt control travel.”

Aerobatic pilots should be familiar with the definition provided by CASA in their CAAP 155-1, Aerobatics, which states:

“Manoeuvring speed (VA) is the speed above which full deflection of the elevator control will exceed aircraft structural limitations. Below VA the aircraft will stall before structural limits can be exceeded.”

All are woefully inadequate definitions of VA and it is particularly disappointing to see that CASA’s advice to aerobatic pilots is also inadequate.

The original articles are:

The fourth and final article is provided here:

Ozaeros Maneuvring Speed Myths Part 4

The correct definition is provided by the FAA Special Airwothiness Information Bulletin CE-11-17:

“The Design Maneuvering Speed (VA) is the speed below which you can move a single flight control, one time, to its full deflection, for one axis of airplane rotation only (pitch, roll or yaw), in smooth air, without risk of damage to the airplane.”

Short Field Tailwheel Operations

My tailwheel training course in the Super Decathlon does not conform to CASA’s Part 61 Manual of Standards for the reasons explained below. 

Short Take-off

      • 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.

Short Landing

  • 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.

CAAP 155-1, Aerobatics

CASA’s CAAP 155-1, Aerobatics used to be a good place to start reading about aerobatics and does include some of the information that you must know but it has a number of deficiencies:

  • it does not adequately explain the structural limitations associated with VA, Manoeuvring Speed
  • it does not have the new, additional underpinning knowledge requirements of the Part 61 MOS
  • it has not been updated with the new licensing regulations of September 2014

What is Aerobatics?

A good place to start is with the definition of aerobatics :

The International Civil Aviation Organization defines aerobatics as “maneuvers intentionally performed by an aircraft involving an abrupt change in its attitude, an abnormal attitude, or abnormal variation in speed.”

CASA used to have that exact same definition but in September 2015 they changed it to:

“aerobatic manoeuvres, for an aircraft, means manoeuvres of the aircraft that involve:

(a)  bank angles that are greater than 60°; or

(b)  pitch angles that are greater than 45°, or are otherwise abnormal to the aircraft type; or

(c)  abrupt changes of speed, direction, angle of bank or angle of pitch.”

Why did CASA change their definition of aerobatics?

The USA and Europe have definitions which are almost exactly like the ICAO definition. The USA has an additional rule requiring the wearing of parachutes in some circumstances when an aircraft exceeds 30 degrees of pitch or 60 degrees of bank relative to the horizon; their definition of aerobatic flight, however does not specify pitch attitude or bank angle. EASA has an additional rule clarifying that training undertaken for a licence is not aerobatics.

Why did CASA remove the word “intentionally” from the definition of aerobatics? Consider what CASA requires for training towards a licence and consider whether any unintentional wing-drop etc is aerobatics per CASA’s definition. Not a problem of course if it is a dual flight and the instructor has an aerobatic training endorsement.

Have fun!