Back again with more disinformation from the Australian Government’s Civil Aviation Safety Authority at Performance charts: believe what you see | Flight Safety Australia
“In the US, 14 CFR 23.45 says, ‘In determining the take-off and landing distance, these procedures must be able to be executed consistently by pilots of average skill …” Unfortunately, for authors such as Tom, the regulations change over time and that statement is generally not true!
Take the 8KCAB Decathlon for example. It was certified to FAR 23 23 as of February 1, 1965, which only required:
• 23.51 – The takeoff may not require exceptional piloting skill
• 23.75 – must be able to be landed safely and come to a stop without exceptional piloting skill
Back then FAR 23.51 did not even require that the distance required to takeoff and climb over a 50-foot obstacle be determined.
So, the 8KCAB was not required to determine take-off and landing distances for the FAA Approved Airplane Flight Manual – there is no take-off and landing distance data in the Flight Manual. The 8KCAB was not required to have a take-off safety speed of 1.2 Vs nor a landing approach speed of 1.3 Vs per the later FAR 23.53 & 23.75.
The 8KCAB did not require landing techniques to be achievable by an average pilot. The Operating 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”.
Landing approach speed in the Operating Manual is 52 kts which is very close to the stall speed of 47 kts.
The Operating Manual warns of risk of injury or fatality with this technique and emphasizes that the landing distances in the Operating 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.
“One persistent myth is that aircraft performance charts do not reflect reality for most pilots, because the charts were created by professional test pilots flying brand-new aeroplanes with brand-new engines.” It is not a myth!