Malibuflyer wrote:
“judgement based on experience” is that we almost always lack the required experience on how it works when we do things differently
You are correct: a lot of judgement is required to implement that sentence successfully: for example, nevermind what regs say, get good instruction before venturing into the altiport on your own. Try progressively higher weights before venturing at MLW. Build in additional extra margins before venturing into a shortish grass field and only lower them progressively. By all means speak to different sources about grass runway condition, historical and recent…
In my book that is all common sense, but I agree it is not always so common
In general we are only properly “protected” if we just follow POH procedures. Staying there always would limit our flying in ways not all of us a re willing to accept, as long, again, it is not explicitly prohibited.
As Col Eduardo Cuadrado said: know your airplane, know yourself, know how both together get along as crew, then use your best judgement, including what the regs and POH say, and err on the safe side. It all comes down to personal choice and risk management, even if some would tend to remove that from us.
finding the right braking pressure is enough of a challenge
That is the main brake-related point of flap retraction in the rollout: minimising such challenge as the increased weight on wheels makes it a non-event.
Malibuflyer wrote optimum speed and optimum glideslope being more important than immediate flap retraction after touchdown, but there is something IMO which is even more important and doesn’t appear in the POH and that is optimum aiming point. And yet I bet it is not something that many pilots really consider, and instead just aim for the numbers or displaced threshold.
Lot of people do try to land short by aiming before the threshold and flaring before, then touching down right after which I find to be an “interesting technique”, especially as the published paved runway LDA they talk about does already factor some threshold crossing height, it’s not raw runway length 
On techniques, I come across a long body Mooney owner, who was doing that in 600m tarmac runway with no obstructions around, here is his “magical technique”:
- Fly shallow 0deg approach, 65kts, holding nose with lot of power and aim for threshold – 10m
- Full flaps, no flare, cut power, raise flaps and open airbreaks, and wheel breaks
He already changed one propeller & engine because his wheels hit the threshold once
He could not understand how I can land it shorter power off, on slightly faster airspeed, crossing threshold on “double deck bus height” without even using wheel breaks
Took ages to grasp the concept of high AoA on steep approach and bleeding energy on positive flare, I estimated he does his approach & float with AoA = 1 deg and hope it hits 14deg when airbreaks & flaps are raised
The thing is a shallow dragged in approach makes it hard to consistently touch down accurately at the intended touchdown point. It’s always easier to be accurate with your touchdown with a steeper approach.
There’s a good bush type flying video about high AoA on steep approaches (with high AoA), and minimum energy.
Aiming point. Touchdown point. The mantra of the mountain rating
yep, and also here quite a few examples of Retracting flaps on touchdown to maximise braking
alioth wrote:
There’s a good bush type flying video about high AoA on steep approaches (with high AoA), and minimum energy.
Looks like a technique you’d want to practice at altitude. A bit slower and “That’s all, folks!”.
There’s a good bush type flying video about high AoA on steep approaches (with high AoA), and minimum energy.
Steep on high AoA you are still lot exposed to gusts (most STOL videos are done in cold calm days for a reason ), however, you tend to have plenty of ground under due to geometry, the only problem is if you want to go-around you need to lower AoA for climb (lower the nose a lot and you already have high VSI)
Shallow on high AoA is clearly big NO, no height & no speed & no go-around, all you need is a blip in the wind to go to the rats
Airborne_Again wrote:
It is often said that you shouldn’t trust POH performance values because they were obtained by “factory test pilots”
I have heard that some times Talking about ancient technology here (Cessna, Piper etc) it’s similar to engine operation. These engines are manual with several levers and with a limited and less than accurate set of sensors. The certification of the engine in the air frame was all about using the limited set of sensors together with the levers to prevent the engine from being damaged. Today we use ECUs for this, a much better approach. However when doing the certification, the engine had a vast array of sensors installed for exact monitoring and recording. It’s exactly the same with aircraft performance parameters. They are set to always be within the flight envelope at any given circumstance.
But even so, FIs today generally think/believe that these performance numbers are “faked” to give an impression of greater pay load, more fuel, longer endurance, higher alt etc. This is done exclusively for marketing purposes (according to the FIs ) AND remember that those numbers only can be achieved if you are a test pilot to start with All nonsense of course, and it say a thing or two about the utter ignorance of some FIs
Anyway, back to braking. I learned to use as little (wheel) braking as possible. Better to do aerodynamic braking with a high nose (nose wheel) than to even touch the brakes. A perfect landing is a landing where the brakes isn’t touched. In snow and ice, the brakes has close to zero effect, so better get used to it. Speaking of which. In this very moment I received a message about ski operation, a course being held. No brakes with skis. Have to attend that course
Ibra wrote:
Steep on high AoA you are still lot exposed to gusts
Days with gusts usually have a decent wind component, so there’s generally less need to go for maximum effort short landing technique, because the headwind factor hugely shortens the ground roll (and steepens the approach) anyway.
With gliders we always factor in the headwind to our final approach speed. Days with wind, our approach speed is a little bit higher.
