Avoiding the Base-to-Final Stall/Spin

[kaz3g]

Turboplanner, I don't think anybody was suggesting to do a circular circuits at places like Moorabin, horses for courses

 

Most of my arrivals at MOorabbin have been straight in because  southerlies are the dominant wind direction. Don’t think I’ve ever done a full circuit there.

 

But just in response to another post, in a high wing you lose sight of the  threshold in a square turn but keep it in sight in a descending slipping turn.

 

Curved circuits were de rigour on Spitfires, especially at night when it was all too easy to lose sight of the glim lights and, in particular, the Chance light. Read “First Light” by Boy Wellum for an instructive commentary (one of the best RAF autobiographies I have read).

 

kaz

 

 

[facthunter]

 IF a military (service) plane arrives it will do the racecourse pattern . I would say there is a trend away from the squared circuit but I think it's easier taught in the early stages. IF your downwind is close in and you get a bit of tailwind on base you will end up doing a continuous turn anyhow. The "article" considers it less dangerous regarding the final turn problem, but the bank is NOT constant. It IS in theory but.... There are subtle variations all the way in making adjustments for speed reduction reconfiguring, and wind effect as you experience it. The only way to adjust is slight changes to the turn radius (bank angle). If you think about it it's much harder to judge especially in a plane with a lot of flap  extension speeds and a big speed change from downwind, to TTS. You are looking at the threshold al the way around the turn, and even before to judge when you commence it. (as normal) You also have a shortish straight final from 400 to 600 feet where you are supposed to be "stabilized". That's excessive for U/L's (in my view) as there's no point  being slow  (threshold speed+ factors for gusts etc) for much longer than necessary. Nev

 

 

[turboplanner]

Most of my arrivals at MOorabbin have been straight in because  southerlies are the dominant wind direction. Don’t think I’ve ever done a full circuit there.

 

But just in response to another post, in a high wing you lose sight of the  threshold in a square turn but keep it in sight in a descending slipping turn.

 

Curved circuits were de rigour on Spitfires, especially at night when it was all too easy to lose sight of the glim lights and, in particular, the Chance light. Read “First Light” by Boy Wellum for an instructive commentary (one of the best RAF autobiographies I have read).

 

kaz

The tower operators would probably be helping you with straight ins because of the Auster's slower circuit speed; probably telling the next pilot around the base turn to extend.

 

There are times there where you need maximum cruise speed to be sure the Baron you entered in front of, who was turning base when you let down doesn't catch up to you.

 

I was lucky enough to have a deadly first instructor who explained to me that when I pulled back the throttle on base, that was the last touch. I was to look over my shoulder and make the final turn based on the runway threshold matching some item like the wing. My accurate climb out would have set the distance from the runway so my final turn adjustment for wind component only needed to be the crosswind on base, which I would adjust along with my speed as I was getting ready to turn final. I would be making Rate 1 turns in the circuit, so the turn would put be in a direct line with the runway and I would touch down just over the threshold, and on touch down pull the throttle back.  The fact that I can't ever remember pulling that off in real life, is another matter. Strangely enough, the instructor who taught me on Jabiru more or less did the same, but added an inner wing lift for a few seconds in the turns. The reference point for the base turn vs runway threshold was a certain distance up the diagonal stay, which you might be able to use, but as long as the tower operators are happy with straight ins, I'm more than happy to extend slightly.

 

 

 

[kaz3g]

Enough of the slow ?

 

I’m doing at least 100 knots downwind...at least for part of it. Then I have to slow down for base to less than 56 just to get the flaps out. And I might dawdle a bit on final at 45 or so (allowing plenty for gusts) as the stall is just 26 knots.

 

and Turbs...did you have to post that photo of KAZ?

 

John not only beat me for 1st prize at the Auster flyin, but he parked his next to mine!!!

 

it is one of the nicest Austers I’ve seen, I have to admit. Beautifully restored by the owner and an absolute credit to him.

 

kaz

 

Meant to say a girl has to work really hard to slow a speedster up that much!

 

 

[Student Pilot]

 Most of this procedure is done at Primary airports where separation is applied by the controller but visual  still plays a part even there. Nev

That statement dates you a bit Nev, haven't had primary's since we started using alphabet airspace. Must admit I still refer to them as primary's, remember the days when you could walk down to the briefing office to get weather and have a yarn at places like Bankstown and Moorabin?

 

 

[Roundsounds]

This is actually a very poor video for the following reasons:

 

- he introduces the PARE spin recovery technique before commencing the demos, but never mentions the A (aileron) during any of the recoveries. If you enter a spin and not centre the ailerons you will likely not recover (aircraft type dependent). 

 

- he continually refers to airspeed being the primary factor in stalling - it’s angle of attack, you can stall / spin from any airspeed. 

 

- he introduces a non standard method of using roll to identify which rudder to apply during spin recovery. This will kill you if you try this method with inverted spinning. The only way to reliably identify the direction of rotation is yaw, best way is to sight down the nose of the aircraft. I agree that looking at the balance ball is unrealistic unless in IMC. 

 

- he never mentions removing the opposite rudder when the spin rotation stops. Leaving full rudder in will cause some aircraft to spin in the opposite direction, some will flick into an inverted spin if you also hold the forward stick in too. The Yak 52 being a great example. 

 

If you’re going to produce a training video on a topic it must be done correctly. In this case give the full recovery method and apply all steps through to established back in the climb. It is very difficult to retrain people who have been taught incorrect techniques, teach the correct ones from the outset.

 

In summary;

 

- it’s angle of attack not airspeed leading to stall / spins.

 

- Use all steps of an acceptable procedure every time, especially when instructing. 

 

- don’t try to make up your own recovery tips without thinking them through and doing some research. (Using roll to identify which rudder to use)

 

On the positive side, I agree with his scenario based entry method by simulating an overshoot onto final. 

 

 

[APenNameAndThatA]

Here's why I am not going to go with the Jacobson Flair technique of throttle for speed and pitch for height. 

 

Conventional Technique

 

Too slow + panic = nose down + speed up + survival (and full power if that makes you too low) (kinetic energy of aircraft increased)

 

Too low + panic = full power + climb + survival (kinetic energy increased)

 

Jacobson Flair

 

Too slow + panic = full power and survive (kinetic energy increased)

 

Too low + panic = nose up + stall + die (kinetic energy is decreased by lifting the nose... until the stall, after which the kinetic energy actually increases...)

 

Disclaimer: recent flight experience = 5 hrs. 

 

 

[derekliston]

Interesting reading though this is, when I actually think about it, I couldn’t tell you which, if any technique I use. I make sure my turns aren’t too tight and keep my speed where I want it. I tend to fly pretty much glide approaches and keep my circuits close ‘just in case’ that means my downwind to final tends more to the circular than the square. I keep the speed where I want it and keep the ‘picture’ right, I fly at idle down to the runway and only put in a bit of power when I encounter sink. Don’t know if right or wrong, but works for me!

 

 

[djpacro]

I like to have a good written reference such  as https://www.faa.gov/regulations_policies/handbooks_manuals/aviation/airplane_handbook/media/06_afh_ch4.pdf "Maintaining Aircraft Control: Upset Prevention and Recovery Training" supported by short videos as appropriate.

 

I've done a lot of tight base/final turns at Moorabbin, this one is quite mild with a bit of a xwind. Legal since the minimum distance for a final approach was removed from the regs some years ago. Of course, at Moorabbin it depends on other traffic however the Tower is generally very helpful.

 

PittsApproachMB0515.mp4

 

PittsApproachMB0515.mp4

[facthunter]

 They are no doubt used to the way you do things, not that there's anything particularly radical about what you did. Specific POH's or Approved Company Operations Manuals will stipulate what height one should/must be stabilized  by on final.  Fixed gear and no flaps make the configuration issue,  a non issue.. The wide variation of circuit size and circuit speeds is a flow issue that must take a bit of coping with, and I don't see any obvious solution  for the cross country circuits some do.. A slow aircraft in those circumstances can hold up a lot of traffic..Nev

 

 

[Methusala]

G'day Kaz, just ordered a copy of, “First Light” by Geoffery Wellum on your recommendation. Thank you Don

 

 

[turboplanner]

 They are no doubt used to the way you do things, not that there's anything particularly radical about what you did. Specific POH's or Approved Company Operations Manuals will stipulate what height one should/must be stabilized  by on final.  Fixed gear and no flaps make the configuration issue,  a non issue.. The wide variation of circuit size and circuit speeds is a flow issue that must take a bit of coping with, and I don't see any obvious solution  for the cross country circuits some do.. A slow aircraft in those circumstances can hold up a lot of traffic..Nev

It all works itself out quite well at a busy airport. For example, if you are in something like a C172 or PA28 and are following a C150/152 on take off, since the turn at 500' will determine how far out he got, which is not far, and the turn at 1000' will have him on a wide or cross-country downwind, with the gap when you were cleared for take off you will be well clear of him. When you turn base, he'll usually be a minute after you turning base and so far out that he's not going to catch you for the rest of the circuit. If there are a lot of aircraft in the circuit, and he still uses the old turning point references you know where he is at all times; even with visual only, a quick look to the right will tell you where to turn base so you don't interfere, so your finals in relation to a C152 will almost always be your standard uninterrupted approach. If you take off in front of a higher powered aircraft, you will be running wider than him, so he has the same chance to get past you and on to his standard final.  If you add more aircraft of different performance to the circuit they will all be tracking slightly differently, and where identical aircraft are involved you adjust the spacing down, run on the leg etc. but if you don't run the turn to final on, you call going round if there's someone right in front of you and you can't fix it by slowing down on final. At country airfields that pattern is harder to learn because there will never be enough aircraft in the circuit happen at many of them. It's pretty similar to a country driver not being trained on the anticipation moves by city drivers.

 

 

[Love to fly]

 

 

I've done a lot of tight base/final turns at Moorabbin, this one is quite mild with a bit of a xwind. Legal since the minimum distance for a final approach was removed from the regs some years ago. Of course, at Moorabbin it depends on other traffic however the Tower is generally very helpful.

 

[ATTACH]38442[/ATTACH]

Great looking passenger ?

 

 

[kaz3g]

G'day Kaz, just ordered a copy of, “First Light” by Geoffery Wellum on your recommendation. Thank you Don

 

Hi Don

 

im sure you will enjoy reading it as I have many times.

 

there is a bot of YouTube stuff around with interviews of him in later years. Understated and self-effacing, and very brave.

 

kaz