What do you teach for the Forced Approach

[Big Pistons Forever]

I teach the figure 8's to a half mile key point and always have. TC is big on overhead 360's, other instructors I know teach the downwind, base final. What do you guys do and why ?

[ant_321]

I personally learned with the 360 Method on a low wing. Now I teach on Cessna's and find that the high wing makes it difficult to see the key points and touchdown points so I just teach a circuit method. The students have flown plenty of circuits and have practiced many engine failures in the circuit so they normally catch on fairly easily.

[YYZSaabGuy]

Not an instructor, but I was taught to use the standard circuit approach where possible, i.e. where you've got the altitude and where there's no critical need to get on the ground ASAP (e.g. engine fire vs. engine failure). Makes planning your entry and downwind/base/final legs more straightforward, makes altitude control easier, and to some extent circuit muscle memory kicks in and makes actually flying the approach that much more straightforward while you're busy with cause checks, re-start attempts, radio calls, passenger briefs, etc. Not saying this is necessarily the best way, but it works for me.

[Rowdy Burns]

I teach the 360 method.

All three methods have their PROs and CONs. On the 360, students get too caught up in the math (it doesn't matter if your a couple hundred feet off, you can fix it when you are in the circle) or have a hard time compensating for wind. On the Figure 8 (bow-tie, etc.) students don't like to angle out and I find they make the turns in a big rush (make a small figure 8 ) and they end up crowding the field with more of an S-turn. On the down-wind base method, distance to the field changes (pythagoream theory) which throws off POZM and judgement. All of these can be worked through with proper instruction, practice, placement, etc.

Here is an interesting thought - why is it when you do a simulated engine failure from downwind, most students can make the field (even pre-solo) and commercial students can hit the TD point to within 1200' (on a bad day), but then when you do it from altitude into a field where the "alloted" TD zone is the first 1/3 of the field (1000' - 1500') they miss it? Probably has something to do with the structure of a circuit, you are always somewhere around 3/4 mile to 1 mile from the Runway, and somewhere near 1000' AAE.

I think there is a link between these exercises that gets skipped, and it's getting the aircraft into a zone where it's makeable. I find the second half of the 360 method and the 180 glide are very similar (increase BA, decrease BA, bit of a slipping turn, etc.).

[B-rad]

figure 8 over key point. best way to go.
you're always turning toward the field.

[5x5]

Figure 8 over key point. By going direct to the keypoint you're angling towards the field and if you get low you can easily turn in. Once at the keypoint, you can descend in the figure 8s to an altitude just a bit higher (adjusted accordingly for wind) than a normal final, then turn in and it works reliably and repeatably.

[trey kule]

First of all, it has been several decades since my instructor rating lapsed. But I think that gravity and the laws of aerodynamics, and human nature have not evolved that much . Nowadays, I do checkrides, and get to see the results of the training., So, for what its worth , here are my thoughts.

When coming back into the circuit , or when doing circuits, have the student work at picking a pointon the downwind and then reducing the throttle to idle, and make a power off approach and landing to he runway.
This takes no extra training time, and begins the process of learning to think about the wind, altitude, and getting to the right spot. I understand that cold weather can be a problem here in terms of engines getting to cold, and traffic may preclude this type of exercise, but when it is possible it is a good start.
The emphasis here is on speed, altitude, aircraft control., and learning to recognize the landing spot by movement in the windscreen. .Get that burned into their brains.

Once the student can do this , the whole making the field and touching down close to the actual predicted landing spot becomes easier. It is a precude to the actual exercise.

When doing the exercise, do thorough ground preparation and briefing. Emphasize the objective is to control the aircraft and make the field.. IF TIME ALLOWS.....the do all the other procedures, but never at the expense of aircraft control.

I dont know all the niftly FTU or TC nomclature for this exercise, but the figure 8 sounds quite similar to both what I was taught, and what works best from any altitude, not just the flight test, nose bleed altitude start of the exercise.

On check rides, what I see from new CPLs is they initially get it right, and then they try to remember all the good stuff about pax briefings, re starts, mayday calls, txpdr changes, and lose their situational awareness and control of the airplane.

Again, it has been a very long time since I tried to impart wisdom in a new pilot, so maybe my K.I.S.S. principle is out of date, and the real objective is to just pass the flight test.

[cgzro]

On check rides, what I see from new CPLs is they initially get it right, and then they try to remember all the good stuff about pax briefings, re starts, mayday calls, txpdr changes, and lose their situational awareness and control of the airplane.

I remember having exactly that experience

I think technique depends a lot on the type of aircraft. The old blind stuff with glide ratio's of bricks requires heavy use of slipping for visibility and for drag control. So you setup very very high (nothing like a circuit altitude) downwind and then slant onto the final with almost full slip, then vary the slip to set the touchdown point. In a biplane or something with a big radial you really need to work hard to keep the landing sight in view so its a whole other kettle of fish.

[loopa]

I teach them something all the flight test examiners I've had for my students loved.

Way way way back when I teach descent management I talk about direct miles, and track miles and what the difference is. Once they understand that track miles are the miles you fly with the aircraft throughout the procedure versus how direct miles is the distance you fly to go direct the field, it makes it very simple to judge descent planning on a power off glide (which is once again taught at a very basic level when they first learn Ex8).

For the background knowledge purposes of understanding this, say the ideal field is a mile by a mile. And they are descending from 5000 to sea level at 500fpm. That's 10 minutes worth of descents. At a ground speed of 60 (1nm/min) it works out to be 500'/nm (like what we teach in the circuit method, turn final at approximately 500 feet).

Hence plan your approach so that by the time you hit your field, you have flown across 10 square mile fields. Makes it very easy to plan from the air. Count 7 fields ahead (downwind), 1 to the side (base), and 1 before the field (final) giving you a mile buffer to be high.

Since the typical 172 approach is flown at 65kts and 6-700 fpm it just works out very close to the 60kts/500fpm

Now no sane person is going to figure out descent gradients in a real life forced approach, so using this background knowledge I teach them that 1% of your altitude to lose times 2 is going to give you the number of square mile fields to count ahead. This sounds like math again doesn't it? But it's very simple.

Altitude to lose 4000, 1% = 4 x 2 = 8 track miles (or 7 fields to final for buffer).

Obviously when its windy you reduce the track miles just like how you might do a figure 8 approach procedure closer to the field.

I have yet to find a student fail the forced approach exercise using this method. Maybe i'll get ripped apart by the old timers here. But I get them to practice this non-power-assisted approach management way way back when they first start learning descents.


Therefore the answer to your question is that amongst teaching the other methods I find that this method works best for the students I've had.

Would love your feedback!

Cheers

[lownslow]

If you're in a heavily (wing)loaded or draggy airplane, simply throw a brick out the window when the engine stops and aim for the same field it's heading towards. Caution: in some aircraft you may have to exit the airplane as soon as it stops as the brick will still be headed straight for you.

Apart from that, in airplanes that could glide decently I'd do the figure eights to final. When I started teaching in airplanes that suck at gliding I'd prefer the overhead 360 but would also teach the base/final keypoint method. Turns out the DFTEs in my neighbourhood loved the 360s as they'd always pull power directly over an ideal field.

LnS.

[trey kule]

Count 7 fields ahead (downwind), 1 to the side (base), and 1 before the field (final) giving you a mile buffer to be high

sometimes the mountains get in the way and it is hard to count the fields on the prairie

[gaamin]

Edit

[erics2b]

figure 8 over key point. best way to go.
you're always turning toward the field.

You're always turning toward the field in a 360 too. The difference is your tangential velocity vector never points to the field in a 360, while they momentarily do in a figure 8.

[loopa]

Count 7 fields ahead (downwind), 1 to the side (base), and 1 before the field (final) giving you a mile buffer to be high

sometimes the mountains get in the way and it is hard to count the fields on the prairie

Obviously very in effective if that's the region you flight train in. Thank god for the mountain checks

[Beefitarian]

figure 8 over key point. best way to go.
you're always turning toward the field.

You're always turning toward the field in a 360 too. The difference is your tangential velocity vector never points to the field in a 360, while they momentarily do in a figure 8.

Presuming that straight arrow is the "tangential velocity vector." it points at the field once per revolution doing 360s and twice per cycle of figure eights, no?

[Colonel Sanders]

it points at the field once per revolution doing 360s

Not if the field is the blue dot at the center of the circle.

[Beefitarian]

it points at the field once per revolution doing 360s

Not if the field is the blue dot at the center of the circle.

Ahhhhh got it.

[Colonel Sanders]

your tangential velocity vector never points to the field in a 360

I think some people might find Eric somewhat intimidating (see twitter posts of his compsci-tutored students).

I was nowhere near as good a pilot when I was his age, and I didn't get 99% in my University courses, either.

[trey kule]

Loopa
that was very interesting, and you have obviously put some thought into it. Unfortunately there are one or two pilots that dont fly on the prairies, and cant use this method, besides the fact it assume you know your height agl, your planned field elevation, and the wind effect.
I look at the exercise from this viewpoint.
While we all talk about continually looking for a place to land if the engines decides to take a break, the truth is we typically are not doing that. After a couple of hours humming along on a nice smooth day that is not number one on your mind.....so if the engine stops the first thing is your going to get a big shot of adrenilin which never occurred during training.. And all the numbers and formulas go out the window, so to speak.

In the very first lesson a student is shown that if they look far away they can pick a spot in the window that is not moving left or right. The plane will fly there . When they start to learn to land, they are taught that if they pick a spot on the runway and it moves down in the windscreen they are going to overshoot. If it moves up they are going to undeshoot. And as they are never going to be out of the circuit solo there is no need pre solo to be teaching them the full meal deal of a forced approach from altitude.

This means that the student should be able to pick their field , point the nose of the plane at it and pretty much determine if they will arrive high or to low. No need for fancy math. K.I.S.S. when things are a bit dicey. If this happens for real , it is a skill, and is not a time to be doing math...do you know exaxtly how high above the ground you are? The elevation of the field you planning? But once you set up the correct glide attitude you can determine whether you are going to make the field or not in a few seconds.

It is simple, quick, and will work just as well in a no duff situation as on a flight test. The thing I see from this thread with regard to the flight test, is you are going to typically arrive over the field with extra altitude, and what is the best way to lose the proper amount of altitude.
that is a bit different problem , and while I have my way, which I like, someothers have different ways, and I am sure they work too. But when schools teach this or that particular method because it is sort of approved, that is not good.

Just my thoughts, but I dont teach ab initio flying anymore.

[trampbike]

your tangential velocity vector never points to the field in a 360

I think some people might find Eric somewhat intimidating (see twitter posts of his compsci-tutored students).

I was nowhere near as good a pilot when I was his age, and I didn't get 99% in my University courses, either.

And your point is...?