PFLs - good and bad practice
 

Whilst "safety piloting" a fellow syndicate member this morning, we decided to spend some time flying PFLs - since I'm a great fan of regular practice and he admitted to being badly out of currency. This concentrated the mind for a while and it would be fair to say that we were both glad that the engine hadn't actually stopped on one or two of them, but we got to the point of both being quite happy about the best way to fly it in that particular aeroplane, and went home for tea and medals.

But, this concentrated the mind somewhat. I am personally quite happy about my approach to PFLs, which in simplistic terms is:-

(1) Establish best glide-angle speed and pick a field that I can reach, if the wind is strong, ideally into wind, if it isn't (or not clear) ideally up a gentle slope.

(2) Pick an aiming point that gives me enough landing distance before I run out of field, and preferably well into the field (the old 1/3 rule works quite well).

(3) Imagine a runway starting at that aiming point, set myself up as efficiently as possible (a) ideally downwind, (b) if absolutely necessary on base, or (c) if I was very low, in which case I was flying field to field anyway, on finals.

(4) Fly a constant aspect approach - that is with a continuous slope angle to my aiming point as I turn reasonably gently, tightening or slackening the turn for drift and misjudgement.

(5) At 100-200ft ( a bit higher if a really big field), roll wings level, establish approach speed, and set up to land. If too high, sideslip, dive or S-turn the excess off, depending upon preference and type - but always aim to err on being slightly too high.


(Then, of-course, going around only once I'm absolutely certain I'll make it, which personally I take at around 50ft.)



But my approach is not the only approach I've ever seen. For example, one very experienced FI I flew with once insisted upon rectangular circuits, as I'd fly at a civil airfield - which to me is totally wrong since once established on base the ability to correct misjudgement is very poor. Another approach I've seen is to set up close to finals then lose a lot of height with continuous S-turns, not something I'm at-all fond of, since it's very hard in most aeroplanes to accurately monitor height and position relative to the aiming point that way.

So, am I right or wrong in my prejudices here? Does anybody agree or disagree with me? Is there another way I've not mentioned? Instructors - how do you teach PFLs, and how low do you take them?

G

Genghis,

This is an area where I found big differences between microlight and light aircraft training, as I assume you probably did as well.

In microlights it is usual to get very close to the ground before going around from a PFL, both during training and in the GFT. 50 feet or less seems quite usual.

On the other hand, when I subsequently did my JAR SEP training I was surprised to be told to go around at 500 feet, which is before it starts to get really interesting.

The roots of this cultural difference are obvious enough, since light aircraft engines have been generally reliable for several decades whereas microlight engines have only become so in relatively recent years.

I tend to agree with you that trying to preserve the pleasing aesthetics of a nice square circuit should not be top priority during a forced landing. Some of the techniques illustrated in the textbooks do tend to assume that you have all the time in the world to sort things out. If however you have been flying quite low (<2,500 under the London TMA example) in something with a high wing loading and a poor glide ratio then you're doing well if you can find a field and position for it at all, let alone fly a neat circuit around it.

Good thinking Genghis, let me add my pennyworth:

(1) Establish best glide-angle speed and pick a field that I can reach, if the wind is strong, ideally into wind, if it isn't (or not clear) ideally up a gentle slope.

Why not pick an area of fields so that you can refine your choice as you get closer? Ideal fields are often surrounded by similar fields! If you can see a gentle slope from the air, it will be a marked slope on the ground! If you land uphill you invariably land in the undershoot.

(3) Imagine a runway starting at that aiming point, set myself up as efficiently as possible (a) ideally downwind, (b) if absolutely necessary on base, or (c) if I was very low, in which case I was flying field to field anyway, on finals.

Why restrict yourself to an imaginary runway, a large grass area is better as you can come at it from any direction thereby regulating the track distance.
If you fly constant aspect, you need to establish the ideal low key height for the aircraft type; that should place you downwind with the aiming point just aft of the wing tip.

(5) At 100-200ft ( a bit higher if a really big field), roll wings level, establish approach speed, and set up to land. If too high, sideslip, dive or S-turn the excess off, depending upon preference and type - but always aim to err on being slightly too high.

Try to roll out wings level on final by 400 feet, with no flap. Then take flap in stages lowering the nose to retain the glide speed whilst bring the aiming point towards you. Retain the glide speed untill you flare, initially to a normal approach attitude (that washes off the extra speed) then to a normal flare for landing.

If you fly a machine with retractable gear and a VP prop you need to establish the basic parameters before it happens for real, some need a lot of height at "low key".

Remember don't let the other pilot get you into a position where you can't get it into a field!

Genghis

I practise regularly and think your procedure is pretty similar to mine. My only difference is that my machine rapidly runs out of energy so I don't fly a constant approach. I leave a bit of height in reserve just in case the wind gradient is less than expected.

Field size, surface and shape is also more important to me than being perfectly into wind.

I also go down very low as I think the last bit is the most important bit. I have thought I was in nicely at 400ft only to be short in a wind that was strong down to the deck.

I had major carb ice on take off, a few weeks ago. My only option, from 150ft was a field at 90deg to my path. The engine didn't actually stop but for some time sounded like it was just about to. Either that, or the fierce vibration and spluttering meant it would fall off. I was glad for regular practise and even though the engine ate the ice and recovered, the whole thing wasn't really a worry.

PFLs, down to the deck, are something we should all do regularly. Interestingly the latest height minima regs are designed to allow this.

Well worth the practice. I guess we all get too complainant.

A few years back I was talking to an ex-RAF instructor who told a great story about 2 engine problems within a week.

The first happened to a student who had recently completed his 50 hour Ab initio and the second to an experienced RAF pilot. Can't remember type.

The 50 hour guy landed in a field no probs as he was well versed in PFL's and was on form. The experienced guy got his wings and rings from St Pete at the pearly gates.

I'm flying this week and will put some practice in.

Big thanks for the reminder.

Sorry to divert off track there!

My view is that statistically one is just as likely to have a suitable field(s) nearby, as far away.

So there isn't much point in aiming to glide absolutely as far as possible. Obviously one wants to maximise time in the air to check obvious things (fuel tank change, carb heat perhaps) but I bet most real engine en-route failures cannot be restarted, and to make a mayday call and set 7700.

As it is a lot easier to control the glide in azimuth (left to right) than it is to guess where one will end up in terms of gliding range (especially given wind shear) I would pick a direction, into wind if possible, where there is a number of fields lined-up on one's track. Then if you miss one field, you can go into the one behind it.

Anybody should be able to do this, even without practice. Doing an accurate forced landing into a specific field requires a lot of practice, and if it is for real, one will be doing this stuff under a LOT of pressure. Just think how some ATCO with a personality problem, or a passenger being sick, or kids fighting in the back, can spook you into making mistakes, and multiply that 10 times for a real forced landing.

Genghis,

Just my little piece, (oh err)

Anyways, the gliding fraternity avoid standard square circuits like the plague because the last thing you want is to fly a downwind, away from your landing area only to turn base and find you are no longer in gliding distance of your field. They have adapted the circuit to include a 45 degree leg between the latter stages of downwind and base. The result is that they are always within gliding distance of their target field.

I have taken this over to my powered flying, I just wish I had variable airbrakes.;)

Any instructor who forces students to fly a standard circuit pattern is setting them up for trouble IMHO.

The other technique I am practicing at the moment is as you describe with a constant sight picture and varying the turn on a long curved approach from downwind onto final.

As my instructor said time and again, keep sight of your field and never turn your back on it.

Obs cop

I am going to be controversial.

In my opinion the very best way to practice PFls is to take the unsuspecting group member to an airfield to practice touch and gos. Let them set up down wind or where ever and cut the power. That is how it happens when you least expect it and a successful landing demonstrates just how well or badly the PFL went. Having got one out the way go back and practice technique – and thereby comes the earlier contributions on best methods.

My rule when i fly is...if my engine stops now where can i go?
I do this every now and again (especially if doing aeros) then if it does stop there's no mad panic trying to find a suitable field!

I tend to agree with IO540, in that suitable fields are probably very close. This stems from my old habit of looking for a field in the distance, aiming for it, then choosing another, going for that, then deciding the original was the best, by which time I am out of height.

I was subsequently taught by an instructor on a syndicate check out to pick a close field, preferably a little ahead and to the left (and stick to it), head towards it choosing an aiming point 1/3 the way in, and fly an oval pattern about this field, adjusting as nescessary (from the aspect.....picking a point on the left window). When "downwind" select the start of the field as the aiming point and fly a relatively normal pattern, adjusting as nescessary, bearing in mind that final should be into wind (hence steeper glide path) and leaving flaps until late, if at all....If I am too high, I can widen the circuit, and if too low, tighten it in.

EA

Obs cop,
Just to clear a matter, pedantic I'm sure, but it is relevant. As a glider pilot I learned always to make the circuit on the downwind side (how rare is a wind straight down the strip?) The point being, and this is the whole point of the constant aspect approach, you can at any time during the circuit, turn in and land with minimal manouvering as close to into wind as the conditions permit.

I had an instructor try to teach me these square thingies; he couldn't do it as well as I could do a constant aspect PFL.

He also reckoned that one should fly a straight line from the high-key to the low key positions (and then a straight base and final).

I have heard only one argument for square circuit PFL's that holds any water. It is so that an engine failure is handled like a normal landing.

I believe if you take a look at the accident statistics you will see that the number of stall/spin/loss of control/poorly judged accidents after such a simple event as an engine failure show this argument to be seriously flawed.

Miserlou,

I agree with all that you added to my original post.;)

Mind you I have far more time on powered than on gliders but they must be doing something right cos they get virtually all landings out away from the home strip right.

My feelings are that the gliding fraternity are far more concious of safety than most powered pilots and more importantly, practice constantly.

I think the idea of doing square circuits to make engine failures more akin to a regular landing is also asking for trouble, because it quite clearly won't be a regular landing. Surely by frequent practice of a specific PFL routine,you could rely more solidly on that. By trying to do something akin to a regular circuit, then in a stressful situation you may use the incorrect visual and height cues leaving yourself too far from the relative safety of the field.

I believe in KISS. Practice a simple and straightforward routine for PFL's and you have something straight forward and simple to revert to in times of pressure. I tend to practice PFL's about once every 3 to 5 hours. I find the easiest way is to throw in your practice engine failure in on return from a nav route on the final leg to my home airfield. Firstly it doesn't cause too many problems time wise and is a nice way to get down ready for joining the circuit.

Obs cop

In PPL training we are taught to fly at a particular best glide speed, but in the :mad: ATPL notes i'm reading, in order to get the best gliding range you have to add the headwind factor or subtract the tailwind factor to best glide speed. I know it adds to the complexity of the situation but is worth keeping at the back of one's mind when range becomes an issue.
Capt. M

Capt M for an aircraft gliding at 200+ knts from 30,000+' the gliding range may be significantly altered by the prevailing windspeed at the different levels. For yer average Cessna / Piper / Robin etc at best glidespeed of 65-ish knts and 1,500-2,500' height, the best range is academic. In the latter circumstances it's best to pick a field that you can reach even if the windspeed at low level is 30knts against you. If you end up too high then you have the option of picking another field or adjusting your height to suit your first choice. Best range would only really be applicable in an SEP (or light twin) if you are within a reasonable distance of an airfield and you need to know if you have the height to make it.

Depending on the situation, the best options in an engine failure are;

1. Land ahead - (EFATO, low level, flying into wind)
2. Establish on final as high as possible and complete figure of 8 holding pattern (turning towards the field) until a straight in landing is available
3. If too low for 2, complete a constant aspect turning approach into the field.

During the lesson I demonstrate the two things one should not sensibly try - turn back in EFATO (or engine failure after PFL) and the square circuit.

Quite true to say that there usually a field close at hand. I impress that having suffered an engine failure, it is far better to land well in a small field and hit the far hedge at 10Kt than not make it into the big field while hitting the near hedge at 65Kt.

Agree that taking the approach as low as possible makes it more realistic however, aside from rule 5, when doing such a low go-arround one must have made allowance for a) the engine not responding or b) the engine failing for real during the climb away at low level.

Regards,

DFC

Not enough people practice PFLs often enough.

Not enough PPLs practice glide approached often enough.

If people would fly more appropriate circuits all the time (which I know at some places is not possible due to local noise abatement procedures) they would be a lot better at gauging aircraft performance and approach angles from different locations in the circuit.

I would be hesitant to advocate a completely different circuit for (P)FLs if people are used to flying rectangular once for normal circuits. Modify what you are used to rather than try to do a constant aspect approach, cause they require training and regular practice too.

If you look at accidents for FLs and outlandings for gliding it transpires that people come to grief for 2 reasons.

1. They go too slow near the ground and stall/spin

2. They go too fast and go through the hedge at the far end.

3. They change their field of choice in the latter stages.

The advantage of practising FLs is not just that you get better skilled at flying the aeroplane in a different configuration but also that the mindset changes from 'it won't happen' to 'it is happening and I am going to deal with it'

This is probably one of the reasons why off field landings in gliders are less likely to be a serious event than in an aeroplane. Everyone involved in XC gliding sets off knowing that an off field landing is on the cards.

Interestingly there is some evidence that people who fly gliders with a retrieve engine in their glider do not do so well as their engineless counterparts when the thing refuses to work. Again I think suggesting that mindset is an important factor.

I have said on here before that I think that by 500ft you should know whether you are in the 'slot' after that there is nor the time nor the room to make any meaningful changes.

If you are not sure whether you can judge whether you have it right by then you need to do more glide approaches at your homefield.

FD

DFC - Could you explain what you mean by a figure of 8 holding pattern - that's a new one to me. And don't you teach field-to-field low level, including climbing out from a PFL, that's certainly how I was taught and have flown ever since. I'm also fascinated that you teach a straight in out of preference - is that your normal circuit join with students as well, and do you S-turn or sideslip off extra height?

FD - I disagree that you meaningfully know whether, in most smaller aeroplanes, you are going to make a PFL by 500ft or not, unless you have a HUGE field in front of you - and you do have room for corrections, small heading changes to avoid a ditch, sidelipping to lose some extra height are both quite normal. Also you need to get used to the view as you roundout into a field with no runway edges and often a slope - you won't get that at your home field. I know that it feels much more comfortable to go-around from 500ft, but I really don't think it's a truly meaningful exercise.

G

G,

Not surprisingly I don't agree with your view on this one.

If you only spot the ditch below 500ft you have obviously got to work on your field selection. Unless you are very proficient in sideslipping, starting one at 500ft is going to be a recipy for disaster.

If you want to practice landing without the visual clues of a RWY you can go to some grass strips/airfields.

The notion that one can only do a meaningful PFL if you continue into the flare is not only incorrect but also does not encourage a lot of people to do them as they are worried about breaching rule 5 or being alleged of it.

I put it to you that if a pilot can consistently pull off a good landing on the spot from a glide approach and they are able to set themselves up consistently from a random 'pull the power PFL' to 500ft that they are likely able to pull off a decent FL.

FD

It is many years since I have done any gliding and, in my day, there were two distinct factions who spent many bar hours arguing about the correct way to carry out the approach to land.

One side supported the square circuit, carrying out S turns at the end of the downwind leg if necessary.

The other argued for S turns on base leg as DFC appears to be advocating.

As an ATC gliding instructor I was, and still am as far as PFL's are concerned, very much in the first camp for the following reason:

180 degree turns are not the best manoeuvres, especially under near panic conditions, for controlling speed, position and rate of descent , making it easy to misjudge the approach into the field. . It would not surprise me if most of the spins off final approach aren't due to having to turn too late and too low. However, if you have completely misjudged and are far too high, then this one way to recover

Before the 1000' point on downwind, level with the touch down point, it is easier to assess the conditions and then adjust final turn. As FD says, by 500' you should really be "in the slot".

In my last biennual flight with an instructor I spent almost the whole flight carrying out PFL's from a range of heights. For one we deliberately started the final turn much too high and resorted to S turns. Yes it worked but I would much rather make those sort of adjustments above 1000' where it's safer.

Well, FD, I think you are correct in identifying 'mindset' as something you can positively affect when practicing forced landings. Statement of the bleeding obvious time - the thing that kills you is hitting the ground, and I'd guess that means it helps to be in the right frame of mind when you are close to the ground, i.e in those final 50ft. If you've never been down there how do you know how you will react? Most people have only ever landed on tarmac and even a nicely mown field will cause people to panic if they have never seen one close up. Take them down and show them it's not a death trap, and if they are down there for real one day they will be able to concentrate on a proper final approach and flare.

I never really appreciated this until I started doing engine out practice in a tail-dragger. In a nosewheel spam-can I'd always have this dread in the back of my mind that I'd get the nosewheel caught and flip over. Going down to 20ft in a tail-dragger and actually setting up for the landing made me realise that even a really nasty field was totally survivable. So I'm now believing that if the engine did fail I'd not be worrying myself into a fatal mistake in those final 50ft. I would not have known this if I'd never gone below 500ft.

Another reason to fly a tail-dragger, not that you need many, but they are designed to hate tarmac so you will surely do better in an off field landing flying one.