Precautionary landings

[Newguy]

What type of situation do you simulate when teaching a precautionary search and landing. Is there a perfered method for putting this across to the student or is it just do a few circuits to check the field, then land in it.

[FormationFlyer]

I did this recently with a student combined with low level nav...one reason we might be tempted to fly at 700-800' agl is bad wx...so off we went and did a little low level route...and then I said 'well this really isnt your day...its starting to get dark, the wx isnt improving and now we are starting to be concerned about fuel...time to think about a precautionary landing eh?'

So we then went through the motions...and went around off of the approach when I deemed it was enough for our purposes...(read low...). But within the confines of Rule 5.

If you actually land on an unprepared surface you leave yourself in for all sorts of hassle, apart from the fact you put down a perfectly good airplane etc etc...

Does this help?
FF

[Tinstaafl]

It depends on the situation eg weather related, a/c servicability, time available such as from lack of fuel, encroaching darkness etc


With lots of time a prec. search could take as many circuits around the field as needed to determine if it is, or is not, a reasonable choice.

With limited time or worsening circumstances then some of that 'leisure' is lost. Time might only allow a precursory inspection..

The basic procedure is a guide & gets modified to suit circumstances.

I base my teaching on a nominal 3 circuits, each one with a progressively lower & closer final ---> upwind. The idea is that each subsequent lower flight path is only over terrain that has been observed from the previous and higher circuit. It may involve a a few orbits of the chosen paddock first to decide if it really is worth the time & fuel to observe further, general circuit direction etc. Generally pax. would be briefed, radio calls done etc prior to commencing this procedure. Establish a 15 or 20 min radio call time with someone so that if you don't call by then they'll come start the SAR process.

Each circuit is flown at approx. 500' apart from the final ---> upwind. Fly the approach on base/final as if you are trying to land on the selected aim point. The only difference is that sufficient power is added to stop the descent at each of the minimum descent heights.

The first circuit is one at approx 500' to establish generalities such as obvious items that prevent the use of the field, major obstacles, line features (power lines, fences) & colour changes on the paddock's surface etc to be examined during subsequent & lower circuits, time to ensure a/c configuration is acceptable eg 1st stage of flap.

Make sure final ---> upwind is offset far enough to the right so that the ground path of the subsequent lower approaches can be observed. Fly upwind far enough along to allow the climb out ground path of the lower circuits to be seen too. Pick an easily seen feature to be a go around marker on the subsequent circuits.

Next one descends to approx 200-250' on final, flying level until the go around marker then a full power Vx climb back to 500'. This time assessing the viability of the approach & climb out paths, any obstacles that would modify these or are too close for comfort for a further lower approach. Look at any line features or colour changes as well. Evaluate how the approach, offset flyover & climb out went. Were there things that would adversely affect a lower approach? Should the go around marker be changed to start the go around earlier?

If that was OK then next circuit will involve an approx 50-100' descent on final, againflying it towards the landing aim point as if a landing is intended. Add power at the nominal height to maintain this while flying directly over the landing surface. Look again at any doubful features and for smaller things eg electric fences, that weren't spotted from the previous circuits.

At the marker (adjusted back if necessary) climb at Vx to 500'.

Now is the important part. These have all be purely information gathering exercises and it is now time to review & assess all that was seen. Should it be used or not?

If not what are the options? What are the constraints?

Make a decision to land or to check a different paddock and use the radio to keep someone informed.

Brief the passengers about what's happening. If a landing review the exits, seatbelts tight, possibly a rougher than usual landing.


Sorry, didn't intend to make it so long winded. It's easier to describe with a white board & in practice.




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Why are you looking down here? The message is up there! .. |

[I Fly]

All the above is good stuff. I presume you are an instructor trainee. When we teach Prec. S.&L. we need to consider what the reasons might be for it. Weather, Daylight, Fuel, Sickness, Birdstrike etc. etc. Probably the most critical is the situation described by Formation Flyer and that is why we mostly teach that. The not below 500' rule is a problem, but there are Ag strips or other ALAs that 'look' very much like a paddock but we could actually land. I also use my local aerodrome with the tower's permission. I pretend to inspect the area between the first and second taxyway, between the runway and the parallel taxyway. This way I can safely and legally do the 200' and 50' run (over the runway) and then do a short field landing on the runway and see if we made it.

[GoneWest]

I Fly - seem to remember some pilot getting burned doing something similar to that. Did some low level stuff within the confines of the aerodrome (in the sad UK of course). Was prosecuted by somebody for low flying.

He argued that he was approaching an airfield and therefore entitled to fly below 500 feet. He lost the case when the Court agreed that the permission to fly below 500 feet over person, vehicle, vessel, structure was WHEN FLYING IN ACCORDANCE WITH NORMAL AVIATION PRACTICE - and doing his deliberate low level fly by/go around...and what you describe - was NOT (according to the Court) flying in accordance with normal aviation practice.

Before you growl at me - I agree with YOU. It should be allowed, for training purposes. But he lost the case.

[I Fly]

As stated, it is done with tower's approval. I fly downwind at 500' agl, approach along the normal approach path down to 200' agl, fly along above the runway, climb to 500' agl, next approach I fly down to 50' agl, again over the runway and next time I land. What is abnormal in that. Our Day VFR Syllabus requires that I teach precautionary search and landing. The Day VFR Syllabus states, amongst other things:
"Circuit conducted at 500 feet or 100 feet below cloud.
Landing strip is flown over at 100 feet and to the right or directly over the landing strip depending on forward visibility from the aircraft type and surface conditions assessed.
Dummy approach is completed rechecking surface and drift.
Final circuit is completed and aeroplane is landed according to prevailing conditions with short landing if applicable."
I suppose different lands have different legal systems. Our basic law says "you can land anywhere you like, if you don't crash - it was legal, if you crash - it was not. There is a whole CAAP on how to assess a landing field.

[FormationFlyer]

Yeah. This is a problem. At one school I teach at we have an issue about EFATO - we must teach them but doing so with a recovery height of 500-600' is unrealistic. But thats the situation we are faced with as there are a few houses on the take-off path. We have been warned that the CAA may take action if a complaint is made.

One interesting thing is when I did aerobatics at a grass strip in the UK every flight finished with a PFL from the overhead -> deck. This was great - because you *HAD* to get in...AND you were allowed ALL the way to the ground. So I can really appreciate the value and benefit of getting the student down low.

As I say to students on PFLs/precautionary - 'I will take you when to go around, as far as you are concerned we *are* landing for real.'. This at least seems to get them to follow through rather than hope that I always call go-around at 500'agl. (yeah I know...500' rule 5...but one or two clubs I fly at also lay down rules that all recovers will be at 500'agl...)

However, the other catch-u here is that the airstrip that you go into MUST be licensed for traning to take place, and there are relatively few grass strips in the UK that are...shame really because I think there could be great benefit in using these 'field like' runways...

[FormationFlyer]

I Fly: Coo. Lucky beggar! Over here in the UK you could be done for trespass - all landings must be done with the permission of the land owner.

[dragchute]

It should be stressed to the student that ‘P-search’ is usually the result of poor airmanship such as: running out of daylight, low on fuel, lost, structural failure, etc. I find the standard technique of teaching three circuits at varying levels will in most cases aggravate the problem. Three circuits at about six minutes each equates to eighteen minutes. By then the sun has probably set, the rain has set in or the tanks are dry!

A better technique may be to fly the centreline with a 90/270 procedure turn at each end using a wing tip reference point for the initial turn. In cross wind conditions the initial turn must always be made downwind so that bank angle may be reduced during the turn onto centreline. This technique will cut ‘P-search’ time in half.

[Newguy]

Thanks for all the replies.
I was taught to use the three circuit method, but Dragchute offers an interesting alternative. Any other ideas ?.

[Tinstaafl]

Don't forget that the typically '3 circuits' procedure is nothing more than a guide to provide some basic structure to the process.

Circumstances will force changes including the number circuits you're able to do, the heights, whether it's a left or right circuit etc etc

[Checkboard]

When I was instructing, a long time ago now, I took a week off in Summer to take a 172 with a friend of mine to a remote strip. We hung up a "joyflight" shingle, and did a week's worth of tourist joyflights, refeulling from a couple of drums.

Now this was under a charter AOC, with the airfield owner's permission et etc - all very legal.

At the end of a fun week, we had a couple of friends down at the strip, and decided to go for a jolly up the coast, to a well known tourist site. Flying aorund the site, my friend and I decided to land in an adjacent paddock, for a closer look.

Prec search and landing conducted - all as we taught and had learned (and the two girls in the back were students at the time), with the final check pass at 50 feet. On landing it was amazing how different the surface was to the expectation - quite a slope (it looked level from 50 feet) and pretty rough. Pulling the aircraft up, while our passengers were wandering around we had a serious discussion on whether we could actually get out of the paddock at all - uphill and into the stiff wind, or downhill, with a tail wind? In the end we compromised, taking off on an angle down the hill.

One of my "more nervous" times, watching the airspeed creep up the guage, with the windscreen full of bouncing sheep bums (there was a flock in the field, running away from us), and finally managing to "jump" the fence by applying full flap at the end of the run. Bit of an eye opener, that :eek:

Bloody good fun though:D

[poteroo]

Agree that teaching 'precautionaries' should be as realistic as you can, and still be legal. In Australia, that's becoming a debatable issue.

Not long ago, or far away, I was prevented from demonstrating low level manoeuvring at an Airshow, by the State Manager of CASA, on the grounds that the airport was not a legally authorised low flying area as per CAR 141. I should add that I'm qualified and authorised to teach this work, and have my own approved area near Perth WA.

What it seems to boil down to is this. Unless the paddock, ag strip, or airport, is an authorised low flying area as per 141, then you are exposing yourself to action from the regulator. This especially if there is a complaint from the landholder re the paddock use, or from the airports neighbours or users, who are 'concerned for your safety'. Don't think you're safe to do this stuff over a properly authorised airport - it's not necessarily the case.

I've always beleived that too much stuffing about at lower levels is likely to further unsettle a low time pilot ,who's lost the plot sufficiently to be needing to land. What you can't see from 200 ft isn't worth worrying about. Overdoing the practice approaches, climbing away at vx etc, is tempting fate to intervene with carby ice, or even loss of control in turbulence. Get on with it!

The whole question of less experienced instructors taking students below 500 agl is one that the industry needs to address. My view is that every instructor should be required to be low level trained so that both precautionaries and PFL's can be continued down to a level where it is realistic, yet safe.

cheers:eek: :eek:

[martinidoc]

The other day I took a PPL for a club 28 day currency check. The cloud base was reported at 800ft so I suggested we did a couple of bad weather circuits. With ATC approval. we took off and levelled at 500ft. vis circa 3K and cloud base actually 600ft.

What was interesting that the PPL became quite rapidly disorientated by the poximity of cloud and poor vis, and we ended up diving down on finals at 95kts (normal 70kt).

This PPL was reasonably experienced, but had never done a bad weather circuit in "anger" before, and it made me wonder how valuable the simulated precautionary landing lesson is in relation to the real situation. One think we are not short of in the UK is bad weather, perhaps we should use it a bit more constructively?

[john_tullamarine]

Tinny's comments are good but, just to clarify a point which I am sure he would echo ....

(a) engine failure, etc ... fine .. do the best you can in the circumstances

(b) a precautionary paddock landing is a whole different ballgame .. because it is an OPTION, not a NECESSITY.. in almost all cases there will be alternatives which the lawyers will investigate quite thoroughly at the Inquest ...

I have always had a very jaundiced view of the typical Instructor's poor knowledge of the associated problems, having been checked out as a tug pilot for paddock retrieves by a very old and canny ag pilot who knew about such things.

The one point I would add to Tinny's treatise is that the effect of sun, shadow, and ground texture etc can make the detection of wire hazards especially difficult.

On my checkout, the ag pilot took me to his favourite paddock for such things .. and asked something along the lines of "look OK, does it ?" .. to which I replied, after due consideration "sure does". He then suggested I fly a very wide circuit around the WHOLE of the intended paddock landing area (this was in the order of about half a mile at around 500 feet .. much higher than that and you can't see much anything at all. Flying along the OTHER side I nearly died of fright .... all the wires I COULD NOT see from the first side .. and they crisscrossed the paddock like you wouldn't believe .. were crystal clear from the other due to sun position etc. Of course, he had set me up to learn a valuable lesson which has never left my memory.

For me, if you haven't got half an hour or more to check out a paddock in thorough detail prior to throwing the bird into it .. then you are sticking your neck out so far that it is very likely to get the chop .... be careful there, people. And I might add that I did a lot of paddock retrieves .. never came to grief but, in spite of very very thorough checks, I frightened myself on more than one occasion when something not seen materialised during the landing roll.

Mind you .. there were some funny things happen when it came to pulling gliders out of paddocks ... but I digress .. as usual.

Hopefully, we can get some experienced ag guys and gals to offer more comments on these sorts of problems ... they are the experts on low level ops ..

[Centaurus]

On final approach for the precautionary landing what IAS are people taught to cross the fence at? I have heard of two main techniques. Some aim at the normal 1.3Vs (Flight Manual) speed over the fence which means a significant float in order to touch down right on the stall. This becomes a problem on a short field.

Others of the old school of thinking, come in hanging on the prop at 1.1Vs or even 1.05Vs which means the stall warning is coming on intermittently. I have noticed that ex Navy pilots (now civilian instructors) who are used used to landing on aircraft carriers, favour the very low speed approach - which in turn gives no float at the flare and absolute minimum touch down speed with minimum landing run. I guess that is the safest option if the field is short and the grass is wet. Also means less energy if the wheels hit something hidden in the grass.

[Blue Hauler]

Centaurus

Certainly in the days of tail-draggers 1.1 Vs ensured the lowest touchdown speed in the three-point attitude. This allowed for full and immediate application of brakes. The P-charts back then were fairly sketchy until DCA addressed the problem by publishing a Flight Manual that took precedence over the manufacturers handbook.

It seems that modern flight manuals and more specifically landing P-charts specify a Vref/Vapp/TTS of 1.3 Vs and I don’t see that instructors are in a position to advocate otherwise. But having said that, such speed is normally attained at fifty feet above the landing surface and some five or six hundred feet short of the touch-down point.
The Cessna 208 manual for instance states:

"After all approach obstacles are cleared, reduce power to idle. Maintain 78 KIAS approach speed by lowering the nose of the airplane. Touchdown should be made with the power lever at IDLE and on the main wheels first. Immediately after touchdown, lower the nose gear, reposition the power lever against the spring in BETA range, and apply heavy braking as required."

The airspeed for emergency operation is specified “Precautionary Landing (Engine Power / Flaps Down) … 80KIAS”. The manual specifies Vso at 50 KIAS!

Since the approach speed is determined having due regard to possible turbulence or engine failure, operation at a lower speed would be outside the manufacturers instructions. Should we be training students otherwise? Would the consequences of taking out a barb wire fence at the end of a paddock be worse than loss of control on short finals?

[Centaurus]

Blue Hauler. I agree with you 100%. The 1.3Vs technique is the safest way to go. But by the very nature of the extra speed above the stall which must be dissipated by floating (in order to touch down at the stall), means that there is no such animal as a precautionary landing in terms of the actual handling technique. All it is, is a normal landing albeit more carefully aimed at a specific touch-down point.

Interestingly, one hears instructor briefings on the precautionary landing that emphasise that there is no float because of the low approach and flare speed and that power is kept on right to the flare lest one stalls if power is reduced prematurely. How can this be so if 1.3Vs Vref is 30% above the stall?

I believe that the misconception of the aircraft falling out of the sky if you use 1.3Vs at the fence, is a throw back to when precautionary landings were always at 1.1Vs - where the float was zero. Somehow, the myth has been passed down over the years that one is always on the razor's edge of a stall on a precautionary landing. Not so if you are using the Flight Manual recommendation of 1.3Vs- which is the speed used in the landing tables.

Also the speed at 50 feet means nothing except that when carrying out certification flight tests the speed chosen for approach must be maintained to 50 feet as a certification standard. It does not mean that the pilot can now make a dirty dive at the deck with all bets off at fifty feet.

If John_at Tullamarine is watching this thread perhaps he can clarify this?

[Blue Hauler]

Centaurus

"by the very nature of the extra speed…means that there is no such animal as a precautionary landing in terms of the actual handling technique."

The same could be said for the short field landing. On every approach (transport operations) I calculate landing weight and determine Vref or Approach Speed, fly a three degree glide path, touch down on the thousand foot markers and stop the aircraft. Any excess runway used is in the roll-out simply minimises brake wear. Ignoring the stopping distance I am flying a short field approach because the book does not give information for a long field approach.

However in teaching STOL I would emphasise, in addition to the above, the need for maximum braking. Any other techniques instructed are simply airmanship to help the student achieve an accurate speed and flight-path - a stabilised approach.

P-search is just as much about field selection as flying the approach and landing. In some instances other considerations may take precedence. I once recall completing a P-search during a SAR operation that required a soft field technique; a long clay runway, partially submerged and very slippery. Other off-field landings have involved rough ground, long grass, sand and tricky approaches. But although the strips were often short I have never been faced with running out of distance! Probably lucky you say or perhaps early training in P-search led to better management.

[john_tullamarine]

The comments I might make would be

(a) STOL is not a civilian operation. The certification addresses the normal sort of approach .. not a near stall beastie. I would be very reluctant to play with this in anger if it had not been investigated formally.

(b) an engine failure becomes a guaranteed crash in all likelihood for a very low speed approach. My attitude is that one is better to land very definitely under control and take the risk of a possible overrun if the assessment turns out to be wrong (terrain having been considered) rather than spearing in short after losing control.

(c) there may be undesirable longitudinal stability problems, especially with a bigger motor, trying to shoot an approach at the lower speeds .. especially in the event of a missed approach .. even the lovely old SuperCub is a handful (and footful to help the hands trying to push the stick forward) on a missed approach ... maybe the 30 year gap since I last flew one has mellowed the recollection .. but the basics are still correct.

(d) as we are talking precautionary landings, there is the inference of sufficient time to make a detailed assessment of the relevant paddocks so the probability is that there will not be too many surprises .. the only times I have frightened myself a little in years gone by on glider paddock retrieves is (as is sometimes the case) having to approach into sun in the late afternoon...

(e) I would keep in mind that the origin of performance landing data in the books involves a worked up mathematical model for the aircraft which is validated by a TP doing his best to get "good" data. The most exciting (terrifying ?) of my flying has been on just such flights in GA aircraft.

One ought not to expect that one, being an ordinary sort of mug pilot, can achieve anything like what the usual test program might demonstrate. The sort of flare which I have seen some TPs do is not, shall we say, what you or I might do in normal operations. Far better to do a nice, stabilised approach and a well controlled flare with minimum float and an early touchdown.

Trying for a dive at the ground to save a few yards ground roll is just plain silly. The risks associated with destabilising an approach are great .. and there is the very real risk, on occasion, of doing the nosewheel in due to an inappropriate assessment of the surface hardness.

(f) I would be most reluctant to try for a near stall touchdown ... difficult to control the touchdown and, in any case, the aircraft decelerates far better on the ground under braking than it does in the air. No percentage at all in doing this ... quite silly