Take off and landing performance

[TractorBoy]

I've only recently (about 4 weeks ago) passed my PPL after a hectic 6 months, and am beginning to look round for places to go. However, I have a question which I hope the more knowledgeable amoungst you may be able to help me with.

I'm currently flying a Cessna 152, and if I look in the POH at the short field landing figures (for example) for SL and 20 degrees C, I see that the landing distance from 50 feet is 1215 ft. This translates to 370.3 metres. If I apply the factor for dry grass of 1.15, this gives 425.8 metres. If I then apply the safety factor of 1.43, this gives 609 metres (for wet grass it goes up to 714 metres). If I look through Pooleys, there are numerous airfields where the quoted LDA is a lot less than this e.g Clacton (502 / 542 metres), Stapleford ( 500 m on the crosswind runway ). These are the ones nearest me, although I'm sure there are lots more.

Technically, if I go by the calculated figures, then a 152 should not be able to land on them at all - now I know that the Stapleford runway is regularily used, as I learnt there and have landed on it myself, and 152s are operated from Clacton. The same thing can also be done for the TODA figures. In some cases, the quoted values are exceeded BEFORE applying the safety factors.

Shouldn't we be basing our decisions on the values calculated this way - and if so, how come anyone operates from Clacton at all ? ( I'm not picking on Clacton, it's just near me and I want to use it !!! ) - the discrepancies in values aren't small, either.

So what's going on?

[Gertrude the Wombat]

Well, of course you can theoretically deduct a few percent for a headwind, but personally I never do, just to be on the safe side and after all this sort of field might not be able to give you a reliable wind report just before you touch down and they probably don't publish a TAF and the forecast wind for the airfield fifteen miles down the road might not turn out to be applicable.

Net result: I go somewhere that's just on the margin according to these calculations and use just under half the runway. (Having practised short field landings on a proper runway first.)

What happens to people who ignore the results of these calculations? Well, there must be some explanation for the several people who go into the hedge at the far end each year.

I haven't yet tried to fly anywhere that

(1) is well outside the calculated requirements, and:
(2) has several based aircraft of the same type regually engaged in ab initio training

but I guess I'll want to one of these days (popping into Clacton in a 172 to take the kids to the beach was something I was maybe thinking of wanting to do this year but I never actually planned it as the weather was never good enough the right day).

[Flyin'Dutch']

I see that the landing distance from 50 feet is 1215 ft.

You don't have to be at 50ft over the threshold.

If your calculations look 'tight' speak to someone who knows the airfield and the aeroplane and ideally you too and get their advice.

As time goes on and you will gain experience from both flying on your own and with a good instructor you will become better and more comfortable in operating into airports and airfields that are less big.

[Genghis the Engineer]

Yes, experienced pilots the world over use headwind, light weight, experience, etc. to modify the size of runway they need. On the other hand, they also sometimes make the same judgment and increase the amount they use ABOVE the calculated distance.

My advice would be to use the manual to the letter for at-least a year, you recognise yourself that you aren't all that experienced yet (the rest of us just have to keep reminding ourselves that we aren't experienced enough either). Until you are really familiar with your regular flying machine, in and out of a selection of runway types, you'd be best using the strict numbers and safety factors - that's what they're there for.

If it's a runway you trained on, then carry on as before, but I'd just quietly regard any "unknowns" as out of bounds if the sums don't work out for now.

Also, download the GASCo performance calculator from here (http://www.bmaa.org/techdocs.asp?DocumentTypeID=7&DocumentType=Miscellaneous). It should make doing the sums relatively easy without having to get your calculator out.

G

[IO540]

The problem with all these generic calculators is that they are just that... generic.

Every pilot should obtain the proper takeoff performance chart for the specific type. The figures in that are usually right, for a max performance (i.e. rotate at just above Vs) takeoff. That will be for a hard runway.

What the CAA flyers tell you is to add 30% for grass, another 30% for wet grass, etc, which is probably excessive for short grass.

I can't make the links work, BTW.

[Chimbu chuckles]

Tractorboy the point you, and others, are missing is that about half that 1215' you quote from 50' is air distance.....i.e distance travelled BEFORE you get to the threshold.

On short grass strips of the type you are referring to you would typically be touching down around 30-50m in from the actual threshold. Just past the first cone marker. 50' would be easily 200m before that point...over the field before the one you're landing in...and that's why we always SEEM to stop in 'half' the distance reqd by the graphs. Having pulled the figures and buffered them up hill and down dale and decided the strip is 'marginal' we white knuckle our way down and then stop mid field..and wonder why?

The same applies on takeoff...you can, and often do, climb out to that 'magical' 50' past the far end.

In neither case is the 50' point within the confines of the 'flight strip' ...nor does it have to be....in airliners/transport category aircraft we call it Clearway.

God grief as a young fella with 300 hrs I used to operate C185s and Islanders in and out of 385m/3000-5000 elevation and ISA+20...500m in a Cessna 152/172 is a doddle:ok:

[FlyingForFun]

Just as a point of interest, see if you can find yourself an airport with an instrument approach, and a full set of PAPIs. The PAPIs are, near enough, where an aircraft "should" touch down if it is 50' over the runway threshold. You will notice that, as per the comments above, this is a long way into the field.

However, as Genghis suggests, I'd stick to either what the manual says, or else runways which you're familiar with, until you have a little more experience. If you particularly want to go into a field which the manual seems to suggest shouldn't be possible but which you think would be, then discuss it with an instructor first (preferably one who knows your abilities, the aircraft's abilities, and the field in question), and if you're still in any doubt get the instructor to go with you the first time.

Bear in mind that in most "spam-can" types of aircraft, the landing distance will be much shorter than the take-off distance, so it is your short-field take-offs which you need to be practicing.

FFF
---------------

[Genghis the Engineer]

Bear in mind that in most "spam-can" types of aircraft, the landing distance will be much shorter than the take-off distance, so it is your short-field take-offs which you need to be practicing.
However, also bear in mind that whilst we all can accurately predict where we'll start the take-off, the start of the landing can be a bit less predictable.

G

[john_tullamarine]

Three observations ..

(a) factor me this ... after one attempts a take off/landing at a strip which is significantly less than whatever the relevant airworthiness authority dictates and fails to complete the exercise with a huge level of success .... (history shows many examples of such events) .... at the enquiry/court case/insurance claim/whatever ... how does one explain away the situation without leaving oneself a tad open to censure ?

Not suggesting that I have never done anything stupid in an aeroplane (I flew SuperCubs for quite a few hundred hours and that Type is a blatant temptation for a young chap to be innovative when it comes to paddocks and other off aerodrome operations) ... but one ought to have a few brain cells thinking about the enquiry which might ensue from one's more cavalier actions ...

This is not to suggest that one cannot fit the bird into the field by doing appropriate things .. but that is a bit short of showing compliance with the design and operating Standards relevant to the operating environment within which the fitting might be done...

(b) if I may echo Genghis' helpful observations from time to time ... one is at risk if one assigns a VERY high level of accuracy to whatever numbers come out of a performance chart .. they ought to be used in a somewhat rubbery, conservative manner lest one be embarrassed by the scatter inherent in such animals.

(c) while I will not waste my time checking Genghis' reference corrections (I know his technical competence to be somewhat more than necessary for his assessment of the charts' validity) they look to be fairly typical and consistent with normal models. If one is operating to the typical POH with unfactored data then their use ought to be mandatory at the personal level.

[Chimbu chuckles]

Ghengis I don't quite understand what that graph is for...it has no specific aircraft type on it that I can discern?

JT are you suggesting no difference between TODA and TORA and the same for the landing case?

That we shouldn't apply a bit of common sense to the book figures?

Can't quite figure out your post otherwise.

Brgds

Chuck

[Genghis the Engineer]

Exactly!

The graph has general scales on both the left and the right hand side. Using any units that suit you (feet, metres, leagues, furlongs...) mark the standardised take-off or landing distance on the left hand side.

Then, the various lines allow you to apply, accurately the standard safety factors for tailwind, slope, wet grass, variability, etc. as published and used pretty much worldwide (but I happen to know that this chart used the specific figures published by the British CAA in AIC Pink something_or_other).

This leads you to a value on the right hand side which you can read-off for the safe planning figure for the runway you choose to use.


You'll notice that it does not show proverse factors - that is anything in your favour (high pressure, headwind, lightweight aircraft) is ignored. Whilst you might disagree with this approach (I do!) it is safe, and is the approach promulgated by most national authorities for light aircraft planning.

Where "common sense" comes in (and we all apply it) is where we allow for a lightweight aircraft, downwind take-off, headwind - things that are taken account of in big aeroplane manuals but not usually little aeroplane manuals (the obvious exception being the PA28 for some reason). But, I'd be reluctant to suggest that somebody recently qualified should try to make those judgements.

G

[S-Works]

perhaps it is the ground roll that needs explaining here rather than going into great discussions about clearways etc.

The actual landing roll on a 152 if flown to the correct speeds and not the 70kts that seem tobe taught by most instructors is actually very short indeed. The take off role is also short in a 152 again if flown correctly.

I own a 152 and over the last thousand or so hours have put it into a lot of very short strips. I look for the landing role distance available as being from the point the wheels touch the ground on t he way in and from the point the wheels leave the ground on the way out. On a normal day I can get in and out of 300m without breaking sweat.

The problem with most spamcam drivers is they fly the aircraft to fast, either through bad instruction or bad technique.

So here is a question, what is the safe approach speed for a 152 with full flap that will give the shortest landing distance?

Next what is the correct rotate speed that will get you cleanly of the runway in the shortest distance.

Lets compare notes.

[Final 3 Greens]

Bose

Been a while since I flew a 152, but I seem to remember that it worked pretty well at 55kias for both.

However, I'd be interested to hear your views as your 152 experience is an order of magnitude more than mine.

[S-Works]

Pretty close. You are right it will work pretty well at the speeds you quote and on long runways at other speeds as well!

All figures at Max weight.

Short Field: The correct lift off speed is 50kts IAS and accelerate to 54kt IAS by 50ft. At sea level on an unfactored surface this will give you a ground roll at 10c of 210m.

My aircraft has the "sparrow hawk" conversion with Sensenich prop rather than the standard cocktail stick on the front and a gap seal drag reduction kit K&N Filter etc which takes another 15% off the ground roll.

Approach speeds: The straight and level clean stall speed at normal CofG is 36kts IAS (on my aircraft it is 33kts IAS due to the drag reduction kit flapped speeds are also reduced). At 10d flap stall speed is also 36kts IAS and at 30d flap its 31kts IAS

The 50ft speed is 54kts IAS with a threshold speed of 45kts at full flap. On a 10c day on an unfactored surface this gives a ground roll of under 140m. Lowering the threshold speed with currency on type further lowers the ground roll. On a good day I can beat 100m.

[Maxflyer]

Bose-X

When I land your 152 you need to add approx 200M to your figures!

[Genghis the Engineer]

Without doubt you can improve upon the published figures for any aeroplanes - the values are based upon the speeds in the POH, normal handling techniques and include a requirement that the speed at 50ft (both on approach and climb-out) must be no less than 30% above the stalling speed in that flap/gear setting.

BUT, whilst that may be reasonable behaviour on the part of somebody with hundreds of hours on type, it would be unwise of somebody new to a type (or new to a licence) to attempt such practices, and EXTREMELY unwise of an experienced pilot to encourage such a person to try.

G

[S-Works]

Actually Genghis, I WAS quoting book figures! Which makes my point that most people fly the average spam can at the wrong speeds.

I also stated the figures were unfactored and as such it is the responsibility of the pilot to factor as they see fit. The point being that if the aircraft is flown at the correct numbers it will easily go in and out of these places.

In capable hands my plane will go in and out much better than the book figures.

[Genghis the Engineer]

However, you were quoting roll, not distance. Planning is generally done to distance.

G

[S-Works]

Genhis, I say again, I say again....

I WAS quoting the POH, would you like the page and paragraph numbers as well......

My POH gives both sets of figures and I quoted roll to explain why people can and do safely fly into runways that seem to be to short on the face of it.

:p :D

[Chimbu chuckles]

Ghengis how can one make an informed decision on whether a strip is suitable or not without having a knowledge of the difference between T/O or Landing roll and distance...either available or required?

If you approach to land on a normal 3 degree slope (and single engined light aircraft don't generally but it gives some basis to begin understanding) that equates to 320'/nm. 320' every 6080' or 50' every 1000 odd feet.

Now I think a C152 approaches steeper than that but since it's been 20 + years since I flew them a lot I have no idea of a super accurate figure....to be conservative lets call it half the foregoing...500' before the aiming point you pass 50'...151m. So a minimum of 151m (my first estimate you will recall was 200m which I think is more accurate but still conservative) out of the 370m figure from the first post is before the touchdown point. These rough figures seem to gell with bose x's POH.

The touchdown/aiming point on strips of the type discussed here should be between the first and second cone marker...if not down by the third cone marker good airmanship dictates a go around in my opinion.

The 50' screen hieghts are certification figures...how many airstrips actually have a 50' tree/hill/building/power lines at the bitter end of the TORA? Precious few.

I am all for being conservative with new pilots just starting out but is not 3 times the landing run required being available conservative enough? In my opinion a 30% buffer is completely adequate unless conditions are extreme....far to many pilots buffer their buffers for no good reason and then decide something is not safe, possible or 'legal'.

In PNG for reasons, generally, of DA and slope the vast majority of strips did not fit on the P charts at all and yet we generally took full loads in and out safely and with ease...I am not suggesting bush flying is the realm of newly minted PPLs but some common sense must be taught and applied lest the aircraft's basic utility be ignored and the nanny state/fun police be allowed to take over:ok:

Brgds,
Chuck.

editted for poor spooling.

[Genghis the Engineer]

But we are talking about a newly qualified pilot - that is the purpose of the thread.

Yes, we can, should, and do split up TODR and TORR, but we ALSO consider clearway. The approach of using the 50ft clearance height whilst still over the runway avoids a lot of calculations and judgements. The ability to handle those is not taught in the PPL, and I'm still of the opinion that a year or so of club flying to get the basic information bedded in, to build up some experience upon which judgments can be formed, and not least to become consistent enough in your flying that it's safe to make any kind of judgement - all of those are needed.

I'd defend to the death (well, yours anyway) the right of an experienced pilot to make those sort of judgements, and would only comment that they MUST develop enough understanding and consistency first. BUT, I really don't think it's appropriate to recommend to either a new PPL, or the average (12 hours per year) club pilot that they even contemplate it.

G

[Chimbu chuckles]

Fair enough...I feel suitably chastised:ouch: :ooh: :uhoh: :ugh: :{ :( :}

[S-Works]

.... and none of us were reccomend that a newly minted PPL tried to do anything outside of the POH. Which is WHY I quoted the POH figures.

The question was also being answered as to why people fly at these common TRAINING airfields when the figures state that it should be impossible. I say again.... TRAINING airfields not tight little strips that require an experianced pilot on type.

What I am saying is that I think a year of "club" flying will probably make them incapable of flying into tighter strips because they fly the aircraft incorrectly either through evolution of bad practice or more commonly through bad instruction.

I sit and watch people fly 152's like they are airliners, massive circuits and eating runway like a model on coke.

If the pilot fly's the aicraft in accordance with the POH and is taught to fly it that way correctly then all of the airfields mentioned at the start of this post are easily achievable.

A good pilot who wanted to fly to one of these fields and was concerned would seek guidance and maybe an accompanied flight with an instructor first.

And if pilots flew the correct numbers instead of the common 10 -20kts over the correct speed they would need less runway!

[Genghis the Engineer]

And if pilots flew the correct numbers instead of the common 10 -20kts over the correct speed they would need less runway!
Amen!

G

[S-Works]

ah, at last we agree!

:p :D :cool:

[Genghis the Engineer]

Also agree totally on the circuit size issue.

I recall flying my PA28 into Sywell last year, slotted in downwind, followed the aircraft in front (similar type), turned crosswind when he turned finals, then had to get the *&^&^& chart out because we were actually out of sight of the runway. I could have got in two circuits in that time.

Wouldn't mind so much, but I was paying for that flight!

G

[TractorBoy]

I must take issue with a few points raised here.

1. It's true that most of the landing distance involved is due to being at a height of 50 feet at the threshold, but if you refer to CAA Safety Leaflet 7, it points out that after applying all relevant factors, that the LDR from a height of 50 feet should not exceed the LDA (with is measured as being from a height of 50 feet above the threshold). So we have to base all calculations on this figure.

2. It has been pointed out that if pilots fly in accordance with the POH and at the correct speed, that all the examples used are within limits. They are not. The figures I used at the start of the post were taken verbatim from the 152 POH and assume a correct short field landing technique being applied ( at 54Kias / 30 degree flaps ). In fact, the POH only contain figures for short field landings & take offs and does not contain any others.


3. If I had taken my test on the short field runway that is available at my home airfield, and applied all the required factors, using the correct figures issued by the CAA, and showed it to my examiner - he would have been well within his rights to fail me for even attempting to take off, even though the runway is regularily used.


Now I accept that the safety factors are a little excessive, that you can clearly land in a much shorter distance - indeed even I, with my limited experience, can quite happily stop within 200 metres using short field technique, and the safety factors are only suggested, but they are the only guide we have. Why ignore them? Indeed in the case of public transport, they are a legal requirement. What happens in these cases?

If the figures are so pessimistic, shouldn't they be altered?

[S-Works]

Its called arse covering and our CAA are very good at that.....

In inexperianced pilot would be wise to think about it. With experiance comes the ability to assess risk more accuratly and then you decide for yourself just how much of your arse you want to cover at any moment in time.

The CAA safety leaflets are advisory only not law for private or public transport. For public transport the operators have there own set of rules for factoring.

If you believed every advisory the CAA issued you would never use a GPS, fly in reduced viz or croswinds in fact never leave the ground.

Dont get to hung up on it, go out and fly these fields and if you are unsure take an instructor with you, they should be experianced enough to help you make the correct choices.

Where are you based? If you would like to come and see where a 152 wil go SAFELY I will take you for a trip.

[DFC]

With regard to proverse issues, one is required to be able to land at an aerodrome on the longest runway in no wind and on other runways in whatever wind is available (50% headwind).

Thus it is expected that one will use the longest runway until the crosswind exceeds the limts then uses the cross runway which by then will have a good headwind factor.

Since most GA operations are from single runway airfields, this is seen as an unnecessary complication for the ammateur pilot.

If anyone has a copy of Campbells book there is a nice graph for using the headwind.

Regards,

DFC

[Chimbu chuckles]

Tractorboy I think you're missinterpreting what is written in that leaflet...yes you're supposed to be at 50' at the 'beginning of the LDA' but that DOES NOT mean 50' over the threshold.

If a representative of CAA has told you that he is just plane wrong.

Do you really think that CAA would tolerate all these operations off short strips if they were illegal?

Surely the examiner you mention would be out at the field recording registrations and times for the enforcement actions that would follow.

Given the early stage of your flying career you may not yet have realised that CAA has a significant % of employees (pilots and others) who are there because they couldn't cut it in the real world, it is the public service after all...unemployable so joined CASA is very common in Australia...the FAA are no different....and yes I do have enough Brit and Yank pilot mates to be comfortable making that assertion...Kiwi ones too....the BS doesn't vary, just the country.

I recently was angered enough by an article in Australian Flying that I blasted off an email to the editor, which was published albeit edited.

The article referred to 'CASA's preference' for landing light piston twins at blue line speed...which is single engine climb speed...and depending on the aircraft 20-30kts to fast. At the takeoff end of the article it purveyed a technique where the aircraft was rotated at some low speed and climbed out before 'turning off the boost pumps, raising the flaps and accelerating to blue line speed at 500'. There is just no better way to die in a light piston twin!!

I have trained more than my fare share of relatively inexperienced CPLs (2-300 odd hrs) to bush fly C180, C185, C182 and C206 and a bunch more in Bn2, C402, 404, Twin Otter.

I think you should crawl over broken glass, if that is what it takes, to go for a fly with bose x.:ok:

Brgds,
Chuckles:ok:

[J.A.F.O.]

And given the numbers I was taught I should crawl over broken, molten glass.

[S-Works]

There is a man who flies a certain taylor craft at my club that can land in the 6 inch gap that I leave between white line and wheels on the spot landing competition......

Chalk dust, there was definatly chalk dust.........

And I am gonna beat him next year, if not at spot landing then black and blue......

:O :cool:

[Gertrude the Wombat]

In fact, the POH only contain figures for short field landings & take offs and does not contain any others. Ah yes, that one. I have wondered how you know when a runway is long enough not to need the short field techniques (flaps. full power against brakes, whatever) - it sure ain't from the POH.

[DFC]

yes you're supposed to be at 50' at the 'beginning of the LDA' but that DOES NOT mean 50' over the threshold

It means that on a normal approach profile you are to be at 50ft at the beginning of the LDA which is at the threshold.

That threshold may have been displaced leaving some runway prior to the displaced threshold but that is usually for obstacle clearance requirements where having the aircraft at 50ft at the start of the runway surface would not provide the minimum separation from as an example traffic on a road.

It could be argued that while one is exempt from the requirements of rule 5 when making an approach to land in accordance with normal aviation practice, making that approach below the normal approach surfaces would not be normal aviation practice. Thus, creep over the hedge to touch at the start of the displaced ie well below normal minimum approach path) and frighten a horse rider on the public pathway that underlies the approach and they could claim that you did not operate in accordance with normal aviation practice or for that matter safely!

If of course it is an unlicensed airfield then many of the interesting ones are over a hedge and the 50ft is immaterial!

Cessna and other manufacturers only publish the best performance figures because they are in no small part a sales measure.

If you want to use other than the published method then;

a) Think about what the insurance implications are

b) If using a higher speed then it could be useful to use the tailwind factor as in part that is what you are doing in effect by travelling at a higher ground speed before lift off.

c) For different flap settings - flaps shorten ground roll but reduce climb rate - work it out for yourself!

Get some lessons in landing with a good side-slip can help! :)

Regards,

DFC

[Chimbu chuckles]

CAO 20.7.4 say the following....I am reasonably sure your CAA equivalent is worded very similarly.

10 LANDING DISTANCE REQUIRED

10.1 Subject to paragraphs 10.3 and 10.4, an aeroplane must not land unless the
landing distance available is equal to or greater than the distance required to
bring the aeroplane to a complete stop or, in the case of aeroplanes operated on
water, to a speed of 3 knots, following an approach to land at a speed not less
than 1.3VS maintained to within 50 feet of the landing surface. This distance is
to be measured from the point where the aeroplane first reaches a height of 50
feet above the landing surface and must be multiplied by the following factors:
(a) 1.15 for aeroplanes with maximum take-off weights of 2 000 kg or less;
(b) 1.43 for aeroplanes with maximum take-off weights of 4 500 kg or
greater;
(c) for aeroplanes with maximum take-off weights between 2 000 kg and
4500 kg, a factor derived by linear interpolation between 1.15 and 1.43
according to the maximum take-off weight of the aeroplane.

10.2 For aeroplanes operated on land, landing distances are to be determined for a
level short dry grass surface. For aeroplanes operated on water, landing
distances are to be determined on flat broken water.

10.3 Subject to paragraph 10.4, where there is an approved foreign flight manual or
a manufacturer’s data manual for an aeroplane that sets out the landing
distance required for that aeroplane, then that aeroplane must be operated so as
to comply with the requirements set out in paragraphs 10.1 and 10.2 or the
requirements relating to landing distance set out in either of those manuals.

Note: The data contained in some manufacturers’ data manuals is unfactored and makes no
allowance for degraded aircraft performance. Where there is a considerable difference
between the data in a manufacturer’s data manual and the data in the flight manual for the
aeroplane then the manufacturer’s data should be treated with caution.

Now I would agree that it is not worded particularly well and this is usually the case with these things...heaven forbid they would make something unequivical:ugh:

It is my contention that the statement 'this distance is measured from the point where aircraft first reaches a height of 50' above the landing surface' refers purely to height not geographically above the runway.

This rule covers both water landing capable aircraft as well as non...where on an open stretch of water that meets the requirments of an alighting zone is the threshold?

So in the case of a Cessna 180 on floats the LDR starts when that aircraft passes 50' above the 'landing surface'...an altitude not a geographic location.

Why would a landing on a runway be considered so different and yet still be covered under the same Order?

In the normal course of events when on approach to a runway with no obstacles to that approach you fly a normal approach, at an appropriate speed, to the touchdown point/aiming area/zone whatever you want to call it. LDR, IMHO, begins over the geographical point that correspondes to an altitude of 50'....but you might in fact pass the threshold markers at 30' or 20'. If trees have grown tall on the approach causing a normal approach to be made to a point further away from the threshold then you have a reduced effective length and Land Roll Available/Required would certainly be an important factor....an exxperienced pilot might chose to side slip past the trees and still touchdown at the same point as before the tree grew and I think that would be appropriate in the class of aircraft we are discussing...but that is not the point.

If this is not the way the CAA choses to interpret the rules then why are the airstrips mentioned in this thread allowed to exist...let alone be used as training fields which surely need to be approved for the class of aircraft to be used? Surely any airstrip to short for a Cessna 152 is to short to be of use to any aircraft save an ultralight or Pilatus Porter?

I don't blame todays new pilots for being confused about this stuff....it's been a VERY long time since the average instructor has had the practical knowledge, desire and skill to teach this stuff...all most are interested in is that shiny jet job and they filter all knowledge through that prism..."In the big jets they do things this way or that...so that is the way it must be done"....and guess what? Most CASA, CAA,FAA examiners of airmen are ex instructors who never made it passed instructing to the real world of aviation....and yes the real world is a LOT different to the flying school world.

That is why you get dumbarse 'preferences' for landing a piston twin at Vyse...95% of their twin time is instructing, 5% is charter but they have never operated one on limiting runways day in and out....They just don't know what they don't know and pass that ignorance on to their students...and then people like me, when I was in GA, have to retrain them out in the world.

The only similarity between a C152 and 767 is they both carry people and are capable of powered flight...and there it ends. A Cessna 152 is just the modern equivalent of a Piper Cub and should be flown accordingly....with feeling and a little art!

Where do you think the expression "...kts over the fence" came from? But sadly the art and practical application of a light aircraft is being lost under a pile of arse covering crap dealt out by the lowest common denominator.

[djpil]

'this distance is measured from the point where aircraft first reaches a height of 50' above the landing surface' As stated, this is how it is measured. Now reread this bit:
an aeroplane must not land unless the landing distance available is equal to or greater than the distance required to
bring the aeroplane to a complete stop What's the definition of "landing distance available"?
"... the distance specified by CASA as being the effective operational length available for use by aircraft for landing at Government or licensed aerodromes or the distance available for landing on an authorised landing area .." So, for a licensed airfield you must get that distance from the good book and the distance required from the POH gotta be less than that. Some room for debate for an ALA but not a lot - if an area is not available for landing then it is not included in the distance available for landing.

As some-one previously stated, we're discussing the rules for less experienced pilots. I know an experienced pilot who operates 3 aircraft from his 450 m one-way strip quite happily.
A student asked to go in there with me on a nav exercise. After checking the POH for the PA-28 he still wanted to go. I declined and took him to a nearby unlicensed strip which was much longer. Even that caused him some grey hairs.

We have lots of places for long runways in Australia, so personally I don't see a need to go anywhere with marginal distance. If I was flying a Husky I'd be happy to land almost anywhere though.

[Chimbu chuckles]

Now I am prepared to admit the wording is a little restrictive but let's take a look at effective operational length.

CAO 20.7.somethingorother

Corrected Effective Operational Length: A length of runway — including
over-run — expressed in feet, corrected for slope, runway surface, and
approaches, declared by CASA as usable for take-off or landing by a particular
aeroplane.

So here effective operation length includes overrun. It also makes mention of 'approaches'.

Effective Operational Length can include stopway and clearway for takeoff.

So is EOL always going to be = the actual length of the runway?

I think I've never seen a runway, grass or other, where the threshold was the beginning of the overrun.

So if a runway has an overrun (with clear 'approaches':E )...and most certainly do...I can be at 50' at the beginning of the overrun which is the beginning of the EOL?

So therefore the EOL is the distance between the point at which I pass 50' and the far end of the runway...and if that distance is equal to or greater than the LDR as found in the POH I am legal...and wasn't at 50' over the threshold.

I have looked and looked but can't find where Operational Length and Effective Operational Length are defined differently...in fact I find no reference to OL at all. References can be found to ground roll and clearly the rules deferentiate between that and distance which has a component which is airborne. No where does it say you must be at 50' over the threshold.

It would be an interesting point of Law:ok:

Out of interest what types did the fella operate from the 450m strip 'quite happily'? I don't think I'd be keen to take a PA28 into a 450m strip either but did the numbers say it was long enough EFFECTIVELY:E

I love thrashing this sort of stuff out :}

Brgds,
Chuck :ok:

[djpil]

Yep, 20.7.0 it is - and, as you say, again a reference to a CASA declaration. "For the purposes of computing take-off and landing weights the corrected effective operational length shall be determined by reference to Aeronautical Information Publications, subject to variations contained in NOTAMS." I was looking forward to finding the answer in ERSA but no mention of that.
ERSA defines take-off distance (TODA) available as the length of the take-off run available plus the length of any clearway and landing distance available (LDA) as the length of the runway declared available and suitable for the the ground run of an aircraft landing (in most cases this corresponds to the physical length of the runway pavement).
Leongatha RW 36 for example has a TODA of 729 m. At the northern end there's at least another 700 m of grass before the fence. (However, the take-off run available is 669 m i.e. suitable for the ground run.) I note the hill further to the north.
Terminology of ERSA is consistent with CAO 20.7.4 - although I see that extra 700 m and there's 669 m I can use to run along the ground - I must use the distance of 729 m in my calcs.

That Warrior has an ISA SL take-off distance of 503 m and a landing distance of 354 m per the POH for a paved, level runway - unfactored distances. Effect of short dry grass outside the scope of tonight's post.

Dunno whether I can tell you what types without giving enuff info to identify him from the register. One type is heavier and faster than a Warrior. Another has no flaps.

[englishal]

If it doesn't look right, it probably isn't.
;)