Calculating Approach speed --additions

[RansS9]

Aside from 1.3Vs (computed to the landing configuration) what other additions do you make and why?
I've read about a number of different additions including half max gust strength (is that the whole gust strength or just the additional"gust" above the steady wind ?). Alternatively steady state wind plus "Gust Factor". Are the winds those reported or their resolved components ie those (hopefully) headwind components only?
This is particularly in relation to light aircraft.

Thanks TIM

[renrut]

I've always used 1/2 the factored wind speed plus all the gust

[UncleNobby]

Half gust factor - if wind is 10G20 add 5kts to approach speed.

[A and C]

In a light aircraft the 1.3Vs is all that is required, far too much is made of approach speed by those who want to make themselfs feel important by turning flying into a black art.

Far too many short runways have holes in hedges at the ends made by people who have added a few Knots for this and a few knots for that to the approach speed resulting in an approach speed that looks like the Vref for an airliner.

Next time someone starts this adding speed to what is in the flight manual tell him he is being TFC and remind them that the extra speed blows holes in the flight manual landing distance.

[one dot right]

It also blows holes in the flight manual performance to stall into the near hedge, makes a complete mockery of the ldr, reduces it something chronic.:oh:

Half the gust factor added to 1.3 vs, perfectly acceptable practice.

[Chuck Ellsworth]

How many pilots are taught how to find and fly optimum alpha angle for short strip approaches and landings?

[NigelOnDraft]

Half the gust factor added to 1.3 vs, perfectly acceptable practiceMaybe, but so long as it is now understood to be the "average" speed, not a "minimum" ;)

NoD

[S-Works]

In a light aircraft the 1.3Vs is all that is required, far too much is made of approach speed by those who want to make themselfs feel important by turning flying into a black art.

It is nice to see sometimes we agree on things A and C.
:)

[Pilot DAR]

It will sound like a harsh rebuke of the question, which I don't intend, but;

Where the choice is being made to fly an actual airplane, as opposed to a numbers based simulator, enjoy flying the plane, and practicing with greater precision and skill each time! Feel the plane. It will tell you what the optimum speed will be on final based upon the conditions. Not to suggest that there are not occasions where a slight increase in approach speed might be warranted, but generally, it should not be needed. Aircraft have lots of control.

Adding speed will just mean that you will be displacing your touchdown point further down the runway. If you have the space, or that is what you intend, great. If you are planning to touch down in the touch down area of the runway, then approach at the approach speed published by the aircraft manufacturer, or 1.3Vs1.

If the conditions are so gusty that this speed leaves you feeling not confident, then increasing your speed will probably just take you to a place to feel less confident, a little further away! If things are that bad, perhaps landing somewhere else is a better idea.

Under suitably skilled supervision, fly a few circuits with no airspeed information presented to you (pretend a failed ASI) You'll find that once you learn to feel the plane, you'll actually fly your approaches a little slower than the book speed, and feel quite fine about it.

[one dot right]

In a light aircraft the 1.3Vs is all that is required, far too much is made of approach speed by those who want to make themselfs feel important by turning flying into a black art.

I believe airbus uses something called 'groundspeed mini' which is an increase in airspeed to maintain a groundspeed that would be equal to 1.3 VS should your headwind suddenly not be there, leaving you out of height,speed,control and ideas all at the same time.

While I agree the effects of inertia are far less on a light aircraft, why should you not safeguard yourself against such an event by a moderate increase in airspeed?

[Chuck Ellsworth]

I still dabble around at teaching advanced flight skills and here is what I prefer to using the airspeed indicator as my safe speed profile.

Alpha System Lift Reserve Indicator (http://www.mountainflying.com/Pages/articles/alpha_systems_aoa.html)

[RansS9]

--Feeling the force, improving awareness of the plane is all admirable and should be practised but I'm not sure how that helps when you need a buffer in gusty conditions. My understanding is that it is done by pilots repeatedly testing "buoyancy" levels through the response to small inputs and is a problem for FBW to replicate; but with gust induced windshear I suspect reaction times are such that you could easily overstep the mark.

--Alpha indicators good idea only instrument on the Wright Flyer. However if the variation in aircraft weight is minimal I suspect the ASI is as good in which case it's the same question asked a different way. What airspeed would you target as opposed to what AOA would you target?

--Like other posters I am not looking at endless additions just ideas on altering approach speed / AOA to leave exceptable safety margins in gusty conditions. Safe so as not to stall out on approach nor to overshoot the end due to excess energy.

TIM

[WorkingHard]

Do what you like on thousands of yards of tarmac BUT try some additions to approach speed into a short strip and be quick to execute a go around or else find the far hedge. Get your speed right on the approach and make sure your approach is long enough to get it right. Oh and of course make sure you are familiar with the aircraft you are flying.

[gordon field]

Chuck: Some seriously good advice on your link under Mountain Flying. Alpha System Lift Reserve Indicator

[BackPacker]

If you're doing a homebuild/permit aircraft and get the Dynon EFIS with the AoA pitot head, you've got the same system. It measures AoA through a pressure differential between two ports placed at a different angle. Not very much unlike your ASI, which measures a pressure differential too.

[Maoraigh1]

If you're not making much over-the -ground speed, you're unlikely to hit the far hedge. You're likely to lose a lot of airspeed with windshear. Know your strip as well as your plane. 20+ knots wind along the runway has a big effect on landing and take-off distance for light aircraft. Trees etc will produce turbulence and downdraft.

[Rod1]

I have been spending some time at my local licensed airfield drinking tea and watching the landings. I would say that a lot of the approaches are much too fast, so adding even more speed would be a really bad idea. I was talking to one pilot after who was saying he had been told to approach at 75kn. I used to own an identical aircraft and the correct speed was 65kn. Why keep adding more and more speed?

Rod1

[one dot right]

If you're not making much over-the -ground speed, you're unlikely to hit the far hedge

Thats the most sensible thing anyone's said all night. All these naysayers warning that we're all doomed if we add a couple of knots are all forgetting the effect on GROUNDSPEED of a headwind.

Damned sure i'd rather go through the far hedge at 20 knots than the near one vertically and just under VS.

[A and C]

I have flown with the Airbus "groundspeed mini" and dont like it, I would rather fly the Boeing way but these are aircraft with far more inerta to overcome and GS mini is not relivent to light aircraft with no next to inerta.

[Chuck Ellsworth]

Chuck: Some seriously good advice on your link under Mountain Flying. Alpha System Lift Reserve Indicator

Yes it is a good system and I am installing it in a Cub project I am building for off airstrip training on big wheels.

I will have the vertical led light projected on the windshield so it will be right in the line of vision during the approach.

If using an AOA indicator is good enough for carrier landing it should be good for any other airplane.

With the led light AOA indicator the target is the blue light which is optimum Alfa.

As to wind gusts yes there are circumstances where carrying extra airspeed is an added safety margin....but if it becomes necessary to add speed not only above optimum Alfa but also above 1.3 of stall you won't be doing a very short landing.

[Pilot DAR]

I have one of the Alpha System Lift Reserve Indicator, and had it installed on my STOL Cessna 150 for a while. I am very impressed with the concept, and experimented quite a lot. What I found though was that my aircraft was capable of flight speeds which were slower than the apparent capability of the system. The pointer just kind of wallowed at low speeds, I suppose because the total dynamic pressure was not quite enough to activate the indicator, so the differential could not be measured diffinatively. I found I could get airborne before I had certain a "fly" indication. It thus left me not totally confident about the information provided on approach at low speeds (the whole reason for having it). Thus I removed it, and it remains on the shelf.

That said, I am still quite impressed with it. On a faster aircraft it would probably work very well. I have a 182 coming up, which perhaps I will experiment on.

As for my 150, I will continue to use a combination of the ASI, and "the force!" on approach. The results are very much to my liking!

[mad_jock]

I would go with the fact that the majority of people are normally running 5-10knts above the book speeds anyway.

If you do an approach speed that is by the book I reckon the majority of instructors would get very twitchy.

The whole point of adding a bit for gusts is because of the momentum of the aircraft and spool up times for engines.

Light aircraft with a petrol donk is virtually instant power and your light there really isn't any need for sticking on 5 to 10 knts because for gusts if your flying visually.

In my icle turboprop I wouldn't start adding anything until over 30knts of gust.

Bigger heavy machines without instant power you need the buffer of carrying some extra energy. In my opinion its not require for your average spam can.

[one dot right]

Light aircraft with a petrol donk is virtually instant power and your light there really isn't any need for sticking on 5 to 10 knts because for gusts if your flying visually.


Agreed, IF the pilot notices. There are many weekend warriors out there who fly the minimum to keep their licence current who may not recognise/react to a rapid speed loss.

A and C

Good lord, is there anything you haven't flown:hmm:. Just because you don't like the groundspeed mini system doesn't make it any less valuable as a safety tool!

[mad_jock]

If they were taught how to fly properly they wouldn't need a an ASI.

Set the correct attitude trim the bugger and let the aircraft do the work. To many pilots chase the needles instead of letting the aircraft do whats its design to do which is to fly.

If I had a pound for every student/FO that i have told to let go of the controls for suddenly all the turbulence to disappear, the aircraft start tracking in a straight line and for the airspeed to become stable I would be a rich man.

Instrument approaches require a bit more point and power. Visually its over controlling which leads to speed instability in the majority of cases.

My current machine is a 10 tonne TP with 3300SHP on the wings and I fly it excatly the same as a tommahawk on approach. I have a Vat range of 10 knots. But I don't need to worry about it cause its exactly the same picture whatever the weight because your flying an approach angle of attack on the wings. Set the picture, power as required to keep the decent profile and bobs your uncle the speed is right.

Please note flying on instruments requires more of a point and power technique my comments only refer to approaches flown visually.

[Mark1234]

The problem is thus: We are taught a 'safe' approach speed - it's normally a bit more than 1.3 Vso, for 'safety'. Then we add a bit for the wind, a bit for the gust, and a bit for mother/wife/kids, uncle tom cobley and all.

Another factor usually forgotten is that your 'book' stall speeds are based on max gross weight. They reduce as you reduce the a/c weight, so your landing speeds should reduce accordingly.

You finish up with a bunch of people dragging something like a PA28 over the hedge at 75 kts with full flap (and I know people who go faster). There lies the road to broken nosewheels as well as holes in the hedge.

Frankly we're taught so much to fear the stall, I believe there's far more of a danger of people going off the far end than stalling in - how many accident reports have you seen recently where someone with a functioning engine come up short? You've also got a pretty good AOA indicator in the cockpit of every plane I've ever flown.. here's a clue.. it's right in your hand :E

P.S. I'm a weekend warrior too...

[Lister Noble]

If I had a pound for every student/FO that i have told to let go of the controls for suddenly all the turbulence to disappear, the aircraft start tracking in a straight line and for the airspeed to become stable I would be a rich man.

That was me exactly,he also told me I was holding the yoke like it was a cobra about to strike me.

I let go,and hey presto,the turbulence dissapeared.

Amazing,must be Magic;)

[englishal]

I tend not to use "numbers" so much when coming in to land, even the altimeter. I join the circuit at the correct height and speed and from that moment on don't use the altimeter at all (as long as I can see the runway). Regarding airspeed, I glance at the ASI occasionally to make sure that I am not getting hideously slow but most of the time one can set power and feel the aeroplane and see where you're going to touch down and adjust that based upon the winds. Too slow and sink rate increases and it becomes sloppy, too fast and you'll overshoot the TD point. As long as you pitch for speed you won't stall.

One really useful bit of training I did years ago when I did my Commercial (I had a great instructor who was highly experienced) was to take off and then the FI covered all the instruments, except for oil pressure and oil temp. He then made me come in and land. In a varying theme on this he then made me do the above without touching the yoke, but only using rudder and trim. I'd highly recommend some advanced training to anyone who has their PPL...

[Chuck Ellsworth]

One of the most annoying type of pilot is the " roller coaster " pilot that constantly pitches up and down because they are airspeed chasers.

And that mishandling of the controls comes from poor instructors who were taught by poor instructors......

[hatzflyer]

I wish I had all you lot sat in with me last Saturday. I hit sink / wind shear / rota turbulance on a crosswind past trees and decided it was too much. Fully fine and full throttle we were dropping like a lift.
Could have done with some ideas.

[Chuck Ellsworth]

I wish I had all you lot sat in with me last Saturday. I hit sink / wind shear / rota turbulance on a crosswind past trees and decided it was too much. Fully fine and full throttle we were dropping like a lift.
Could have done with some ideas.

Seeing as we were not there and have no idea of what transpired can you describe why it happened and how you handled the incident?

For instance was there any indication during the approach that that situation existed?

[RatherBeFlying]

Another factor usually forgotten is that your 'book' stall speeds are based on max gross weight. They reduce as you reduce the a/c weight, so your landing speeds should reduce accordingly.The Grumman Cheetah taught me a few lessons on that. When I showed up for my checkout, the instructor asked if his buddy could come along in the back and I said yes. While his buddy was not obese, he was husky and in winter clothing like the rest of us at that time of year. On landing at book speed I stalled in the flare a little higher than expected. A look at the Flight manual showed I had gone overgross -- don't trust instructors not to set you up;)

I flew the plane from Toronto to Philadelphia. Landing at Wings Field the airplane did not want to come down. With not much fuel in the tanks, I went around the first time and touched down two thirds down the runway the second time. I would have gone around a second time but the runway elevation had an upslope two thirds the way down.

Quite a few knots too fast for the low weight:\

These days I prefer steeper approaches. If you suddenly need great gobs of power to maintain your chosen approach slope, you have allowed yourself to get suckered.

Glider flying is a good cure for those prone to two mile finals in SEPs; mind you there's not much in the way of a weight change affecting approach speed as long as you've remembered to dump the water ballast.

[Chuck Ellsworth]

On landing at book speed I stalled in the flare a little higher than expected.

Do you mean you were a little higher above the runway when the airplane stalled, or do you mean it stalled at a higher indicated airspeed?


A look at the Flight manual showed I had gone overgross -- don't trust instructors not to set you up

If the instructor set you up and he/she knew the airplane was over legal gross weight why did he/she fly in it?

[Woy Wogers]

Here's a question for the panel.

If one is landing in a 10kt headwind (straight down the runway) at 150ft, and this suddenly reduces to zero, what is the effect on the aircraft's airspeed, groundspeed, rate of descent, angle of descent and touchdown point, assuming that no changes are made to power or attitude?

OK, it's somewhat theoretical, but serves to illustrate the thought.

Similarly, what would the answers be if one was in the same situation in still air, and a sudden headwind of 10kts appeared?

If you want to take a specific, assume 1.3Vs = 60kt, and ROD = 300 fpm, just to make the math easier.

WW

[Mark1234]

I don't know what the thought is, but to calculate, you would need some pretty clever maths as mass and inertia need to be considered.

In the first instance the a/c would reduce to 50kts (instantaneously, and still above the 46kt stall, even assuming you're magically landing at MGW) it would now be out of trim, pitch nose down and fall under glide accelerating. Once returned to 60kts it would have a flatter glide relative to the ground, therefore the affect on touchdown etc would depend upon the inertia and the altitude at which the shear occurred.

If you assumed the a/c to have no inertia, it would maintain 60kt and finish up touching down long :E

In the reverse instance it would initially balloon over glide, then commence a steeper glideslope. Again whether it fell short or long would depend upon inertia and shear altitude.

It's also somewhat irrelevant 'cos any pilot who is half on the ball should react to correct, and possibly even anticipate!

[Woy Wogers]

In the first instance the a/c would reduce to 50kts

Is that airspeed or groundspeed? Isn't an aircraft's airspeed relative to the air mass it is flying in? Surely a 10kt change in the windspeed only affects the groundspeed (and angle of descent)?

WW

[Mark1234]

Nope. There's a nasty little thing called inertia - the tendancy of a body in motion to continue so. (sorry, yes, 50kts airspeed)

It's pretty complicated, and you soon get into territory I don't understand, mythical downwind turns, loss of airspeed and such, but, suffice to say if you're flying at 60kts into a 60kt headwind, and someone turns off the headwind, you will *NOT* have 60kts on the ASI. You'll have an uncomfortable fall for a while until you overcome your inertia and start flying again - assuming the ground does not intervene!

Otherwise we could all fly in at 5kts above the stall and not worry :)

[RatherBeFlying]

On landing at book speed I stalled in the flare a little higher than expected.

Do you mean you were a little higher above the runway when the airplane stalled, or do you mean it stalled at a higher indicated airspeed?

A look at the Flight manual showed I had gone overgross -- don't trust instructors not to set you up

If the instructor set you up and he/she knew the airplane was over legal gross weight why did he/she fly in it?Slighty higher altitude a few knots faster.

I was more trusting of instructors at that stage of my career and never thought an instructor would ever suggest anything outside the regs. What was going on in the instructor's mind a couple decades ago I have no idea. It was a good lesson for me, even though poorly delivered.

[englishal]

Bearing in mind, an aeroplane can stall at any airspeed, any altitude and any attitude...... ;) I've seen the ASI read zero at 3000' and not been stalled....

PS we all know that aeroplanes fly perfectly well over max weight ;)

[goldeneaglepilot]

1.3 is a good figure to work with. My own experience has taught me that even if the wind is gusty with a properly trimmed aeroplane (thats elevator power and rudder) then you only have to react to gusts, turbulence or wind shear. I flew the tug aeroplane for a gliding club in my early hours of flying (to gain experince and hours), that was from a hilltop site which was prone to lots of turbulence. You soon learn to follow the trend rather than trying to fly every tiny movement of the instruments. You react to the big events and ignore the little events unless they develop into a trend.

When its very windy my prefered technique is to do an approach with less flap, that way you have a higher approach speed (at 1.3vso) and the aircraft is more reactive to control input should you need to do something quickly. Yes the approach is shallower than full flap but given the wind, you should still be at a sensible angle of approach, relative to the runway. Try doing a flapless landing on a calm day and then on a windy day, you will see what I mean about the angle of approach. If you dont understand what I mean draw out a triangle of velocities and you will see - the hypotenuse being the airspeed, the base being the relative groundspeed,

It seems to me that the perpetual argument about an aircraft flying in a different way in a wind continues - how does the aircraft know its going downwind or into wind? The groundspeed alters but not the airspeed, turbulence increases low level in stronger winds. Your speed should remain the same (1.3vso) your approach technique (amount of flap and/or sideslip) should alter dependant on the turbulence, crosswind and strength of wind and known turbulence / gustiness, not the approach speed (1.3Vso)

My answer to Woy Rogers question is that if the wind suddenly dropped then your airspeed would remain the same, your approach angle shallower and you would land further along the runway. Has anyone done the inertia / mass sums v groundspeed, the difference a sudden loss of a headwind makes to the sums does not really affect airspeed, only groundspeed to any significant amount, I cant fly accuratly to 0.01kts....

[BEagle]

Please read the comments of A and C and bose-x - with which I agree wholeheartedly!

Fly the aeroplane as per POH and do NOT add ANYTHING for gusts, wind, people in the back, plagues of frogs or anything else UNLESS the POH so advises!

Some years ago, after a couple of damaging incidents, we reviewed our guidance and insisted on correct approach speeds as per POH. Thereafter we had not a single problem.

Too many people are keen to export half-understood people-tube techniques to little spamcans. DON'T!! The POH is the ONLY reference you should be using.

Fly an accurate POH approach speed with the 'point-and-power' technique and you won't go wrong.

[Woy Wogers]

My answer to Woy Rogers question is that if the wind suddenly dropped then your airspeed would remain the same, your approach angle shallower and you would land further along the runway.

goldeneaglepilot, thanks - that is my understanding of the situation also, and of course the opposite if the headwind increases, i.e. an increased angle of approach and a reduction in groundspeed, possibly resulting in an undershoot without intervention.

This is the point at which inertia comes into play - a force must be applied (increased lift and / or thrust), to change the steady state airspeed and / or rate of descent to correct the approach, and force = inertial mass x acceleration.

WW

[Chuck Ellsworth]

Slighty higher altitude a few knots faster.

I can understand your being able to judge a slightly higher height above the runway, however I am puzzled at how you know the exact difference in airspeed that close to runway contact?

[Maoraigh1]

"Fly the aeroplane as per POH and do NOT add ANYTHING for gusts, wind, people in the back, plagues of frogs or anything else UNLESS the POH so advises!"
If approaching for an uphill landing, on a 600 altitude hill top strip, with wind gusting 28 knots at a nearby almost sea level airport, instruction for how to crash.
Inertia will tend to maintain speed of aircraft relative to the ground.
Windshear will lead to airspeed loss. Inertia will have to be overcome to accelerate the aircraft, relative to the ground, to avoid stalling.
The POHs I've read do not give specific instructions for difficult strips.
As regards excess airspeed, I agree.
This month, I tried the effect of coming low over the fence, but with 70 kts, on a flat 700m runway, in flat calm. Without using brakes, I used all but about 30 metres.
But approach and landing technique have to be adjusted for runway and for weather, as well as for aircraft

[IO540]

A slightly different angle on the question is that one can fly the approach at 500kt, etc.

What really matters is the speed one is doing during the flare.

[Mark1234]

This is the point at which inertia comes into play - a force must be applied (increased lift and / or thrust), to change the steady state airspeed and / or rate of descent to correct the approach, and force = inertial mass x acceleration.

Pseudo science I'm afraid. You're applying newton in completely the wrong manner. Goldeneaglepilot is mostly right - and right to all intents and purposes, fly the trend, ignore the deviations in the main. I note you don't say inertia isn't real, just dismiss it as .01 of a kt. Inertia is very very real. That's precisely WHY the ASI goes up and down in the gusts, and that's why if you fly into a big windshear you have airspeed changes.

As best as I can explain it, inertia is the property of an object - I may be using the wrong scientific term, but it's dimensionless.

1) Remove the earth, (ground) wind etc, and your plane is floating in interstellar space going nowhere (bear with me!)
2) Now add in a big lump of air blown at the plane at 60kts. What do you think will happen?

Bet you say the ASI jumps to 60kts, not that the airspeed stays at zero and the plane jumps backwards at 60kts! You intuitively know that it cannot instantly move.

The frame of reference thing gets complicated.. Groundspeed is as you correctly state, irrelevant, so is airspeed. Inertia is the tendancy of a body in motion to carry on in the same manner. What changed speed is the *air*; for the aircraft to keep the same airspeed it has to accelerate / decelerate - The motion of aircraft has to change. It will return to equilibrium with the new air mass because that is all that acts on it BUT that cannot be instantaneous because of inertia. The lighter the a/c the quicker it will change. Microlights minimal; 747's massive.

Generally a 10kt instantaneous change is a pretty unlikely scenario. Gusts are generally variations, so will go up and down. A proper, windshear is the main source of an instantaneous and sustained change in wind.

If woy's example was from 1000, or 10,000ft I'd agree, the transient would be minimal in comparison to the overall glide, however at low level the ground might well be reached before the transient effect is overcome.

Also goldeneaglepilot, talk to some of your glider buddies about what the ASI does when you fly into a thermal - very often it will surge by a few kts. Old friend inertia again..

I do however completely agree with A and C, Beagle, Bose, etc. **except in very special circumstances, but 1) I'd avoid going there, and 2) by the time you do such things, you *know* what you're doing.

One note however
Inertia will tend to maintain speed of aircraft relative to the ground.


The effect is true, but inertia is not relative to the ground, just that the ground has a very very large amount of inertia, and doesn't tend to vary it's motion too much :E

[RansS9]

Does the POH advise?

Anybody able to quote theirs?

Just looked at mine and it doesn't.But then it doesn't give any advice on approach speeds either--I'll complain to Curtis the next time I see him (Actually ---no I wouldn't --how can you complain to the man that gave us the S1 !)

Suggested pionts of agreement;

--we fly light planes not heavy planes the same rules MAY not apply.
--we don't want to carry anymore energy than we need
--we would rather hit the fence at the far end at 20kts than spin/stall in at the near end. IDEALLY we don't want to hit ANYTHING.
--low level windshear and inertia effects are a reality and potentialy dangerous.
--there are many factors to be taken into account aside from approach speed in determining whether a landing is safe. It just happens that aprroach speed is the one under discussion at the moment

"Inertia will tend to maintain speed of aircraft relative to the ground.
Windshear will lead to airspeed loss. Inertia will have to be overcome to accelerate the aircraft, relative to the ground, to avoid stalling."
IMHO the above is the best description of why I've read!!

Just to irritate the moderators I've started another thread (Flight Testing)on why 1.3 was chosen. Early indications seem to suggest that this is to do with large jet requirements. Now some will come along and blow that thoery out the water by showing the Royal Flying Corps used it to calculate approach speeds!!

[mad_jock]

But approach and landing technique have to be adjusted for runway and for weather, as well as for aircraft

I disagree with that.

If you use the same techinque which gives you best performace for getting into short strip it will always work on longer runways. If the runway is way long you just move your touch down point futher up the runway if you are stopping.

Everyone knows at INV you can get a PA28/38 C150 down on the numbers and be stopped by the first touch down marker. But time and time again the lights go sailing passed Foxtrot. Pilots going for 23 with 15knts of xwind instead of having it on the nose down the short. You ask them why they do it and they say its airmanship to take the longest runway. Which is of course pish. The lack of PAPI's and the apparent shortness of it makes them struggle on with 23 with sometimes hurrenous rotar when the short would be a piece of piss. But they really don't like the ground rush going over water and the deer fence on short finals. So they preffer to take an outside demonstrated on the long runway

[hatzflyer]

Beagle, you are talking absolute rubbish.
point one). I have owned 80+ aircraft over the years. I have never seen a POH that has a section dealing with windshear/sink /severe turbulance on landing.
Point 2). I currently own 3 aircraft. Not one of them has a POH. So how can I comply with your post?
Last Saturday I experienced severe wind shear in my RV4.I had a passenger and it was witnessed from the ground.My Rv has a climb rate in excess of 3000ft per min.( as witnessed by many peole on here).
At full power, fine pitch we were decending below the level of the trees on the approach and only just cleared them.

Please don't try to tell me that I could have just sat there without increasing power and speed and I would have been OK. I have somewhere over 10,000 landings including 28 total engine failures under my belt and I don't believe you.
Aviation is NOT a one size fits all passtime. I have pulled too many people out of hedges over the last 30 odd years ( a very high proportion of whom have been instructors[ a few of them from a famous " farm strip conversion" specialists] ) and as we are loading them in the ambulance or driving in to casaulty it is always the same " I just don't know why that happened, according to the POH we had plenty of room"

Mad jock, how can you say that you disagree with the statement that says you have to vary technique for different aircraft? So would you approach a short strip in a Longeze the same as a Cessna 150 with 40 flap?

[mad_jock]

The only thing you can do is the wind sheer training that commercial pilots get in the sim.

1. Max power and pitch to the stick shaker/stall warner.
2. Don't change configuration.
3. Start swearing under your breath.

Thats still not garanteed to stop you crashing. On a loft exercise we got a wind sheer event and from 5000ft we just skimmed the ground by 100ft before getting it back into the air flying again where an engine promptly packed in. I was expecting some rather straight talking in the debrief but all we got told was that we were the first crew out of 15 not to have crashed and sorry about the engine failure but the exercise was meant to stop there followed by a reset to practise windshear events.

[rans6andrew]

I find that, sometimes, there is a need to approach somewhat faster than Vs, even getting on for Vne. The exact increase is dependant upon the bladder pressure at the time. It is amazing just how much speed you can dump by a bit of spirited side slipping as you come over the hedge.

Rans6..

[mad_jock]

Now that reason for a spirited approach speed is more than acceptable in my book. Also being bored with a ground speed of 40knots when your used to shooting approaches at 140 knots is also acceptable. Fitting in and helping out ATC while operating into commercial airports is also acceptable.

But that is for experenced current pilots. The altering of the approach speed with some bollocks theory based reason is not accpetable. And the inability to do it properly is the key. Which I am sure you can without any difficulty.

[Chuck Ellsworth]

including 28 total engine failures under my belt

That is quite a lot.

I also have been flying for quite a while and can not remember more than maybe five total failures.

What kind of aircraft did you fly that had so many total failures?

[madlandrover]

Listening to wind reports can often give you a fair clue as to what to expect. EG a few months ago (bringing a twin back from Switzerland) I had the choice of diverting to Cov with wind on the ATIS of (approx) 22025G40 160V230 (for those who don't know it, Cov is 23/05) or continuing on to my home base for a reported wind of 20020G40 (Home base R16 for night ops). On paper surely better to go for Coventry? I carried on for home. Why?

Local knowledge mainly - I knew from past experience that winds like that at Cov meant swirling gusts around a set of hangars on very short final, and on that night (2mb difference between Cov and BHX QNH...) I didn't fancy adding rotor to everything else. I was also happier going into an airfield I knew well and had reasonable experience instructing at in most conditions, day or night. The subsequent arrival wasn't especially pretty (flew a high downwind at 2000' agl, then put some drag down and kept the speed up until shortish final, then reduce to Vfe and a bit more flap, with windshear taking care of the excess speed!) but the aircraft was useable afterwards.

So, the clues: "fun" wind speeds coupled with any terrain or other ground features that could change the airflow on final. And, equally importantly, as IO540 says: the speed that matters is the arrival speed - the approach speed mustn't overstress the aircraft, but that's about it...

[mad_jock]

He proberly was one of the first rotrax pilots.

Some of the test pilots for the permit boys were clocking up 10-20 engine failures a year. One guy I saw had 4 in one day of testing. I did say to him one was unlucky, two was getting annoying, three is taking the piss and four someone isd trying to kill you. Must admit on the fifth attempt they manged to complete the sortie.

[hatzflyer]

I used to do test/ ferry flying for a dodgy maintenance out fit no longer in buisness ( thankfully). The worst one was a Cessna that the nosewheel came down and not the mains, and the bloody nose wheel wouldn't go back up.That and the Tommahawk that filled the cockpit with avgas when the tap sprung a leak.
I was young and foolish then, now.......

Just noticed that the same poster has now asked the same question under the flight testing banner.
He asked in relation to light aircraft, he's had loads of answers relating to 250 tonne jets and aircraft fitted with retracts,slats ,spoilers,flaps , known ice etc etc.....Is it mee....????:ugh:

[S-Works]

I was young and foolish then, now.......

Now you are old and ugly....... :p:p:p:p

[BackPacker]

Is it mee....???

So what you're saying is that over there there's even more anoraks than here?

Mmm. I might just drag myself over there sometime...:ok:

[RansS9]

Hatzflyer-- In my defense it's not quite the same question. This thread "CalculatingApproach Speeds--additions" the other "Why 1.3Vs for the approach?". Interrelated agreed but subtly and importantly different.

TIM
"the same poster"

[hatzflyer]

Not so much of the old if you don't mind!

[Big Pistons Forever]

my 02 cents

The questions should not IMO be how much airspeed should be added for adverse conditions but rather what is different during these approaches as compared to benign conditions and how do I prepare for those differences. I tell my students not to add any extra airspeed because the POH recommended approach airspeeds in all teh common trainers, provides plenty of margin.

The thing I emhasize for approaches in adverse conditions is the absolute requirement to recognize when the aircraft flight path and/or airspeed is diverging from what is desired and to take immediate action to correct those divergences. That and the importance of not forcing a bad approach. While a pilot should always be ready for a overshoot he/she needs to be doubly conservative when dealing with adverse conditions.

[Pilot DAR]

for gusts, wind, people in the back, plagues of frogs or anything else UNLESS the POH so advises!


Well.... For plagues of frogs, I would be adding a few knots. All of those gizzards smeared all over the lifting surfaces can affect stall speed...

[RansS9]

"because the POH recommended approach airspeeds in all the common trainers, provides plenty of margin. "

Margin for what?

Please correct me if I am wrong but !.3 is the margin the designers make to Vso for the approach speed. If it is not for gust protection (which I understand it is not) what is it for? And does a degradation of that margin
matter when in my trainer (Vso 50kt app 68kt wind down the runway 10kt gusting20kt) I lose 10kt headwind as I am starting the flare?

TIM

[mad_jock]

You put a nudge of power on which you get instantly.

A jet on the other hand would take 10-15 seconds to give you any extra thrust to help you out so they add a bit to give a bit more energy to play with.

To be honest in my experence its not the decrease of wind speed that cause problems with inexperenced pilots. The dramatic increase in sink rate makes them shove the throttle forward.

Now an increase gust doesn't give the same effect especially if there back at idle anyway. They balloon up then panic put the nose down the gust goes and everything is setup for a nose wheel landing. If they do manage to correct it we are into a PIO situation now. And excess energy is just going to make matters worse.

[Robin400]

Mad Jock your last paragraph is correct:D

This post worries me, i do hope student pilot are not reading this post and listen the their instructor regarding safe speeds.

[mad_jock]

Unfortunately I think that Instructors are teaching this procedure.

Hell if they can't get a job or afford to pay to fly a jet they can pretend to fly one.

Sorry Haz just spotted your question. I will give you each aircraft has its own picture on approach (but most ga aircraft it will be within a ball hair the same). And under some circumstances eg steep appoach the configuartion points will be different. But I don't make a change generally be it a huge space shuttle sized runway or some titchy just in limits regional airport/grass strip. As I have stated inside the operating enevelope I do the normal appoach. I always land with full flap, none of this pish of reducing some cause its gusty or xwind.

[Mark1234]

And does a degradation of that margin
matter when in my trainer (Vso 50kt app 68kt wind down the runway 10kt gusting20kt) I lose 10kt headwind as I am starting the flare?From those numbers I think we might be considering the venerable PA28, perhaps this might allay some fears:

Considering a PA28-161:
50kts is the clean stall speed - try 44 with full flap.
You're probably at something less than MTOW, so can grab a few more knots off the stall speed (placarded stall speeds are at MTOW, and there's a chart in the manual somewhere that deals with factoring them for reduced weight)
Who can read 68kts, so you're probably flying at 70(ish) anyway..(also, according to the last checklist I looked at, 63kts vref for the 2nd and 3rd stages of flap)

So the reality is that you're probably doing 70kts when stall is a bit above 40. Suprising? That's the problem with all the cumulative 'err on the safe side' assumptions. Given the above, a 10kt loss is neither here nor there really; pull back a bit on the yoke. Worst case you touch a bit harder than normal.

If you're faster, 1) you still have to stop, and 2) you spend more time skimming the ground slowing down - where you're far more likely to PIO and break something.

Lastly, when did you last stall an aircraft - you might remember that it actually takes a pretty concerted effort :)

[Robin400]

Touch down speed is between 47-56 kts at max weight.
Approach speed 75 kts
So you need to reduce speed by 19kts before touch down.
If you loose 28kts. you will be at minimum touch down speed.

[Big Pistons Forever]

Rather than add a bunch of extra airspeed when flying in gusty unstable days, IMO for light training/touring aircraft using less flap works better. This is particularly for true for Cessna's, because of their big, effective flap system. For the Cessna 150/172 series I personnally use flaps 10 deg on those ugly windy days.

[Maoraigh1]

"You put a nudge of power on which you get instantly."
But you don't accelerate instantly. You accelerate at the same slow rate as from lift off, to climb out speed. If the gust is enough to take you well below stall speed, you're in trouble at low altitude. Look at the effects of gusts near thunderstorms.

[Piltdown Man]

This month, I tried the effect of coming low over the fence, but with 70 kts, on a flat 700m runway, in flat calm. Without using brakes, I used all but about 30 metres.

In a full F50, touching down in the TDZ I also didn't need brakes, but I'm probably 15-19 tons heavier. For a 41ton E190 at Flaps Full and moderate braking, I'd expect a similar field length performance. So something is wrong here!

May I suggest that what is broken is the training. It certainly was none too hot when I was being taught in bug smashers. The approach speed was always 65, the climb speed was 65 etc. Neither the weight nor wind etc. was ever dialled in as a parameter. Then we have the some for "Mum & the kids" Safety Brigade (aka "Some for the wire, hedge and ditch brigade").

What did I teach? I taught what the book said. Use the weight from the plan and the approach speed from the book and add half the wind strength up to a maximum of 15kts. At maximum landing weigh in the 172 model I flew , that would be 44kts plus a maximum increment of 15kts would give a maximum approach speed of 59kts. No hedges were ever seen vertically although we had lots of fun watching the safety merchants go farming.

Ugly, windy days if I had to fly, I used to do the same. And just like everyone else, I used less runway to stop.

PM

[RansS9]

"From those numbers I think we might be considering the venerable PA28, perhaps this might allay some fears"
---I think you might be wrong and no it doesn't allay any fears. The figures were chosen for a hypothetical trainer (I've never flown A PA-- anything.) SO if the Vso is 50 1.3 is approx 68. Agreed being a low hours PPL I'd be flying 70 (not for the kids, or plague of frogs, just because there is likely to be a mark on the ASI to indicate it) but you know what PPruners' are like some wag would have corrected us saying it was actually 68! This makes the energy excess over the stall slightly less "surprising".

"Lastly, when did you last stall an aircraft - you might remember that it actually takes a pretty concerted effort http://images.ibsrv.net/ibsrv/res/src:www.pprune.org/get/images/smilies/smile.gif "
--- 6 months ago. But then I haven't flown since. Actually as I remember it doesn't but then my airplane has a powerful elevator in part to help bring it to the stall quickly. In other aircraft the effort I supposed depends and how fastidious you are in your trimming. My memory maybe playing me tricks but since I'll be seeing an instructor down your way(White Waltham) next week for a pre-reason wake-up call (involving almost certainly repeated departures in almost every conceivable aircraft attitude/energy state...OH JOY!?!) I'll let you know.

"This post worries me, i do hope student pilot are not reading this post and listen the their instructor regarding safe speeds"
---It does me to..... Conversely I do hope Student Pilots read the post (I count myself as one being low hours.) Why? Well perhaps you could illuminate as to which particular instructor we students should be listening to. Todate I've heard everything from forget airspeed and airspeed indicators"feel the force Luke"; Vso1.3 irrespective of gusts; Vso1.3 plus the whole gust factor; Vso1.3 plus half the wind (which wind ..the total or the resolved component down the runway) no mention of gusts; do what it says in the POH(unfortunately many POH's say nothing); and finally add a bit for the wind add a bit for the kids blah blah!

Oh and before anyone pipes up this information is earnestly given by pilots with lifetimes worth of experience, in all manner of aircraft. Yes..it worries me. Perhaps they are all right and that there is more than one way to "skin a rabbit". Alternatively perhaps they are not all right ...just exceedingly lucky!

Interesting post on the sister thread in Flight Testing about when 1.3 first started to appear in the literature .

TIM

[mad_jock]

You don't need to accelerate you just need to increase you slip stream. The combination of that and ground effect will sort the problem out.

And your into a wind sheer event if your getting that much instant change in wind speed.

And your all focusing on "stall speed" when you should be thinking about stall attitude. If you have the picture right and maintain it you won't stall.

And the size of gusts you are talking about 30-40knts you will only get in gust front infront of continetal CB's. And in those conditions I would be questioning your airmanship attempting an approach anyway. Yes we do get gust of 20-30knts in the UK but its in wx conditions that no GA will be airbourne. Thats middle of winter western isles and Shetland wx when the seagulls are grounded.

It seems to me the we have a group of experenced instructors and big tin drivers who have flown in these conditions many times saying don't add anything. And a group of GA only drivers who say add it in or you will die.

[one dot right]

Mad Jock, have you been on the sauce?

You don't need to accelerate you just need to increase you slip stream. The combination of that and ground effect will sort the problem out.


Er, how is increasing slipstream over the fuselage and tail going to increase your lift?

And as for ground effect helping you out, don't you think it's a bit last minute ish to be sitting there thinking, 'it's ok, sink rate's a bit high, airspeed's a bit low, but ground effect will intervene in just a sec, oh wait, i'm in a high wing 152/172/182/Partenavia/Tripacer/insert as appropriate, BANG "oh bother"':ugh:

I'm not just a 'GA only' driver, and my last turboprop had 5000 horsepower on the wings (whatever difference that makes):hmm:!

[mad_jock]

Engerises the airflow over your wings and decreases your stall speed. Also the thrust line helps you out.

Stalling exercise ppl course.

Again it is not your airspeed which makes you stall it is your angle of attack.

If your not in ground effect you have enough room to lower the nose a bit add a bit of power and sort it out.

And if you have driven a machine with that much power on the wing you should know that its your power to weight ratio which counts not the sum total of your SHP.

What size of gusts are we talking about here? Your normal GA pilot aint going to be flying in more that 25-30 Knots of wind anyway, the most likely situation would be 10G20 knots which has already been proved makes cock all difference in the grand scope of things. Now if it was 10G30 or maybe even 10G40 your average PPL after they get on the deck is more than likely going to flip it taxying.

[Robin400]

Er, how is increasing slipstream over the fuselage and tail going to increase your lift?


The slip stream from your 5000shp over the wing area behind the prop arc....try closing the thrust levers before touchdown dash and thump.

sorry mad jock you posted whilst was typing

[mad_jock]

Nae bother.

And your always meant to be at flight idle by the time you put the wheels on the deck. A bit like this discussion there are some out there that recommend you leave a bit of power on for a gusty landing.

Similar to this situation all that does is add energy into the equation which means when you do actually want to stop flying you end up 2 foot off the deck trying to control the aircraft in ground effect while bleeding the energy off.

[Robin400]

:D all simple stuff.

[one dot right]

Robin 400 and Mad Jock. Do try to keep up chaps, this is about light aircraft the majority of which are single engine.

Single engines are generally in the middle of the aeroplane, attached to the fuselage not the wings, so the concept of energising the airflow over the wings is irrelevant:rolleyes:

And if you have driven a machine with that much power on the wing you should know that its your power to weight ratio which counts not the sum total of your SHP.

Yup, well aware of that, but you were using your turboprop experience to compare to a tomahawk. My old turboprop was gloriously overpowered as probably is yours, a Tomahawk is not. My old turboprop responded to the power in the blink of an eye, a Tomahawk does not.

[Pace]

Again it is not your airspeed which makes you stall it is your angle of attack.

Mad Jock

I thought you guys up in the wilds of Scotland were experts with wind ;) 50 kts is light up there :{

Of course its the angle of attack which causes the aircraft to stall but it is the airflow over the wing which allows you to reduces or increases the AOA while maintaining flight.

In any flight we are looking at energy management. In the case of a glider using potential energy in still conditions trading off altitude for airspeed.
Glider pilots seek lift from air movement. In rising air they can reduce the AOA to maintain altitude which will give an increase in speed or use that energy to climb.
In descending air to maintain an altitude they will have to increase the AOA with a reduction in airspeed and an increase in drag.

The only way around this is to increase the rate of descend tapping into potential energy and reducing the AOA and drag.

The powered aircraft follows the same principals but has an extra energy source from the engine. I always think of the aircraft having two throttles, one for the engine one in the elevator, both allow you to access energy.

What happens in gusty conditions near the ground is no different, with rising and falling pockets of air.
Hence it is a matter of tapping into both energy sources as conditions require.

Normally 1.3 x The landing stall speed is all that is required in normal conditions. Bring in windshear and you have the .3 of airspeed over the stall the potential energy in the aircraft and the energy from the engine.

That may not be enough. You only have so much engine power available! You can tap into the potential energy in the aircraft which may put you in the ground or you can increase your approach speed to 1.3 plus X kts the X kts giving you an extra source of energy to tap into.

It then comes down to how good a pilot is at sensing those movements and how accurate he is at juggling all the parameters available to him.
Sadly many are not and become mere passengers to the aircraft rather than the commander of the aircraft they should be.

Pace

[mad_jock]

I am taking about single engine pistons, One dot I suggest you go and have a look at your principles of flight or get a FI to go over stalling part 1 & 2 with you.

And yes it is about energy management. The book speeds give you the required amount end of story.

If it wasn't the required amount for gusty conditions it would say so in the POH.

And yes I am no stranger to windy conditions 20G30 is a normal days work out west. 40G60 a bit less so and a couple of times 40G70. But as you say its light aircraft which won't be flying in those conditions.

Per say there is nothing wrong with strong winds until your taxi limit is reached or its from the wrong direction. Its gusts we are talking about you have the same issues with 5G20 as you do with 40G55.

If the pilot is not capable of controlling the aircraft on approach at the correct speed they have no buisness being PIC of it.

Adding extra on, landing with power on just points out how talent limited the PIC is.

And to add i have 700 hours in tommy's flying in the Highlands of Scotland summer and Winter. I used to send students solo with 15knt gusts down the runway. Why because they were taught how to fly properly and it wasn't a factor, added to the fact you would be limited to when you could send them solo for 50% of the year. Even Pink Aviator used to be able to handle 15knts of gust without adding to the approach speed.

[one dot right]

I tell you what Mad Jock, to save me the trouble of finding a FI and seeing as I have the benefit of your wealth of knowledge right now, why don't you explain how a centre mounted engine can energise the airflow over the wings that are located to the left and right of the propeller generated slipstream? Please, I'd be really grateful;)

[mad_jock]

Nope i think is safer for all concerned if you spent some quality time with an FI.

I will give you a hint its the reason why tommahawks are pish for soft field and short field takeoff techniques.

[one dot right]

You've got yourself to the point that you can't expand any further without shooting yourself in the foot haven't you? Slipstream over the tail doesn't count, all that does is increase elevator/rudder authority (rudder only on the T tailed tomahawk) so you can increase angle of attack on an already overburdened wing!

And what evidence do you have that i'm not an FI?

I rest my case.

[Mark1234]

"From those numbers I think we might be considering the venerable PA28, perhaps this might allay some fears"
---I think you might be wrong and no it doesn't allay any fears. The figures were chosen for a hypothetical trainer (I've never flown A PA-- anything.) SO if the Vso is 50 1.3 is approx 68. Agreed being a low hours PPL I'd be flying 70 (not for the kids, or plague of frogs, just because there is likely to be a mark on the ASI to indicate it) but you know what PPruners' are like some wag would have corrected us saying it was actually 68! This makes the energy excess over the stall slightly less "surprising".

"Lastly, when did you last stall an aircraft - you might remember that it actually takes a pretty concerted effort http://images.ibsrv.net/ibsrv/res/src:www.pprune.org/get/images/smilies/smile.gif "
--- 6 months ago. But then I haven't flown since. Actually as I remember it doesn't but then my airplane has a powerful elevator in part to help bring it to the stall quickly. In other aircraft the effort I supposed depends and how fastidious you are in your trimming. My memory maybe playing me tricks but since I'll be seeing an instructor down your way(White Waltham) next week for a pre-reason wake-up call (involving almost certainly repeated departures in almost every conceivable aircraft attitude/energy state...OH JOY!?!) I'll let you know.

Fair enough - your hypothetical trainer has a rather high Vs0, but the other factors such as being below MTOW still apply. I'd also note that the book figures for the PA28 are >1.3Vs0. Guess you've just got to know your own aeroplane.

It will always be possible to construct a scenario where you're too slow; as pace said you only have so much power at your disposal. However, I will stand by my assertion that *most* aircraft are flown over the hedge too fast.

As for stalling, you'll still need an 'abnormally' rearward stick position. If you don't move the stick that far back, you won't stall - trim, control effort and everything else aside, at 1G and the same load, the aircraft will stall at the same stick position - it's an extension of the trim sets speed principle.

Enjoy your departures.. they're fun, honest :)

[mad_jock]

The increase in wash from the increase of RPM, which travels down the aircraft fusilage causes an apparent decrease in the angle of attack as it passes the wing root section. This is because the thrust vector is along the physical longitudinal axis of the aircraft. The pilot will see that as an increased attitude of the stall but this has no effect at all on the critical angle of attack. If the pilot maintains the intial attitude they have in effect decreased the angle of attack so if they were all ready at the critical angle of attack at xxknts they would have to increase the angle of attack to get back to the critical angle of attack which would be at a reduced airspeed.

And the hint was that the tommy has a T-tail which means you don't get any advantage from the wash which means you can't wheelie it on high power.

Have a look at you principles of flight before you do another effects of controls or stalling please.

[one dot right]

The increase in wash from the increase of RPM, which travels down the aircraft fusilage causes an apparent decrease in the angle of attack as it passes the wing root section.

VERY GOOD. thereby leaving the tips at a higher AOA which is a recognised technique for entering a spin:D

And the hint was that the tommy has a T-tail which means you don't get any advantage from the wash which means you can't wheelie it on high power.

I know that, hence-

Slipstream over the tail doesn't count, all that does is increase elevator/rudder authority (rudder only on the T tailed tomahawk) so you can increase angle of attack on an already overburdened wing!


As I said, you're shooting yourself in the foot.

And why is it that when people run out of arguments/ideas/knowledge they resort to insults or personal attacks?

[Robin400]

VERY GOOD. thereby leaving the tips at a higher AOA which is a recognised technique for entering a s

At a guess the AOA to stall a typical light arcraft wing is about 18deg.

We are talking about an approach to landing here, where nothing like that AOA will should occur.:eek:

[one dot right]

We are talking about an approach to landing here, where nothing like that AOA will should occur

And there you have the crux of the matter, SHOULD occur! Someone already slow,gust in the wrong direction, touch of power, hold the attitude, BAM.

[Mark1234]

Oh please! We're not talking about back of the power curve 'bush' approaches here, we're talking about do I approach at 65 or 75kts. That's the kind of irrational paranoia that sends people through the far hedge.

And, for the record, a spin requires yaw rate AND excessive back stick, AND persistent mishandling.

[one dot right]

Aren't we. I hadn't realised the approach parameters had been laid down as 65 or 75 knots. Thanks for the clarification.

Well aware of how a spin occurs thanks, I'm just a little concerned at the number of people who are advocating the same approach speed WHATEVER the conditions are, be it calm or 25kt G40. An example of mob mentality.

Incidentally, in that condition, adding half the gust would give an increase in airspeed of 7.5 kts but an overall REDUCTION in groundspeed of - Approach speed,say 65kt+7.5 =72.5 MINUS the mean HWC of 25kt = 47.5 kts. Compared to a calm day and a groundspeed equalling airspeed of 65 knots.

So 17.5 kts LESS groundspeed on a windy day, and a safety margin, what am I thinking?

Your pontification about going through the far hedge is nonsense!

[mikehallam]

Actual A of A isn't normally the same at wing tips - if normal wash-out is designed in.
[AFIR to ensure the roots stall first, maybe give rumble to let you know it's close to stall, yet allow the outer wing to keep flying.

I'm NOT an FI !!

mike.

[mad_jock]

VERY GOOD. thereby leaving the tips at a higher AOA which is a recognised technique for entering a spin

The certification test flights will have highlight any nasty tendency's in that direction. And flaps will help that not occur.

The size of gust that would get you anywhere near trouble would be classed as a windshear event. The only option you have is to go around.

And I haven't run out arguments/ideas/knowledge.

Or shall we just agree that if your talent limited and out of practise to the point you shouldn't be flying the aircraft in the conditions (the fact you are talent limited will mean you won't be able to hold the airspeed anyway) you can add what ever makes you happy to the approach speed. And then its luck of the draw if you nose wheel it in or go off the end or off the side. Which is pretty much the recurring theme in alot of accident reports of GA aircraft.

If you are competent and fit to be the PIC of the aircraft in the conditions you fly the book approach speed.

O and to add I have landed a tommy in 25G40 with full flap, normal approach speed and not a chirp out of the stall warner

[Robin400]

Do any of you academic people know the speed where a typical light aircraft will land nose wheel first, leaving the main wheels in the air.

Vref33 + 11 is the only one I know (so all the additions for surface wind wife, kids, granchildren and the dog could never be above 11kts (not a light a/c)

[mad_jock]

I know we will never be spot on but even if you drop 20knt's below your approach speed your not going to stall you might get the warner to chirp but thats about it. By that point you should be going around anyway.

Go and try it at altitude if you don't believe us. In fact every one that thinks you are going to stall if you get a 10knts gust go and try it. Look at the attitude just before the stall have a look at the airspeed as well. Remember the attitude and if you ever get near it go around. Try it with different flap settings, try and stall it as well being cack handed pulling the controls back without adding power. The try it again this time with power see what the difference is. So many instrutors teach stalling as a series of exercises for the test. The recognition of an impending stall is over looked, know the danger attitudes for the different stages of flight. To be honest that would be a cracking hour with an instructor flight.

There are very very few GA aircraft stall in or spin in on final approach. There are many many times more taking nose wheels out or going off road on landing.

I say again it is an increase in wind speed which causes most accidents not a decrease. Be it far out and the aircraft gets lifted high on profile and the pilot pushes a bad approach or in the flare with PIO's or getting pushed sideways off the runway.

[what next]

There are very very few GA aircraft stall in or spin in on final approach. There are many many times more taking nose wheels out or going off road on landing.

Yes. But every stall-in and every spin-in results in a casualty. Not the bent nosewheels and the bent propellers. They can bend as many of them as they want, I couldn't care less. But I care for every fellow aviator who dies for nothing - and "nothing" includes trying to be a "skilled" pilot by not wasting a single knot of airspeed on the approach . That's why adding a couple of knots is not such a bad idea.

Luckily, this decision is taken away from me because both as a commercial pilot and as an instructor I have operating and training manuals that state exactly how many knots to add to the book figures...

[Chuck Ellsworth]

Yes. But every stall-in and every spin-in results in a casualty. Not the bent nosewheels and the bent propellers. They can bend as many of them as they want, I couldn't care less.

I'm sure glad you don't teach on any of my airplanes, because bent nose wheels and bent propellers are very expensive.

[S-Works]

Luckily, this decision is taken away from me because both as a commercial pilot and as an instructor I have operating and training manuals that state exactly how many knots to add to the book figures...

Ooooh, I like your skill delegate the decision making to someone else, then if it goes wrong you have someone else to blame! Cunning!

[goldeneaglepilot]

Fly the speeds in the book with good technique (by that I mean correctly trimmed) and you don't go far wrong.

Interesting comments about T tails, lets have a look at the Arrow and how the T tail handles different at low speeds compared to the straight tail (more control authority - out of the turbulent airflow from a wing at low speeds and high angle of attacks)

Anyone remember the incidents with Tomahawks killing people when they spun in due to poor handling. Spinning is much more than yaw and low airspseed, an aircraft can be prone to spinning due to design (factors include wing section and tail moment / authority). Anyone wondered why the only time Tomahawks were spun deliberatly in the UK was during a CofA airtest (to ensure they recovered) Anyone who is writing who has been in one when it has been spun will tell you they entered easily and went flat within two rotations and you had to use correct technique to recover or you overstressed the airframe. You could look over your shoulder and see the fueslage skin buckling.

And yes I speak from first hand experience - I have in my log book 43 CofA test flights on the terrorhawk which included full spin and recovery.

I copy below part of the AOPA report of 1997 into the handling of the Tomahawk.

Tomahawk Safety Review



By Bruce Landsberg


All aircraft have reputations. For some they take years to evolve, while for others the reputations develop quickly. From the beginning the Piper PA-38 Tomahawk attracted attention. When it was introduced in 1977, it looked different from any other two-place trainer; and it flew differently.
It didn't take long for the airplane to get a reputation. The handling characteristics stemmed from a relatively new airfoil known as the GAW-1, which is quite efficient but in certain configurations has rather abrupt stall and spin qualities. Additionally, the PA-38 was one of the first light airplanes to sport a T-tail. Both of these items cause the Tomahawk to fly a little differently than other light trainers. The PA-38 is the eleventh in a continuing series of safety reviews that the AOPA Air Safety Foundation has undertaken in order to evaluate the safety records of particular aircraft.
The area of greatest interest to ASF was the aircraft's safety record. The PA-38 has been involved in a significantly higher number of stall/spin accidents than comparable aircraft — the Cessna 150/152, the Beech Skipper, and the Grumman AA-1 trainer. The latter two are not present in great numbers in the fleet, but the Cessnas have had a virtual lock on the two-place trainer market for decades.
The Tomahawk has a reputation for being "aggressive" in a stall and for spinning readily if yaw is introduced at the right time. It also has a tendency to drop a wing in the stall — and if the pilot mishandles the rudder, elevator, or ailerons, a spin may rapidly develop. None of this is news. When the PA-38 was introduced, it was clear that this aircraft required a different approach from that applied to the relatively docile Cessnas. Pilots who fail to understand that the PA-38 handles much differently in the stall and spin regime may be surprised by the aircraft's response.
The adage "Be careful what you ask for, because you just might get it" probably applies here. According to Piper, in the course of designing the Tomahawk, the company surveyed 10,000 flight instructors. Forty percent of the respondents asked for a more readily spinnable aircraft than the Cessna150/152. By design, the PA-38 does exactly that

[ak7274]

And on a lighter note. As a low hours PPL I have learnt one thing from this thread.

Instructors are neither gods nor always right, if they can argue they will and at the expense of some one like me, who read these threads hoping to improve my flying skills. I am more confused now than I was at the start. Thanks for not a lot. :p

[hatzflyer]

I nominate this thread for the biggest bollox of the year award.:ugh:

[RansS9]

"I'm sure glad you don't teach on any of my airplanes, because bent nose wheels and bent propellers are very expensive"

--mmmhhh what to make of this? I think I'll stick with the instructor who values mine and his life above the nosewheel of the aircraft rather than the owner who appears to favour the reverse.

"Ooooh, I like your skill delegate the decision making to someone else, then if it goes wrong you have someone else to blame! Cunning"

--And I bet you further delegate your decision making to those ridiculous weight and balance chart thingys. Come on they only designed and built the thing what do they know!

Personally I am with AK7274.

By the way are there any ex-military who can shine a light on the advise given concerning approach speeds in their basic trainers ?

TIM

[Chuck Ellsworth]

"I'm sure glad you don't teach on any of my airplanes, because bent nose wheels and bent propellers are very expensive"

--mmmhhh what to make of this? I think I'll stick with the instructor who values mine and his life above the nosewheel of the aircraft rather than the owner who appears to favour the reverse.

You have read my comment in the wrong context.

A competent flight instructor will ensure his students do not have an accident or incident of any kind period.

To suggest that breaking nose wheels and propellers is acceptable as long as you do not lose control in the air and spin in is an astounding comment.

Lets try this another way.

If this were driving a car would you have someone working for you who was only interested in the renters not smashing into highway over passes at high speed but beating the hell out of the car parking it was O.K.?

[RansS9]

Understood.

I didn't really have you down as some psychotic aircraft owner!

TIM

[Maoraigh1]

Excess speed at touchdown is a problem. Too low speed before roundout is a more serious problem. Excess speed on approach should not be carried to touchdown. You feel the difference in ground effect if the speed is too high. Hold off until the plane sinks.
The aim of excess speed on approach to some runways is to arrive over the threshhold at the correct speed.
And 05/23 at Inverness has no problems for GA types.
Aircraft mass, and wing section, affect handling on landing. On PA38 checkouts, I've been told by instructors to have a "Stabilised approach by 200 ft".
I don't disagree, but with a Jodel 1050, in gusty conditions, I don't feel it is stabilised until I have it half inside the hangar.
I have become airborne in a gust after landing on 23 Inverness, when I thought I was at a safe taxi speed. It took me longer to taxi to the hangar that day than it had taken me to fly 15 NM.

[Big Pistons Forever]

And on a lighter note. As a low hours PPL I have learnt one thing from this thread.

Instructors are neither gods nor always right, if they can argue they will and at the expense of some one like me, who read these threads hoping to improve my flying skills. I am more confused now than I was at the start. Thanks for not a lot. :p

Bottom line is simple. You fly the airplane don't let it fly you. You want to get better at landing in adverse conditions work at flying accurate approaches on the good days. Try to keep approach speed + - 2 knots and aim for a nice constant approach path right to your selected touchdown point. The skills you building are the essence of what will keep you safe on the ugly days. If you feel you need to add some extra airspeed, you can, understanding that it will need to be shed prior to touchdown, but I bet instead you will find an accurately flown approach at the normal airspeeds with prompt corrections to airspeed and flight path deviations will actually be easier to fly and safer than just adding a bunch of airspeed according to some arbitrary formula

Finally if conditions are bad don't force the approach. If you are feeling like things are not going right.... go around. Full power and a wings level slight nose up attitude will make things better pretty much regardless of the situation.

[mad_jock]

Rans have a search for BEagles posts I am sure his background will answer your question.

As your in Cov why don't you go and have a hour or 2 with one of the FII's at Ontrack at Wellsbourne most of them are ex Mil QFI's or do the CRI course. You can debate the pro's and cons to your hearts content with them about a whole range of habits. I would throughly recommend them to anyone.

[RansS9]

I'll have a sift thru BEagles posts for inspiration.

Thanks for the On-Track tip.I have the pleasure of their advice and teaching when flying at Wellesbourne Aviation ;they did the aero checkouts and a series of mid winter Flying lectures which were excellent.I was hoping to arrange my Revalidation Flight with them (not sure if they do them) due mid Summer, so I'll ask then and get the RAF view!

TIM

[mad_jock]

If you have the hours/time/money do the CRI course you might make the cost back in reduced insurance premiums anyway.

Also exposure to other pilots habits does somewhat focus your opnions about certain things. Wait to you get your first +10knt approach ring twitcher with the aircraft floating halfway down the runway. If your lucky down the middle,if your unlucky with you wondering when to take it cause those runway lights are looking pretty bloody close.

But I think big piston's summary is the correct one.

O and it looks like a pretty normal day up north and west winds dropping though must be spring in the air.

EGPO 190750Z 25034G47KT 9999 -RA SCT022 BKN028 08/05 Q0987
EGPB 190750Z 21020KT 9999 FEW038 08/05 Q0986 TEMPO 24030G45KT

[Robin400]

A fab spring day.........how about some X/W circuits.:eek:

A bent prop requires the engine to undergo "shock loading"
Now that is expensive!!!!!
Failure to do so may result on prop separation.

[Maoraigh1]

Two landings on grass runways, of about the same length, in nil wind. Would you use the same approach speed for both with a 20 knot wind, with some crosswind element from the left?

http://www.youtube.com/watch?v=7t0y7C4krGQ (http://www.youtube.com/watch?v=7t0y7C4krGQ)

http://www.youtube.com/watch?v=ZmVQPCZBbXk (http://www.youtube.com/watch?v=ZmVQPCZBbXk)

[mad_jock]

The two grass fields I have done the most flying into.

And yes I would, Donnoch I have taught students grass field there in 0 wind , gusty conditions and 20-30 knts of breeze. To be honest it's usually where I take them for want of something better to do for the hour with the instructor. And the approach speed is the same every time.

Cracking video's although I would say the first one you were spot on with your speed and the knockbain one you were a bit fast. Personally with the tommys if they hadn't got it on the deck before the first whit marker I maded them go around. Downhill wet/damp grass no thanks. The tommys used to stop just on the top of the hill when done properly the Jodel I thought has much better STOL performance. Although I ain't tail wheel so there might be some other factor I might not know about.

[mad_jock]

http://www.youtube.com/watch?v=HRkjZn-kw4Y&feature=player_embedded

Sorry I could find any light aircraft video of gusty approaches

Towards the end on approach you can see that he proberly has about 15 knts of xwind So the winds proberly about 35G45 at altitude. Dropping down to 20G30 at landing. The reason why I know his speed is stable ( Apart from he is a TRE) is because there is no attitude changes down approach. He just sits there playing with the gusts, letting the aircraft do the work. Gets it down kicks off the drift and doesn't float, no fannying around try to stop it drifting to the side or nose bobbing up and down trying to choose the moment to put the wheels down which is indicative of being to fast.

He will have chopped the put down so as not to scare young children :p

[Them thar hills]

"Although I ain't tail wheel"
Now you tell us ! :*

[mad_jock]

Doesn't make any difference at all to your approach speed. I have a couple of hours in them but ain't qualified. And that was in your usual highland wx.
I don't know if you guys have to do something special about up hill grass landings. Never heard of anything said though. And if its not in your POH you don't need to do it.

Chuck would have brought up the subject if there was anything different about tail draggers or anything that floats.

[Dreadful]

"The reason why I know his speed is stable ( Apart from he is a TRE) is because there is no attitude changes down approach. He just sits there playing with the gusts, letting the aircraft do the work. Gets it down kicks off the drift and doesn't float, no fannying around try to stop it drifting to the side or nose bobbing up and down trying to choose the moment to put the wheels down which is indicative of being to fast.

He will have chopped the put down so as not to scare young children "

I dont understand this. What d'you mean by his speed is stable becaus he is a Type Rating Examiner? What do you mean by he is playing with the gusts? :confused:

Chopped the put down? :confused:

I hope if you instruct your briefings aren't like this.

[mad_jock]

Chopped the put down was refering to cutting the video before touch down. And the reason why i use put down instead of touchdown is because it will be a consious choice when the wheels will touch. Instead of reacting to the gust he will just go with it allowing the aircraft to sink to make the touchdown.

If you watch the nose going down the approach you will see no huge attitude changes.

If the speed was hunting you would see the nose going up and down. You just see small corrections allowing the aircraft doing the work. Which is the way personally I know what the student is doing in relation to airspeed

And how does someones postings on pprune relate to thier lesson briefings?

Personally I use the ontrack viewfoils

[Dreadful]

Nope still none the wiser!

TRE? Significance? Using sink from a gust? Scaring children? Who is Donnoch? Telling someone theyre too fast from a video with no ASI in view?

I dont get any of this its all a bit weird.

[madlandrover]

Before anyone else wonders if they've somehow left an aviation forum...

TRE: Type Rating Examiner.
Dornoch: nice grass strip near Inverness, free from BS.
Stable Approach: one where nothing changes significantly all the way down - best way to do it.

It's relatively easy to guess the correct speed from an approach where there's no significant attitude change and the aircraft lands in the touchdown zone. Excess speed would lead to the aircraft floating down the runway, while not enough tends to leave the aircraft a bit short of the threshhold if not corrected...

[Maoraigh1]

Your right about Knockbain being fast, but not at touchdown. Knockbain was aimed to roll to end, Dornoch to vacate for the Terminal and Fire Station. But I've lost a lot more than 0.3 of stall speed, along with a lot of height, at Knockbain, in the downdraft with a wind at Inverness 20+kts from about 200 direction.

[mad_jock]

I didn't think you were fast on touchdown. From my limited experence of tailwails that can be a bit of a handfull.

Fire station and terminal at Donnoch??? Have they built that since October?

And I did realise you were going to the end. Personally if to much runway infront of me I do the same approach as usual but move my aiming point further down the runway.

The approach at Dornoch was a pleasure to watch and if you don't mind I might use it in briefings before taking people up there for the first time. :ok:

[Chuck Ellsworth]

Remember that if your airspeed is to high at the point of flare you will be floating in ground effect waiting for the excess airspeed to decay.

If there is a X/wind and or abrupt wind changes at runway height you have set your self up to make it more difficult to maintain the path over the runway you need for a controllable touch down.

The longer you float the more risk of becoming unstabalized especially with regard to drift and lateral alignment at touch down.

[Maoraigh1]

Dornoch used to be licensed. The big yellow/brownish shed was the firestation. The other building was the terminal. I think Loganair had a service.

[mad_jock]

You learn something new....... How long ago was that?

[Pilot DAR]

You learn something new....... How long ago was that?

Friday - Rockwell 114

[mad_jock]

http://www.secretscotland.org.uk/index.php/Secrets/RAFDornoch?from=Secrets.DornochAirfield

[Kiltie]

Dornoch was licenced up until 1983. Fire engine was a yellow 4wd Austin, removed some years later from the hut. The fire engine was rolled out on the occasions chartered flights required its presence.

Loganair operated a Trislander on a schedule Inverness-Dornoch-Wick 1972. It was about this time the north/south cross runway was abandoned. Prior to the installation of wooden stakes in the 1990s, airrcraft parking was available on the tarmac area making use of the iron ring tie downs.