Landing and flaps.

[B767PL]

I'm a CFI and recently got a job at a new flight school.

My original flight school always taught, and everyone used full flaps on landing, and this I understood to be the best way to do it.

I am not sure if this was being taught in the past at my present flight school, but I have flown with some students, and renters there who all already have their PPL, and many of them use only 2 of the 3 available notches of flaps. The aircraft is a Piper Cherokee. Now these are not my "students", some have come in for a BFR and others requested me to fly with them a trip through the Hudson VFR Corridor.

I have been reluctant to say anything to them as to why they use 2 notches of flaps (25 deg.) instead of the full 3 (40 deg.). The reason for that being is that I am not sure if there is anything seriously wrong with that.

Comming in with less flaps at a given speed = you landing with a higher nose up attitude, which may not always be desirable.

Also, using less flaps you would tend to land with a slightly higher speed, and we always want to touch down at the minimum speed, and as slow as possible.

Adding an extra notch of flaps also lowers your stall speed by a little bit, which can aid in slowing the aircraft down farther to touch down at a minimum speed.

Full flaps also requires you to come in during a standard approach, with a higher power setting to maintain a certain airspeed, then does an approach with less then full flaps, giving you better speed control.

Although on really gusty, windy days, a landing with 2 notches may be more desirable, as it increases the controlability of the aircraft during landing by increasing the stall speed a little.

Does that all make sense to everyone?

What do you guys think? Thanks. :}w

[Notsonew]

Yes,
I too have met the '2 notches only' brigade.

I am guessing, but I believe they may have been told that there is less chance of ballooning,either through a mis judged flare or a sudden gust of wind.

There at least 10 reasons for using flap on the approach and landing and some of them may suggest full flap is even better

1. Lower stalling speed.
2. Lower approach speed.
3. Lower ground speed.
4. Faster retardation on the ground.
5. Higher drag therefore more power/slipstream thus more elevator control.
6. Lower nose to see better.
7. More lateral stability -I think the flapped spanwise distribution of the Cl values enhances the 'dihedral effect'
8. Lower nose actually means more effective ailerons. (work than one out -I believe it is due to the flapped wing neutral postion of the ailerons is lower relative to the airflow than the unflapped position and thus has a greater effective range of travel)
9.Higher power means a quicker response to full power for a 'go around' (or following a bounce)
10. Keeps you in the 'speed stable' part of the drag curve.

On the Cherokee 10 degrees flap is nearly only extra lift.
25 degrees is a lot of lift and a fair amount of drag, 40 degrees a lot of drag and only a bit more lift. (I believe).

Now there is a thread on Pprune that discusses the occasions when 25 degrees of flap may be better. If the crosswind is say 45 degrees off the runway and very gusty then use 25.Example 45 degrees 'off' at 16 kts would be 12kts xwind component and 12 kts headwind component.
Now 90 degree crosswind and very gusty and it may be better to use 40 degree and thus spend less time in the flare/float but this a fine judgement and gut feeling/experience could be the deciding factor (and the strength of the wind/gusts)
Certainly I have felt happier in a strong cross wind by staying in the flare/float as long as possible to judge the crosswind touchdown (whether it is crab or wing down or a combination of the two). The longer float is possible in a 90 degree crosswind whether you have 25 degrees or 40 due to the lack of headwind component).

I emphasise that all the above is my personal slant on the subject but I hope it helps.

[18greens]

Most schools in the UK teach 2 stages for a normal landing and full for short field in a Warrior/Cherokee. For the cessnas with 40 degree flap this was generally used again only for short field , 30 being the norm.

As I recall the last stage of flap does not change the pitch so the picture does not improve by applying stage 3. Stage 3 just adds drag requiring more power to remain stable. Unless the rwy is short I guess most people have compromised on the 2 stage approach. Going around with full flap makes climbing hard or impossible so I guess thats another reason to use 2 stages.
It probably all goes back to the first chaps to write the checklists when the cherries first arrived and its been done like that ever since.

Having said all of the that the military stuff (bulldog, firefly, Chippy) only have two settings for the simple Takeoff (10deg?) and Landing (More degrees).

As for gusty conditions I used to go for no flap and loads of speed (perhaps a bit too bullish)

[CityFlyer]

When I learned to fly, my instructor regularly had me land in different configurations so that I would be ready for any eventuality.

The problem I found was that although I fully understood when to use different stages of flap, the need to use anything less than full flap did not occur for several years, so I had not had to consider the consequences.
I ended up on final approach with full flap in a C150 and a vicious headwind. I needed full power to maintain height. Of course I realised very quickly that I needed less flap, but I did not know what the consequences of removing flap would be at 300ft. I thought I might sink, but by how much?

Experience, has taught me to remember to check the flaps required every time in the circuit - of course that is obvious, but not if you have not needed to worry for several years; it is possible to forget. What I wish I had learned whilst training was how much I would sink by (if at all) if I removed the flap.
So how much flap should you have on final? It doesn't matter, so long as you fully understand why you have made your choice and know if there are better options and what the effect is if you change your mind. Robotic learning is fine on day one, but a full understanding maketh the pilot.

[Chuck Ellsworth]

Deleted........

[chris keeping]

I agree with all of the above posts, much depends on conditions. When I was undergoing my PPL training and later training as an instructor, I was taught that full flap landings were generally the ones to aim for and that is what I passed on to my students.

[BEagle]

Always land with full flap, unless the system has failed. Why else did the designers provide it?

Which UK schools teach '2 notches for a normal landing, 3 for short field'? In any case, there is no 'short field landing' technique in the POH for either the Warrior or Cherokee. You should use the configurations specified in the POH and nothing else. Same goes for approach speed - in a Warrior at any weight and in normal/strong/gusty winds, a closely monitored 63 KIAS is fine, for example. Which is whyt we teach 'point and power' - keep aiming at the touchdown point with the control column and keep correcting the IAS with small positive power changes and the aircraft will be entirely straightforward to land. You shouldn't be flying if the gusts and/or vertical air motions are so severe that you can't control the approach normally.

2 notches, excessive approach speed, balloon and crunch needs to be beaten out of students and renters alike.

As for needing full power to maintain height in a C150 with 40 deg flap on the approach - get the engine checked! I was taught to use 40 deg flap for all landings in the F150 whilst doing my PPL at Cranfield in 1968 - we also practised full flap overhsoots and, whilst the climb performance wasn't brilliant, it was perfectly manageable.

[Insane]

Couldn't agree with you more BEagle!!

[BristolScout]

I agree with most of the above but, in the case of the C150, 40 degrees of flap is excessive for most landing situations and can get the infrequent flyer into trouble, which is why Cessna limited the setting to 30 degrees on the 152. It's satisfying to carry out a short field landing into wind with 40 degrees and stop in a matter of feet but it's a technique which requires constant practice. 30 degrees has sufficient drag to give a sensible landing run on most runways - a short stop followed by a long taxy to the next turn-off won't endear you to the tower if there's traffic backed up behind you on finals. Obviously, we all need to keep proficient in short-field technique because tomorrow might just be the day we head down into that meadow with the engine stopped.

[SNS3Guppy]

If you're not teaching the student both flaps up, and flaps down landings, then you're doing the student a grave disservice. The student should be fully comfortable landing with any flap setting, and a variety of power settings. Initially one airspeed and one flap setting may help the student get the basics of landing the airplane...but by the time a student becomes a private pilot, the student should be entirely comfortable landing the airplane no matter what the flap setting. Flaps fail, and the student needs to be able to handle that without a second thought.

[hugh flung_dung]

18 Greens: methinks that "Most schools in the UK teach 2 stages ... " is possibly a little too sweeping a statement. I'd agree that it's common in the early stages of 12/13 to stick to 2 stages because the FI can be a little more relaxed about errors, but the aim must be to get the stude to full flap landings ASAP, and then to flapless.

As for gusty conditions, adding half the in-to-wind gust component to the Vat is all that's needed, maybe a little less flap if you want optimum roll control.

HFD

[jb5000]

Don't forget that all performance data you've calculated is now completely useless as the charts (for the types I've flown anyway) specify full flap as part of the configuration.

I was also taught to use landing flap in any level of crosswind. I'm not sure if this happens to be type specific (C172 / DA42) as I suppose some aircraft are more of a handful than others, but I haven't experienced too much hardship in using full flap in all scenarios.

[BEagle]

1. DO NOT increase approach speed for gusty crosswinds - the POH value is the only one to use. Far too many airliner-drivers (who don't really understand the difference between large aircraft with high inertia and small aircraft with low inertia) have imported their 'big aircraft' ideas into PPL-level flight training.

When we conducted a review of the 'Club' PA28 checklists some years ago, we found that someone had said 'add 5 knots if 3 poB', someone else had suggested adding 1/3 the wind if that was above 15kts and, worst of all, they were teaching an approach speed which was 10 kts above the speed which they thought was the so-called 'threshold speed'. So, with a 15G20 headwind, with 3 PoB, people were flying at 63 + 7 + 5 + 10 = 85KIAS all the way to touchdown.... Or what they hoped would result in a touchdown. The aircraft ballooned, they found themselves 22 knots out of trim and we lost a couple of props and nosewheels.

Since throwing out all the 'old wives' crap - and flying base leg at approach +10 with 2 notches, final at POH approach speed and 3 notches, we haven't had a single problem, tocuh wood.

I will personally throw the next ATCO who I hear tell a student on final approach to "Keep your speed up, one heavy behind you at (whatever) miles" off the roof of the control tower!

2. The 'optimum roll control' is another roseate aquatic animal. The only aircraft I've flown where it was sometimes a good idea to use approach flap rather than landing flap in a gusty crosswind was the VC10. Because inexperienced pilots could be caught out by unexpected roll when yawing to align with the centreline - and the inboard flap fairings were quite close to the ground...

3. Teach landings with full flap from the word go. If an FI cannot cope with that, he/she shouldn't be an FI. Mind you, from what my FIE colleagues tell me, that would probably result in very few FIs left - the general standard is pretty low, they say.

4. In the PA28, the only time I would accept a less-than-full-flap landing would be either a deliberate flapless landing, or a glide approach which the student hasn't got quite right - and hasn't been able to select full flap before reaching 200 ft agl. Below that point, the change of pitch attitude to maintain the glide speed, followed by the opposite sense change of attitude before the flare will all happen too quickly for the student to manage safely.

[fireflybob]

Agree with every single comment from Beagle there! Too many old wives tales floating around about approach speeds and configurations.

[homeguard]

BEagle, I agree, but.....
This absolute idea that only full flap is acceptable - to me is un-acceptable. Unless the POH forbids (the PA28 manual has nothing to say on it) then with good reason use the configuration that best suits the aim of the exercise but just the same fly the correct speeds and allow nothing else. If the speeds not correct, GO AROUND!
Stall speeds are shown in the POH for level flight and differing angles of bank. From memory the stall speed for the PA28 is no higher for 25 degrees of flap than when the max flap 40 degrees is used. The final 15 degrees is not a critical setting therefore and there is no discernable pitch change for the student to learn, when applied.
BEagle note 4 and earlier comments;
One of the issues not addressed is the amount of appalling flat landings anyone can witness with students/PPLs landing the PA28 series. Partly, I blame this on the absolute insistance of the use of full flap during training, whatever! One problem with the PA28 is the limit in pitch control, at below landing speeds, from the stabilator. This is different from the greater sensitivity of a conventional fixed tailplane/elevator. Even at taxy speeds you can pitch a Cessna. Should the student retard power a mite too early or round out a tad too high they will almost always land flat at best or even worse on the nose wheel. Landing can be something like a belly flop and you can get away with it although not with me and i'm certain not with you. Allowing this will only encourages the wrong image to fester in the students head. If allowed they will probably be quite pleased just the same and not grasp the reason why you complain afterward. The PA28 is not so keen to porpoise unlike many other types such as the Cessna series and lessons therefore may not be learned as they might.
Certainly during the early sessions in the circuit landing with 25 degrees means speed is not lost so rapidly and allows the student more time to observe and experiment during the hold-off and the instructor more time to coach them through. Should they 'balloon', whats the problem with that, the answer is simple, it is to go around - i'm sure we all agree - and you cannot practise that too much.
With the landing attitude thoroughly learned then introduce max flap and the factors that go along with that. However, I would certainly require the student to be competent at max flap landing on the mains, prior to solo.
Approaching using the correct speeds and landing on the main wheels is by far the most important rule to foster. Second is the willingness to go around. Thirdly, well, some aeroplanes don't have flaps.

[llanfairpg]

Funny how people always quote the POH when it agrees with their way of doing something. Presumably POHs must say that only full flap can be used for landing.

As for increasing speed on the approach in gusty conditions what is incorrect about that? Its the speed that you cross the threshold that's most important.

I wonder if our ex RAF guru would fly a 4 mile final approach into Leeds with a 30 knot crosswind with the same approach speed that he flys into Wellesbourne with zero wind.

The most important aspect in a flying school is that all instructors teach the same flap setting rather than whether its two notch tor three notch.

By the way if you are going to criticise airline pilot technique why mention VC10s.

[foxmoth]

One of the issues not addressed is the amount of appalling flat landings anyone can witness with students/PPLs landing the PA28 series. Partly, I blame this on the absolute insistence of the use of full flap during training, whatever! One problem with the PA28 is the limit in pitch control, at below landing speeds, from the stabilator.

Rubbish, the Pa28 has no problem with this if you use correct technique, there is a thread elsewhere asking about when to reduce power on the Pa28 on landing and if you reduce after roundout there is plenty of elevator authority to achieve a good nose high landing.

[Notsonew]

When I was young I was not so sure. Now I am old I am not so certain.

Interestingly the POH performance graph suggests 63 kts approach speed after full flap selection and a full stall on touch down. Strikes me that needs the skill level required to achieve a 0 - 0 landing in a helicopter.

A point on the strong advocacy for 'point and power' I would just like to say that a very experienced Instructor, even older than me, argues cogently and convincingly that 'point and power' is not suitable for light pistons. I have never heard his arguments first hand but I can guess some of the points i.e. 55kts and 200 ft up and elevator is faster than power to regain the 63 kts (reduction of induced drag) etc. etc.The Instructor I believe had a RAF background where 'point and power' seems to be the rule so his 'sea change' is all the more surprising.

[BristolScout]

Notsonew. I'd like to be associated with the sentiments of your first sentence!

I agree that point and power is probably best left to the fast, pointy aeroplanes. I've always taught light aircraft students to control speed with elevator and height with power because, although it's as old as the hills, it still works.

[Troy McClure]

I was taught, and teach, that in a Warrior 2 stages of flap is a 'normal' landing, 3 stages is short field. I teach both, and flapless too of course. Am I doing something wrong? Don't think so...

[llanfairpg]

Course your not doing anything wrong but you are disgreeing with some of the people on here that believe everything they do and say is the only way to fly an aircraft. Still it keeps me reminded why I never want to get back into PPL flying training again

[hugh flung_dung]

Initially teaching landings with F2 in a PA28 gives slightly more time to learn the correct hold-off picture and techniques so studes seem to learn faster as a result; it's then an easy step to teach full flap landings. I fail to understand what's wrong with doing this provided that the correct technique is used and that full flap landings are understood as the norm. - can someone enlighten me?

As far as the rest of this goes ... we're trying to teach judgement as well as simple motor skills and how to follow the book; judgement requires knowledge. Whenever possible we're also teaching generic skills, rather than PA28 (or whatever) skills.
Plainly the stude needs to understand that they only have a chance of achieving the POH performance if they use the POH techniques but they also need to know when they might want to deviate from the POH. The effect of flap on roll control is info that they may need in some types (speaking as someone who came to grief many years ago because of this :{). They also need to understand inertia and the risks of being fast/slow, or of strong gusts.

BTW, if anybody here hasn't read "think like a bird" yet I strongly recommend that you put it on your Xmas list. It's a great read, especially the parts about short landings!

HFD

[cobber_digger_buddy]

watch the old 182Q/T with a full flap approach (*30Deg) if you have to go around with less than 1/2 tanks, (i.e low weight), if you have trimmed her for approach (as ya do), she'll try and point the nose to heaven on an upwind full power go around and it requires more than a fair physical push to keep the nose down.


Which is in accordance with only using 2/3 flap, it's still a physical push, but a little less mike tyson if you get my drift

[llanfairpg]

I was at Coventry one day on finals when I noticed a smashed up C150 short of the threshold. The pilot had just attempted a full flap GA, they took him away in a body bag. He was on a qualifying cross country from Booker.

Teaching GAs is more important than landings but how many instructors place suitable emphasis on this aspect of 12 & 13. I bet if this pilot had been using 20 degree of flap he would be here today.

The wide range of PPL ability coupled with some of the awful standards of PPL training I have witnessed(in 12 flying schools) lead me to belive that the safest option is always the best. I understand why pilots argue for the use of full flap, I use it myself but I would not teach full flap landings as standard in a C150, not that there are that many around anyway!!!!

[antic81]

Hi

I did my initial training in the mighty PA-28 at Biggin, long runway and so I did most of my early approaches with a flap 2 setting, I felt quite comfortable with this, however I did ask why we didn't train using full flap, the answer I got was something that the last poster eluded to, the fact that most students, in the event of a go-around could forget about the drag flap and end up struggling, especially on a hot day ( I know we don't really get many of them) even in a clean config they tend to climb like a brick and they could run into trouble.

I also agree that perhaps more time should be spent practising Go-Arounds, I got plenty during training, but thats because Biggin tended to be busy with students on the weekend, some of whome forgot to mention that they had finnished their circuits and would, in fact, be landing, slamming on the anchores and then using the whole length to taxi at a fast walking pace...

[foxmoth]

Full flap GA on a C150 is totally different to that on a Pa28 or even a C152, Old 150s (which I learnt on and still did full flap landings) were a real handful - but you were taught to deal with it and IMHO this is how it should be rather than dumbing down the students.

[llanfairpg]

Thats were we differ you see I would not send a PPL to Coventry to land on the Tarmac(in those days) on a cross country using full flap in a C150. I would feel safer briefing him to use 30 in that situation.(strange airfiled perhaps a touch nervous) I quite agree with full flap in every other a/c that has been mentioned.

I think Cessna must have agreed with me to some extent!

[foxmoth]

I think Cessna must have agreed with me to some extent!

Probably more to do with US liability law than flying technique!:rolleyes:

[llanfairpg]

Same difference!

[Fredairstair]

The point is not whether you think that landing with 2/3 or full flap is the answer. The point is if that you're working for a flying school (or airline!) you all have to be singing off the same song sheet as instructors or trainers.

My personal opinion is that teaching folk to land with 2/3 flap is not the answer, for all sorts of reasons already set out in previous posts. However, unless I persuade the Boss to change policy, I have to toe the party line. Or start my own flying school.

[TheOddOne]

Or start my own flying school.

Ah! I take it, then, that you have as a prerequisite, a large fortune from which to make a small fortune.:)

Cheers,
TheOddOne