Downwind to base to final

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iflyforpie
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Re: Downwind to base to final

Post by iflyforpie »

The thing is, you are both right. Trey, speed is golden. Speed is what we want to see. I typically come into the circuit pretty close to the white arc or if I am faster at a manageable speed that I can slow down. But a 172 does not have the inertia of a 737 and can be slowed down in short order. That--in addition to fuel costs :D --is why we don't teach students on 737s. Even the RCAF stopped using the Tutor for elementary training because of the high washout rate.

What AJV was explaining is to use 2200 RPM as a starting point. I remember using an RPM in downwind when I started, now I don't, I just set the power I need it. Just like 1500 RPM on the approach... it's a starting point the student can set and then fine tune as necessary. However, maintaining the correct speed (attitude) should be paramount.
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Re: Downwind to base to final

Post by RenegadeAV8R »

AJV wrote: I agree with another poster about the flaps on downwind not being required.
Flap are not required, but they are useful because with flap at 10° the aircraft nose is lower and the visibility is improved; visibility is important.
Here is a break down of how I teach it

3 hold circuit altitude and lower 10 degree of flaps, 80 mph (70 kts) turn base trimming for 80
4 on base lower another 10 of flap for a total of 20 degrees allowing the A/C to slow to 70-75 mph
5 if needed adjust power for high (reduce) low (add) approach but just a little ie 100 rpm
6 50 ft above threshold we have made the runway reduce power smoothly to idle keeping the now slightly down to maintain
Is it me or it seems that nobody teach to do power on idle approach and landing anymore? What about the idea of doing the circuit within gliding distance of the runway? If power is required during the approach; it is because the aircraft is not within gliding distance of the runway.

Jet engined aircraft required power on approach because of the jet engine slow spool up time from idle, but with a piston engine, power is available as soon as throttle is moved forward. And again, the circuit, including the final leg, should be done within gliding distance from the runway. There is no reason to descent below circuit altitude if the aircraft cannot glide to the runway.

IMHO, in a light aircraft, lowering more flap than 10°, while still having power (while doing a normal landing) is the airplane equivalent to applying brake and pressing the gas pedal *at the same time*, in a car.
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Re: Downwind to base to final

Post by Cat Driver »

I like to keep as much speed as possible during the approach so as to get the airplane down and parked in the shortest time frame, and there is the added bonus of not slowing down faster airplanes in the circuit.

With the Husky that normally cruises around 85 knots on the amphib. floats I maintain cruise power and descend around 120 knots until short final where I gently reduce power to idle so as to cross the threshold at normal threshold crossing speed of 60 knots.
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Re: Downwind to base to final

Post by AJV »

trey kule wrote:bringing your 10 hour student into doing circuits
here is the first problem, what is a student with 7 or 10 hours doing solo when according to the flight instructor guide there are 18 exercises to complete and be demonstrated by the student to a certain level of proficiency? We did the cadet contract for 3 summers in a row and soloed them at 12-15 and almost all of them had glider licences.
trey kule wrote:But you stated positively to set a specific RPM. No mention whatsoever of speed control. So it would be perfectly acceptable for your 10 hours student to comply with this without any undersanding of the possible differences in weight, c of g location, temperature or density altitude. Just set this RPM....and then exactly how are they to nail the speed? You eyes out of the cockpit..Of course. That is just a red herring .
yes I did, and if you instructed then you would know that especially at 10 hours they cannot just glance at the instrument, they stare at it waiting for it to show what the instructor has asked them to make it show. Secondly all the other stuff you said is taught on the ground not in the circuit, people have a hard enough time controlling the plane. Red herring? like I am trying to say something that is not relevant and trying to distract you from the topic?
trey kule wrote:a student should have learned to do in their upper airwork without ever looking in the cockpiit except a brief glance once the airspeed has stabalized. The fact is a student must learn to glance at the airspeed, altimeter, engine guages etc. briefly and with an understanding.
Again at 10 hours not gonna happen
trey kule wrote:And the good news is if I am wrong, no one will suffer as I do not instruct. The bad news is if you are wrong, your students are going to suffer. Just saying
they seem to being doing just fine.
RenegadeAV8R wrote:Is it me or it seems that nobody teach to do power on idle approach and landing anymore? What about the idea of doing the circuit within gliding distance of the runway
Yeah that's how I learned it too but and without use of flaps but when I did my instructor rating my instructor (who has way more experience than me) asked me why? and I didn't have an answer beyond that's how I was taught. He said to me that we want to fly a stabilized approach, whether it is in a 150 or whatever. I see what you are saying with the glide distance and the jet not spooling up, but if we turn to in on final a bit farther out or we have a stronger than expected head wind and we are at idle then we will have to jam on power, why not smoothly control your approach profile with the right amount of power all the way through the approach? Like I said I learned to do it with the a/c at idle too but it is way easier to have a nice smooth approach with the right amount of power.
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Re: Downwind to base to final

Post by DHCdriver »

Cat Driver wrote:I like to keep as much speed as possible during the approach
I agree 100% with that statement, why people like to drag an airplane in at final is beyond me( I'm only referring to light a/c here) I have always believed why not 10 knots/mph above your approach speed until you know you can make the field. It's alot easier to loose that speed then fall below that power curve and try and get it back. Thats where expierenced instructors will teach you practical knowledge compared to some noobe teaching you out of his/hers instructor manual. Just my thoughts. DHC
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Re: Downwind to base to final

Post by System Message »

It won't help this student, but the 1000' traffic pattern altitude is part of the problem. The glide ratio of modern light aircraft is far to efficient to lose 1000' in a proper size circuit. Light training aircraft have a difficult time achieving 1000' and almost immediatly have to do what they can to lose it and the extended cross country type circuits are the result. As a result a student flying for an hour a week gets half a dozen landings before the time is up. 1000' is twice as high as it should be.
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iflyforpie
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Re: Downwind to base to final

Post by iflyforpie »

System Message wrote:It won't help this student, but the 1000' traffic pattern altitude is part of the problem. The glide ratio of modern light aircraft is far to efficient to lose 1000' in a proper size circuit. Light training aircraft have a difficult time achieving 1000' and almost immediatly have to do what they can to lose it and the extended cross country type circuits are the result. As a result a student flying for an hour a week gets half a dozen landings before the time is up. 1000' is twice as high as it should be.
Really? I've never found it to be a problem at all. In fact, I've done circuits in light aircraft at several airfields that are up to 1500' AAE in confined mountain valleys with high DAs and never had a problem.

Light aircraft don't climb fast, but they also don't go fast. The climb angle of a 150 vs a King Air are not day and night different from each other, especially considering that the 150 lifts off much sooner.

The key is to climb to 500 feet below circuit altitude before turning crosswind or maybe a bit higher if your plane isn't climbing as well. This way your downwind isn't in the next town.

And light aircraft were designed to fly steeper than normal approaches. Clyde Cessna must be rolling in his grave when he sees instructors teaching students to fly a three mile final on a three degree glide slope with power above 2000 RPM with no hope in hell of ever being able to make the field with an engine failure. The Cessna 140--which spawned nearly all subsequent Cessna singles--had flaps installed so it could come in steep. Four to five degree slopes work perfectly with most light aircraft.
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Re: Downwind to base to final

Post by Shiny Side Up »

[quote=Iflyforpie"]Really? I've never found it to be a problem at all. In fact, I've done circuits in light aircraft at several airfields that are up to 1500' AAE in confined mountain valleys with high DAs and never had a problem.[/quote]

I would have to agree, even at the relatively high density altitude here, there's rarely a problem getting to altitude within a reasonable distance from the airport. I should note though that it certainly helps that we don't ever run the little beasts full of fuel, shedding that extra 150lbs of weight makes a lot of difference.

Getting down also isn't that hard, if Cessnas do one thing very well, its their ability to do near vertical descents. Of course to do that one might have to do that four letter word...
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Last edited by Shiny Side Up on Sun Jul 17, 2011 7:01 pm, edited 1 time in total.
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Re: Downwind to base to final

Post by robertsailor1 »

Seriously is there anything easier to fly than a 172? You can almost fly them with out rudder and those flaps allow you to pretty much make any field. Put them down sideways and they straighten right up. Nice aircraft but very little skill required to fly them. Definitely designed to the needs of lowest skill level out there.
My wife is training in a Champ, when she can fly that real well then she will move up to something like a 172 BUT she'll at least have good basic stick rudder skills something that's harder to acquire in a 172.
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Re: Downwind to base to final

Post by trey kule »

they seem to being doing just fine
According to who? I do checkflights with the end products , and there has been a huge change in the last 10 years or so.
I am not going to get into the differences, but your claim is in dispute, and I think in the next few years TC will come to the same conclusion and you will see a different emphasis on instructor training standards.

BTW, I do have several thousand hours of instructor time. I just have not held an instructor rating for about the last 20 years, and I still occassionally train commercial pilots for initial on type. I think I have a fairly good idea of the changes in overall basic understanding of new CPLs....and they were PPL students at one time.

Suggesting a power setting is one thing. Stating it as a fact is another. And the second leads to the student never understanding the whole process.

Lastly, I think you took my 10 hour student comment out of context.

In any event, it seems I , and some others are going to have to continue to deal with CPLs who insist on trying to set a specific power setting without understanding that it is only luck or randomness that will allow them to nail their speed accurately.
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Re: Downwind to base to final

Post by Trematode »

iflyforpie wrote:And light aircraft were designed to fly steeper than normal approaches. Clyde Cessna must be rolling in his grave when he sees instructors teaching students to fly a three mile final on a three degree glide slope with power above 2000 RPM with no hope in hell of ever being able to make the field with an engine failure. The Cessna 140--which spawned nearly all subsequent Cessna singles--had flaps installed so it could come in steep. Four to five degree slopes work perfectly with most light aircraft.
Speaking of this -- have you guys had any experience with pilots/student pilots trained in the states fixating on the VASI and PAPI installations and using them as the sole source of approach guidance? I've had a couple now and am wondering what they are smoking south of the border. Correct me if I'm wrong, but those indicators are calibrated for a 3 degree slope passing over the threshold at 50 feet! You are out to lunch if you are relying on them for your VFR approach in a 150.
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Re: Downwind to base to final

Post by CpnCrunch »

Trematode wrote: Speaking of this -- have you guys had any experience with pilots/student pilots trained in the states fixating on the VASI and PAPI installations and using them as the sole source of approach guidance? I've had a couple now and am wondering what they are smoking south of the border. Correct me if I'm wrong, but those indicators are calibrated for a 3 degree slope passing over the threshold at 50 feet! You are out to lunch if you are relying on them for your VFR approach in a 150.
I was trained to use the PAPI at EGSG, but it's set to 4.5 degrees so you don't come in too shallow. I think it can be a useful tool for helping the student to figure out the correct glide path.
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Re: Downwind to base to final

Post by DHCdriver »

Trematode wrote:VASI and PAPI
I've always said if the airfield is equipped with these installations, why not use them. Teach the student the basics then introduce the VASI/PAPI, they will have to use them eventually. Yes,No?
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Re: Downwind to base to final

Post by robertsailor1 »

I also meant to add that if your taught to fly a 150 or a 172 really really well then you will still end up with good skills. Problem is that most instructors don't teach or demand that level of skill so the student puts it down slightly crabbed or doesn't stall it right out or keep the stick back and its so forgiving it still lands OK.
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Re: Downwind to base to final

Post by Grantmac »

robertsailor1 wrote:I also meant to add that if your taught to fly a 150 or a 172 really really well then you will still end up with good skills. Problem is that most instructors don't teach or demand that level of skill so the student puts it down slightly crabbed or doesn't stall it right out or keep the stick back and its so forgiving it still lands OK.
I got my license in a 172, but I learned to fly in a Citabria.
If I remember correctly we weren't permitted to use the flaps in the 172 unless we could demonstrate that we were able to land to PPL flight test standards without them. To this day I treat a normal landing as one where flaps aren't used, and on any runway longer than 1500ft it should be a normal landing for a 172.

-Grant
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Re: Downwind to base to final

Post by Trematode »

I was trained to use the PAPI at EGSG, but it's set to 4.5 degrees so you don't come in too shallow. I think it can be a useful tool for helping the student to figure out the correct glide path.
Well this might explain why their use for VFR is more prevalent in the states -- but a quick glance at all the aerodrome diagrams in the CAP 3, and I couldn't find a single papi or vasi installation calibrated for anything other than 3 degrees; moreover, most are P2 or even P3 (Eye-to-wheel heights of 25', 45'). Plus the 50' over the threshold clearance.

All these combined mean that it's a bit useless for VFR in light SEL aircraft. Worse still is that it gives you the WRONG information if your objective is to fly a proper approach.

all of this of course ignores the fact that we should be training students to judge their approaches with proper visual queues (eg. a selected aimpoint/touchdown point, runway shape/size, ~500' AGL/~1 mile out) -- so even if the PAPI was calibrated properly, they know how to fly an approach without them!
I've always said if the airfield is equipped with these installations, why not use them. Teach the student the basics then introduce the VASI/PAPI, they will have to use them eventually. Yes,No?
See above -- I think if you teach them to use them, even as a secondary indication, they will only end up confusing the student. Save them for IFR work when transitioning from the instruments to the runway -- unless I am badly mistaken, that's what they're meant for, and not the VFR light aircraft approach.
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Re: Downwind to base to final

Post by CpnCrunch »

Trematode wrote:
Well this might explain why their use for VFR is more prevalent in the states -- but a quick glance at all the aerodrome diagrams in the CAP 3, and I couldn't find a single papi or vasi installation calibrated for anything other than 3 degrees; moreover, most are P2 or even P3 (Eye-to-wheel heights of 25', 45'). Plus the 50' over the threshold clearance.
Well EGSC isn't in the states, and here is the info about it showing the 4.5 degree APAPI:

http://www.ead.eurocontrol.int/eadbasic ... -12-16.pdf

MEHT is 26ft (i.e. your eyes will be 26ft when crossing the threshold if on-slope), which seems reasonable.

In Canada I'm not aware of PAPIs or VASIs at smaller airports - they all seem to be at larger airports, and have a shallower glideslope as you say. Even then, it's not necessarily a bad thing to be following the 3 degree glideslope if you're at a larger airport and having to fit in with other traffic.
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Re: Downwind to base to final

Post by Trematode »

oops -- yeah sorry about that, I just googled it and saw stapleford and realized it wasnt a canadian airport. I made the false assumption the folks here did their training in north america... the identifier makes a bit more sense now! apologies!
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Re: Downwind to base to final

Post by zed »

Welcome to the forum Nikcht. You'll see that there is a lot of really good advice coming your way...

My two bits... Are you keeping the right distance away from the runway on your downwind leg? Are you starting your turn at the right location?

If you are closing in on the runway on your downwind leg, are too close to begin with, or are starting your turn too early, all will result in you feeling/being high when you turn final. Cutting corners when you turn base and final will also have the same effect.

Next time you are up with your instructor ask him to criticize/evaluate your spacing and turn location. You shouldn't need them, but in most places people use specific ground references to make sure they are doing it right. Very helpful when you are starting out, but like training wheels something you should grow out of with experience.

Good luck, and enjoy yourself.
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Re: Downwind to base to final

Post by CpnCrunch »

Getting back on topic...

I agree with zed that it's likely you are just turning too early. Also make sure you have brought your speed back to at least 70 knots by the time you turn final. It could be that you are simply taking too long to slow down from your 95kt downwind (which is unusually fast for circuits, but perhaps you need to keep the speed up for some reason).

Also, talk to your instructor and maybe get some more dual time until you nail it.
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Re: Downwind to base to final

Post by ogc »

RenegadeAV8R wrote:
Is it me or it seems that nobody teach to do power on idle approach and landing anymore? What about the idea of doing the circuit within gliding distance of the runway? If power is required during the approach; it is because the aircraft is not within gliding distance of the runway.
I wasnt taught this initially, but after about 50 hours and my PPL I started doing circuits like this almost exclusively.

Keeps em tight and quick, really allows you to become proficient at judging glide distance, and it gave me plenty of practice for that power off 180 needed on the CPL flight test.

The practice paid off, as when that flight test came around I could reliably land within 0 to +10 feet of the spot I had chosen when doing that "exercise". Which I later found out is the most commonly failed item.
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Re: Downwind to base to final

Post by iflyforpie »

ogc wrote:
RenegadeAV8R wrote:
Is it me or it seems that nobody teach to do power on idle approach and landing anymore? What about the idea of doing the circuit within gliding distance of the runway? If power is required during the approach; it is because the aircraft is not within gliding distance of the runway.
I wasnt taught this initially, but after about 50 hours and my PPL I started doing circuits like this almost exclusively.

Keeps em tight and quick, really allows you to become proficient at judging glide distance, and it gave me plenty of practice for that power off 180 needed on the CPL flight test.

The practice paid off, as when that flight test came around I could reliably land within 0 to +10 feet of the spot I had chosen when doing that "exercise". Which I later found out is the most commonly failed item.
The problem with doing approaches at idle is the engine can cool down too much and not respond in case you have to overshoot.

You can simulate a power off approach in most Cessnas with full flaps and around 1500 RPM, which is the approach I use the most operationally (one runway with no taxiway tends to make you want to keep circuits tight, especially with gliders around). Typically, I don't need to touch the throttle until the flare.
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Re: Downwind to base to final

Post by niss »

The way I was taught and the way I fly the circuit now is as follows:

1) Establish myself in the downwind at around 100mph.
2) Right before I turn base, reduce power and raise the nose to lower my airspeed to 80mph while adding 10 degrees of flaps. Once I am at my 80mph I turn to base.

These numbers are for my Cherokee 140, 80mph is approach speed and best glide. I can knock off 3mph for each notch of flaps. Since I am stabilized in my approach speed before I turn base then there is no slowing down further during the base and final. From then on I just use the power and pitch to keep my speed and height in check as the wind requires. I also add flap if required.

Double check with your instructor but try getting yourself set up with your approach speed nailed right before you turn to base rather than have different speeds for different phases of the circuit.
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Re: Downwind to base to final

Post by robertsailor1 »

I don't disagree that shock cooling is not good for engines and it probably is better to carry a little power on when landing. That said the little engines I learned on were operated with idle power on approach almost 100% of the time and those engines rarely if ever had problems. Friends that flew similar aircraft also flew power off approaches almost all the time and I never heard of one of them with a cracked jug so its just my opinion that smaller engines seem to have more tolerance. It seems to me that the larger more powerful engines are not quite as tolerant and when I was flying planes like 210's or Bonanza's I made it a practice to carry power through out the let down and approach.
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Re: Downwind to base to final

Post by photofly »

The problem with doing approaches at idle is the engine can cool down too much and not respond in case you have to overshoot.
(my emphasis) Really? as a function of its temperature?
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