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Small Planes: Why Land Left Of The Centerline?  
User currently offlineManuCH From Switzerland, joined Jun 2005, 3011 posts, RR: 47
Posted (7 years 6 months 3 weeks 1 day 4 hours ago) and read 5717 times:
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Recently there was a discussion with a couple of flight instructors at the flight school where I trained for my PPL. We were talking about the fact that students (and even non-students) often land their Piper/Cessna/whatever single engine aircraft left of the runway centerline, but they hardly ever land on the right.

First I though it could have something to do with gyroscopic precession, P-factor, you name them. But if this were the case, it should be the opposite - I mean, the airplane wants to yaw to the left during take-off, but when cutting power on landing, if anything should happen, it should tend to yaw to the right. Or not?

Anyway, nobody could give a clear answer. Any suggestions?  Smile

-Manuel


Never trust a statistic you didn't fake yourself
38 replies: All unread, showing first 25:
 
User currently offlineKELPkid From United States of America, joined Nov 2005, 6343 posts, RR: 3
Reply 1, posted (7 years 6 months 3 weeks 1 day 4 hours ago) and read 5709 times:

Perspective?

The instructor always told us to taxi with the centerline down the spinner...this probably results in some left-hand displacement.



Celebrating the birth of KELPkidJR on August 5, 2009 :-)
User currently offlineFlymatt2bermud From United States of America, joined Jan 2006, 563 posts, RR: 7
Reply 2, posted (7 years 6 months 3 weeks 1 day 3 hours ago) and read 5680 times:

Unless the runway has centerline lighting or heavy paint on a wet runway we always try to split the nose tires with the centerline paint. This gives you 50/50 on both sides of the runway in the event of a tire failure or other directional control issue.


"When once you have tasted flight, you will forever walk the earth with your eyes turned skyward" Leonardo Da Vinci
User currently offline2H4 From United States of America, joined Oct 2004, 8955 posts, RR: 60
Reply 3, posted (7 years 6 months 3 weeks 1 day 3 hours ago) and read 5665 times:
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Quoting ManuCH (Thread starter):
We were talking about the fact that students (and even non-students) often land their Piper/Cessna/whatever single engine aircraft left of the runway centerline, but they hardly ever land on the right.

I think many new pilots correct for being seated on the left side of the aircraft when they really shouldn't be doing so.

In small aircraft, the center of the fuselage is only a few inches (or less) from your inside leg, so really, they should be attempting to "straddle" centerline, as opposed to correcting to the left.


2H4





Intentionally Left Blank
User currently offlineAirTran737 From United States of America, joined Apr 2004, 3702 posts, RR: 12
Reply 4, posted (7 years 6 months 3 weeks 1 day 3 hours ago) and read 5644 times:
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Quoting ManuCH (Thread starter):
Piper/Cessna/whatever single engine aircraft left of the runway centerline, but they hardly ever land on the right.

Because centerline lighting is a pain in the ass as you keep running it over. I think your natural reaction sitting in the left seat is to land on the left side of the line.



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User currently offlineBoeingFixer From Canada, joined Jul 2005, 529 posts, RR: 0
Reply 5, posted (7 years 6 months 3 weeks 1 day 2 hours ago) and read 5636 times:

Not much centreline lighting where most light singles fly to. Only Cat II and higher runways require centreline lighting.

Cheers,

John



Cheers, John YYC
User currently offlineN231YE From , joined Dec 1969, posts, RR:
Reply 6, posted (7 years 6 months 3 weeks 1 day 2 hours ago) and read 5607 times:

Would the aircraft's natural left-turning tendencies (P-Factor, Torque, Gyroscopic Precession, Asymmetrical Thrust, Spiraling Slipstream, etc...) also have an effect?

User currently offline2H4 From United States of America, joined Oct 2004, 8955 posts, RR: 60
Reply 7, posted (7 years 6 months 3 weeks 1 day 2 hours ago) and read 5598 times:
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Quoting N231YE (Reply 6):
Would the aircraft's natural left-turning tendencies (P-Factor, Torque, Gyroscopic Precession, Asymmetrical Thrust, Spiraling Slipstream, etc...) also have an effect?

Those tendencies wouldn't have much of an effect. Remember, during landing....and particularly, during the flare, the engine should be at very low/idle power settings.

The left-turning tendencies you mentioned are most prevalent during climb and at high power settings.


2H4





Intentionally Left Blank
User currently offlineN231YE From , joined Dec 1969, posts, RR:
Reply 8, posted (7 years 6 months 3 weeks 1 day 2 hours ago) and read 5596 times:

Quoting 2H4 (Reply 7):

I see...I figured that maybe newer students may not be as experienced with the flare (good angle of attack) as a more experienced pilot, and thus may be "owned" by the airplane, but I see that is not the case.


User currently offline2H4 From United States of America, joined Oct 2004, 8955 posts, RR: 60
Reply 9, posted (7 years 6 months 3 weeks 1 day 2 hours ago) and read 5590 times:
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Well, there's certainly going to be a certain degree of gyroscopic precession as the pitch of the airplane is increased, but I think the effect is minuscule when compared with the vast number of pilot-induced effects involved in a student pilot landing.  biggrin 


2H4





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User currently offlineSlamClick From United States of America, joined Nov 2003, 10062 posts, RR: 68
Reply 10, posted (7 years 6 months 3 weeks 1 day 1 hour ago) and read 5563 times:

Quoting ManuCH (Thread starter):
First I though it could have something to do with gyroscopic precession, P-factor, you name them.



Quoting N231YE (Reply 6):
Would the aircraft's natural left-turning tendencies



Quoting 2H4 (Reply 7):
Remember, during landing....and particularly, during the flare, the engine should be at very low/idle power settings.

Actually with airplane wings having wash-in and wash-out and the vertical fin being aligned to counteract P-factor at high power settings, I would expect that during landing at very low power (idle) for there to be a right-turning tendency although very slight because speed (air loading) is also low.

Quoting 2H4 (Reply 9):
Well, there's certainly going to be a certain degree of gyroscopic precession

So the question is, what is the effect of gyroscopic precession on a back-loaded, windmilling prop?

Greatest airload on the descending blade?
Becomes manifest 90° in the direction of rotation later.
Therefore a pitch-down moment?

On further reflection I believe the pilots in question are just sloppy and I'd appreciate it if they'd straighen up and fly right or stay the hell away from my airspace.



Happiness is not seeing another trite Ste. Maarten photo all week long.
User currently offlineBoeingFixer From Canada, joined Jul 2005, 529 posts, RR: 0
Reply 11, posted (7 years 6 months 3 weeks 1 day 1 hour ago) and read 5540 times:

Quoting SlamClick (Reply 10):
On further reflection I believe the pilots in question are just sloppy and I'd appreciate it if they'd straighen up and fly right or stay the hell away from my airspace.

 checkmark  checkmark  That's by far the best reply so far  rotfl 



Cheers, John YYC
User currently offlineN231YE From , joined Dec 1969, posts, RR:
Reply 12, posted (7 years 6 months 3 weeks 23 hours ago) and read 5484 times:

Quoting SlamClick (Reply 10):
On further reflection I believe the pilots in question are just sloppy and I'd appreciate it if they'd straighen up and fly right or stay the hell away from my airspace.

On a side note from the discussion; there is a gentleman who flies out of the same airport my university uses. According to my roommate, his instructor warned him to watch out for this guy, as he will try to collide with other people.  eek 

From my own encounters, this guy has sloppy pattern work.


User currently offlineFutureualpilot From United States of America, joined May 2000, 2602 posts, RR: 8
Reply 13, posted (7 years 6 months 3 weeks 22 hours ago) and read 5462 times:

Quoting N231YE (Reply 12):
According to my roommate, his instructor warned him to watch out for this guy, as he will try to collide with other people.

Perhaps a subtle hint to the FAA is at hand...I hate to see a pilot loose his wings, but if it means getting someone out of the air who not only endangers themselves, but other people...on purpose no less then I would say it is the right thing to do.


As for the original post, I would suspect that at low airspeeds with a low power setting, any gyroscopic forces would have little effect on ones alignment with the runway centerline, but perhaps it has to do more with an optical illusion of sorts.

[Edited 2007-01-10 05:09:01]


Life is better when you surf.
User currently offlineL-188 From United States of America, joined Jul 1999, 29791 posts, RR: 58
Reply 14, posted (7 years 6 months 3 weeks 21 hours ago) and read 5428 times:

The pilots aren't compensating for the rotation of the earth.

So if you don't do that and are landing to the north, you will land to the left side of the runway, headed south and you will end up on the right. Of course if you land East West, the coriolis effect will take over and you will be off to the side 90 degrees due to gyroscopic delay (Sorry can't think of the term)

 eyepopping 

I'd explain more but I have got to go and put more wax on those wings I am making.



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User currently offlineN243NW From United States of America, joined Jul 2003, 1626 posts, RR: 20
Reply 15, posted (7 years 6 months 3 weeks 19 hours ago) and read 5396 times:

If I were to take a random guess, I'd say that this phenomenon may be due to pilots of small aircraft thinking that their seat is farther from the runway's centerline than it actually is. The left seat on most GA planes isn't more than a couple feet left of the nosewheel, so theoretically if the pilot aims right at the centerline, he/she won't be far off upon touchdown (a little to the right of center if anything). But if the pilot believes that the seat is further left than it really is, he/she may compensate too much and therefore land too far left. Anyone else think this is plausible?

-N243NW Big grin



B-52s don't take off. They scare the ground away.
User currently offline9VSIO From United Kingdom, joined Dec 2006, 708 posts, RR: 2
Reply 16, posted (7 years 6 months 3 weeks 16 hours ago) and read 5349 times:
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As I'm still doing circuit training, I'll give my two cents worth.

This certainly was an issue for me when I started, I reckon what happened was that I was using the edge of the runway to judge as well as the centerline. It seems to have vanished now, so it seems to be a matter of experience. Interestingly, this only happened when I was landing on the nice big tarmac runway. Never had this issue with the grass runway (possibly due to lack of centerline?)

P.S An instructor of mine once told me when people started training, they would brake to the left. He figured this was due to the fact that they drive manual cars, thus their left foot has less finesse compared to their right. Anyone else encounter this?



Me: (Lining up on final) I shall now select an aiming point. || Instructor: Well, I hope it's the runway...
User currently offlineThirtyEcho From United States of America, joined Dec 2001, 1643 posts, RR: 1
Reply 17, posted (7 years 6 months 3 weeks 16 hours ago) and read 5338 times:

This happens for the same reason that most roll-axis upsets are to the left when non-IFR pilots fly into IMC; the natural tendency of novices when pulling the yoke back is to, also, induce a left turn. They mistakenly compensate with right rudder, which induces a left forward slip. Bingo, you are left of the centerline and the left gear contacts the runway first with beaucoup side load.

In the days of the old spring-steel Cessna landing gear, you would get a big BOIIING, roll right, screeching right main touchdown, nosewheel slam and a landing right down the left side of the runway.

Been there, done that


User currently offlineNoelg From , joined Dec 1969, posts, RR:
Reply 18, posted (7 years 6 months 1 week 8 hours ago) and read 4831 times:

I was always taught to takeoff/land with the nose wheel slightly off centreline as the cats eyes can damage the landing gear at high speed. In wet weather the runway centre lines are also slippy so the tarmac offers more grip.

I guess the left hand seat makes to tend to land left rather than right!


User currently offlineN243NW From United States of America, joined Jul 2003, 1626 posts, RR: 20
Reply 19, posted (7 years 6 months 1 week 7 hours ago) and read 4787 times:

Quoting 9VSIO (Reply 16):
P.S An instructor of mine once told me when people started training, they would brake to the left. He figured this was due to the fact that they drive manual cars, thus their left foot has less finesse compared to their right. Anyone else encounter this?

I never thought about this before, but it certainly is true with me! I'm not an actual pilot [yet], but I do a lot of simulator flying with rudder pedals. The instant the nose gear touches the tarmac, I immediately apply too much left brake and have to counter it with my right foot. And yes, my daily driver is a manual transmission Wink

-N243NW Big grin



B-52s don't take off. They scare the ground away.
User currently offlineTlfd29 From United States of America, joined Jul 2005, 81 posts, RR: 0
Reply 20, posted (7 years 6 months 1 week 3 hours ago) and read 4729 times:

Just a poke in the dark, but sitting on the left side of the aircraft the pilot has a better reference as to how much distance is between the left main gear and the runway edge. The runway I land on is quite wide so I tend to stick a little closer to the left side because I can see quite clearly how much room I have to play with. Like I said, just a thought.

User currently offlineJetstar From United States of America, joined May 2003, 1642 posts, RR: 10
Reply 21, posted (7 years 6 months 1 week 1 hour ago) and read 4706 times:
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In my Air Force days years ago, one time I was riding in the cockpit jump seat just behind the left pilots seat of a C-97 while we were landing at McDill Air Force Base in Tampa, Florida. At the time the main runway there was 500 feet wide, going back to the days when the Strategic Air Command had B-47’s based there on active alert and when they had to scramble they took off 2 abreast.

The pilot commented that because the runway was so wide it was hard to gauge his distance above the runway to flare out so he landed on the left side of the runway and was able to see the grass area, which he used for depth perception.

I have had the same problem on occasion in my own C-150 when I have landed on very wide runways so I used the same procedure and would land on the left side for better depth perception.


User currently offline9VSIO From United Kingdom, joined Dec 2006, 708 posts, RR: 2
Reply 22, posted (7 years 6 months 1 week ago) and read 4676 times:
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Well, I was typically more accurate on the smaller grass runways, but the last few times I used the concrete, I ended up on the centreline! But, I once glanced to the side, and the next thing I knew, I was a few meters to the side of the centreline.

I wonder if the reverse is true, that when flying from the right seat, you tend to land left.



Me: (Lining up on final) I shall now select an aiming point. || Instructor: Well, I hope it's the runway...
User currently offlineDeltaGuy From , joined Dec 1969, posts, RR:
Reply 23, posted (7 years 6 months 6 days 22 hours ago) and read 4630 times:

Quoting Jetstar (Reply 21):
I have had the same problem on occasion in my own C-150 when I have landed on very wide runways so I used the same procedure and would land on the left side for better depth perception.

A few of the planes I rent are based at a military airfield with a pretty wide runway- same problem, but you get used to it after awhile. Then when you get to a small uncontrolled field, with <75' wide runways, you feel alot different.

DeltaGuy


User currently offlineCptSpeaking From United States of America, joined Apr 2006, 639 posts, RR: 1
Reply 24, posted (7 years 6 months 6 days 8 hours ago) and read 4519 times:

One possible explanation could be that the left hand is used on the yoke from the left seat. When on final approach and in the flare, a lot of times the student will not pull the yoke directly back, but will kind of pull down a bit with their hand too. I understand that this would cause the airplane to bank and that this would be fixed by returning to level, but it may not be corrected for in the early stages of flight training.

Just an idea...could be why I was consistently a foot right of center when I was doing my CFI training...

Your CptSpeaking



...and don't call me Shirley!!
25 SlamClick : This was a real problem the first few times I landed on huge alkali flats like the Black Rock Desert. No reference, it was almost like an instrument
26 ThirtyEcho : Who cares? Just plunk it down anywhere? When you land on as many 35 foot runways and one 25 footer, as I did as a kid, you will learn to respect naili
27 FlyUSCG : I think many of you are over thinking it waaay to much. I always land on the centerline (it's there for a reason). But I've heard from instructors tha
28 Post contains images Cptspeaking : Hahaha thats just ridiculous. It's paint, not a bunch of mirrors. And yes, the centerline lights are annoying, but they aren't exactly on the middle
29 FlyUSCG : If your a pilot... you obviously need to pay more attention. If your not a pilot... shut up because you don't know what your talking about. The paint
30 Post contains images 2H4 : Actually, they're pretty interesting little lights: Here they are being installed in a new runway: 2H4
31 FlyUSCG : I just read your profile and see your a pilot and have several ratings. So I take that back and replace it with "I see your a pilot, and your an idio
32 2H4 : Have some respect, FlyUSCG. You can only make it to national-level competition after beating 5-7 other schools. At nationals, you're up against about
33 CptSpeaking : Wow. First of all, I wasn't saying you were ridiculous at all, just the comments of those instructors you quoted, so there was no reason to get defen
34 Pilotpip : When you start instructing, you'll likely land to the right of centerline. It's all perspective. People have a habit of trying to line the prop spinne
35 FlyUSCG : I know all about flight teams, I go to Embry-riddle in Prescott and ours is nationally ranked blah blah blah. The general consensus on this campus is
36 CptSpeaking : True...I personally still haven't had an issue with this in 172RGs, 152s and Arrows, all of which have landing lights in the nose. It's your opinion
37 2H4 : With all due respect, until you've competed for a year or two, you really have no idea... CptSpeaking, you underestimate how effective your flight te
38 Post contains images FLY2HMO : They would be if you were a Golden Ego.. errr Eagle Very true.
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