Pushing and Pulling A/C
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Pushing and Pulling A/C
Hi All,
Have been flying all types of a/c for many years now, but nowhere in my training or in the literature can I find information on how to push and pull light aircraft. By that I mean when no tow-bar is available and the aircraft needs to be manouvered by hand. Where are the reccommended push/pull points on common a/c. e.g warrior and cessnas.
Thanks
Have been flying all types of a/c for many years now, but nowhere in my training or in the literature can I find information on how to push and pull light aircraft. By that I mean when no tow-bar is available and the aircraft needs to be manouvered by hand. Where are the reccommended push/pull points on common a/c. e.g warrior and cessnas.
Thanks
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Depends on aircraft type, but any flying club should be able to show you. Generally, the key points are:
Check that prop is NOT live (mags off, etc.)
Generally you can push on prop (close to hub, one hand either side), leading edges of wing, and anywhere it doesn't say "no push". Obviously don't push on any control surfaces. Front edges are generally good.
I suspect the reason you have been told not to push down on the rear fuselage to turn the aircraft is because it will then pivot around the main wheels, taking some rubber off the tyres at the same time, which is not a good idea.
On many aircraft there are handles in front of the tail, on the fuselage, so you can push or lift on these.
Safety is the main consideration. Be aware of things like sloping ground and always always double check that the prop's not live.
You are best off having two or more people pushing the aircraft, with one person allocated as in charge, to direct everyone. Brief the others they can shout "stop" loudly at any time they are not happy.
Check that prop is NOT live (mags off, etc.)
Generally you can push on prop (close to hub, one hand either side), leading edges of wing, and anywhere it doesn't say "no push". Obviously don't push on any control surfaces. Front edges are generally good.
I suspect the reason you have been told not to push down on the rear fuselage to turn the aircraft is because it will then pivot around the main wheels, taking some rubber off the tyres at the same time, which is not a good idea.
On many aircraft there are handles in front of the tail, on the fuselage, so you can push or lift on these.
Safety is the main consideration. Be aware of things like sloping ground and always always double check that the prop's not live.
You are best off having two or more people pushing the aircraft, with one person allocated as in charge, to direct everyone. Brief the others they can shout "stop" loudly at any time they are not happy.
Joined: Jan 1999
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From: north of barlu
Pushing down on the rear of an aircraft is not a problem as long as it is in the right place IE at the root of the tailplane on the spar.
I move PA38 on my own by pulling them by the tail tie down once the thing is on the move it can be steered by very light pressure on the rudder.
I move PA38 on my own by pulling them by the tail tie down once the thing is on the move it can be steered by very light pressure on the rudder.
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To push on the leading edge is not recommended as it is soft skin and can be bent. Any a/c can be pushed by the prop as long as it is done near the hub. NEVER push by the prop tips as they might bent! Cessna can also be pushed by the struts. Also, not recommended to push by the wing tips (Force X Arm = Moment).
Regarding the other question, ‘Why not to push down on the end of the a/c’. I remember reading many years ago that Cessna published a warning not to do so as it creates high stress on the tail assembly which in turn cause cracks, especially if done by pushing the stabiliser. If the a/c is fitted with handles they can be used to lift the tail while turning the a/c.
It is bad practice to push on the tail cone but many are doing so including mechanics, I told mine off.
Regarding the other question, ‘Why not to push down on the end of the a/c’. I remember reading many years ago that Cessna published a warning not to do so as it creates high stress on the tail assembly which in turn cause cracks, especially if done by pushing the stabiliser. If the a/c is fitted with handles they can be used to lift the tail while turning the a/c.
It is bad practice to push on the tail cone but many are doing so including mechanics, I told mine off.
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The worst thing is seeing someone 'testing the oleo' in the preflight walk around by manipulating the spinner on a prop up and down. Doesn't take much to start a crack against the fixing screws, they're not designed for that load.
On my PPL (C150/C152) I was initially taught that if I needed to move the nosewheel out of a rut before start, or position it onto a parking 'slab' in the grass when I'd invariably just missed it, I could (with brakes off, mags off, etc etc) lean over the fuselage at the very FRONT of the tail, (where the tail meets the fuselage), spreading the load with body and arm, and just see-saw the front wheel into the air and manouevre it back onto the slab. I've never questioned this before, as it 'went in' so early on in my flying. Any problems with that, C150 structural experts?
On my PPL (C150/C152) I was initially taught that if I needed to move the nosewheel out of a rut before start, or position it onto a parking 'slab' in the grass when I'd invariably just missed it, I could (with brakes off, mags off, etc etc) lean over the fuselage at the very FRONT of the tail, (where the tail meets the fuselage), spreading the load with body and arm, and just see-saw the front wheel into the air and manouevre it back onto the slab. I've never questioned this before, as it 'went in' so early on in my flying. Any problems with that, C150 structural experts?
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Wherever possible I always ask the owner or pilot where to grab the aircraft. Especially with the imaginative designs of the home-builds with which I am usually surrounded, the only way to know for sure is to consult the flight manual, which the pilot is supposed to know (especially if he built it himself.
Otherwise you have to go by the basic principles and common sense - like avoiding wobbly parts, skinny bits and propellor tips.
If a member of an exclusive club which I will not name here (I'm sure present company would not stoop to this, and I thought it had died out, but I've seen it), you don't push or pull it at all: you simply dress in white, flutter your eyelashes, click your fingers and get someone else to do it for you, with a casual warning to avoid touching the tail rotor!
Otherwise you have to go by the basic principles and common sense - like avoiding wobbly parts, skinny bits and propellor tips.
If a member of an exclusive club which I will not name here (I'm sure present company would not stoop to this, and I thought it had died out, but I've seen it), you don't push or pull it at all: you simply dress in white, flutter your eyelashes, click your fingers and get someone else to do it for you, with a casual warning to avoid touching the tail rotor!
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Flying I
I wa taught the same technique - again v early on in my flying career. Have used it on 150/152/172 and so far I haven't seen or heard anything deleterious.
However I am no structural engineer
Merry Xmas all
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I wa taught the same technique - again v early on in my flying career. Have used it on 150/152/172 and so far I haven't seen or heard anything deleterious.
However I am no structural engineer
Merry Xmas all
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Pushing down on the tailplane could cause damage to the spars as the load is localised. There were incidences of cracks in the rear fuselages of C150's as a result of heavy handed handling of the tail. Take it easy and spread the load and it should be OK.
Props blades close to the hub are OK for pulling and pushing. Cub's have a neat little handle for lifting the tail. Pity other aircraft didn't have something similar to reduce confusion and damage
Props blades close to the hub are OK for pulling and pushing. Cub's have a neat little handle for lifting the tail. Pity other aircraft didn't have something similar to reduce confusion and damage
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Flying I and Code Blue,
there will be no difference in the maximum stress in the fuselage (above the main wheels) but obvously none further down near the tail. However you put a higher shear stress on the section which is not good. Overall i don't know which outweighs the other.
I certainly think that pushing on the tail plane itself is a bad practice, as it puts a torsional load on the fuselage, but most of all stresses the connection between the fuselage and the tail plane.
Does anyone know what kind of loads (vertically) the tail plane takes in flight??
there will be no difference in the maximum stress in the fuselage (above the main wheels) but obvously none further down near the tail. However you put a higher shear stress on the section which is not good. Overall i don't know which outweighs the other.
I certainly think that pushing on the tail plane itself is a bad practice, as it puts a torsional load on the fuselage, but most of all stresses the connection between the fuselage and the tail plane.
Does anyone know what kind of loads (vertically) the tail plane takes in flight??
Joined: Jan 1999
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From: north of barlu
I might just have missed some thing here but when the aircraft is pitched up in flight it must be because of a down load on the tailplane and i was under the impresion that the load was carried by the spar,so why cant the spar take the load of an empty aircraft on the ground but is OK to take the load of a much more heavy aircraft plus the buffet from the slipstream in the air ?
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A & C it's because the load is localised rather than spread over the whole area of the tailplane; ie the front spar of the tailplane is taking the whole load rather than it being spread over the front and rear (main) spars.
[This message has been edited by LowNSlow (edited 28 December 2000).]
[This message has been edited by LowNSlow (edited 28 December 2000).]
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I'm with A and C
Are you (LowNSlow) saying that the pressure from my hand is going to puncture through the steel spar? Or is the total load on the spar more than there normally would be?
AC-DC
I thought the ribs were to keep the skin from being sucked out by the low pressure. As such they aren't the main load bearing members because they transfer their force onto the spar for transmission to the fuselage. That's what I thought anyway.
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Confident, cocky, lazy, dead.
Are you (LowNSlow) saying that the pressure from my hand is going to puncture through the steel spar? Or is the total load on the spar more than there normally would be?
AC-DC
I thought the ribs were to keep the skin from being sucked out by the low pressure. As such they aren't the main load bearing members because they transfer their force onto the spar for transmission to the fuselage. That's what I thought anyway.
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Confident, cocky, lazy, dead.
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Chicken6 on a C150/2 and C172 the tailplane has 2 spars, the rear one is the main spar and carries the elevator hinges. If you push down on the tailplane, you are exerting leverage sufficient to lift the nose, ie equivalent to a sizeable proportion of the weight of the aircraft. This force is being exerted mainly onto the secondary spar on one side of the tailplane. This can exceed the loads that the spar and it's mounting on the fuselage was designed to take. End result, expensive and potentially dangerous cracks in the spar and or mountings. A secondary effect is the twisting moment applied to the fuselage which was never designed to accommodate rotary forces.
These cracks do happen, I've seen a stripped down C150 tailplane and it wasn't pretty. Fortunately it wasn't mine!
It is far better to push down on the fuselage than the tailplane because the load is being taken by a structure that is designed to take vertical forces.
These cracks do happen, I've seen a stripped down C150 tailplane and it wasn't pretty. Fortunately it wasn't mine!
It is far better to push down on the fuselage than the tailplane because the load is being taken by a structure that is designed to take vertical forces.
Joined: Jan 1999
Posts: 6,209
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From: north of barlu
Having removed the tailplane on a number of c150/152 aircraft usualy for cracks in the rear spar casting i,v come to the conclusion that cessna are trying to smoke screen a slight weekness in the back end .
I dont think that it is a problem that should alarm us and that with normal maintenance eny cracks will be picked up but if the issue can be clouded then if a problem should happen the lawers have some thing to hide behind.
In short i think that product liability is at the bottom of all this ,about 10 years back piper issued an SB stating that you should never turn the prop by hand ,then if some one turns the thing by hand with the mags on and gets hurt pipers lawers can use the SB as evidence in court.
I dont think that it is a problem that should alarm us and that with normal maintenance eny cracks will be picked up but if the issue can be clouded then if a problem should happen the lawers have some thing to hide behind.
In short i think that product liability is at the bottom of all this ,about 10 years back piper issued an SB stating that you should never turn the prop by hand ,then if some one turns the thing by hand with the mags on and gets hurt pipers lawers can use the SB as evidence in court.
